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1.  The Promise of Prevention: The Effects of Four Preventable Risk Factors on National Life Expectancy and Life Expectancy Disparities by Race and County in the United States 
PLoS Medicine  2010;7(3):e1000248.
Majid Ezzati and colleagues examine the contribution of a set of risk factors (smoking, high blood pressure, elevated blood glucose, and adiposity) to socioeconomic disparities in life expectancy in the US population.
Background
There has been substantial research on psychosocial and health care determinants of health disparities in the United States (US) but less on the role of modifiable risk factors. We estimated the effects of smoking, high blood pressure, elevated blood glucose, and adiposity on national life expectancy and on disparities in life expectancy and disease-specific mortality among eight subgroups of the US population (the “Eight Americas”) defined on the basis of race and the location and socioeconomic characteristics of county of residence, in 2005.
Methods and Findings
We combined data from the National Health and Nutrition Examination Survey and the Behavioral Risk Factor Surveillance System to estimate unbiased risk factor levels for the Eight Americas. We used data from the National Center for Health Statistics to estimate age–sex–disease-specific number of deaths in 2005. We used systematic reviews and meta-analyses of epidemiologic studies to obtain risk factor effect sizes for disease-specific mortality. We used epidemiologic methods for multiple risk factors to estimate the effects of current exposure to these risk factors on death rates, and life table methods to estimate effects on life expectancy. Asians had the lowest mean body mass index, fasting plasma glucose, and smoking; whites had the lowest systolic blood pressure (SBP). SBP was highest in blacks, especially in the rural South—5–7 mmHg higher than whites. The other three risk factors were highest in Western Native Americans, Southern low-income rural blacks, and/or low-income whites in Appalachia and the Mississippi Valley. Nationally, these four risk factors reduced life expectancy at birth in 2005 by an estimated 4.9 y in men and 4.1 y in women. Life expectancy effects were smallest in Asians (M, 4.1 y; F, 3.6 y) and largest in Southern rural blacks (M, 6.7 y; F, 5.7 y). Standard deviation of life expectancies in the Eight Americas would decline by 0.50 y (18%) in men and 0.45 y (21%) in women if these risks had been reduced to optimal levels. Disparities in the probabilities of dying from cardiovascular diseases and diabetes at different ages would decline by 69%–80%; the corresponding reduction for probabilities of dying from cancers would be 29%–50%. Individually, smoking and high blood pressure had the largest effect on life expectancy disparities.
Conclusions
Disparities in smoking, blood pressure, blood glucose, and adiposity explain a significant proportion of disparities in mortality from cardiovascular diseases and cancers, and some of the life expectancy disparities in the US.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Life expectancy (a measure of longevity and premature death) and overall health have increased steadily in the United States over recent years. New drugs, new medical technologies, and better disease prevention have all helped Americans to lead longer, healthier lives. However, even now, some Americans live much longer and much healthier lives than others. Health disparities—differences in how often certain diseases occur and cause death in groups of people classified according to their ethnicity, geographical location, sex, or age—are extremely large and persistent in the US. On average, black men and women in the US live 6.3 and 4.5 years less, respectively, than their white counterparts; the gap between life expectancy in the US counties with the lowest and highest life expectancies is 18.4 years for men and 14.3 years for women. Disparities in deaths (mortality) from chronic diseases such as cardiovascular diseases (for example, heart attacks and stroke), cancers, and diabetes are known to be the main determinants of these life expectancy disparities.
Why Was This Study Done?
Preventable risk factors such as smoking, high blood pressure, excessive body fat (adiposity), and high blood sugar are responsible for many thousands of deaths from chronic diseases. Exposure to these risk factors varies widely by race, state of residence, and socioeconomic status. However, the effects of these observed disparities in exposure to modifiable risk factors on US life expectancy disparities have only been examined in selected groups of people and it is not known how multiple modifiable risk factors affect US health disparities. A better knowledge about how disparities in risk factor exposure contribute to health disparities is needed to ensure that prevention programs not only improve the average health status but also reduce health disparities. In this study, the researchers estimate the effects of smoking, high blood pressure, high blood sugar, and adiposity on US life expectancy and on disparities in life expectancy and disease-specific deaths among the “Eight Americas,” population groups defined by race and by the location and socioeconomic characteristics of their county of residence.
What Did the Researchers Do and Find?
The researchers extracted data on exposure to these risk factors from US national health surveys, information on deaths from different diseases in 2005 from the US National Center for Health Statistics, and estimates of how much each risk factor increases the risk of death from each disease from published studies. They then used modeling methods to estimate the effects of risk factor exposure on death rates and life expectancy. The Asian subgroup had the lowest adiposity, blood sugar, and smoking rates, they report, and the three white subgroups had the lowest blood pressure. Blood pressure was highest in the three black subgroups, whereas the other three risk factors were highest in Western Native Americans, Southern rural blacks, and whites living in Appalachia and the Mississippi Valley. The effects on life expectancy of these factors were smallest in Asians and largest in Southern rural blacks but, overall, these risk factors reduced the life expectancy for men and women born in 2005 by 4.9 and 4.1 years, respectively. Other calculations indicate that if these four risk factors were reduced to optimal levels, disparities among the subgroups in deaths from cardiovascular diseases and diabetes and from cancers would be reduced by up to 80% and 50%, respectively.
What Do These Findings Mean?
These findings suggest that disparities in smoking, blood pressure, blood sugar, and adiposity among US racial and geographical subgroups explain a substantial proportion of the disparities in deaths from cardiovascular diseases, diabetes, and cancers among these subgroups. The disparities in risk factor exposure also explain some of the disparities in life expectancy. The remaining disparities in deaths and life expectancy could be the result of preventable risk factors not included in this study—one of its limitations is that it does not consider the effect of dietary fat, alcohol use, and dietary salt, which are major contributors to different diseases. Thus, suggest the researchers, reduced exposure to preventable risk factors through the implementation of relevant policies and programs should reduce life expectancy and mortality disparities in the US and yield health benefits at a national scale.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000248.
The US Centers for Disease Control and Prevention, the US Office of Minority Health, and the US National Center on Minority Health and Health Disparities all provide information on health disparities in the US
MedlinePlus provides links to information on health disparities and on healthy living (in English and Spanish)
The US Centers for Disease Control and Prevention provides information on all aspects of healthy living
The American Heart Association and the American Cancer Society provide information on modifiable risk factors for patients and caregivers
Healthy People 2010 is a national framework designed to improve the health of people living in the US
The US National Health and Nutrition Examination Survey (NHANES) and the Behavioral Risk Factor Surveillance System (BRFSS) collect information on risk factor exposures in the US
doi:10.1371/journal.pmed.1000248
PMCID: PMC2843596  PMID: 20351772
2.  Personalized Prediction of Lifetime Benefits with Statin Therapy for Asymptomatic Individuals: A Modeling Study 
PLoS Medicine  2012;9(12):e1001361.
In a modeling study conducted by Myriam Hunink and colleagues, a population-based cohort from Rotterdam is used to predict the possible lifetime benefits of statin therapy, on a personalized basis.
Background
Physicians need to inform asymptomatic individuals about personalized outcomes of statin therapy for primary prevention of cardiovascular disease (CVD). However, current prediction models focus on short-term outcomes and ignore the competing risk of death due to other causes. We aimed to predict the potential lifetime benefits with statin therapy, taking into account competing risks.
Methods and Findings
A microsimulation model based on 5-y follow-up data from the Rotterdam Study, a population-based cohort of individuals aged 55 y and older living in the Ommoord district of Rotterdam, the Netherlands, was used to estimate lifetime outcomes with and without statin therapy. The model was validated in-sample using 10-y follow-up data. We used baseline variables and model output to construct (1) a web-based calculator for gains in total and CVD-free life expectancy and (2) color charts for comparing these gains to the Systematic Coronary Risk Evaluation (SCORE) charts. In 2,428 participants (mean age 67.7 y, 35.5% men), statin therapy increased total life expectancy by 0.3 y (SD 0.2) and CVD-free life expectancy by 0.7 y (SD 0.4). Age, sex, smoking, blood pressure, hypertension, lipids, diabetes, glucose, body mass index, waist-to-hip ratio, and creatinine were included in the calculator. Gains in total and CVD-free life expectancy increased with blood pressure, unfavorable lipid levels, and body mass index after multivariable adjustment. Gains decreased considerably with advancing age, while SCORE 10-y CVD mortality risk increased with age. Twenty-five percent of participants with a low SCORE risk achieved equal or larger gains in CVD-free life expectancy than the median gain in participants with a high SCORE risk.
Conclusions
We developed tools to predict personalized increases in total and CVD-free life expectancy with statin therapy. The predicted gains we found are small. If the underlying model is validated in an independent cohort, the tools may be useful in discussing with patients their individual outcomes with statin therapy.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Cardiovascular disease (CVD) affects the heart and/or the blood vessels and is a major cause of illness and death worldwide. In the US, for example, coronary heart disease—a CVD in which narrowing of the heart's blood vessels by fatty deposits slows the blood supply to the heart and may eventually cause a heart attack—is the leading cause of death, and stroke—a CVD in which the brain's blood supply is interrupted—is the fourth leading cause of death. Established risk factors for CVD include smoking, high blood pressure, obesity, and high blood levels of a fat called low-density lipoprotein (“bad cholesterol”). Because many of these risk factors can be modified by lifestyle changes and by drugs, CVD can be prevented. Thus, physicians can assess a healthy individual's risk of developing CVD using a CVD prediction model (equations that take into account the CVD risk factors to which the individual is exposed) and can then recommend lifestyle changes and medications to reduce that individual's CVD risk.
Why Was This Study Done?
Current guidelines recommend that asymptomatic (healthy) individuals whose likely CVD risk is high should be encouraged to take statins—cholesterol-lowering drugs—as a preventative measure. Statins help to prevent CVD in healthy people with a high predicted risk of CVD, but, like all medicines, they have some unwanted side effects, so it is important that physicians can communicate both the benefits and drawbacks of statins to their patients in a way that allows them to make an informed decision about taking these drugs. Telling a patient that statins will reduce his or her short-term risk of CVD is not always helpful—patients really need to know the potential lifetime benefits of statin therapy. That is, they need to know how much longer they might live if they take statins. Here, the researchers use a mathematical model to predict the personalized lifetime benefits (increased total and CVD-free life expectancy) of statin therapy for individuals without a history of CVD.
What Did the Researchers Do and Find?
The researchers used the Rotterdam Ischemic Heart Disease & Stroke Computer Simulation (RISC) model, which simulates the life courses of individuals through six health states, from well through to CVD or non-CVD death, to estimate lifetime outcomes with and without statin therapy in a population of healthy elderly individuals. They then used these outcomes and information on baseline risk factors to develop a web-based calculator suitable for personalized prediction of the lifetime benefits of statins in routine clinical practice. The model estimated that statin therapy increases average life expectancy in the study population by 0.3 years and average CVD-free life expectancy by 0.7 years. The gains in total and CVD-free life expectancy associated with statin therapy increased with blood pressure, unfavorable cholesterol levels, and body mass index (an indicator of body fat) but decreased with age. Notably, the web-based calculator predicted that some individuals with a low ten-year CVD risk might achieve a similar or larger gain in CVD-free life expectancy with statin therapy than some individuals with a high ten-year risk. So, for example, both a 55-year-old non-smoking woman with a ten-year CVD mortality risk of 2% (a two in a hundred chance of dying of CVD within ten years) and a 65-year-old male smoker with a ten-year CVD mortality risk of 15% might both gain one year of CVD-free life expectancy with statin therapy.
What Do These Findings Mean?
These findings suggest that statin therapy can lead on average to small gains in total life expectancy and slightly larger gains in CVD-free life expectancy among healthy individuals, and show that life expectancy benefits can be predicted using an individual's risk factor profile. The accuracy and generalizability of these findings is limited by the assumptions included in the model (in particular, the model did not allow for the known side effects of statin therapy) and by the data fed into it—importantly, the risk prediction model needs to be validated using an independent dataset. If future research confirms the findings of this study, the researchers' web-based calculator could provide complementary information to the currently recommended ten-year CVD mortality risk assessment. Whether communication of personalized outcomes will ultimately result in better clinical outcomes remains to be seen, however, because patients may be less likely to choose statin therapy when provided with more information about its likely benefits.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001361.
The web-based calculator for personalized prediction of lifetime benefits with statin therapy is available (after agreement to software license)
The American Heart Association provides information about many types of cardiovascular disease for patients, carers, and professionals, including information about drug therapy for cholesterol and a heart attack risk calculator
The UK National Health Service Choices website provides information about cardiovascular disease and about statins
Information is available from the British Heart Foundation on heart disease and keeping the heart healthy; information is also available on statins, including personal stories about deciding to take statins
The US National Heart Lung and Blood Institute provides information on a wide range of cardiovascular diseases
The European Society of Cardiology's cardiovascular disease risk assessment model (SCORE) is available
MedlinePlus provides links to many other sources of information on heart diseases, vascular diseases, stroke, and statins (in English and Spanish)
doi:10.1371/journal.pmed.1001361
PMCID: PMC3531501  PMID: 23300388
3.  Adult Mortality Attributable to Preventable Risk Factors for Non-Communicable Diseases and Injuries in Japan: A Comparative Risk Assessment 
PLoS Medicine  2012;9(1):e1001160.
Using a combination of published data and modeling, Nayu Ikeda and colleagues identify tobacco smoking and high blood pressure as major risk factors for death from noncommunicable diseases among adults in Japan.
Background
The population of Japan has achieved the longest life expectancy in the world. To further improve population health, consistent and comparative evidence on mortality attributable to preventable risk factors is necessary for setting priorities for health policies and programs. Although several past studies have quantified the impact of individual risk factors in Japan, to our knowledge no study has assessed and compared the effects of multiple modifiable risk factors for non-communicable diseases and injuries using a standard framework. We estimated the effects of 16 risk factors on cause-specific deaths and life expectancy in Japan.
Methods and Findings
We obtained data on risk factor exposures from the National Health and Nutrition Survey and epidemiological studies, data on the number of cause-specific deaths from vital records adjusted for ill-defined codes, and data on relative risks from epidemiological studies and meta-analyses. We applied a comparative risk assessment framework to estimate effects of excess risks on deaths and life expectancy at age 40 y. In 2007, tobacco smoking and high blood pressure accounted for 129,000 deaths (95% CI: 115,000–154,000) and 104,000 deaths (95% CI: 86,000–119,000), respectively, followed by physical inactivity (52,000 deaths, 95% CI: 47,000–58,000), high blood glucose (34,000 deaths, 95% CI: 26,000–43,000), high dietary salt intake (34,000 deaths, 95% CI: 27,000–39,000), and alcohol use (31,000 deaths, 95% CI: 28,000–35,000). In recent decades, cancer mortality attributable to tobacco smoking has increased in the elderly, while stroke mortality attributable to high blood pressure has declined. Life expectancy at age 40 y in 2007 would have been extended by 1.4 y for both sexes (men, 95% CI: 1.3–1.6; women, 95% CI: 1.2–1.7) if exposures to multiple cardiovascular risk factors had been reduced to their optimal levels as determined by a theoretical-minimum-risk exposure distribution.
Conclusions
Tobacco smoking and high blood pressure are the two major risk factors for adult mortality from non-communicable diseases and injuries in Japan. There is a large potential population health gain if multiple risk factors are jointly controlled.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Worldwide, a small number of modifiable risk factors are responsible for many premature or preventable deaths. For example, having high blood pressure (hypertension) increases a person's risk of developing life-threatening heart problems and stroke (cardiovascular disease). Similarly, having a high blood sugar level increases the risk of developing diabetes, a chronic (long-term) disease that can lead to cardiovascular problems and kidney failure, and half of all long-term tobacco smokers in Western populations will die prematurely from diseases related to smoking, such as lung cancer. Importantly, the five major risk factors for death globally—high blood pressure, tobacco use, high blood sugar, physical inactivity, and overweight and obesity—are all modifiable. That is, lifestyle changes and dietary changes such as exercising more, reducing salt intake, and increasing fruit and vegetable intake can reduce an individual's exposure to these risk factors and one's chances of premature death. Moreover, public health programs designed to reduce a population's exposure to modifiable risk factors should reduce preventable deaths in that population.
Why Was This Study Done?
In 2000, the Japanese government initiated Health Japan 21, a ten-year national health promotion campaign designed to prevent premature death from non-communicable (noninfectious) diseases and injuries. This campaign set 59 goals to monitor and improve risk factor management in the Japanese population, which has one of the longest life expectancies at birth in the world (the life expectancy of a person born in Japan in 2009 was 83.1 years). Because the campaign's final evaluation revealed deterioration or no improvement on some of these goals, the Japanese government recently released new guidelines that stress the importance of simultaneously controlling multiple risk factors for chronic diseases. However, although several studies have quantified the impacts on life expectancy and cause-specific death of individual modifiable risk factors in Japan, the effects of multiple risk factors have not been assessed. In this study, the researchers use a “comparative risk assessment” framework to estimate the effects of 16 risk factors on cause-specific deaths and life expectancy in Japan. Comparative risk assessment estimates the number of deaths that would be prevented if current distributions of risk factor exposures were changed to hypothetical optimal distributions.
What Did the Researchers Do and Find?
The researchers obtained data on exposure to the selected risk factors from the 2007 Japanese National Health and Nutrition Survey and from epidemiological studies, and information on the number of deaths in 2007 from different diseases from official records. They used published studies to estimate how much each factor increases the risk of death from each disease and then used a mathematical formula to estimate the effects of the risk factors on the number of deaths in Japan and on life expectancy at age 40. In 2007, tobacco smoking and high blood pressure accounted for 129,000 and 104,000 deaths, respectively, in Japan. Physical inactivity accounted for 52,000 deaths, high blood glucose and high dietary salt intake accounted for 34,000 deaths each, and alcohol use for 31,000 deaths. Life expectancy at age 40 in 2007 would have been extended by 1.4 years for both sexes, the researchers estimate, if exposure to multiple cardiovascular risk factors had been reduced to calculated optimal distributions, or by 0.7 years if these risk factors had been reduced to the distributions defined by national guidelines and goals.
What Do These Findings Mean?
These findings identify tobacco smoking and high blood pressure as the major risk factors for death from non-communicable diseases among adults in Japan, a result consistent with previous findings from the US. They also indicate that simultaneous control of multiple risk factors has great potential for producing health gains among the Japanese population. Although the researchers focused on estimating the effect of these risk factors on mortality and did not include illness and disability in this study, these findings nevertheless identify two areas of public health policy that need to be strengthened to improve health, reduce death rates, and increase life expectancy among the Japanese population. First, they highlight the need to reduce tobacco smoking, particularly among men. Second and most importantly, these findings emphasize the need to improve ongoing programs designed to help people manage multiple cardiovascular risk factors, including high blood pressure.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001160.
The US Centers for Disease Control and Prevention provides information on all aspects of healthy living
The World Health Report 2002—Reducing Risks, Promoting Healthy Life provides a global analysis of how healthy life expectancy could be increased
The American Heart Association and the American Cancer Society provide information on many important risk factors for noncommunicable diseases and include some personal stories about keeping healthy
Details about Health Japan 21 are provided by the Japanese Ministry of Health, Labour and Welfare. Further details about this campaign are available from the World Health Organization
MedlinePlus provides links to further resources on healthy living and on healthy aging (in English and Spanish)
doi:10.1371/journal.pmed.1001160
PMCID: PMC3265534  PMID: 22291576
4.  The Preventable Causes of Death in the United States: Comparative Risk Assessment of Dietary, Lifestyle, and Metabolic Risk Factors 
PLoS Medicine  2009;6(4):e1000058.
Majid Ezzati and colleagues examine US data on risk factor exposures and disease-specific mortality and find that smoking and hypertension, which both have effective interventions, are responsible for the largest number of deaths.
Background
Knowledge of the number of deaths caused by risk factors is needed for health policy and priority setting. Our aim was to estimate the mortality effects of the following 12 modifiable dietary, lifestyle, and metabolic risk factors in the United States (US) using consistent and comparable methods: high blood glucose, low-density lipoprotein (LDL) cholesterol, and blood pressure; overweight–obesity; high dietary trans fatty acids and salt; low dietary polyunsaturated fatty acids, omega-3 fatty acids (seafood), and fruits and vegetables; physical inactivity; alcohol use; and tobacco smoking.
Methods and Findings
We used data on risk factor exposures in the US population from nationally representative health surveys and disease-specific mortality statistics from the National Center for Health Statistics. We obtained the etiological effects of risk factors on disease-specific mortality, by age, from systematic reviews and meta-analyses of epidemiological studies that had adjusted (i) for major potential confounders, and (ii) where possible for regression dilution bias. We estimated the number of disease-specific deaths attributable to all non-optimal levels of each risk factor exposure, by age and sex. In 2005, tobacco smoking and high blood pressure were responsible for an estimated 467,000 (95% confidence interval [CI] 436,000–500,000) and 395,000 (372,000–414,000) deaths, accounting for about one in five or six deaths in US adults. Overweight–obesity (216,000; 188,000–237,000) and physical inactivity (191,000; 164,000–222,000) were each responsible for nearly 1 in 10 deaths. High dietary salt (102,000; 97,000–107,000), low dietary omega-3 fatty acids (84,000; 72,000–96,000), and high dietary trans fatty acids (82,000; 63,000–97,000) were the dietary risks with the largest mortality effects. Although 26,000 (23,000–40,000) deaths from ischemic heart disease, ischemic stroke, and diabetes were averted by current alcohol use, they were outweighed by 90,000 (88,000–94,000) deaths from other cardiovascular diseases, cancers, liver cirrhosis, pancreatitis, alcohol use disorders, road traffic and other injuries, and violence.
Conclusions
Smoking and high blood pressure, which both have effective interventions, are responsible for the largest number of deaths in the US. Other dietary, lifestyle, and metabolic risk factors for chronic diseases also cause a substantial number of deaths in the US.
Please see later in the article for Editors' Summary
Editors' Summary
Background
A number of modifiable factors are responsible for many premature or preventable deaths. For example, being overweight or obese shortens life expectancy, while half of all long-term tobacco smokers in Western populations will die prematurely from a disease directly related to smoking. Modifiable risk factors fall into three main groups. First, there are lifestyle risk factors. These include tobacco smoking, physical inactivity, and excessive alcohol use (small amounts of alcohol may actually prevent diabetes and some types of heart disease and stroke). Second, there are dietary risk factors such as a high salt intake and a low intake of fruits and vegetables. Finally, there are “metabolic risk factors,” which shorten life expectancy by increasing a person's chances of developing cardiovascular disease (in particular, heart problems and strokes) and diabetes. Metabolic risk factors include having high blood pressure or blood cholesterol and being overweight or obese.
Why Was This Study Done?
It should be possible to reduce preventable deaths by changing modifiable risk factors through introducing public health policies, programs and regulations that reduce exposures to these risk factors. However, it is important to know how many deaths are caused by each risk factor before developing policies and programs that aim to improve a nation's health. Although previous studies have provided some information on the numbers of premature deaths caused by modifiable risk factors, there are two problems with these studies. First, they have not used consistent and comparable methods to estimate the number of deaths attributable to different risk factors. Second, they have rarely considered the effects of dietary and metabolic risk factors. In this new study, the researchers estimate the number of deaths due to 12 different modifiable dietary, lifestyle, and metabolic risk factors for the United States population. They use a method called “comparative risk assessment.” This approach estimates the number of deaths that would be prevented if current distributions of risk factor exposures were changed to hypothetical optimal distributions.
What Did the Researchers Do and Find?
The researchers extracted data on exposures to these 12 selected risk factors from US national health surveys, and they obtained information on deaths from difference diseases for 2005 from the US National Center for Health Statistics. They used previously published studies to estimate how much each risk factor increases the risk of death from each disease. The researchers then used a mathematical formula to estimate the numbers of deaths caused by each risk factor. Of the 2.5 million US deaths in 2005, they estimate that nearly half a million were associated with tobacco smoking and about 400,000 were associated with high blood pressure. These two risk factors therefore each accounted for about 1 in 5 deaths in US adults. Overweight–obesity and physical inactivity were each responsible for nearly 1 in 10 deaths. Among the dietary factors examined, high dietary salt intake had the largest effect, being responsible for 4% of deaths in adults. Finally, while alcohol use prevented 26,000 deaths from ischemic heart disease, ischemic stroke, and diabetes, the researchers estimate that it caused 90,000 deaths from other types of cardiovascular diseases, other medical conditions, and road traffic accidents and violence.
What Do These Findings Mean?
These findings indicate that smoking and high blood pressure are responsible for the largest number of preventable deaths in the US, but that several other modifiable risk factors also cause many deaths. Although the accuracy of some of the estimates obtained in this study will be affected by the quality of the data used, these findings suggest that targeting a handful of risk factors could greatly reduce premature mortality in the US. The findings might also apply to other countries, although the risk factors responsible for most preventable deaths may vary between countries. Importantly, effective individual-level and population-wide interventions are already available to reduce people's exposure to the two risk factors responsible for most preventable deaths in the US. The researchers also suggest that combinations of regulation, pricing, and education have the potential to reduce the exposure of US residents to other risk factors that are likely to shorten their lives.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000058.
The MedlinePlus encyclopedia contains a page on healthy living (in English and Spanish)
The US Centers for Disease Control and Prevention provides information on all aspects of healthy living
Healthy People 2010 is a national framework designed to improve the health of people living in the US. The Healthy People 2020 Framework is due to be launched in January 2010
The World Health Report 2002Reducing Risks, Promoting Healthy Life provides a global analysis of how healthy life expectancy could be increased
The National Health and Nutrition Examination Survey (NHANES) is “a program of studies designed to assess the health and nutritional status of adults and children in the United States”
The US Centers for Disease Control and Prevention's site Smoking and Tobacco Use offers a large number of informational and data resources on this important risk factor
The American Heart Association and American Cancer Society provide a rich resource for patients and caregivers on many important risk factors including diet, sodium intake, and smoking
doi:10.1371/journal.pmed.1000058
PMCID: PMC2667673  PMID: 19399161
5.  The Reversal of Fortunes: Trends in County Mortality and Cross-County Mortality Disparities in the United States  
PLoS Medicine  2008;5(4):e66.
Background
Counties are the smallest unit for which mortality data are routinely available, allowing consistent and comparable long-term analysis of trends in health disparities. Average life expectancy has steadily increased in the United States but there is limited information on long-term mortality trends in the US counties This study aimed to investigate trends in county mortality and cross-county mortality disparities, including the contributions of specific diseases to county level mortality trends.
Methods and Findings
We used mortality statistics (from the National Center for Health Statistics [NCHS]) and population (from the US Census) to estimate sex-specific life expectancy for US counties for every year between 1961 and 1999. Data for analyses in subsequent years were not provided to us by the NCHS. We calculated different metrics of cross-county mortality disparity, and also grouped counties on the basis of whether their mortality changed favorably or unfavorably relative to the national average. We estimated the probability of death from specific diseases for counties with above- or below-average mortality performance. We simulated the effect of cross-county migration on each county's life expectancy using a time-based simulation model. Between 1961 and 1999, the standard deviation (SD) of life expectancy across US counties was at its lowest in 1983, at 1.9 and 1.4 y for men and women, respectively. Cross-county life expectancy SD increased to 2.3 and 1.7 y in 1999. Between 1961 and 1983 no counties had a statistically significant increase in mortality; the major cause of mortality decline for both sexes was reduction in cardiovascular mortality. From 1983 to 1999, life expectancy declined significantly in 11 counties for men (by 1.3 y) and in 180 counties for women (by 1.3 y); another 48 (men) and 783 (women) counties had nonsignificant life expectancy decline. Life expectancy decline in both sexes was caused by increased mortality from lung cancer, chronic obstructive pulmonary disease (COPD), diabetes, and a range of other noncommunicable diseases, which were no longer compensated for by the decline in cardiovascular mortality. Higher HIV/AIDS and homicide deaths also contributed substantially to life expectancy decline for men, but not for women. Alternative specifications of the effects of migration showed that the rise in cross-county life expectancy SD was unlikely to be caused by migration.
Conclusions
There was a steady increase in mortality inequality across the US counties between 1983 and 1999, resulting from stagnation or increase in mortality among the worst-off segment of the population. Female mortality increased in a large number of counties, primarily because of chronic diseases related to smoking, overweight and obesity, and high blood pressure.
Majid Ezzati and colleagues analyze US county-level mortality data for 1961 to 1999, and find a steady increase in mortality inequality across counties between 1983 and 1999.
Editors' Summary
Background.
It has long been recognized that the number of years that distinct groups of people in the United States would be expected to live based on their current mortality patterns (“life expectancy”) varies enormously. For example, white Americans tend to live longer than black Americans, the poor tend to have shorter life expectancies than the wealthy, and women tend to outlive men. Where one lives might also be a factor that determines his or her life expectancy, because of social conditions and health programs in different parts of the country.
Why Was the Study Done?
While life expectancies have generally been rising across the United States over time, there is little information, especially over the long term, on the differences in life expectancies across different counties. The researchers therefore set out to examine whether there were different life expectancies across different US counties over the last four decades. The researchers chose to look at counties—the smallest geographic units for which data on death rates are collected in the US—because it allowed them to make comparisons between small subgroups of people that share the same administrative structure.
What Did the Researchers Do and Find?
The researchers looked at differences in death rates between all counties in US states plus the District of Columbia over four decades, from 1961 to 1999. They obtained the data on number of deaths from the National Center for Health Statistics, and they obtained data on the number of people living in each county from the US Census. The NCHS did not provide death data after 2001. They broke the death rates down by sex and by disease to assess trends over time for women and men, and for different causes of death.
Over these four decades, the researchers found that the overall US life expectancy increased from 67 to 74 years of age for men and from 74 to 80 years for women. Between 1961 and 1983 the death rate fell in both men and women, largely due to reductions in deaths from cardiovascular disease (heart disease and stroke). During this same period, 1961–1983, the differences in death rates among/across different counties fell. However, beginning in the early 1980s the differences in death rates among/across different counties began to increase. The worst-off counties no longer experienced a fall in death rates, and in a substantial number of counties, mortality actually increased, especially for women, a shift that the researchers call “the reversal of fortunes.” This stagnation in the worst-off counties was primarily caused by a slowdown or halt in the reduction of deaths from cardiovascular disease coupled with a moderate rise in a number of other diseases, such as lung cancer, chronic lung disease, and diabetes, in both men and women, and a rise in HIV/AIDS and homicide in men. The researchers' key finding, therefore, was that the differences in life expectancy across different counties initially narrowed and then widened.
What Do these Findings Mean?
The findings suggest that beginning in the early 1980s and continuing through 1999 those who were already disadvantaged did not benefit from the gains in life expectancy experienced by the advantaged, and some became even worse off. The study emphasizes how important it is to monitor health inequalities between different groups, in order to ensure that everyone—and not just the well-off—can experience gains in life expectancy. Although the “reversal of fortune” that the researchers found applied to only a minority of the population, the authors argue that their study results are troubling because an oft-stated aim of the US health system is the improvement of the health of “all people, and especially those at greater risk of health disparities” (see, for example http://www.cdc.gov/osi/goals/SIHPGPostcard.pdf).
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050066.
A study by Nancy Krieger and colleagues, published in PLoS Medicine in February 2008, documented a similar “fall and rise” in health inequities. Krieger and colleagues reported that the difference in health between rich and poor and between different racial/ethnic groups, as measured by rates of dying young and of infant deaths, shrank in the US from 1966 to 1980 then widened from 1980 to 2002
Murray and colleagues, in a 2006 PLoS Medicine article, calculated US mortality rates according to “race-county” units and divided into the “eight Americas,” and found disparities in life expectancy across them
The US Centers for Disease Control has an Office of Minority Health and Health Disparities. The office “aims to accelerate CDC's health impact in the US population and to eliminate health disparities for vulnerable populations as defined by race/ethnicity, socioeconomic status, geography, gender, age, disability status, risk status related to sex and gender, and among other populations identified to be at-risk for health disparities”
Wikipedia has a chapter on health disparities (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
In 2001 the US Agency for Healthcare Research and Quality sponsored a workshop on “strategies to reduce health disparities”
doi:10.1371/journal.pmed.0050066
PMCID: PMC2323303  PMID: 18433290
6.  Associations between smoking, components of metabolic syndrome and lipoprotein particle size 
BMC Medicine  2013;11:195.
Background
The clustering of metabolic and cardiovascular risk factors is known as metabolic syndrome (MetS). The risk of having MetS is strongly associated with increased adiposity and can be further modified by smoking behavior. Apolipoproteins (apo) associated with low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol (HDL-C) may be altered in MetS. This study aimed to examine the association between smoking and the following parameters: MetS and its components, levels of apolipoproteins and estimated lipoprotein particle size, separately for men and women, and in different body mass index (BMI) classes.
Methods
We included 24,389 men and 35,078 women aged between 18 and 80 years who participated in the LifeLines Cohort Study between December 2006 and January 2012; 5,685 men and 6,989 women were current smokers. Participants were categorized into three different body mass index (BMI) classes (BMI <25; BMI 25 to 30; BMI ≥30 kg/m2). MetS was defined according to the National Cholesterol Education Program’s Adult Treatment Panel III (NCEP:ATPIII) criteria. Blood pressure, anthropometric and lipid measurements were rigorously standardized, and the large sample size enabled a powerful estimate of quantitative changes. The association between smoking and the individual MetS components, and apoA1 and apoB, was tested with linear regression. Logistic regression was used to examine the effect of smoking and daily tobacco smoked on risk of having MetS. All models were age adjusted and stratified by sex and BMI class.
Results
Prevalence of MetS increased with higher BMI levels. A total of 64% of obese men and 42% of obese women had MetS. Current smoking was associated with a higher risk of MetS in both sexes and all BMI classes (odds ratio 1.7 to 2.4 for men, 1.8 to 2.3 for women, all P values <0.001). Current smokers had lower levels of HDL cholesterol and apoA1, higher levels of triglycerides and apoB, and higher waist circumference than non-smokers (all P <0.001). Smoking had no consistent association with blood pressure or fasting blood glucose. In all BMI classes, we found a dose-dependent association of daily tobacco consumption with MetS prevalence as well as with lower levels of HDL cholesterol, higher triglyceride levels and lower ratios of HDL cholesterol/apoA1 and, only in those with BMI <30, LDL cholesterol/apoB (all P <0.001).
Conclusions
Smoking is associated with an increased prevalence of MetS, independent of sex and BMI class. This increased risk is mainly related to lower HDL cholesterol, and higher triglycerides and waist circumference. In addition, smoking was associated with unfavorable changes in apoA1 and apoB, and in lipoprotein particle size.
Please see related commentary: http://www.biomedcentral.com/1741-7015/11/196.
doi:10.1186/1741-7015-11-195
PMCID: PMC3766075  PMID: 24228807
Metabolic syndrome; Smoking; HDL; Cholesterol; Apolipoproteins; Triglycerides; Obesity; Cross-sectional; BMI classes
7.  Blood Glucose and Risk of Incident and Fatal Cancer in the Metabolic Syndrome and Cancer Project (Me-Can): Analysis of Six Prospective Cohorts 
PLoS Medicine  2009;6(12):e1000201.
Tanja Stocks and colleagues carry out an analysis of six European cohorts and confirm that abnormal glucose metabolism is linked with increased risk of cancer overall and at specific sites.
Background
Prospective studies have indicated that elevated blood glucose levels may be linked with increased cancer risk, but the strength of the association is unclear. We examined the association between blood glucose and cancer risk in a prospective study of six European cohorts.
Methods and Findings
The Metabolic syndrome and Cancer project (Me-Can) includes cohorts from Norway, Austria, and Sweden; the current study included 274,126 men and 275,818 women. Mean age at baseline was 44.8 years and mean follow-up time was 10.4 years. Excluding the first year of follow-up, 18,621 men and 11,664 women were diagnosed with cancer, and 6,973 men and 3,088 women died of cancer. We used Cox regression models to calculate relative risk (RR) for glucose levels, and included adjustment for body mass index (BMI) and smoking status in the analyses. RRs were corrected for regression dilution ratio of glucose. RR (95% confidence interval) per 1 mmol/l increment of glucose for overall incident cancer was 1.05 (1.01–1.10) in men and 1.11 (1.05–1.16) in women, and corresponding RRs for fatal cancer were 1.15 (1.07–1.22) and 1.21 (1.11–1.33), respectively. Significant increases in risk among men were found for incident and fatal cancer of the liver, gallbladder, and respiratory tract, for incident thyroid cancer and multiple myeloma, and for fatal rectal cancer. In women, significant associations were found for incident and fatal cancer of the pancreas, for incident urinary bladder cancer, and for fatal cancer of the uterine corpus, cervix uteri, and stomach.
Conclusions
Data from our study indicate that abnormal glucose metabolism, independent of BMI, is associated with an increased risk of cancer overall and at several cancer sites. Our data showed stronger associations among women than among men, and for fatal cancer compared to incident cancer.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Large prospective population-based research studies can have the power to discover new associations, and to verify previously proposed associations, between specific risk factors and the subsequent occurrence of disease. One such study, the “Me-Can” (Metabolic syndrome and Cancer project) is investigating associations between cancer incidence and a cluster of metabolic risk factors that make up metabolic syndrome: a large waistline; a high level of fats called triglycerides in the blood; a low level of “good” cholesterol; high blood pressure; and raised blood glucose (hyperglycemia). Here the researchers investigate the associations between one of these risk factors—raised blood glucose—and cancer. It is normal for blood glucose levels to vary before and after meals, but raised levels that persist long-term are known to lead to organ damage and severe complications. It is thought that more than 30% of cancer-related deaths could be prevented by modifying key risk factors, such as tobacco control, modifying diet, staying active, and limiting exposure to environmental risk factors.
Why Was This Study Done?
A previous large research study (including roughly 1.3 million men and women, conducted in Korea) has already evaluated the association between high blood glucose levels and cancer risk, and found that high blood glucose levels were linked with increased risk of cancer—both getting it and dying from it. Studies in European and US populations have also found a link, but they considered relatively small numbers of people and so these could not be used to calculate the risk with respect to specific cancer sites. The researchers carrying out the Me-Can project wanted to verify whether the associations reported in the Korean study also held true for European populations.
What Did the Researchers Do and Find?
The researchers identified 274,126 men and 275,818 women from existing health studies in Norway, Austria, and Sweden for whom data had been recorded on blood glucose level, height, and weight. For each participant a baseline measurement was defined, consisting of data from the first health examination, which had complete data (including a blood glucose measurement and whether the participant smoked). The participants were tracked via national registers for up to around 25 years after the baseline measurement but most commonly for around a decade. Any cancer diagnosis was recorded, whether the participant survived to the end of the study, and causes of death for participants who died during the study. The researchers analyzed the data to assess whether a higher blood glucose level was associated with increased risk of certain cancers, in both men and women. The researchers took weight for height, and smoking into account and adjusted for measurement error from additional blood glucose measurements. The researchers found that, overall, the higher the level of blood glucose, the higher the risk of getting and dying from cancer. Average normal blood glucose levels are about 5 mmol/l, also expressed as 5 mM or 90 mg/dl. For each additional 1 mmol/l increase in blood glucose level, the risk of getting cancer was increased by 5% for men and 11% for women.
What Do These Findings Mean?
The authors concluded that high blood glucose is associated with increased cancer risk. The results largely confirm findings from the Korean study, although there are some differences in the risks of cancers at some specific sites, which may be due to differences in the populations such as genetics, diet, and rates of smoking. Among the strengths of the study are its large sample size and that glucose were measured more than once for many individuals in the study. However, the study is limited in that the researchers did not have data on other possible factors such as genetics, physical activity, or dietary factors, which are linked to cancer incidence and also may be related to blood glucose levels. The researchers propose that controlling blood glucose may lower cancer risk in the population. Although this interpretation is consistent with the data, the study design cannot conclusively demonstrate a causal association between glucose levels and cancer risk.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000201.
The US National Cancer Institute provides online information and statistics on cancer, including risk factors for cancer
The American Heart Association provides information on sugars in the diet, including helpful hints on how to reduce the amount eaten
The UK's National Health Service's Change4Life campaign provides information and ideas for those wishing to make their lifestyle, including diet, more healthy
Cancer Research UK is the world's leading charity dedicated to beating cancer through research. Its websites provide information about cancer and the research it funds
doi:10.1371/journal.pmed.1000201
PMCID: PMC2791167  PMID: 20027213
8.  Comparison of weight in middle age, weight at 18 years, and weight change between, in predicting subsequent 14 year mortality and coronary events: Caerphilly Prospective Study 
OBJECTIVE—The prevalence of obesity is increasing in many European countries and in the United States. This report examines the mortality and morbidity associated with being overweight and obese in the Caerphilly Prospective Study and the relative effects of weight in middle age and self reported weight at 18 years.
DESIGN—All men aged 45 to 59 years from the town of Caerphilly, South Wales and outlying villages were identified and 2512 men were examined for the first time between 1979 and 1983. Men were asked to recall their weight at 18 years of age (when the majority had been examined for National Service) so that weight then, weight at screening, and the difference could be related to their 14 year follow up from screening. A total of 2335 men could recall their weight at 18 years. By 14 years of follow up from screening 465 men had died and 382 had had coronary events.
RESULTS—Mean body mass index in men who reported their weight at 18 years was 22.3 (SD 2.8) kg/m2 and only 41 of these men (1.8%) were classified as obese (index ⩾ 30 kg/m2). The index did not predict all cause mortality when examined by quintile. For major ischaemic heart disease (non-fatal or fatal ischaemic heart disease) the relative odds was 1.73 (95% CI 1.21, 2.48) in the top fifth of the distribution (body mass index ⩾ 24.2 kg/m2) compared with the bottom fifth (body mass index <20.1 kg/m2). In men with an index ⩾ 30 kg/m2 however, the relative odds were 2.03 (95% CI, 1.03, 4.01) for all cause mortality and 2.17 (95% CI, 1.08, 4.34) for major ischaemic heart disease, adjusted for age, smoking habit and social class. When men were recruited to the study, from 1979 to 1983; the mean body mass index had increased to 26.2 (SD 3.6), a mean increase of 3.9 kg/m2 or 11.2 kg; 299 men (12.1%) were classified as obese and showed significantly increased relative odds of both all cause mortality (1.53 (95% CI 1.14, 2.06) and major ischaemic heart disease (1.55 (95% CI 1.13, 2.11)), adjusted for age, smoking habit and social class relative to the non-obese men. The effect of gain in weight from 18 years to recruitment was also examined; all cause mortality showed highest mortality in the fifth of the distribution who experienced weight loss or minimal weight gain. For major ischaemic heart disease an inconsistent, weak trend was shown, the relative odds rising to a maximum of 1.26 (0.89, 1.80) in the top fifth of weight gain compared with the bottom fifth. Weight gain showed strong associations with potential cardiovascular risk factors measured at recruitment; insulin, triglyceride, glucose, diastolic and systolic blood pressure and high density lipoprotein-cholesterol.
CONCLUSIONS—Body mass at 18 years of age of 30 kg/m2 or more conferred increased risk for all cause mortality and major ischaemic heart disease during 14 years of follow up of men aged 45 to 59 years. By the baseline examination the prevalence of obesity (body mass index ⩾30) had increased from 1.8% to 12.1%; obese men also showed an excess risk of major ischaemic heart disease and overall mortality, but these risks were lower than those predicted from 18 years of age. Weight gain was strongly associated with smoking habit, the greatest weight gain being among ex-smokers and the least among light smokers. Weight gain from 18 years of age to baseline examination showed little relation with subsequent mortality and risk of major ischaemic heart disease when adjusted for age, smoking habit and social class. The lowest mortality rate occurred in the "fifth" of men who gained a mean weight of 16.1 kg. Weight gain is closely associated with some adverse cardiovascular risk factors; in particular with insulin, triglyceride, glucose and diastolic blood pressure.


Keywords: obesity; prospective study; ischaemic heart disease
doi:10.1136/jech.54.5.344
PMCID: PMC1731668  PMID: 10814654
9.  Early-Life Family Structure and Microbially Induced Cancer Risk 
PLoS Medicine  2007;4(1):e7.
Background
Cancer may follow exposure to an environmental agent after many decades. The bacterium Helicobacter pylori, known to be acquired early in life, increases risk for gastric adenocarcinoma, but other factors are also important. In this study, we considered whether early-life family structure affects the risk of later developing gastric cancer among H. pylori+ men.
Methods and Findings
We examined a long-term cohort of Japanese-American men followed for 28 y, and performed a nested case-control study among those carrying H. pylori or the subset carrying the most virulent cagA+ H. pylori strains to address whether family structure predicted cancer development. We found that among the men who were H. pylori+ and/or cagA+ (it is possible to be cagA+ and H. pylori− if the H. pylori test is falsely negative), belonging to a large sibship or higher birth order was associated with a significantly increased risk of developing gastric adenocarcinoma late in life. For those with cagA+ strains, the risk of developing gastric cancer was more than twice as high (odds ratio 2.2; 95% confidence interval 1.2–4.0) among those in a sibship of seven or more individuals than in a sibship of between one and three persons.
Conclusions
These results provide evidence that early-life social environment plays a significant role in risk of microbially induced malignancies expressing five to eight decades later, and these findings lead to new models to explain these interactions.
This study suggests that early-life social environment has a significant role in risk of microbially induced malignancies such as gastric adenocarcinoma occuring five to eight decades later.
Editors' Summary
Background.
Although the theory that certain cancers might be caused by infectious agents (such as bacteria and viruses) has been around for some time, concrete evidence linking specific cancers and infections is only recently beginning to emerge. There is now very good evidence that stomach cancer, once one of the frequent types worldwide but now less common, is strongly associated with a particular infection of the stomach lining. This specific bacterium colonizing the stomach, Helicobacter pylori (or H. pylori), often infects people early in childhood through close contact with other people, and tends to stay in the body throughout life. However, most people do not suffer any symptoms as a result of being colonized with H. pylori. Researchers are interested in the relationship between stomach cancer and aspects of someone's upbringing, for example whether an individual has a large number of sisters and brothers and whether they are the youngest or oldest in a large group of siblings. One reason for being interested in this topic is that if H. pylori is mainly spread from one child to another in the home, we might expect children from large sibling groups, and the youngest children in a group, to be at greater risk of being infected, and then more likely to get stomach cancer later in life. Furthermore—and this was the primary reason for the study—the researchers wished to determine whether, among H. pylori+ people, the structure of the family affects the risk of developing stomach cancer much later in life. With all study participants being H. pylori+, the essential comparison was between people of high and low birth order.
Why Was This Study Done?
This group of researchers had already done a previous study that had shown that people who carry H. pylori in their stomachs are more likely to get stomach cancer, and also that younger children in a sibling group are more likely to get stomach cancer. In the period following that study, the examined population has become older and more of the people concerned have developed stomach cancer. This meant that the researchers could go back and extend their previous work to see, more reliably, whether stomach cancer was linked to family structure. It also meant that the researchers could look at the effects of each factor not only in isolation, but also the combined effect of all the different factors. The researchers also stratified for the most virulent strains (those that were cagA+).
What Did the Researchers Do and Find?
In this study, the researchers started out with a pool of 7,429 Japanese-American men living in Hawaii, USA, who had donated blood samples between 1967 and 1975. Of these men, 261 eventually developed stomach cancer. Each of the 261 men was then matched with a similarly aged man from the original pool of 7,429 men who did not have stomach cancer. The researchers then went back to the original blood samples taken many years before and tested the samples to see if the men were infected with H. pylori at the time the sample was taken and, if so, whether a particular strain of the bacterium, cagA, was present. The researchers then looked at whether the risk of getting stomach cancer was associated with the number of siblings a man had and whether he was older or younger than the other siblings.
Similar to the prior study, they found that men who had stomach cancer were three times more likely to carry H. pylori compared to men who did not develop stomach cancer. In men who had H. pylori, those with large numbers of siblings were more likely to get stomach cancer, and this was especially true for men who had the cagA strain of H. pylori. In the whole group of men with cancer, the order of birth (whether a man was older or younger in his sibling group) did not seem to be particularly linked to development of stomach cancer. However, in men who had the cagA strain of H. pylori, those from the largest sibships were at highest risk of developing gastric cancer; in this group, one particular type of cancer (the most common type—intestinal-type gastric cancer) was also associated with later birth order.
What Do These Findings Mean?
The researchers initially thought that men with H. pylori would be at a higher risk of getting stomach cancer if they had a large number of sisters and brothers, and especially if they were a younger sibling in a large group. This idea was supported by their data. These findings support the idea that people often get H. pylori from their older sisters and brothers, but there is not conclusive proof of this. There might be some other factor that explains the association between large family size and stomach cancer, for example that people from large families might be poorer and more at risk from stomach cancer for some other reason. Currently, most doctors do not recommend routinely testing people without any symptoms to see if they have H. pylori, but people with pain or discomfort in the upper abdomen would generally be screened for H. pylori and then treated to eliminate the infection if it is found. The main novel idea is that those people who are born in a large sibship, and/or are of higher birth order, are more likely to acquire their H. pylori from a genetically related person (a sibling) than from an unrelated person (friend/classmate). This “family-structure effect” could be the explanation as to why there is a higher risk of stomach cancer developing later—the strain from a genetically related person already is “preadapted” to the new host, and has a “head-start” on immunity, compared to a strain from an unrelated person. The researchers hypothesize that it is the nature of that initial interaction with the host that sets the stage for the kind of events that lead to cancers decades later.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040007.
A Perspective article by Dimitrios Trichopoulos and Pagona Lagiou discusses these findings further
MedLine Plus encyclopedia entry on stomach cancer
Wikipedia entry on Helicobacter pylori (Wikipedia is an internet encyclopedia that anyone can edit)
The US National Cancer Institute publishes information about stomach cancer
doi:10.1371/journal.pmed.0040007
PMCID: PMC1769414  PMID: 17227131
10.  Survival in treated hypertension: follow up study after two decades 
BMJ : British Medical Journal  1998;317(7152):167-171.
Objective: To compare survival and cause specific mortality in hypertensive men with non-hypertensive men derived from the same random population, and to study mortality and morbidity from cardiovascular diseases in the hypertensive men in relation to effects on cardiovascular risk factors during 22-23 years of follow up.
Design: Prospective, population based observational study.
Subjects and methods: 686 hypertensive men aged 47-55 at screening compared with 6810 non-hypertensive men. The hypertensive men were having stepped care treatment with either β adrenergic blocking drugs, thiazide diuretics, or combination treatment. Mortality, morbidity, and adverse effects were registered at yearly examinations and from death certificates.
Main outcome measures: All cause mortality and cause specific mortality.
Results: Treated hypertensive men had significantly impaired probability of total survival as well as survival from coronary heart disease and stroke. All cause mortality as well as coronary heart disease and stroke mortality were very similar in hypertensive men and normotensive men during the first decade, but increased steadily thereafter despite continuous good blood pressure control. Smoking, signs of target organ damage, and high serum cholesterol levels, but not blood pressure at screening, were significantly related to the incidence of coronary heart disease during follow up. In time dependent Cox’s regression analysis, the incidence of coronary heart disease was significantly related only to serum cholesterol concentrations in the study. Cancer mortality was almost similar in treated hypertensive men (61/686, 8.9%) and non-hypertensive men (732/6810, 10.8%).
Conclusion: Treated hypertensive men had impaired survival and increased mortality from cardiovascular disease compared with non-hypertensive men of similar age. These differences were observed during the second decade of follow up. During an observation period of 22-23 years—about 15 000 patient years—hypertensive men receiving diuretics and β blockers had no increased risk of cancer or non-cardiovascular disease.
Key messages Hypertension is a prevalent (10-20%) and important risk factor for cardiovascular disease. In controlled trials over 3-5 years drug treatment for hypertension prevents these complications, but little is known about long term prognosis During 20-22 years treated hypertensive men had a significantly increased mortality, especially from coronary heart disease, compared with non-hypertensive men from the same population The high incidence of myocardial infarction was related to organ damage, smoking, and cholesterol at the time of entry to the study, and to achieved serum cholesterol concentrations during follow up The poor prognosis for mortality from coronary heart disease is dependent upon strict monitoring of serum cholesterol concentrations
PMCID: PMC28606  PMID: 9665894
11.  British family heart study: its design and method, and prevalence of cardiovascular risk factors. Family heart study group. 
AIM. The aim of this paper is to describe the prevalence of cardiovascular risk factors in families screened systematically by nurses in British general practice, and in subgroups with reported hypertension, hypercholesterolaemia, diabetes and coronary heart disease. METHOD. Twenty six general practices (13 intervention and 13 control practices) in 13 towns in England, Wales and Scotland were involved in a randomized control trial. Randomly ordered invitations were sent for a family health check to 4158 households (men aged 40-59 years and their partners) registered with the 13 intervention practices. RESULTS. One or more adult members from 2373 households (57%) were screened; in 1477 visits the selected man and his female partner attended of whom 98% were married. In all, 3850 individuals were screened (2246 men and 1604 women); 15% of men and women were in the predefined top quintile of the British family heart study risk score. Twenty four per cent of men and 22% of women smoked cigarettes and 62% of men and 44% of women were overweight (body mass index 25+). One third of men and one sixth of women with no known history of high blood pressure had a diastolic blood pressure of 90+ mmHg. Among the 491 individuals with previously reported high blood pressure 64% were not adequately controlled, having a diastolic blood pressure of 90+ mmHg, while 26% had diastolic blood pressure of 100+ mmHg. Eighteen per cent of men and women with no known history of a high cholesterol level had a random cholesterol level of 6.5+ mmol l-1. In the 173 people with a previously reported high cholesterol level and who had their level measured over half had a cholesterol level of 6.5+ mmol l-1 and in 7% this level was 8.0+ mmol l-1. One per cent of men and 0.3% of women were newly identified as diabetic (random glucose level of 10.0+ mmol l-1). In the 52 with previously diagnosed diabetes unsatisfactory control was found in 52% (random level of 10.0+ mmol l-1). A total of 3034 men and women overall (79%) qualified for follow up for one or more risk factor; 1909 men (85%) and 1125 women (70%). Among the 139 with pre-existing coronary heart disease 119 (86%) had modifiable risk factors: 27% were cigarette smokers, 68% had a body mass index of 25+, 40% had diastolic hypertension, 29% had hypercholesterolaemia and 19% had hyperglycaemia. Five per cent of men and women were taking antihypertensive drugs, 0.3% cholesterol lowering drugs and 0.7% drugs for diabetes. CONCLUSION. There is considerable scope for primary and secondary prevention among families registered with general practices, but whether nursing and medical intervention can reduce the risk factors related to cardiovascular disease in this setting remains unknown.
PMCID: PMC1238785  PMID: 8179948
12.  Patterns of Obesity Development before the Diagnosis of Type 2 Diabetes: The Whitehall II Cohort Study 
PLoS Medicine  2014;11(2):e1001602.
Examining patterns of change in body mass index (BMI) and other cardiometabolic risk factors in individuals during the years before they were diagnosed with diabetes, Kristine Færch and colleagues report that few of them experienced dramatic BMI changes.
Please see later in the article for the Editors' Summary
Background
Patients with type 2 diabetes vary greatly with respect to degree of obesity at time of diagnosis. To address the heterogeneity of type 2 diabetes, we characterised patterns of change in body mass index (BMI) and other cardiometabolic risk factors before type 2 diabetes diagnosis.
Methods and Findings
We studied 6,705 participants from the Whitehall II study, an observational prospective cohort study of civil servants based in London. White men and women, initially free of diabetes, were followed with 5-yearly clinical examinations from 1991–2009 for a median of 14.1 years (interquartile range [IQR]: 8.7–16.2 years). Type 2 diabetes developed in 645 (1,209 person-examinations) and 6,060 remained free of diabetes during follow-up (14,060 person-examinations). Latent class trajectory analysis of incident diabetes cases was used to identify patterns of pre-disease BMI. Associated trajectories of cardiometabolic risk factors were studied using adjusted mixed-effects models. Three patterns of BMI changes were identified. Most participants belonged to the “stable overweight” group (n = 604, 94%) with a relatively constant BMI level within the overweight category throughout follow-up. They experienced slightly worsening of beta cell function and insulin sensitivity from 5 years prior to diagnosis. A small group of “progressive weight gainers” (n = 15) exhibited a pattern of consistent weight gain before diagnosis. Linear increases in blood pressure and an exponential increase in insulin resistance a few years before diagnosis accompanied the weight gain. The “persistently obese” (n = 26) were severely obese throughout the whole 18 years before diabetes diagnosis. They experienced an initial beta cell compensation followed by loss of beta cell function, whereas insulin sensitivity was relatively stable. Since the generalizability of these findings is limited, the results need confirmation in other study populations.
Conclusions
Three patterns of obesity changes prior to diabetes diagnosis were accompanied by distinct trajectories of insulin resistance and other cardiometabolic risk factors in a white, British population. While these results should be verified independently, the great majority of patients had modest weight gain prior to diagnosis. These results suggest that strategies focusing on small weight reductions for the entire population may be more beneficial than predominantly focusing on weight loss for high-risk individuals.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Worldwide, more than 350 million people have diabetes, a metabolic disorder characterized by high amounts of glucose (sugar) in the blood. Blood sugar levels are normally controlled by insulin, a hormone released by the pancreas after meals (digestion of food produces glucose). In people with type 2 diabetes (the commonest form of diabetes) blood sugar control fails because the fat and muscle cells that normally respond to insulin by removing sugar from the blood become insulin resistant. Type 2 diabetes, which was previously called adult-onset diabetes, can be controlled with diet and exercise, and with drugs that help the pancreas make more insulin or that make cells more sensitive to insulin. Long-term complications, which include an increased risk of heart disease and stroke, reduce the life expectancy of people with diabetes by about 10 years compared to people without diabetes. The number of people with diabetes is expected to increase dramatically over the next decades, coinciding with rising obesity rates in many countries. To better understand diabetes development, to identify people at risk, and to find ways to prevent the disease are urgent public health goals.
Why Was This Study Done?
It is known that people who are overweight or obese have a higher risk of developing diabetes. Because of this association, a common assumption is that people who experienced recent weight gain are more likely to be diagnosed with diabetes. In this prospective cohort study (an investigation that records the baseline characteristics of a group of people and then follows them to see who develops specific conditions), the researchers tested the hypothesis that substantial weight gain precedes a diagnosis of diabetes and explored more generally the patterns of body weight and composition in the years before people develop diabetes. They then examined whether changes in body weight corresponded with changes in other risk factors for diabetes (such as insulin resistance), lipid profiles and blood pressure.
What Did the Researchers Do and Find?
The researchers studied participants from the Whitehall II study, a prospective cohort study initiated in 1985 to investigate the socioeconomic inequalities in disease. Whitehall II enrolled more than 10,000 London-based government employees. Participants underwent regular health checks during which their weight and height were measured, blood tests were done, and they filled out questionnaires for other relevant information. From 1991 onwards, participants were tested every five years for diabetes. The 6,705 participants included in this study were initially free of diabetes, and most of them were followed for at least 14 years. During the follow-up, 645 participants developed diabetes, while 6,060 remained free of the disease.
The researchers used a statistical tool called “latent class trajectory analysis” to study patterns of changes in body mass index (BMI) in the years before people developed diabetes. BMI is a measure of human obesity based on a person's weight and height. Latent class trajectory analysis is an unbiased way to subdivide a number of people into groups that differ based on specified parameters. In this case, the researchers wanted to identify several groups among all the people who eventually developed diabetes each with a distinct pattern of BMI development. Having identified such groups, they also examined how a variety of tests associated with diabetes risk, and risks for heart disease and stroke changed in the identified groups over time.
They identified three different patterns of BMI changes in the 645 participants who developed diabetes. The vast majority (606 individuals, or 94%) belonged to a group they called “stable-overweight.” These people showed no dramatic change in their BMI in the years before they were diagnosed. They were overweight when they first entered the study and gained or lost little weight during the follow-up years. They showed only minor signs of insulin-resistance, starting five years before they developed diabetes. A second, much smaller group of 15 people gained weight consistently in the years before diagnosis. As they were gaining weight, these people also had raises in blood pressure and substantial gains in insulin resistance. The 26 remaining participants who formed the third group were persistently obese for the entire time they participated in the study, in some cases up to 18 years before they were diagnosed with diabetes. They had some signs of insulin resistance in the years before diagnosis, but not the substantial gain often seen as the hallmark of “pre-diabetes.”
What Do These Findings Mean?
These results suggest that diabetes development is a complicated process, and one that differs between individuals who end up with the disease. They call into question the common notion that most people who develop diabetes have recently gained a lot of weight or are obese. A substantial rise in insulin resistance, another established risk factor for diabetes, was only seen in the smallest of the groups, namely the people who gained weight consistently for years before they were diagnosed. When the scientists applied a commonly used predictor of diabetes called the “Framingham diabetes risk score” to their largest “stably overweight” group, they found that these people were not classified as having a particularly high risk, and that their risk scores actually declined in the last five years before their diabetes diagnosis. This suggests that predicting diabetes in this group might be difficult.
The researchers applied their methodology only to this one cohort of white civil servants in England. Before drawing more firm conclusions on the process of diabetes development, it will be important to test whether similar results are seen in other cohorts and among more diverse individuals. If the three groups identified here are found in other cohorts, another question is whether they are as unequal in size as in this example. And if they are, can the large group of stably overweight people be further subdivided in ways that suggest specific mechanisms of disease development? Even without knowing how generalizable the provocative findings of this study are, they should stimulate debate on how to identify people at risk for diabetes and how to prevent the disease or delay its onset.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001602.
The US National Diabetes Information Clearinghouse provides information about diabetes for patients, health-care professionals, and the general public, including information on diabetes prevention (in English and Spanish)
The UK National Health Service Choices website provides information for patients and carers about type 2 diabetes; it includes people's stories about diabetes
The charity Diabetes UK also provides detailed information about diabetes for patients and carers, including information on healthy lifestyles for people with diabetes, and has a further selection of stories from people with diabetes; the charity Healthtalkonline has interviews with people about their experiences of diabetes
MedlinePlus provides links to further resources and advice about diabetes (in English and Spanish)
More information about the Whitehall II study is available
doi:10.1371/journal.pmed.1001602
PMCID: PMC3921118  PMID: 24523667
13.  Risk of Cardiovascular Disease and Total Mortality in Adults with Type 1 Diabetes: Scottish Registry Linkage Study 
PLoS Medicine  2012;9(10):e1001321.
Helen Colhoun and colleagues report findings from a Scottish registry linkage study regarding contemporary risks for cardiovascular events and all-cause mortality among individuals diagnosed with type 1 diabetes.
Background
Randomized controlled trials have shown the importance of tight glucose control in type 1 diabetes (T1DM), but few recent studies have evaluated the risk of cardiovascular disease (CVD) and all-cause mortality among adults with T1DM. We evaluated these risks in adults with T1DM compared with the non-diabetic population in a nationwide study from Scotland and examined control of CVD risk factors in those with T1DM.
Methods and Findings
The Scottish Care Information-Diabetes Collaboration database was used to identify all people registered with T1DM and aged ≥20 years in 2005–2007 and to provide risk factor data. Major CVD events and deaths were obtained from the national hospital admissions database and death register. The age-adjusted incidence rate ratio (IRR) for CVD and mortality in T1DM (n = 21,789) versus the non-diabetic population (3.96 million) was estimated using Poisson regression. The age-adjusted IRR for first CVD event associated with T1DM versus the non-diabetic population was higher in women (3.0: 95% CI 2.4–3.8, p<0.001) than men (2.3: 2.0–2.7, p<0.001) while the IRR for all-cause mortality associated with T1DM was comparable at 2.6 (2.2–3.0, p<0.001) in men and 2.7 (2.2–3.4, p<0.001) in women. Between 2005–2007, among individuals with T1DM, 34 of 123 deaths among 10,173 who were <40 years and 37 of 907 deaths among 12,739 who were ≥40 years had an underlying cause of death of coma or diabetic ketoacidosis. Among individuals 60–69 years, approximately three extra deaths per 100 per year occurred among men with T1DM (28.51/1,000 person years at risk), and two per 100 per year for women (17.99/1,000 person years at risk). 28% of those with T1DM were current smokers, 13% achieved target HbA1c of <7% and 37% had very poor (≥9%) glycaemic control. Among those aged ≥40, 37% had blood pressures above even conservative targets (≥140/90 mmHg) and 39% of those ≥40 years were not on a statin. Although many of these risk factors were comparable to those previously reported in other developed countries, CVD and mortality rates may not be generalizable to other countries. Limitations included lack of information on the specific insulin therapy used.
Conclusions
Although the relative risks for CVD and total mortality associated with T1DM in this population have declined relative to earlier studies, T1DM continues to be associated with higher CVD and death rates than the non-diabetic population. Risk factor management should be improved to further reduce risk but better treatment approaches for achieving good glycaemic control are badly needed.
Please see later in the article for the Editors' Summary
Editors' Summary
Background. People with diabetes are more likely to have cardiovascular disease such as heart attacks and strokes. They also have a higher risk of dying prematurely from any cause. Controlling blood sugar (glucose), blood pressure, and cholesterol can help reduce these risks. Some people with type 1 diabetes can achieve tight blood glucose control through a strict regimen that includes a carefully calculated diet, frequent physical activity, regular blood glucose testing several times a day, and multiple daily doses of insulin. Other drugs can reduce blood pressure and cholesterol levels. Keeping one's weight in the normal range and not smoking are important ways in which all people, including those with type 1 diabetes can reduce their risks of heart disease and premature death.
Why Was This Study Done? Researchers and doctors have known for almost two decades what patients with type 1 diabetes can do to minimize the complications from the disease and thereby reduce their risks for cardiovascular disease and early death. So for some time now, patients should have been treated and counseled accordingly. This study was done to evaluate the current risks for have cardiovascular disease and premature death amongst people living with type 1 diabetes in a high-income country (Scotland).
What Did the Researchers Do and Find? From a national register of all people with type 1 diabetes in Scotland, the researchers selected those who were older than 20 years and alive at any time from January 2005 to May 2008. This included about 19,000 people who had been diagnosed with type 1 diabetes before 2005. Another 2,600 were diagnosed between 2005 and 2008. They also obtained data on heart attacks and strokes in these patients from hospital records and on deaths from the natural death register. To obtain a good picture of the current relative risks, they compared the patients with type 1 diabetes with the non-diabetic general Scottish population with regard to the risk of heart attacks/strokes and death from all causes. They also collected information on how well the people with diabetes controlled their blood glucose, on their weight, and whether they smoked.
They found that the current risks compared with the general Scottish population are quite a bit lower than those of people with type 1 diabetes in earlier decades. However, people with type 1 diabetes in Scotland still have much higher (more than twice) the risk of heart attacks, strokes, or premature death than the general population. Moreover, the researchers found a high number of deaths in younger people with diabetes from coma—caused by either too much blood sugar (hyperglycemia) or too little (hypoglycemia). Severe hyperglycemia and hypoglycemia happen when blood glucose control is poor. When the scientists looked at test results for HbA1c levels (a test that is done once or twice a year to see how well patients controlled their blood sugar over the previous 3 months) for all patients, they found that the majority of them did not come close to controlling their blood glucose within the recommended range.
When the researchers compared body mass index (a measure of weight that takes height into account) and smoking between the people with type 1 diabetes and the general population, they found similar proportions of smokers and overweight or obese people.
What Do these Findings Mean? The results represent a snapshot of the recent situation regarding complications from type 1 diabetes in the Scottish population. The results suggest that within this population, strategies over the past two decades to reduce complications from type 1 diabetes that cause cardiovascular disease and death are working, in principle. However, there is much need for further improvement. This includes the urgent need to understand why so few people with type 1 diabetes achieve good control of their blood sugar, and what can be done to improve this situation. It is also important to put more effort into keeping people with diabetes from taking up smoking or getting them to quit, as well as preventing them from getting overweight or promoting weight reduction, because this could further reduce the risks of cardiovascular disease and premature death.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001321
National Diabetes Information Clearinghouse, a service of the US National Institute of Diabetes and Digestive and Kidney Diseases, has information on heart disease and diabetes, on general complications of diabetes, and on the HbA1c test (on this site and some others called A1C test) that measures control of blood sugar over the past 3 months
Diabetes.co.uk provides general information on type 1 diabetes, its complications, and what people with the disease can do to reduce their risks
The Canadian Diabetes Association offers a cardiovascular risk self-assessment tool and other relevant information
The American Diabetes Association has information on the benefits and challenges of tight blood sugar control and how it is tested
The Juvenile Diabetes Research Foundation funds research to prevent, cure, and treat type 1 diabetes
Diabetes UK provides extensive information on diabetes for patients, carers, and clinicians
doi:10.1371/journal.pmed.1001321
PMCID: PMC3462745  PMID: 23055834
14.  Renal Function and Risk of Coronary Heart Disease in General Populations: New Prospective Study and Systematic Review 
PLoS Medicine  2007;4(9):e270.
Background
End-stage chronic kidney disease is associated with striking excesses of cardiovascular mortality, but it is uncertain to what extent renal function is related to risk of subsequent coronary heart disease (CHD) in apparently healthy adults. This study aims to quantify the association of markers of renal function with CHD risk in essentially general populations.
Methods and Findings
Estimated glomerular filtration rate (eGFR) was calculated using standard prediction equations based on serum creatinine measurements made in 2,007 patients diagnosed with nonfatal myocardial infarction or coronary death during follow-up and in 3,869 people without CHD in the Reykjavik population-based cohort of 18,569 individuals. There were small and nonsignificant odds ratios (ORs) for CHD risk over most of the range in eGFR, except in the lowest category of the lowest fifth (corresponding to values of <60 ml/min/1.73m2), in which the OR was 1.33 (95% confidence interval 1.01–1.75) after adjustment for several established cardiovascular risk factors. Findings from the Reykjavik study were reinforced by a meta-analysis of six previous reports (identified in electronic and other databases) involving a total of 4,720 incident CHD cases (including Reykjavik), which yielded a combined risk ratio of 1.41 (95% confidence interval 1.19–1.68) in individuals with baseline eGFR less than 60 ml/min/1.73m2 compared with those with higher values.
Conclusions
Although there are no strong associations between lower-than-average eGFR and CHD risk in apparently healthy adults over most of the range in renal function, there may be a moderate increase in CHD risk associated with very low eGFR (i.e., renal dysfunction) in the general population. These findings could have implications for the further understanding of CHD and targeting cardioprotective interventions.
John Danesh and colleagues conclude there may be a moderate increase in risk of coronary heart disease associated with very low estimated glomerular filtration rate.
Editors' Summary
Background.
Coronary heart disease (CHD), the leading cause of death in most Western countries, is a “cardiovascular” disease—literally a disorder affecting the heart and/or blood vessels. In CHD, the blood vessels that supply the heart become increasingly narrow. Eventually, the flow of blood to the heart slows or stops, causing chest pains (angina), breathlessness, and heart attacks. Many factors increase the risk of developing CHD and other cardiovascular diseases, including high blood pressure, high blood levels of cholesterol (a type of fat), or being overweight. Individuals can reduce their chances of developing cardiovascular disease by taking drugs to reduce their blood pressure or cholesterol levels or by making lifestyle changes (so-called cardioprotective interventions). Another important risk factor for cardiovascular disease is end-stage chronic kidney disease (CKD), a condition in which the kidneys stop working. (In healthy people, the kidneys remove waste products and excess fluid from the body.) People with end-stage CKD (which is treated by dialysis) have about a five times higher risk of dying from cardiovascular disease compared with healthy people.
Why Was This Study Done?
End-stage CKD is preceded by a gradual loss of kidney function. There is a clear association between non-dialysis–dependent CKD and the incidence of cardiovascular events (such as heart attacks) in people who already have signs of cardiovascular disease. But are people with slightly dysfunctional kidneys (often because of increasing age) but without any obvious cardiovascular disease at greater risk of developing cardiovascular diseases than people with fully functional kidneys? If the answer is yes, it might be possible to reduce CHD deaths by minimizing the exposure of people with CKD to other risk factors for cardiovascular disease. In this study, the researchers have taken two approaches to answer this question. In a population-based study, they have examined whether there is any association in healthy adults between kidney function measured at the start of the study and incident CHD (the first occurrence of CHD) over subsequent years. In addition, they have systematically searched the published literature for similar studies and combined the results of these studies using statistical methods, a so-called “meta-analysis.”
What Did the Researchers Do and Find?
Between 1967 and 1991, nearly 19,000 middle-aged men and women without a history of heart attacks living in Reykjavik, Iceland, enrolled in a prospective study of cardiovascular disease. Baseline blood samples were taken at enrollment and the participants' health monitored for 20 years on average. The researchers identified 2,007 participants who suffered a nonfatal heart attack or died of CHD during follow-up and 3,869 who remained disease free. They then calculated the estimated glomerular filtration rate (eGFR; a measure of kidney function) for each participant from baseline creatinine measurements (creatinine is a muscle waste product). There was no association between lower-than-average eGFRs and the risk of developing CHD over most of the range of eGFR values. However, people whose eGFR was below approximately 60 units had about a 40% higher risk of developing CHD after allowing for established cardiovascular risk factors than individuals with higher eGFRs. This finding was confirmed by the meta-analysis of six previous studies, which included a further 2,700 incident CHD cases.
What Do These Findings Mean?
These findings indicate that people with an eGFR below about 60 units (the cut-off used to define CKD) may have an increased risk of developing CHD. They also indicate a nonliner association between kidney function and CHD risk. That is, any association with CHD became evident only when the eGFR dropped below about 60 units. These findings need confirming in different ethnic groups and by using more accurate methods to measure eGFRs. Nevertheless, they suggest that improving kidney function across the board is unlikely to have much effect on the overall incidence of CHD. Instead, they suggest that targeting cardioprotective interventions at the one in ten adults in Western countries whose eGFR is below 60 units might be a good way to reduce the burden of CHD.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040270.
MedlinePlus encyclopedia pages on coronary heart disease, chronic kidney failure, and end-stage kidney disease (in English and Spanish).
Information for patients and carers from the American Heart Association on all aspects of heart disease, including prevention of CHD
Information from the British Heart Foundation on heart disease and on keeping the heart healthy
Information on chronic kidney disease from the US National Kidney Foundation, and the US National Kidney and Urologic Diseases Information Clearing House (in English and Spanish)
Information on chronic kidney disease from the UK National Kidney Foundation
doi:10.1371/journal.pmed.0040270
PMCID: PMC1961630  PMID: 17803353
15.  Knowledge and awareness of risk factors for cardiovascular disease among Canadians 55 to 74 years of age: results from the Canadian Heart Health Surveys, 1986-1992 
BACKGROUND: Cardiovascular disease is the leading cause of death and disability in older people, who account for an increasing proportion of Canada's population. Knowledge and awareness of risk factors is essential for changes in behaviour, yet little is known about these issues in older people. The Canadian Heart Health Surveys database provides a unique resource to examine knowledge and awareness of cardiovascular risk factors in older Canadians. METHODS: This descriptive cross-sectional study used data from the Canadian provinces' Heart Health Surveys, for the years 1986 to 1992. Sampling within each province consisted of stratified, 2-stage, replicated probability samples; 4976 people 55 to 74 years of age were included in the present analysis. Knowledge and awareness of cardiovascular risk factors was determined from the survey question "Can you tell me what are the major causes of heart disease or heart problems?" Blood pressure was measured during a home visit; anthropometric and blood measurements were obtained during a clinic visit. Cardiovascular health status was determined by self-reporting. RESULTS: Smoking and stress or worry were mentioned as major causes of heart disease by the greatest proportion of participants (41% and 44% respectively); hypertension was mentioned by only 16%. Men and women did not differ in their awareness of high blood cholesterol (cited by 23% of participants), smoking (41%), excess weight (30%) or lack of exercise (28%) as causes of heart disease. A greater proportion of women than men were aware of hypertension (19% v. 12%) and heredity (31% v. 17%) as major causes of heart disease. Awareness of risk factors was consistently lower in the older age group (65-74 v. 55-64 years). Among women, there was greater awareness of the respective risk factors as causes of heart disease among those who were smokers (60% v. 35% of nonsmokers), those who had a body mass index (BMI) of 25 or greater (38% v. 24% of those with a BMI less than 25) and those who were hypertensive (22% v. 17% of those without hypertension). Those who had experienced a heart attack had greater awareness of the major causes of heart disease than those who had not; this pattern was stronger among women than among men. Of those in whom elevated cholesterol level was identified during the course of the study, 62% of men and 67% of women were unaware of their cholesterol status. Of those in whom high blood pressure was diagnosed, 43% of men and 33% of women were unaware of their hypertensive status. INTERPRETATION: Awareness of the major causes of cardiovascular disease is low among older Canadians, especially among men and in those 65 to 74 years of age.
PMCID: PMC1230715  PMID: 10551207
16.  Are Markers of Inflammation More Strongly Associated with Risk for Fatal Than for Nonfatal Vascular Events? 
PLoS Medicine  2009;6(6):e1000099.
In a secondary analysis of a randomized trial comparing pravastatin versus placebo for the prevention of coronary and cerebral events in an elderly at-risk population, Naveed Sattar and colleagues find that inflammatory markers may be more strongly associated with risk of fatal vascular events than nonfatal vascular events.
Background
Circulating inflammatory markers may more strongly relate to risk of fatal versus nonfatal cardiovascular disease (CVD) events, but robust prospective evidence is lacking. We tested whether interleukin (IL)-6, C-reactive protein (CRP), and fibrinogen more strongly associate with fatal compared to nonfatal myocardial infarction (MI) and stroke.
Methods and Findings
In the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER), baseline inflammatory markers in up to 5,680 men and women aged 70–82 y were related to risk for endpoints; nonfatal CVD (i.e., nonfatal MI and nonfatal stroke [n = 672]), fatal CVD (n = 190), death from other CV causes (n = 38), and non-CVD mortality (n = 300), over 3.2-y follow-up. Elevations in baseline IL-6 levels were significantly (p = 0.0009; competing risks model analysis) more strongly associated with fatal CVD (hazard ratio [HR] for 1 log unit increase in IL-6 1.75, 95% confidence interval [CI] 1.44–2.12) than with risk of nonfatal CVD (1.17, 95% CI 1.04–1.31), in analyses adjusted for treatment allocation. The findings were consistent in a fully adjusted model. These broad trends were similar for CRP and, to a lesser extent, for fibrinogen. The results were also similar in placebo and statin recipients (i.e., no interaction). The C-statistic for fatal CVD using traditional risk factors was significantly (+0.017; p<0.0001) improved by inclusion of IL-6 but not so for nonfatal CVD events (p = 0.20).
Conclusions
In PROSPER, inflammatory markers, in particular IL-6 and CRP, are more strongly associated with risk of fatal vascular events than nonfatal vascular events. These novel observations may have important implications for better understanding aetiology of CVD mortality, and have potential clinical relevance.
Please see later in the article for Editors' Summary
Editors' Summary
Background
Cardiovascular disease (CVD)—disease that affects the heart and/or the blood vessels—is a common cause of death in developed countries. In the USA, for example, the leading cause of death is coronary heart disease (CHD), a CVD in which narrowing of the heart's blood vessels by “atherosclerotic plaques” (fatty deposits that build up with age) slows the blood supply to the heart and may eventually cause a heart attack (myocardial infarction). Other types of CVD include stroke (in which atherosclerotic plaques interrupt the brain's blood supply) and heart failure (a condition in which the heart cannot pump enough blood to the rest of the body). Smoking, high blood pressure, high blood levels of cholesterol (a type of fat), having diabetes, and being overweight all increase a person's risk of developing CVD. Tools such as the “Framingham risk calculator” take these and other risk factors into account to assess an individual's overall risk of CVD, which can be reduced by taking drugs to reduce blood pressure or cholesterol levels (for example, pravastatin) and by making lifestyle changes.
Why Was This Study Done?
Inflammation (an immune response to injury) in the walls of blood vessels is thought to play a role in the development of atherosclerotic plaques. Consistent with this idea, several epidemiological studies (investigations of the causes and distribution of disease in populations) have shown that people with high circulating levels of markers of inflammation such as interleukin-6 (IL-6), C-reactive protein (CRP), and fibrinogen are more likely to have a stroke or a heart attack (a CVD event) than people with low levels of these markers. Although these studies have generally lumped together fatal and nonfatal CVD events, some evidence suggests that circulating inflammatory markers may be more strongly associated with fatal than with nonfatal CVD events. If this is the case, the mechanisms that lead to fatal and nonfatal CVD events may be subtly different and knowing about these differences could improve both the prevention and treatment of CVD. In this study, the researchers investigate this possibility using data collected in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER; a trial that examined pravastatin's effect on CVD development among 70–82 year olds with pre-existing CVD or an increased risk of CVD because of smoking, high blood pressure, or diabetes).
What Did the Researchers Do and Find?
The researchers used several statistical models to examine the association between baseline levels of IL-6, CRP, and fibrinogen in the trial participants and nonfatal CVD events (nonfatal heart attacks and nonfatal strokes), fatal CVD events, death from other types of CVD, and deaths from other causes during 3.2 years of follow-up. Increased levels of all three inflammatory markers were more strongly associated with fatal CVD than with nonfatal CVD after adjustment for treatment allocation and for other established CVD risk factors but this pattern was strongest for IL-6. Thus, a unit increase in the log of IL-6 levels increased the risk of fatal CVD by half but increased the risk of nonfatal CVD by significantly less. The researchers also investigated whether including these inflammatory markers in tools designed to predict an individual's CVD risk could improve the tool's ability to distinguish between individuals with a high and low risk. The addition of IL-6 to established risk factors, they report, increased this discriminatory ability for fatal CVD but not for nonfatal CVD.
What Do These Findings Mean?
These findings indicate that, at least for the elderly at-risk patients who were included in PROSPER, inflammatory markers are more strongly associated with the risk of a fatal heart attack or stroke than with nonfatal CVD events. These findings need to be confirmed in younger populations and larger studies also need to be done to discover whether the same association holds when fatal heart attacks and fatal strokes are considered separately. Nevertheless, the present findings suggest that inflammation may specifically help to promote the development of serious, potentially fatal CVD and should stimulate improved research into the use of inflammation markers to predict risk of deaths from CVD.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000099.
The MedlinePlus Encyclopedia has pages on coronary heart disease, stroke, and atherosclerosis (in English and Spanish)
MedlinePlus provides links to many other sources of information on heart diseases, vascular diseases, and stroke (in English and Spanish)
Information for patients and caregivers is provided by the American Heart Association on all aspects of cardiovascular disease, including information on inflammation and heart disease
Information is available from the British Heart Foundation on heart disease and keeping the heart healthy
More information about PROSPER is available on the Web site of the Vascular Biochemistry Department of the University of Glasgow
doi:10.1371/journal.pmed.1000099
PMCID: PMC2694359  PMID: 19554082
17.  Burden of Total and Cause-Specific Mortality Related to Tobacco Smoking among Adults Aged ≥45 Years in Asia: A Pooled Analysis of 21 Cohorts 
PLoS Medicine  2014;11(4):e1001631.
Wei Zheng and colleagues quantify the burden of tobacco-smoking-related deaths for adults in Asia.
Please see later in the article for the Editors' Summary
Background
Tobacco smoking is a major risk factor for many diseases. We sought to quantify the burden of tobacco-smoking-related deaths in Asia, in parts of which men's smoking prevalence is among the world's highest.
Methods and Findings
We performed pooled analyses of data from 1,049,929 participants in 21 cohorts in Asia to quantify the risks of total and cause-specific mortality associated with tobacco smoking using adjusted hazard ratios and their 95% confidence intervals. We then estimated smoking-related deaths among adults aged ≥45 y in 2004 in Bangladesh, India, mainland China, Japan, Republic of Korea, Singapore, and Taiwan—accounting for ∼71% of Asia's total population. An approximately 1.44-fold (95% CI = 1.37–1.51) and 1.48-fold (1.38–1.58) elevated risk of death from any cause was found in male and female ever-smokers, respectively. In 2004, active tobacco smoking accounted for approximately 15.8% (95% CI = 14.3%–17.2%) and 3.3% (2.6%–4.0%) of deaths, respectively, in men and women aged ≥45 y in the seven countries/regions combined, with a total number of estimated deaths of ∼1,575,500 (95% CI = 1,398,000–1,744,700). Among men, approximately 11.4%, 30.5%, and 19.8% of deaths due to cardiovascular diseases, cancer, and respiratory diseases, respectively, were attributable to tobacco smoking. Corresponding proportions for East Asian women were 3.7%, 4.6%, and 1.7%, respectively. The strongest association with tobacco smoking was found for lung cancer: a 3- to 4-fold elevated risk, accounting for 60.5% and 16.7% of lung cancer deaths, respectively, in Asian men and East Asian women aged ≥45 y.
Conclusions
Tobacco smoking is associated with a substantially elevated risk of mortality, accounting for approximately 2 million deaths in adults aged ≥45 y throughout Asia in 2004. It is likely that smoking-related deaths in Asia will continue to rise over the next few decades if no effective smoking control programs are implemented.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Every year, more than 5 million smokers die from tobacco-related diseases. Tobacco smoking is a major risk factor for cardiovascular disease (conditions that affect the heart and the circulation), respiratory disease (conditions that affect breathing), lung cancer, and several other types of cancer. All told, tobacco smoking kills up to half its users. The ongoing global “epidemic” of tobacco smoking and tobacco-related diseases initially affected people living in the US and other Western countries, where the prevalence of smoking (the proportion of the population that smokes) in men began to rise in the early 1900s, peaking in the 1960s. A similar epidemic occurred in women about 40 years later. Smoking-related deaths began to increase in the second half of the 20th century, and by the 1990s, tobacco smoking accounted for a third of all deaths and about half of cancer deaths among men in the US and other Western countries. More recently, increased awareness of the risks of smoking and the introduction of various tobacco control measures has led to a steady decline in tobacco use and in smoking-related diseases in many developed countries.
Why Was This Study Done?
Unfortunately, less well-developed tobacco control programs, inadequate public awareness of smoking risks, and tobacco company marketing have recently led to sharp increases in the prevalence of smoking in many low- and middle-income countries, particularly in Asia. More than 50% of men in many Asian countries are now smokers, about twice the prevalence in many Western countries, and more women in some Asian countries are smoking than previously. More than half of the world's billion smokers now live in Asia. However, little is known about the burden of tobacco-related mortality (deaths) in this region. In this study, the researchers quantify the risk of total and cause-specific mortality associated with tobacco use among adults aged 45 years or older by undertaking a pooled statistical analysis of data collected from 21 Asian cohorts (groups) about their smoking history and health.
What Did the Researchers Do and Find?
For their study, the researchers used data from more than 1 million participants enrolled in studies undertaken in Bangladesh, India, mainland China, Japan, the Republic of Korea, Singapore, and Taiwan (which together account for 71% of Asia's total population). Smoking prevalences among male and female participants were 65.1% and 7.1%, respectively. Compared with never-smokers, ever-smokers had a higher risk of death from any cause in pooled analyses of all the cohorts (adjusted hazard ratios [HRs] of 1.44 and 1.48 for men and women, respectively; an adjusted HR indicates how often an event occurs in one group compared to another group after adjustment for other characteristics that affect an individual's risk of the event). Compared with never smoking, ever smoking was associated with a higher risk of death due to cardiovascular disease, cancer (particularly lung cancer), and respiratory disease among Asian men and among East Asian women. Moreover, the researchers estimate that, in the countries included in this study, tobacco smoking accounted for 15.8% of all deaths among men and 3.3% of deaths among women in 2004—a total of about 1.5 million deaths, which scales up to 2 million deaths for the population of the whole of Asia. Notably, in 2004, tobacco smoking accounted for 60.5% of lung-cancer deaths among Asian men and 16.7% of lung-cancer deaths among East Asian women.
What Do These Findings Mean?
These findings provide strong evidence that tobacco smoking is associated with a substantially raised risk of death among adults aged 45 years or older throughout Asia. The association between smoking and mortality risk in Asia reported here is weaker than that previously reported for Western countries, possibly because widespread tobacco smoking started several decades later in most Asian countries than in Europe and North America and the deleterious effects of smoking take some years to become evident. The researchers note that certain limitations of their analysis are likely to affect the accuracy of its findings. For example, because no data were available to estimate the impact of secondhand smoke, the estimate of deaths attributable to smoking is likely to be an underestimate. However, the finding that nearly 45% of the global deaths from active tobacco smoking occur in Asia highlights the urgent need to implement comprehensive tobacco control programs in Asia to reduce the burden of tobacco-related disease.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001631.
The World Health Organization provides information about the dangers of tobacco (in several languages) and about the WHO Framework Convention on Tobacco Control, an international instrument for tobacco control that came into force in February 2005 and requires parties to implement a set of core tobacco control provisions including legislation to ban tobacco advertising and to increase tobacco taxes; its 2013 report on the global tobacco epidemic is available
The US Centers for Disease Control and Prevention provides detailed information about all aspects of smoking and tobacco use
The UK National Health Services Choices website provides information about the health risks associated with smoking
MedlinePlus has links to further information about the dangers of smoking (in English and Spanish)
SmokeFree, a website provided by the UK National Health Service, offers advice on quitting smoking and includes personal stories from people who have stopped smoking
Smokefree.gov, from the US National Cancer Institute, offers online tools and resources to help people quit smoking
doi:10.1371/journal.pmed.1001631
PMCID: PMC3995657  PMID: 24756146
18.  Predicting the Thirty-year Risk of Cardiovascular Disease: The Framingham Heart Study 
Circulation  2009;119(24):3078-3084.
Background
Present cardiovascular disease (CVD) risk prediction algorithms were developed for the 10-year or shorter period. Clustering of risk factors at younger ages and increasing life expectancy suggest the need for longer term risk prediction tools.
Methods and Results
We prospectively followed 4506 participants (2333 women) of the Framingham Offspring cohort aged 20–59 and free of CVD and cancer at baseline examination in 1971–1974 for the development of `hard' CVD (coronary death, myocardial infarction, stroke). We used modified Cox model that allows adjustment for competing risk of non-cardiovascular death to construct prediction algorithm for 30-year risk of hard CVD. Cross-validated survival c statistic and calibration chi-square were used to assess model performance. The 30-year hard CVD event rates adjusted for the competing risk of death were 7.6% for women and 18.3% for men. Standard risk factors (male sex, blood pressure and antihypertensive treatment, total and HDL cholesterol, smoking, diabetes) measured at baseline, were significantly related to the incidence of hard CVD and remained significant when regularly updated on follow-up. Body mass index was associated with 30-year risk of hard CVD only in models which did not update risk factors. Model performance was excellent as indicated by cross-validated discrimination c = 0.803 and calibration chi-square = 4.25 (p-value=0.894). In contrast, thirty-year risk predictions based on different applications of 10-year functions proved inadequate.
Conclusions
Standard risk factors remain strong predictors of hard CVD over extended follow-up. 30-year functions offer additional risk burden information that complements that of 10-year functions.
doi:10.1161/CIRCULATIONAHA.108.816694
PMCID: PMC2748236  PMID: 19506114
atherosclerosis; obesity; risk factors; competing risk; lifetime risk
19.  National and subnational mortality effects of metabolic risk factors and smoking in Iran: a comparative risk assessment 
Background
Mortality from cardiovascular and other chronic diseases has increased in Iran. Our aim was to estimate the effects of smoking and high systolic blood pressure (SBP), fasting plasma glucose (FPG), total cholesterol (TC), and high body mass index (BMI) on mortality and life expectancy, nationally and subnationally, using representative data and comparable methods.
Methods
We used data from the Non-Communicable Disease Surveillance Survey to estimate means and standard deviations for the metabolic risk factors, nationally and by region. Lung cancer mortality was used to measure cumulative exposure to smoking. We used data from the death registration system to estimate age-, sex-, and disease-specific numbers of deaths in 2005, adjusted for incompleteness using demographic methods. We used systematic reviews and meta-analyses of epidemiologic studies to obtain the effect of risk factors on disease-specific mortality. We estimated deaths and life expectancy loss attributable to risk factors using the comparative risk assessment framework.
Results
In 2005, high SBP was responsible for 41,000 (95% uncertainty interval: 38,000, 44,000) deaths in men and 39,000 (36,000, 42,000) deaths in women in Iran. High FPG, BMI, and TC were responsible for about one-third to one-half of deaths attributable to SBP in men and/or women. Smoking was responsible for 9,000 deaths among men and 2,000 among women. If SBP were reduced to optimal levels, life expectancy at birth would increase by 3.2 years (2.6, 3.9) and 4.1 years (3.2, 4.9) in men and women, respectively; the life expectancy gains ranged from 1.1 to 1.8 years for TC, BMI, and FPG. SBP was also responsible for the largest number of deaths in every region, with age-standardized attributable mortality ranging from 257 to 333 deaths per 100,000 adults in different regions.
Discussion
Management of blood pressure through diet, lifestyle, and pharmacological interventions should be a priority in Iran. Interventions for other metabolic risk factors and smoking can also improve population health.
doi:10.1186/1478-7954-9-55
PMCID: PMC3229448  PMID: 21989074
20.  Midlife vascular risk factors and Alzheimer's disease in later life: longitudinal, population based study 
BMJ : British Medical Journal  2001;322(7300):1447-1451.
Objective
To examine the relation of midlife raised blood pressure and serum cholesterol concentrations to Alzheimer's disease in later life.
Design
Prospective, population based study.
Setting
Populations of Kuopio and Joensuu, eastern Finland.
Participants
Participants were derived from random, population based samples previously studied in a survey carried out in 1972, 1977, 1982, or 1987. After an average of 21 years' follow up, a total of 1449 (73%) participants aged 65-79 took part in the re-examination in 1998.
Main outcome measures
Midlife blood pressure and cholesterol concentrations and development of Alzheimer's disease in later life.
Results
People with raised systolic blood pressure (⩾160 mm Hg) or high serum cholesterol concentration (⩾6.5 mmol/l) in midlife had a significantly higher risk of Alzheimer's disease in later life, even after adjustment for age, body mass index, education, vascular events, smoking status, and alcohol consumption, than those with normal systolic blood pressure (odds ratio 2.3, 95% confidence interval 1.0 to 5.5) or serum cholesterol (odds ratio 2.1, 1.0 to 4.4). Participants with both of these risk factors in midlife had a significantly higher risk of developing Alzheimer's disease than those with either of the risk factors alone (odds ratio 3.5, 1.6 to 7.9). Diastolic blood pressure in midlife had no significant effect on the risk of Alzheimer's disease.
Conclusion
Raised systolic blood pressure and high serum cholesterol concentration, and in particular the combination of these risks, in midlife increase the risk of Alzheimer's disease in later life.
What is already known on this topicVascular risk factors may play an important part as risk factors for Alzheimer's diseaseNo population based studies have evaluated prospectively the impact of both midlife blood pressure and cholesterol concentration in both men and women on the subsequent development of Alzheimer's diseaseWhat this study addsRaised systolic blood pressure and high serum cholesterol concentration, and in particular the combination of these risks, in midlife increased the risk of Alzheimer's disease in later lifeRaised systolic blood pressure and hypercholesterolaemia may have a role in the pathogenesis of Alzheimer's disease; more emphasis should be placed on identification and appropriate treatment of these conditions
PMCID: PMC32306  PMID: 11408299
21.  Reduced Glomerular Filtration Rate and Its Association with Clinical Outcome in Older Patients at Risk of Vascular Events: Secondary Analysis 
PLoS Medicine  2009;6(1):e1000016.
Background
Reduced glomerular filtration rate (GFR) is associated with increased cardiovascular risk in young and middle aged individuals. Associations with cardiovascular disease and mortality in older people are less clearly established. We aimed to determine the predictive value of the GFR for mortality and morbidity using data from the 5,804 participants randomized in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER).
Methods and Findings
Glomerular filtration rate was estimated (eGFR) using the Modification of Diet in Renal Disease equation and was categorized in the ranges ([20–40], [40–50], [50–60]) ≥ 60 ml/min/1.73 m2. Baseline risk factors were analysed by category of eGFR, with and without adjustment for other risk factors. The associations between baseline eGFR and morbidity and mortality outcomes, accrued after an average of 3.2 y, were investigated using Cox proportional hazard models adjusting for traditional risk factors. We tested for evidence of an interaction between the benefit of statin treatment and baseline eGFR status. Age, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, C-reactive protein (CRP), body mass index, fasting glucose, female sex, histories of hypertension and vascular disease were associated with eGFR (p = 0.001 or less) after adjustment for other risk factors. Low eGFR was independently associated with risk of all cause mortality, vascular mortality, and other noncancer mortality and with fatal and nonfatal coronary and heart failure events (hazard ratios adjusted for CRP and other risk factors (95% confidence intervals [CIs]) for eGFR < 40 ml/min/1.73m2 relative to eGFR ≥ 60 ml/min/1.73m2 respectively 2.04 (1.48–2.80), 2.37 (1.53–3.67), 3.52 (1.78–6.96), 1.64 (1.18–2.27), 3.31 (2.03–5.41). There were no nominally statistically significant interactions (p < 0.05) between randomized treatment allocation and eGFR for clinical outcomes, with the exception of the outcome of coronary heart disease death or nonfatal myocardial infarction (p = 0.021), with the interaction suggesting increased benefit of statin treatment in subjects with impaired GFRs.
Conclusions
We have established that, in an elderly population over the age of 70 y, impaired GFR is associated with female sex, with presence of vascular disease, and with levels of other risk factors that would be associated with increased risk of vascular disease. Further, impaired GFR is independently associated with significant levels of increased risk of all cause mortality and fatal vascular events and with composite fatal and nonfatal coronary and heart failure outcomes. Our analyses of the benefits of statin treatment in relation to baseline GFR suggest that there is no reason to exclude elderly patients with impaired renal function from treatment with a statin.
Using data from the PROSPER trial, Ian Ford and colleagues investigate whether reduced glomerular filtration rate is associated with cardiovascular and mortality risk among elderly people.
Editors' Summary
Background.
Cardiovascular disease (CVD)—disease that affects the heart and/or the blood vessels—is a common cause of death in developed countries. In the USA, for example, the single leading cause of death is coronary heart disease, a CVD in which narrowing of the heart's blood vessels slows or stops the blood supply to the heart and eventually causes a heart attack. Other types of CVD include stroke (in which narrowing of the blood vessels interrupts the brain's blood supply) and heart failure (a condition in which the heart can no longer pump enough blood to the rest of the body). Many factors increase the risk of developing CVD, including high blood pressure (hypertension), high blood cholesterol, having diabetes, smoking, and being overweight. Tools such as the “Framingham risk calculator” assess an individual's overall CVD risk by taking these and other risk factors into account. CVD risk can be minimized by taking drugs to reduce blood pressure or cholesterol levels (for example, pravastatin) and by making lifestyle changes.
Why Was This Study Done?
Another potential risk factor for CVD is impaired kidney (renal) function. In healthy people, the kidneys filter waste products and excess fluid out of the blood. A reduced “estimated glomerular filtration rate” (eGFR), which indicates impaired renal function, is associated with increased CVD in young and middle-aged people and increased all-cause and cardiovascular death in people who have vascular disease. But is reduced eGFR also associated with CVD and death in older people? If it is, it would be worth encouraging elderly people with reduced eGFR to avoid other CVD risk factors. In this study, the researchers determine the predictive value of eGFR for all-cause and vascular mortality (deaths caused by CVD) and for incident vascular events (a first heart attack, stroke, or heart failure) using data from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). This clinical trial examined pravastatin's effects on CVD development among 70–82 year olds with pre-existing vascular disease or an increased risk of CVD because of smoking, hypertension, or diabetes.
What Did the Researchers Do and Find?
The trial participants were divided into four groups based on their eGFR at the start of the study. The researchers then investigated the association between baseline CVD risk factors and baseline eGFR and between baseline eGFR and vascular events and deaths that occurred during the 3-year study. Several established CVD risk factors were associated with a reduced eGFR after allowing for other risk factors. In addition, people with a low eGFR (between 20 and 40 units) were twice as likely to die from any cause as people with an eGFR above 60 units (the normal eGFR for a young person is 100 units; eGFR decreases with age) and more than three times as likely to have nonfatal coronary heart disease or heart failure. A low eGFR also increased the risk of vascular mortality, other noncancer deaths, and fatal coronary heart disease and heart failure. Finally, pravastatin treatment reduced coronary heart disease deaths and nonfatal heart attacks most effectively among participants with the greatest degree of eGFR impairment.
What Do These Findings Mean?
These findings suggest that, in elderly people, impaired renal function is associated with levels of established CVD risk factors that increase the risk of vascular disease. They also suggest that impaired kidney function increases the risk of all-cause mortality, fatal vascular events, and fatal and nonfatal coronary heat disease and heart failure. Because the study participants were carefully chosen for inclusion in PROSPER, these findings may not be generalizable to all elderly people with vascular disease or vascular disease risk factors. Nevertheless, increased efforts should probably be made to encourage elderly people with reduced eGFR and other vascular risk factors to make lifestyle changes to reduce their overall CVD risk. Finally, although the effect of statins in elderly patients with renal dysfunction needs to be examined further, these findings suggest that this group of patients should benefit at least as much from statins as elderly patients with healthy kidneys.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000016.
The MedlinePlus Encyclopedia has pages on coronary heart disease, stroke, and heart failure (in English and Spanish)
MedlinePlus provides links to many other sources of information on heart disease, vascular disease, and stroke (in English and Spanish)
The US National Institute of Diabetes and Digestive and Kidney Diseases provides information on how the kidneys work and what can go wrong with them, including a list of links to further information about kidney disease
The American Heart Association provides information on all aspects of cardiovascular disease for patients, caregivers, and professionals (in several languages)
More information about PROSPER is available on the Web site of the Vascular Biochemistry Department of the University of Glasgow
doi:10.1371/journal.pmed.1000016
PMCID: PMC2628400  PMID: 19166266
22.  A score for predicting risk of death from cardiovascular disease in adults with raised blood pressure, based on individual patient data from randomised controlled trials 
BMJ : British Medical Journal  2001;323(7304):75-81.
Objective
To create a risk score for death from cardiovascular disease that can be easily used.
Design
Data from eight randomised controlled trials of antihypertensive treatment.
Setting
Europe and North America.
Participants
47 088 men and women from trials that had differing age ranges and differing eligibility criteria for blood pressure.
Main outcome measure
1639 deaths from cardiovascular causes during a mean 5.2 years of follow up.
Results
Baseline factors were related to risk of death from cardiovascular disease using a multivariate Cox model, adjusting for trial and treatment group (active versus control). A risk score was developed from 11 factors: age, sex, systolic blood pressure, serum total cholesterol concentration, height, serum creatinine concentration, cigarette smoking, diabetes, left ventricular hypertrophy, history of stroke, and history of myocardial infarction. The risk score is an integer, with points added for each factor according to its association with risk. Smoking contributed more in women and in younger age groups. In women total cholesterol concentration mattered less than in men, whereas diabetes had more of an effect. Antihypertensive treatment reduced the score. The five year risk of death from cardiovascular disease for scores of 10, 20, 30, 40, 50, and 60 was 0.1%, 0.3%, 0.8%, 2.3%, 6.1%, and 15.6%, respectively. Age and sex distributions of the score from the two UK trials enabled individual risk assessment to be age and sex specific. Risk prediction models are also presented for fatal coronary heart disease, fatal stroke, and all cause mortality.
Conclusion
The risk score is an objective aid to assessing an individual's risk of cardiovascular disease, including stroke and coronary heart disease. It is useful for physicians when determining an individual's need for antihypertensive treatment and other management strategies for cardiovascular risk.
What is already known on this topicMany other factors are known to affect the risk of cardiovascular disease in patients with raised blood pressureA patient's overall risk should be taken into account when determining their need for antihypertensive drugs and other strategies for improving cardiovascular healthWhat this study addsA new score uses 11 risk factors to quantify an adult's risk of death from cardiovascular disease, including stroke and coronary heart diseaseThe score is based on a large cohort of participants in controlled trials of antihypertensive drugsAn individual's risk can be readily assessed as high or low compared with others of the same age and sexThe website www.riskscore.org.uk is available for users of the risk score
PMCID: PMC34541  PMID: 11451781
23.  Total cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol and coronary heart disease in Scotland. 
BMJ : British Medical Journal  1991;303(6804):678-681.
OBJECTIVE--To investigate long term changes in total cholesterol, high density lipoprotein cholesterol, and low density lipoprotein cholesterol concentrations and in measures of other risk factors for coronary heart disease and to assess their importance for the development of coronary heart disease in Scottish men. DESIGN--Longitudinal study entailing follow up in 1988-9 of men investigated during a study in 1976. SETTING--Edinburgh, Scotland. SUBJECTS--107 men from Edinburgh who had taken part in a comparative study of risk factors for heart disease with Swedish men in 1976 when aged 40. INTERVENTION--The men were invited to attend a follow up clinic in 1988-9 for measurement of cholesterol concentrations and other risk factor measurements. Eighty three attended and 24 refused to or could not attend. MAIN OUTCOME MEASURES--Changes in total cholesterol, high density lipoprotein cholesterol, and low density lipoprotein cholesterol concentrations, body weight, weight to height index, prevalence of smoking, and alcohol intake; number of coronary artery disease events. RESULTS--Mean serum total cholesterol concentration increased over the 12 years mainly due to an increase in the low density lipoprotein cholesterol fraction (from 3.53 (SD 0.09) to 4.56 (0.11) mmol/l) despite a reduction in high density lipoprotein cholesterol concentration. Body weight and weight to height index increased. Fewer men smoked more than 15 cigarettes/day in 1988-9 than in 1976. Blood pressure remained stable and fasting triglyceride concentrations did not change. The frequency of corneal arcus doubled. Alcohol consumption decreased significantly. Eleven men developed clinical coronary heart disease. High low density lipoprotein and low high density lipoprotein cholesterol concentrations in 1976, but not total cholesterol concentration, significantly predicted coronary heart disease (p = 0.05). Almost all of the men who developed coronary heart disease were smokers (91% v 53%, p less than 0.05). CONCLUSION--Over 12 years the lipid profile deteriorated significantly in this healthy cohort of young men. Smoking, a low high density lipoprotein concentration and a raised low density lipoprotein concentration were all associated with coronary heart disease in middle aged Scottish men, whereas there was no association for total cholesterol concentration. The findings have implications for screening programmes.
PMCID: PMC1670961  PMID: 1912914
24.  The Effect of Rural-to-Urban Migration on Obesity and Diabetes in India: A Cross-Sectional Study 
PLoS Medicine  2010;7(4):e1000268.
Shah Ebrahim and colleagues examine the distribution of obesity, diabetes, and other cardiovascular risk factors among urban migrant factory workers in India, together with their rural siblings. The investigators identify patterns of change of cardiovascular risk factors associated with urban migration.
Background
Migration from rural areas of India contributes to urbanisation and may increase the risk of obesity and diabetes. We tested the hypotheses that rural-to-urban migrants have a higher prevalence of obesity and diabetes than rural nonmigrants, that migrants would have an intermediate prevalence of obesity and diabetes compared with life-long urban and rural dwellers, and that longer time since migration would be associated with a higher prevalence of obesity and of diabetes.
Methods and Findings
The place of origin of people working in factories in north, central, and south India was identified. Migrants of rural origin, their rural dwelling sibs, and those of urban origin together with their urban dwelling sibs were assessed by interview, examination, and fasting blood samples. Obesity, diabetes, and other cardiovascular risk factors were compared. A total of 6,510 participants (42% women) were recruited. Among urban, migrant, and rural men the age- and factory-adjusted percentages classified as obese (body mass index [BMI] >25 kg/m2) were 41.9% (95% confidence interval [CI] 39.1–44.7), 37.8% (95% CI 35.0–40.6), and 19.0% (95% CI 17.0–21.0), respectively, and as diabetic were 13.5% (95% CI 11.6–15.4), 14.3% (95% CI 12.2–16.4), and 6.2% (95% CI 5.0–7.4), respectively. Findings for women showed similar patterns. Rural men had lower blood pressure, lipids, and fasting blood glucose than urban and migrant men, whereas no differences were seen in women. Among migrant men, but not women, there was weak evidence for a lower prevalence of both diabetes and obesity among more recent (≤10 y) migrants.
Conclusions
Migration into urban areas is associated with increases in obesity, which drive other risk factor changes. Migrants have adopted modes of life that put them at similar risk to the urban population. Gender differences in some risk factors by place of origin are unexpected and require further exploration.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
India, like the rest of the world, is experiencing an epidemic of diabetes, a chronic disease characterized by dangerous levels of sugar in the blood that cause cardiovascular and kidney disease, which lower life expectancy. The prevalence of diabetes (the proportion of the population with diabetes) has been increasing steadily in India over recent decades, particularly in urban areas. In 1984, only 5% of adults living in the towns and cities of India had diabetes, but by 2004, 15% of adults in urban areas were affected by diabetes. In rural areas of India, diabetes is less common than in urban areas but even here, the prevalence of diabetes is now 6%. Obesity—too much body fat—is a major risk factor for diabetes and, in parallel with the greater increase in diabetes in urban India compared to rural India, there has been a greater increase in obesity in urban areas than in rural areas.
Why Was This Study Done?
Experts think that the increasing prevalence of obesity and diabetes in India (and in other developing countries) is caused in part by increased consumption of saturated fats and sugars and by reduced physical activity, and that these changes are related to urbanization—urban expansion into the countryside and migration from rural to urban areas. If living in an urban setting is a major determinant of obesity and diabetes risk, then people migrating into urban areas should acquire the high risk of the urban population for these two conditions. In this cross-sectional study (a study in which participants are studied at a single time point), the researchers investigate whether rural to urban migrants in India have a higher prevalence of obesity and diabetes than rural nonmigrants. They also ask whether migrants have a prevalence of obesity and diabetes intermediate between that of life-long urban and rural dwellers and whether a longer time since migration is associated with a higher prevalence of obesity and diabetes.
What Did the Researchers Do and Find?
The researchers recruited rural-urban migrants working in four Indian factories in north, central, and south regions and their spouses (if they were living in the same town) into their study. Each migrant worker and spouse asked one nonmigrant brother or sister (sibling) still living in their place of origin to join the study. The researchers also enrolled nonmigrant factory workers and their urban siblings into the study. All the participants (more than 6,500 in total) answered questions about their diet and physical activity and had their fasting blood sugar and their body mass index (BMI; weight in kg divided by height in meters squared) measured; participants with a fasting blood sugar of more than 7.0 nmol/l or a BMI of more than 25 kg/m2 were classified as diabetic or obese, respectively. 41.9% and 37.8% of the urban and migrant men, respectively, but only 19.0% of the rural men were obese. Similarly, 13.5% and 14.3% of the urban and migrant men, respectively, but only 6.2% of the rural men had diabetes. Patterns of obesity and diabetes among the women participants were similar. Finally, although the prevalence of diabetes and obesity was lower in the most recent male migrants than in those who had moved more than 10 years previously, this difference was small and not seen in women migrants.
What Do These Findings Mean?
These findings show that rural-urban migration in India is associated with rapid increases in obesity and in diabetes. They also show that the migrants have adopted modes of life (for example, reduced physical activity) that put them at a similar risk for obesity and diabetes as the urban population. The findings do not show, however, that migrants have an intermediate prevalence of obesity and diabetes compared to urban and rural dwellers and provide only weak support for the idea that a longer time since migration is associated with a higher risk of obesity and diabetes. Although the study's cross-sectional design means that the researchers could not investigate how risk factors for diabetes evolve over time, these findings suggest that urbanization is helping to drive the diabetes epidemic in India. Thus, targeting migrants and their families for health promotion activities and for treatment of risk factors for obesity and diabetes might help to slow the progress of the epidemic.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000268.
The International Diabetes Federation provides information about all aspects of diabetes, including information on diabetes in Southeast Asia (in English, French, and Spanish)
DiabetesIndia.com provides information on the Indian Task Forces on diabetes care in India
Diabetes Foundation (India) has an international collaborative research focus and provides information about health promotion for diabetes; it has also produced consensus guidelines on dietary change for prevention of diabetes in India
The US National Diabetes Information Clearinghouse provides detailed information about diabetes for patients, health care professionals, and the general public (in English and Spanish)
MedlinePlus provides links to further resources and advice about diabetes (in English and Spanish)
doi:10.1371/journal.pmed.1000268
PMCID: PMC2860494  PMID: 20436961
25.  Risk factors for coronary artery disease in non-insulin dependent diabetes mellitus: United Kingdom prospective diabetes study (UKPDS: 23) 
BMJ : British Medical Journal  1998;316(7134):823-828.
Objective: To evaluate baseline risk factors for coronary artery disease in patients with type 2 diabetes mellitus.
Design: A stepwise selection procedure, adjusting for age and sex, was used in 2693 subjects with complete data to determine which risk factors for coronary artery disease should be included in a Cox proportional hazards model.
Subjects: 3055 white patients (mean age 52) with recently diagnosed type 2 diabetes mellitus and without evidence of disease related to atheroma. Median duration of follow up was 7.9 years. 335 patients developed coronary artery disease within 10 years.
Outcome measures: Angina with confirmatory abnormal electrocardiogram; non-fatal and fatal myocardial infarction.
Results: Coronary artery disease was significantly associated with increased concentrations of low density lipoprotein cholesterol, decreased concentrations of high density lipoprotein cholesterol, and increased triglyceride concentration, haemoglobin A1c, systolic blood pressure, fasting plasma glucose concentration, and a history of smoking. The estimated hazard ratios for the upper third relative to the lower third were 2.26 (95% confidence interval 1.70 to 3.00) for low density lipoprotein cholesterol, 0.55 (0.41 to 0.73) for high density lipoprotein cholesterol, 1.52 (1.15 to 2.01) for haemoglobin A1c, and 1.82 (1.34 to 2.47) for systolic blood pressure. The estimated hazard ratio for smokers was 1.41(1.06 to 1.88).
Conclusion: A quintet of potentially modifiable risk factors for coronary artery disease exists in patients with type 2 diabetes mellitus. These risk factors are increased concentrations of low density lipoprotein cholesterol, decreased concentrations of high density lipoprotein cholesterol, raised blood pressure, hyperglycaemia, and smoking.
Key messages Coronary artery disease is the major cause of mortality in patients with type 2 diabetes mellitus Patients without evidence of disease related to atheroma at diagnosis of type 2 diabetes mellitus had an increased standardised mortality ratio compared with the population of the United Kingdom 11% of patients in this study had a myocardial infarction or developed angina over a median of 8 years’ follow up The potentially modifiable risk factors for coronary artery disease were increased concentrations of low density lipoprotein cholesterol, decreased concentrations of high density lipoprotein cholesterol, hypertension, hyperglycaemia, and smoking; these are also risk factors for coronary artery disease in the general population Evidence is needed on whether modifying these risk factors will reduce coronary artery disease in patients with type 2 diabetes mellitus
PMCID: PMC28484  PMID: 9549452

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