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1.  Association of Genetic Loci With Glucose Levels in Childhood and Adolescence 
Diabetes  2011;60(6):1805-1812.
To investigate whether associations of common genetic variants recently identified for fasting glucose or insulin levels in nondiabetic adults are detectable in healthy children and adolescents.
A total of 16 single nucleotide polymorphisms (SNPs) associated with fasting glucose were genotyped in six studies of children and adolescents of European origin, including over 6,000 boys and girls aged 9–16 years. We performed meta-analyses to test associations of individual SNPs and a weighted risk score of the 16 loci with fasting glucose.
Nine loci were associated with glucose levels in healthy children and adolescents, with four of these associations reported in previous studies and five reported here for the first time (GLIS3, PROX1, SLC2A2, ADCY5, and CRY2). Effect sizes were similar to those in adults, suggesting age-independent effects of these fasting glucose loci. Children and adolescents carrying glucose-raising alleles of G6PC2, MTNR1B, GCK, and GLIS3 also showed reduced β-cell function, as indicated by homeostasis model assessment of β-cell function. Analysis using a weighted risk score showed an increase [β (95% CI)] in fasting glucose level of 0.026 mmol/L (0.021–0.031) for each unit increase in the score.
Novel fasting glucose loci identified in genome-wide association studies of adults are associated with altered fasting glucose levels in healthy children and adolescents with effect sizes comparable to adults. In nondiabetic adults, fasting glucose changes little over time, and our results suggest that age-independent effects of fasting glucose loci contribute to long-term interindividual differences in glucose levels from childhood onwards.
PMCID: PMC3114379  PMID: 21515849
2.  Genetic Markers of Adult Obesity Risk Are Associated with Greater Early Infancy Weight Gain and Growth 
PLoS Medicine  2010;7(5):e1000284.
Ken Ong and colleagues genotyped children from the ALSPAC birth cohort and showed an association between greater early infancy gains in weight and length and genetic markers for adult obesity risk.
Genome-wide studies have identified several common genetic variants that are robustly associated with adult obesity risk. Exploration of these genotype associations in children may provide insights into the timing of weight changes leading to adult obesity.
Methods and Findings
Children from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort were genotyped for ten genetic variants previously associated with adult BMI. Eight variants that showed individual associations with childhood BMI (in/near: FTO, MC4R, TMEM18, GNPDA2, KCTD15, NEGR1, BDNF, and ETV5) were used to derive an “obesity-risk-allele score” comprising the total number of risk alleles (range: 2–15 alleles) in each child with complete genotype data (n = 7,146). Repeated measurements of weight, length/height, and body mass index from birth to age 11 years were expressed as standard deviation scores (SDS). Early infancy was defined as birth to age 6 weeks, and early infancy failure to thrive was defined as weight gain between below the 5th centile, adjusted for birth weight. The obesity-risk-allele score showed little association with birth weight (regression coefficient: 0.01 SDS per allele; 95% CI 0.00–0.02), but had an apparently much larger positive effect on early infancy weight gain (0.119 SDS/allele/year; 0.023–0.216) than on subsequent childhood weight gain (0.004 SDS/allele/year; 0.004–0.005). The obesity-risk-allele score was also positively associated with early infancy length gain (0.158 SDS/allele/year; 0.032–0.284) and with reduced risk of early infancy failure to thrive (odds ratio  = 0.92 per allele; 0.86–0.98; p = 0.009).
The use of robust genetic markers identified greater early infancy gains in weight and length as being on the pathway to adult obesity risk in a contemporary birth cohort.
Please see later in the article for the Editors' Summary
Editors' Summary
The proportion of overweight and obese children is increasing across the globe. In the US, the Surgeon General estimates that, compared with 1980, twice as many children and three times the number of adolescents are now overweight. Worldwide, 22 million children under five years old are considered by the World Health Organization to be overweight.
Being overweight or obese in childhood is associated with poor physical and mental health. In addition, childhood obesity is considered a major risk factor for adult obesity, which is itself a major risk factor for cancer, heart disease, diabetes, osteoarthritis, and other chronic conditions.
The most commonly used measure of whether an adult is a healthy weight is body mass index (BMI), defined as weight in kilograms/(height in metres)2. However, adult categories of obese (>30) and overweight (>25) BMI are not directly applicable to children, whose BMI naturally varies as they grow. BMI can be used to screen children for being overweight and or obese but a diagnosis requires further information.
Why Was This Study Done?
As the numbers of obese and overweight children increase, a corresponding rise in future numbers of overweight and obese adults is also expected. This in turn is expected to lead to an increasing incidence of poor health. As a result, there is great interest among health professionals in possible pathways between childhood and adult obesity. It has been proposed that certain periods in childhood may be critical for the development of obesity.
In the last few years, ten genetic variants have been found to be more common in overweight or obese adults. Eight of these have also been linked to childhood BMI and/or obesity. The authors wanted to identify the timing of childhood weight changes that may be associated with adult obesity. Knowledge of obesity risk genetic variants gave them an opportunity to do so now, without following a set of children to adulthood.
What Did the Researchers Do and Find?
The authors analysed data gathered from a subset of 7,146 singleton white European children enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) study, which is investigating associations between genetics, lifestyle, and health outcomes for a group of children in Bristol whose due date of birth fell between April 1991 and December 1992. They used knowledge of the children's genetic makeup to find associations between an obesity risk allele score—a measure of how many of the obesity risk genetic variants a child possessed—and the children's weight, height, BMI, levels of body fat (at nine years old), and rate of weight gain, up to age 11 years.
They found that, at birth, children with a higher obesity risk allele score were not any heavier, but in the immediate postnatal period they were less likely to be in the bottom 5% of the population for weight gain (adjusted for birthweight), often termed “failure to thrive.” At six weeks of age, children with a higher obesity risk allele score tended to be longer and heavier, even allowing for weight at birth.
After six weeks of age, the obesity risk allele score was not associated with any further increase in length/height, but it was associated with a more rapid weight gain between birth and age 11 years. BMI is derived from height and weight measurements, and the association between the obesity risk allele score and BMI was weak between birth and age three-and-a-half years, but after that age the association with BMI increased rapidly. By age nine, children with a higher obesity risk allele score tended to be heavier and taller, with more fat on their bodies.
What Do These Findings Mean?
The combined obesity allele risk score is associated with higher rates of weight gain and adult obesity, and so the authors conclude that weight gain and growth even in the first few weeks after birth may be the beginning of a pathway of greater adult obesity risk.
A study that tracks a population over time can find associations but it cannot show cause and effect. In addition, only a relatively small proportion (1.7%) of the variation in BMI at nine years of age is explained by the obesity risk allele score.
The authors' method of finding associations between childhood events and adult outcomes via genetic markers of risk of disease as an adult has a significant advantage: the authors did not have to follow the children themselves to adulthood, so their findings are more likely to be relevant to current populations. Despite this, this research does not yield advice for parents how to reduce their children's obesity risk. It does suggest that “failure to thrive” in the first six weeks of life is not simply due to a lack of provision of food by the baby's caregiver but that genetic factors also contribute to early weight gain and growth.
The study looked at the combined obesity risk allele score and the authors did not attempt to identify which individual alleles have greater or weaker associations with weight gain and overweight or obesity. This would require further research based on far larger numbers of babies and children. The findings may also not be relevant to children in other types of setting because of the effects of different nutrition and lifestyles.
Additional Information
Please access these Web sites via the online version of this summary at
Further information is available on the ALSPAC study
The UK National Health Service and other partners provide guidance on establishing a healthy lifestyle for children and families in their Change4Life programme
The International Obesity Taskforce is a global network of expertise and the advocacy arm of the International Association for the Study of Obesity. It works with the World Health Organization, other NGOs, and stakeholders and provides information on overweight and obesity
The Centers for Disease Control and Prevention (CDC) in the US provide guidance and tips on maintaining a healthy weight, including BMI calculators in both metric and Imperial measurements for both adults and children. They also provide BMI growth charts for boys and girls showing how healthy ranges vary for each sex at with age
The Royal College of Paediatrics and Child Health provides growth charts for weight and length/height from birth to age 4 years that are based on WHO 2006 growth standards and have been adapted for use in the UK
The CDC Web site provides information on overweight and obesity in adults and children, including definitions, causes, and data
The CDC also provide information on the role of genes in causing obesity.
The World Health Organization publishes a fact sheet on obesity, overweight and weight management, including links to childhood overweight and obesity
Wikipedia includes an article on childhood obesity (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
PMCID: PMC2876048  PMID: 20520848
3.  A Common Variant in the FTO Gene Is Associated with Body Mass Index and Predisposes to Childhood and Adult Obesity 
Science (New York, N.Y.)  2007;316(5826):889-894.
Obesity is a serious international health problem that increases the risk of several common diseases. The genetic factors predisposing to obesity are poorly understood. A genome-wide search for type 2 diabetes–susceptibility genes identified a common variant in the FTO (fat mass and obesity associated) gene that predisposes to diabetes through an effect on body mass index (BMI). An additive association of the variant with BMI was replicated in 13 cohorts with 38,759 participants. The 16% of adults who are homozygous for the risk allele weighed about 3 kilograms more and had 1.67-fold increased odds of obesity when compared with those not inheriting a risk allele. This association was observed from age 7 years upward and reflects a specific increase in fat mass.
PMCID: PMC2646098  PMID: 17434869
4.  Multiple behaviour change intervention and outcomes in recently diagnosed type 2 diabetes: the ADDITION-Plus randomised controlled trial 
Diabetologia  2014;57:1308-1319.
The aim of this study was to assess whether or not a theory-based behaviour change intervention delivered by trained and quality-assured lifestyle facilitators can achieve and maintain improvements in physical activity, dietary change, medication adherence and smoking cessation in people with recently diagnosed type 2 diabetes.
An explanatory randomised controlled trial was conducted in 34 general practices in Eastern England (Anglo–Danish–Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care-Plus [ADDITION-Plus]). In all, 478 patients meeting eligibility criteria (age 40 to 69 years with recently diagnosed screen or clinically detected diabetes) were individually randomised to receive either intensive treatment (n = 239) or intensive treatment plus a theory-based behaviour change intervention led by a facilitator external to the general practice team (n = 239). Randomisation was central and independent using a partial minimisation procedure to balance stratifiers between treatment arms. Facilitators taught patients skills to facilitate change in and maintenance of key health behaviours, including goal setting, self-monitoring and building habits. Primary outcomes included physical activity energy expenditure (individually calibrated heart rate monitoring and movement sensing), change in objectively measured fruit and vegetable intake (plasma vitamin C), medication adherence (plasma drug levels) and smoking status (plasma cotinine levels) at 1 year. Measurements, data entry and laboratory analysis were conducted with staff unaware of participants’ study group allocation.
Of 475 participants still alive, 444 (93%; intervention group 95%, comparison group 92%) attended 1-year follow-up. There were no significant differences between groups in physical activity (difference: +1.50 kJ kg−1 day−1; 95% CI −1.74, 4.74), plasma vitamin C (difference: −3.84 μmol/l; 95% CI −8.07, 0.38), smoking (OR 1.37; 95% CI 0.77, 2.43) and plasma drug levels (difference in metformin levels: −119.5 μmol/l; 95% CI −335.0, 95.9). Cardiovascular risk factors and self-reported behaviour improved in both groups with no significant differences between groups.
For patients with recently diagnosed type 2 diabetes receiving intensive treatment in UK primary care, a facilitator-led individually tailored behaviour change intervention did not improve objectively measured health behaviours or cardiovascular risk factors over 1 year.
Trial registration
The trial is supported by the Medical Research Council, the Wellcome Trust, National Health Service R&D support funding (including the Primary Care Research and Diabetes Research Networks) and National Institute of Health Research under its Programme Grants for Applied Research scheme. The Primary Care Unit is supported by NIHR Research funds. Bio-Rad provided equipment for HbA1c testing during the screening phase.
Electronic supplementary material
The online version of this article (doi:10.1007/s00125-014-3236-6) contains peer-reviewed but unedited supplementary material, which is available to authorised users.
PMCID: PMC4052009  PMID: 24759957
ADDITION-Plus; Diabetes; General practice; Health behaviour; Randomised trial
5.  Change in cardiovascular risk factors following early diagnosis of type 2 diabetes: a cohort analysis of a cluster-randomised trial 
The British Journal of General Practice  2014;64(621):e208-e216.
There is little evidence to inform the targeted treatment of individuals found early in the diabetes disease trajectory.
To describe cardiovascular disease (CVD) risk profiles and treatment of individual CVD risk factors by modelled CVD risk at diagnosis; changes in treatment, modelled CVD risk, and CVD risk factors in the 5 years following diagnosis; and how these are patterned by socioeconomic status.
Design and setting
Cohort analysis of a cluster-randomised trial (ADDITION-Europe) in general practices in Denmark, England, and the Netherlands.
A total of 2418 individuals with screen-detected diabetes were divided into quartiles of modelled 10-year CVD risk at diagnosis. Changes in treatment, modelled CVD risk, and CVD risk factors were assessed at 5 years.
The largest reductions in risk factors and modelled CVD risk were seen in participants who were in the highest quartile of modelled risk at baseline, suggesting that treatment was offered appropriately. Participants in the lowest quartile of risk at baseline had very similar levels of modelled CVD risk at 5 years and showed the least variation in change in modelled risk. No association was found between socioeconomic status and changes in CVD risk factors, suggesting that treatment was equitable.
Diabetes management requires setting of individualised attainable targets. This analysis provides a reference point for patients, clinicians, and policymakers when considering goals for changes in risk factors early in the course of the disease that account for the diverse cardiometabolic profile present in individuals who are newly diagnosed with type 2 diabetes.
PMCID: PMC3964458  PMID: 24686885
cardiovascular diseases; diabetes mellitus, type 2; prevention and control; primary health care; risk assessment; risk factors; treatment heterogeneity
6.  Variation in genes related to hepatic lipid metabolism and changes in waist circumference and body weight 
Genes & Nutrition  2014;9(2):385.
We analysed single nucleotide polymorphisms (SNPs) tagging the genetic variability of six candidate genes (ATF6, FABP1, LPIN2, LPIN3, MLXIPL and MTTP) involved in the regulation of hepatic lipid metabolism, an important regulatory site of energy balance for associations with body mass index (BMI) and changes in weight and waist circumference. We also investigated effect modification by sex and dietary intake. Data of 6,287 individuals participating in the European prospective investigation into cancer and nutrition were included in the analyses. Data on weight and waist circumference were followed up for 6.9 ± 2.5 years. Association of 69 tagSNPs with baseline BMI and annual changes in weight as well as waist circumference were investigated using linear regression analysis. Interactions with sex, GI and intake of carbohydrates, fat as well as saturated, monounsaturated and polyunsaturated fatty acids were examined by including multiplicative SNP-covariate terms into the regression model. Neither baseline BMI nor annual weight or waist circumference changes were significantly associated with variation in the selected genes in the entire study population after correction for multiple testing. One SNP (rs1164) in LPIN2 appeared to be significantly interacting with sex (p = 0.0003) and was associated with greater annual weight gain in men (56.8 ± 23.7 g/year per allele, p = 0.02) than in women (−25.5 ± 19.8 g/year per allele, p = 0.2). With respect to gene–nutrient interaction, we could not detect any significant interactions when accounting for multiple testing. Therefore, out of our six candidate genes, LPIN2 may be considered as a candidate for further studies.
Electronic supplementary material
The online version of this article (doi:10.1007/s12263-014-0385-7) contains supplementary material, which is available to authorized users.
PMCID: PMC3968289  PMID: 24496996
LPIN2; Obesity; Weight gain; Gene–diet interaction
7.  Dietary dairy product intake and incident type 2 diabetes: a prospective study using dietary data from a 7-day food diary 
Diabetologia  2014;57:909-917.
The aim of this study was to investigate the association between total and types of dairy product intake and risk of developing incident type 2 diabetes, using a food diary.
A nested case-cohort within the EPIC-Norfolk Study was examined, including a random subcohort (n = 4,000) and cases of incident diabetes (n = 892, including 143 cases in the subcohort) followed-up for 11 years. Diet was assessed using a prospective 7-day food diary. Total dairy intake (g/day) was estimated and categorised into high-fat (≥3.9%) and low-fat (<3.9% fat) dairy, and by subtype into yoghurt, cheese and milk. Combined fermented dairy product intake (yoghurt, cheese, sour cream) was estimated and categorised into high- and low-fat. Prentice-weighted Cox regression HRs were calculated.
Total dairy, high-fat dairy, milk, cheese and high-fat fermented dairy product intakes were not associated with the development of incident diabetes. Low-fat dairy intake was inversely associated with diabetes in age- and sex-adjusted analyses (tertile [T] 3 vs T1, HR 0.81 [95% CI 0.66, 0.98]), but further adjustment for anthropometric, dietary and diabetes risk factors attenuated this association. In addition, an inverse association was found between diabetes and low-fat fermented dairy product intake (T3 vs T1, HR 0.76 [95% CI 0.60, 0.99]; ptrend = 0.049) and specifically with yoghurt intake (HR 0.72 [95% CI 0.55, 0.95]; ptrend = 0.017) in multivariable adjusted analyses.
Greater low-fat fermented dairy product intake, largely driven by yoghurt intake, was associated with a decreased risk of type 2 diabetes development in prospective analyses. These findings suggest that the consumption of specific dairy types may be beneficial for the prevention of diabetes, highlighting the importance of food group subtypes for public health messages.
Electronic supplementary material
The online version of this article (doi:10.1007/s00125-014-3176-1) contains peer-reviewed but unedited supplementary material, which is available to authorised users.
PMCID: PMC3980034  PMID: 24510203
Cheese; Dairy; Fermented dairy; Milk; Type 2 diabetes; Yoghurt
8.  Social relationships and healthful dietary behaviour: Evidence from over-50s in the EPIC cohort, UK☆ 
Social Science & Medicine (1982)  2014;100(100):167-175.
Social relationships are an important aspect of a person's social environment that can protect against a wide range of chronic conditions and facilitate recovery from disease. Social relationships have also been linked to dietary behaviour which may be an important pathway through which social circumstances exert their influence on health. Yet, questions remain about which structural aspects of social relationships most affect healthful dietary behaviours and whether different structural components interact to produce a combined effect. Using data from adults (≥50 years) in the European Prospective Investigation of Cancer-Norfolk study (1996–2002), we examined marital status, living arrangement and social isolation in relation to scores for variety of fruit and vegetable intake as a marker of diet quality associated with adverse health outcomes. Data were analysed with multivariable linear regression models for gender-specific and interaction associations. We found that being single or widowed was associated with a lower variety score, particularly vegetable variety, and associations were enhanced when combined with male gender, living alone or infrequent friend contact. Lower variety scores for lone-living were also observed, especially for men. Infrequent friend contact interacted with living arrangement to amplify negative associations of lone-living with variety, with statistically significant differences in contact frequency for vegetable variety. Lower levels of friend contact were associated with reduced variety of fruits and vegetables in a graded trend for both genders; the trend was more pronounced among men. Family contact appeared to have limited association with vegetable variety in men; among women, weekly contact was significantly and positively associated with vegetable variety compared to daily family contact. Results highlight the importance of considering living arrangement and/or frequency of social contact when assessing whether widowed, single or lone-living older adults are at risk of lower fruit and vegetable variety.
•Social relationships affect health and can also influence dietary behaviour.•We examined joint effects of diverse structural components of relationships on diet.•We used data from over-50s in an established epidemiological cohort.•Men fared worse than women in reduced variety from poorer structural social ties.•Social isolation altered dietary effects of marital status and living arrangement.
PMCID: PMC3969105  PMID: 24035440
Social relationships; Social ties; Gender; Interactions; Diet variety; Health behaviour; Chronic disease; UK
10.  The association of cycling with all-cause, cardiovascular and cancer mortality: findings from the population-based EPIC-Norfolk cohort 
BMJ Open  2013;3(11):e003797.
To investigate associations between modest levels of total and domain-specific (commuting, other utility, recreational) cycling and mortality from all causes, cardiovascular disease and cancer.
Population-based cohort study (European Prospective Investigation into Cancer and Nutrition study-Norfolk).
Participants were recruited from general practices in the east of England and attended health examinations between 1993 and 1997 and again between 1998 and 2000. At the first health assessment, participants reported their average weekly duration of cycling for all purposes using a simple measure of physical activity. At the second health assessment, participants reported a more detailed breakdown of their weekly cycling behaviour using the EPAQ2 physical activity questionnaire.
Adults aged 40–79 years at the first health assessment.
Primary outcome measure
All participants were followed for mortality (all-cause, cardiovascular and cancer) until March 2011.
There were 22 450 participants with complete data at the first health assessment, of whom 4398 died during follow-up; and 13 346 participants with complete data at the second health assessment, of whom 1670 died during follow-up. Preliminary analyses using exposure data from the first health assessment showed that cycling for at least 60 min/week in total was associated with a 9% reduced risk of all-cause mortality (adjusted HR 0.91, 95% CI 0.84 to 0.99). Using the more precise measures of cycling available from the second health assessment, all types of cycling were associated with greater total moderate-to-vigorous physical activity; however, there was little evidence of an association between overall or domain-specific cycling and mortality.
Cycling, in particular for utility purposes, was associated with greater moderate-to-vigorous and total physical activity. While this study provides tentative evidence that modest levels of cycling may reduce the risk of mortality, further research is required to confirm how much cycling is sufficient to induce health benefits.
PMCID: PMC3831097  PMID: 24231462
active travel; active commuting; physical activity
11.  Association between objectively assessed sedentary time and physical activity with metabolic risk factors among people with recently diagnosed type 2 diabetes 
Diabetologia  2013;57:73-82.
The aim of our study was to examine the associations between sedentary time (SED-time), time spent in moderate-to-vigorous-intensity physical activity (MVPA), total physical activity energy expenditure (PAEE) and cardiorespiratory fitness with metabolic risk among individuals with recently diagnosed type 2 diabetes.
Individuals participating in the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care (ADDITION)-Plus trial underwent measurement of SED-time, MVPA and PAEE using a combined activity and movement sensor (n = 394), and evaluation of cardiorespiratory fitness (n = 291) and anthropometric and metabolic status. Clustered metabolic risk was calculated by summing standardised values for waist circumference, triacylglycerol, HbA1c, systolic blood pressure and the inverse of HDL-cholesterol. Multivariate linear regression analyses were used to quantify the associations between SED-time, MVPA, PAEE and cardiorespiratory fitness with individual metabolic risk factors and clustered metabolic risk.
Each additional 1 h of SED-time was positively associated with clustered metabolic risk, independently of sleep duration and MVPA (β = 0.16 [95% CI 0.03, 0.29]). After accounting for SED-time, MVPA was associated with systolic blood pressure (β = −2.07 [−4.03, −0.11]) but not with clustered metabolic risk (β = 0.01 [−0.28, 0.30]). PAEE and cardiorespiratory fitness were significantly and independently inversely associated with clustered metabolic risk (β = −0.03 [−0.05, −0.02] and β = −0.06 [−0.10, −0.03], respectively). Associations between SED-time and metabolic risk were generally stronger in the low compared with the high fitness group.
PAEE was inversely associated with metabolic risk, whereas SED-time was positively associated with metabolic risk. MVPA was not associated with clustered metabolic risk after accounting for SED-time. Encouraging this high-risk group to decrease SED-time, particularly those with low cardiorespiratory fitness, and increase their overall physical activity may have beneficial effects on disease progression and reduction of cardiovascular risk.
Trial registration: ISRCTN99175498
Electronic supplementary material
The online version of this article (doi:10.1007/s00125-013-3069-8) contains peer-reviewed but unedited supplementary material, which is available to authorised users.
PMCID: PMC3857880  PMID: 24196189
ADDITION-Plus; Cardiovascular risk; Cohort; Physical activity; Sedentary; Type 2 diabetes
12.  Physical activity intensity, sedentary time, and body composition in preschoolers123 
Detailed associations between physical activity (PA) subcomponents, sedentary time, and body composition in preschoolers remain unclear.
We examined the magnitude of associations between objectively measured PA subcomponents and sedentary time with body composition in 4-y-old children.
We conducted a cross-sectional study in 398 preschool children recruited from the Southampton Women’s Survey. PA was measured by using accelerometry, and body composition was measured by using dual-energy X-ray absorptiometry. Associations between light physical activity, moderate physical activity (MPA), vigorous physical activity (VPA), and moderate-to-vigorous physical activity (MVPA) intensity; sedentary time; and body composition were analyzed by using repeated-measures linear regression with adjustment for age, sex, birth weight, maternal education, maternal BMI, smoking during pregnancy, and sleep duration. Sedentary time and PA were also mutually adjusted for one another to determine whether they were independently related to adiposity.
VPA was the only intensity of PA to exhibit strong inverse associations with both total adiposity [P < 0.001 for percentage of body fat and fat mass index (FMI)] and abdominal adiposity (P = 0.002 for trunk FMI). MVPA was inversely associated with total adiposity (P = 0.018 for percentage of body fat; P = 0.022 for FMI) but only because of the contribution of VPA, because MPA was unrelated to fatness (P ≥ 0.077). No associations were shown between the time spent sedentary and body composition (P ≥ 0.11).
In preschoolers, the time spent in VPA is strongly and independently associated with lower adiposity. In contrast, the time spent sedentary and in low-to-moderate–intensity PA was unrelated to adiposity. These results indicate that efforts to challenge pediatric obesity may benefit from prioritizing VPA.
PMCID: PMC3785144  PMID: 23553158
13.  Longitudinal Association of C-Reactive Protein and Lung Function Over 13 Years 
American Journal of Epidemiology  2013;179(1):48-56.
Chronic obstructive pulmonary disease is known to be associated with systemic inflammation. We examined the longitudinal association of C-reactive protein (CRP) and lung function in a cohort of 18,110 men and women from the European Prospective Investigation Into Cancer in Norfolk who were 40–79 years of age at baseline (recruited in 1993–1997) and followed-up through 2011. We assessed lung function by measuring forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) at baseline, 4 years, and 13 years. Serum CRP levels were measured using a high-sensitivity assay at baseline and the 13-year follow up. Cross-sectional and longitudinal associations of loge-CRP and lung function were examined using multivariable linear mixed models. In the cross-sectional analysis, 1-standard-deviation increase in baseline loge-CRP (about 3-fold higher CRP on the original milligrams per liter scale) was associated with a −86.3 mL (95% confidence interval: −93.9, −78.6) reduction in FEV1. In longitudinal analysis, a 1-standard-deviation increase in loge-CRP over 13 years was also associated with a −64.0 mL (95% confidence interval: −72.1, −55.8) decline in FEV1 over the same period. The associations were similar for FVC and persisted among lifetime never-smokers. Baseline CRP levels were not predictive of the rate of change in FEV1 or FVC over time. In the present study, we found longitudinal observational evidence that suggested that increases in systemic inflammation are associated with declines in lung function.
PMCID: PMC3864708  PMID: 24064740
aging; chronic obstructive pulmonary disease; C-reactive protein; inflammation; longitudinal study; lung function
14.  Effect of early intensive multifactorial therapy compared with routine care on self-reported health status, general well-being, diabetes-specific quality of life and treatment satisfaction in screen-detected type 2 diabetes mellitus patients (ADDITION-Europe): a cluster-randomised trial 
Diabetologia  2013;56:2367-2377.
The study aimed to examine the effects of intensive treatment (IT) vs routine care (RC) on patient-reported outcomes after 5 years in screen-detected diabetic patients.
In a pragmatic, cluster-randomised, parallel-group trial, 343 general practices in Denmark, Cambridge and Leicester (UK) and the Netherlands were randomised to screening for type 2 diabetes mellitus plus IT of multiple risk factors in people 40–69 years without known diabetes (n = 1,678 patients) or screening plus RC (n = 1,379 patients). Practices were randomised in a 1:1 ratio according to a computer-generated list. Diabetes mellitus was diagnosed according to WHO criteria. Exclusions were: life expectancy <1 year, housebound, pregnant or lactating, or psychological or psychiatric problems. Treatment targets for IT were: HbA1c <7.0% (53 mmol/mol), BP ≤135/85 mmHg, cholesterol <5 mmol/l in the absence of a history of coronary heart disease and <4.5 mmol/l in patients with cardiovascular (CV) disease; prescription of aspirin to people taking antihypertensive medication and, in cases of CV disease or BP >120/80 mmHg, ACE inhibitors were recommended. After 2003, the treatment algorithm recommended statins to all patients with cholesterol of ≥3.5 mmol/l. Outcome measures were: health status (Euroqol 5 Dimensions [EQ-5D]) at baseline and at follow-up; and health status (36-item Short Form Health Survey [SF-36] and Euroquol Visual Analogue Scale [EQ-VAS]), well-being (12-item Short Form of the Well-Being Questionnaire), diabetes-specific quality of life (Audit of Diabetes-Dependent Quality of Life) and satisfaction with diabetes treatment (Diabetes Treatment Satisfaction Questionnaire) at follow-up. At baseline, standardised self-report questionnaires were used to collect information. Questionnaires were completed at the same health assessment visit as the anthropometric and biochemical measurements. The patients and the staff assessing the outcomes were unaware of the group assignments. Participants were followed for a mean of 5.7 years. Outcome data were available for 1,250 participants in the intensive treatment group (74%) and 967 participants in the routine care group (70%). The estimated differences in means from the four centres were pooled using random effects meta-analysis. Baseline EQ-5D level was used as a covariate in all analyses.
EQ-5D values did not change between diagnosis and follow-up, with a median (interquartile range) of 0.85 (0.73–1.00) at baseline and 0.85 (0.73–1.00) at 5 year follow-up. Health status, well-being, diabetes-specific quality of life and treatment satisfaction did not differ between the intensive treatment and routine care groups. There was some heterogeneity between centres (I2 being between 13% [SF-36 physical functioning] and 73% [EQ-VAS]).
There were no differences in health status, well-being, quality of life and treatment satisfaction between screen-detected type 2 diabetes mellitus patients receiving intensive treatment and those receiving routine care. These results suggest that intensive treatment does not adversely affect patient-reported outcomes.
Trial registration number NCT00237549
ADDITION-Denmark was supported by the National Health Services, the Danish Council for Strategic Research, the Danish Research Foundation for General Practice, Novo Nordisk Foundation, the Danish Centre for Evaluation and Health Technology Assessment, the Diabetes Fund of the National Board of Health, the Danish Medical Research Council and the Aarhus University Research Foundation. In addition, unrestricted grants from pharmaceutical companies were received. ADDITION-Cambridge was supported by the Wellcome Trust, the Medical Research Council, the NIHR Health Technology Assessment Programme, National Health Service R&D support funding and the National Institute for Health Research. SJG received support from the Department of Health NIHR grant funding scheme. ADDITION-Leicester was supported by Department of Health, the NIHR Health Technology Assessment Programme, National Health Service R&D support funding and the National Institute for Health Research. ADDITION-Netherlands was supported by unrestricted grants from Novo Nordisk, Glaxo Smith Kline and Merck, and by the Julius Center for Health Sciences and Primary Care, University Medical Center, Utrecht.
Electronic supplementary material
The online version of this article (doi:10.1007/s00125-013-3011-0) contains peer-reviewed but unedited supplementary material, which is available to authorised users.
PMCID: PMC3824356  PMID: 23959571
Diabetes screening; Health status; Intensive treatment; Patient-reported outcome measures; Primary care; Quality of life; Treatment satisfaction; Type 2 diabetes mellitus
15.  Evaluation of common genetic variants identified by GWAS for early onset and morbid obesity in population-based samples 
Meta-analysis of case-control genome wide association studies (GWAS) for early onset and morbid obesity identified four variants in/near the PRL, PTER, MAF and NPC1 genes.
We aimed to validate association of these variants with obesity-related traits in population-based samples.
Genotypes and anthropometric traits were available in up to 31 083 adults from the Fenland, EPIC-Norfolk, Whitehall II, Ely and Hertfordshire studies and in 2 042 children and adolescents from the European Youth Heart Study. In each study, we tested associations of rs4712652 (near-PRL), rs10508503 (near-PTER), rs1424233 (near-MAF) and rs1805081 (NPC1), or proxy variants (r2>0.8), with the odds of being overweight and obese, as well as with BMI, percentage body fat (%BF) and waist circumference (WC). Associations were adjusted for sex, age and age2 in adults and for sex, age, age-group, country and maturity in children and adolescents. Summary statistics were combined using fixed effects meta-analysis methods.
We had 80% power to detect ORs of 1.046 to 1.092 for overweight and 1.067 to 1.136 for obesity. Variants near PRL, PTER and MAF were not associated with the odds of being overweight or obese, or with BMI, %BF or WC after meta-analysis (P > 0.15). The NPC1 variant rs1805081 showed some evidence of association with %BF (beta=0.013 SD/allele, P =0.040), but not with any of the remaining obesity-related traits (P >0.3).
Overall, these variants, which were identified in a GWAS for early onset and morbid obesity, do not seem to influence obesity-related traits in the general population.
PMCID: PMC3680864  PMID: 22430306
Obesity-susceptibility loci; genome-wide association; morbid; early-onset; anthropometric traits; children and adolescents; population-based
16.  Socio-demographic and behavioural correlates of physical activity perception in individuals with recently diagnosed diabetes: results from a cross-sectional study 
BMC Public Health  2013;13:678.
Physical activity (PA) levels in type 2 diabetes mellitus (T2DM) patients are generally low. Poor PA perception may impede healthy behaviour change in this high risk group. We describe (i) objective PA levels, (ii) the difference between objective and self-reported PA (‘PA disparity’) and the correlates of (iii) PA disparity and (iv) overestimation in recently diagnosed T2DM patients.
Cross-sectional analysis of 425 recently diagnosed T2DM patients aged 42 to 71, participating in the ADDITION-Plus study in Eastern England, UK. We define ‘PA disparity’ as the non-negative value of the difference (in mathematical terms the absolute difference) between objective and self-reported physical activity energy expenditure (PAEE in kJ · kg-1 · day-1). ‘Overestimators’ comprised those whose self-reported- exceeded objective-PAEE by 4.91 kJ · kg-1 · day-1(the equivalent of 30 minutes moderate activity per day). Multivariable linear regression examined the association between PA disparity (continuous) and socio-demographic, clinical, health behaviour, quality of life and psychological characteristics. Logistic regression examined the association between PA overestimation and individual characteristics.
Mean objective and self-reported PAEE levels ± SD were 34.4 ± 17.0 and 22.6 ± 19.4 kJ · kg-1 · day-1, respectively (difference in means =11.8; 95% CI = 9.7 to 13.9 kJ · kg-1 · day-1). Higher PA disparity was associated with male sex, younger age, lower socio-economic status and lower BMI. PA overestimators comprised 19% (n = 80), with those in routine/manual occupations more likely to be overestimators than those in managerial/professional occupations.
T2DM patients with poor physical activity perception are more likely to be male, younger, from a lower socio-economic class and to have a lower BMI. PA overestimators were more likely to be in lower socio-economic categories. Self-monitoring and targeted feedback, particularly to those in lower socio-economic categories, may improve PA perceptions and optimise interventions in T2DM patients. Our findings suggest that strategies for enabling realistic assessment of physical activity levels, through self-monitoring or feedback, warrant further investigation and may help refine and improve physical activity interventions.
PMCID: PMC3729669  PMID: 23883169
Type 2 diabetes mellitus; Physical activity; Overestimation; Awareness; Perception; Health behaviour; Lifestyle behaviour; Social correlates of health; Health promotion intervention
17.  A Prospective Study of the Association Between Quantity and Variety of Fruit and Vegetable Intake and Incident Type 2 Diabetes 
Diabetes Care  2012;35(6):1293-1300.
The association between quantity of fruit and vegetable (F&V) intake and risk of type 2 diabetes (T2D) is not clear, and the relationship with variety of intake is unknown. The current study examined the association of both quantity and variety of F&V intake and risk of T2D.
We examined the 11-year incidence of T2D in relation to quantity and variety of fruit, vegetables, and combined F&V intake in a case-cohort study of 3,704 participants (n = 653 diabetes cases) nested within the European Prospective Investigation into Cancer and Nutrition-Norfolk study, who completed 7-day prospective food diaries. Variety of intake was derived from the total number of different items consumed in a 1-week period. Multivariable, Prentice-weighted Cox regression was used to estimate hazard ratios (HRs) and 95% CIs.
A greater quantity of combined F&V intake was associated with 21% lower hazard of T2D (HR 0.79 [95% CI 0.62–1.00]) comparing extreme tertiles, in adjusted analyses including variety. Separately, quantity of vegetable intake (0.76 [0.60–0.97]), but not fruit, was inversely associated with T2D in adjusted analysis. Greater variety in fruit (0.70 [0.53–0.91]), vegetable (0.77 [0.61–0.98]), and combined F&V (0.61 [0.48–0.78]) intake was associated with a lower hazard of T2D, independent of known confounders and quantity of intake comparing extreme tertiles.
These findings suggest that a diet characterized by a greater quantity of vegetables and a greater variety of both F&V intake is associated with a reduced risk of T2D.
PMCID: PMC3357245  PMID: 22474042
18.  The association of the mitochondrial DNA OriB variant (16184–16193 polycytosine tract) with type 2 diabetes in Europid populations 
Diabetologia  2013;56:1907-1913.
The association between the mitochondrial DNA 16181–16193 polycytosine variant (known as the OriB variant as it maps to the OriB origin of replication) and type 2 diabetes has not been reliably characterised, with studies reporting conflicting results. We report a systematic review of published literature in Europid populations, new data from the Norfolk Diabetes Case–Control Study and a meta-analysis to help quantify this association.
We performed a systematic review identifying all the studies of the OriB variant and type 2 diabetes in Europid populations published before January 2013. We typed the OriB variant by pyrosequencing and sequencing in the Norfolk Diabetes Case–Control Study, which comprised 5,574 type 2 diabetes cases and 6,950 population-based controls.
Overall, the meta-analysis included eight published studies plus the current new results, with a total of 11,794 type 2 diabetes cases and 14,465 controls. In the Norfolk Diabetes Case–Control Study, the OR for type 2 diabetes for the OriB variant was 1.09 (95% CI 0.96, 1.24). In a combined analysis, the relative risk for type 2 diabetes for the OriB variant in Europid populations was 1.10 (95% CI 1.01, 1.20; p = 0.03)
Results from this systematic review and meta-analysis suggest that the mitochondrial DNA OriB variant is modestly associated with an increased risk of type 2 diabetes in Europid populations, with an effect size comparable with that of recently identified variants from genome-wide association studies.
Electronic supplementary material
The online version of this article (doi:10.1007/s00125-013-2945-6) contains peer-reviewed but unedited supplementary material, which is available to authorised users.
PMCID: PMC3737432  PMID: 23702607
Europid populations; Meta-analysis; Mitochondrial DNA; OriB variant; Pyrosequencing; Systematic review; Type 2 diabetes
19.  Intrahepatic Lipid Content and Insulin Resistance Are More Strongly Associated with Impaired NEFA Suppression after Oral Glucose Loading Than with Fasting NEFA Levels in Healthy Older Individuals 
Introduction. The mechanisms underlying the association between insulin resistance and intrahepatic lipid (IHL) accumulation are not completely understood. We sought to determine whether this association was explained by differences in fasting non-esterified fatty acid (NEFA) levels and/or NEFA suppression after oral glucose loading. Materials and Methods. We performed a cross-sectional analysis of 70 healthy participants in the Hertfordshire Physical Activity Trial (39 males, age 71.3 ± 2.4 years) who underwent oral glucose tolerance testing with glucose, insulin, and NEFA levels measured over two hours. IHL was quantified with magnetic resonance spectroscopy. Insulin sensitivity was measured with the oral glucose insulin sensitivity (OGIS) model, the leptin: adiponectin ratio (LAR), and the homeostasis model assessment (HOMA). Results. Measures of insulin sensitivity were not associated with fasting NEFA levels, but OGIS was strongly associated with NEFA suppression at 30 minutes and strongly inversely associated with IHL. Moreover, LAR was strongly inversely associated with NEFA suppression and strongly associated with IHL. This latter association (beta = 1.11 [1.01, 1.21], P = 0.026) was explained by reduced NEFA suppression (P = 0.24 after adjustment). Conclusions. Impaired postprandial NEFA suppression, but not fasting NEFA, contributes to the strong and well-established association between whole body insulin resistance and liver fat accumulation.
PMCID: PMC3659510  PMID: 23737780
20.  Rate of weight gain predicts change in physical activity levels: a longitudinal analysis of the EPIC-Norfolk cohort 
To investigate the relationship of body weight and its changes over time with physical activity.
Population-based prospective cohort study (Norfolk cohort of the European Prospective Investigation into Cancer and Nutrition, EPIC-Norfolk, United Kingdom)
25639 men and women aged 39-79 years at baseline. Physical activity was self-reported. Weight and height were measured by standard clinical procedures at baseline and self-reported at 18-month and 10-y follow-ups (calibrated against clinical measures). Main outcome measure was physical activity at the 10-y follow-up
Body weight and physical activity were inversely associated in cross-sectional analyses. In longitudinal analyses, an increase in weight was associated with higher risk of being inactive 10 years later, after adjusting for baseline activity, 18-month activity, sex, baseline age, prevalent diseases, socioeconomic status, education, smoking, total daily energy intake, and alcohol intake. Compared with stable weight, a gain in weight of >2 kg/y during short-, medium- and long-term was consistently and significantly associated with greater likelihood of physical inactivity after 10 y, with the most pronounced effect for long-term weight gain, OR=1.89 (95% CI: 1.30-2.70) in fully adjusted analysis. Weight gain of 0.5-2 kg/y over long term was substantially associated with physical inactivity after full adjustment, OR=1.26 (95% CI: 1.11-1.41).
Weight gain (during short-, medium- and long-term) is a significant determinant of future physical inactivity independent of baseline weight and activity. Compared with maintaining weight, moderate (0.5-2 kg/y) and large weight gain (>2 kg/y) significantly predict future inactivity; a potentially vicious cycle including further weight gain, obesity and complications associated with a sedentary lifestyle. Based on current predictions of obesity trends, we estimate that the prevalence of inactivity in England would exceed 60% in year 2020.
PMCID: PMC3635037  PMID: 22531093
physical activity; obesity; weight gain; cohort study; epidemiology
21.  Meta-analysis and imputation refines the association of 15q25 with smoking quantity 
Liu, Jason Z. | Tozzi, Federica | Waterworth, Dawn M. | Pillai, Sreekumar G. | Muglia, Pierandrea | Middleton, Lefkos | Berrettini, Wade | Knouff, Christopher W. | Yuan, Xin | Waeber, Gérard | Vollenweider, Peter | Preisig, Martin | Wareham, Nicholas J | Zhao, Jing Hua | Loos, Ruth J.F. | Barroso, Inês | Khaw, Kay-Tee | Grundy, Scott | Barter, Philip | Mahley, Robert | Kesaniemi, Antero | McPherson, Ruth | Vincent, John B. | Strauss, John | Kennedy, James L. | Farmer, Anne | McGuffin, Peter | Day, Richard | Matthews, Keith | Bakke, Per | Gulsvik, Amund | Lucae, Susanne | Ising, Marcus | Brueckl, Tanja | Horstmann, Sonja | Wichmann, H.-Erich | Rawal, Rajesh | Dahmen, Norbert | Lamina, Claudia | Polasek, Ozren | Zgaga, Lina | Huffman, Jennifer | Campbell, Susan | Kooner, Jaspal | Chambers, John C | Burnett, Mary Susan | Devaney, Joseph M. | Pichard, Augusto D. | Kent, Kenneth M. | Satler, Lowell | Lindsay, Joseph M. | Waksman, Ron | Epstein, Stephen | Wilson, James F. | Wild, Sarah H. | Campbell, Harry | Vitart, Veronique | Reilly, Muredach P. | Li, Mingyao | Qu, Liming | Wilensky, Robert | Matthai, William | Hakonarson, Hakon H. | Rader, Daniel J. | Franke, Andre | Wittig, Michael | Schäfer, Arne | Uda, Manuela | Terracciano, Antonio | Xiao, Xiangjun | Busonero, Fabio | Scheet, Paul | Schlessinger, David | St Clair, David | Rujescu, Dan | Abecasis, Gonçalo R. | Grabe, Hans Jörgen | Teumer, Alexander | Völzke, Henry | Petersmann, Astrid | John, Ulrich | Rudan, Igor | Hayward, Caroline | Wright, Alan F. | Kolcic, Ivana | Wright, Benjamin J | Thompson, John R | Balmforth, Anthony J. | Hall, Alistair S. | Samani, Nilesh J. | Anderson, Carl A. | Ahmad, Tariq | Mathew, Christopher G. | Parkes, Miles | Satsangi, Jack | Caulfield, Mark | Munroe, Patricia B. | Farrall, Martin | Dominiczak, Anna | Worthington, Jane | Thomson, Wendy | Eyre, Steve | Barton, Anne | Mooser, Vincent | Francks, Clyde | Marchini, Jonathan
Nature genetics  2010;42(5):436-440.
Smoking is a leading global cause of disease and mortality1. We performed a genomewide meta-analytic association study of smoking-related behavioral traits in a total sample of 41,150 individuals drawn from 20 disease, population, and control cohorts. Our analysis confirmed an effect on smoking quantity (SQ) at a locus on 15q25 (P=9.45e-19) that includes three genes encoding neuronal nicotinic acetylcholine receptor subunits (CHRNA5, CHRNA3, CHRNB4). We used data from the 1000 Genomes project to investigate the region using imputation, which allowed analysis of virtually all common variants in the region and offered a five-fold increase in coverage over the HapMap. This increased the spectrum of potentially causal single nucleotide polymorphisms (SNPs), which included a novel SNP that showed the highest significance, rs55853698, located within the promoter region of CHRNA5. Conditional analysis also identified a secondary locus (rs6495308) in CHRNA3.
PMCID: PMC3612983  PMID: 20418889
22.  Epidemiological Study Designs to Investigate Gene–Behavior Interactions in the Context of Human Obesity 
Obesity (Silver Spring, Md.)  2008;16(Suppl 3):S66-S71.
The epidemiology of obesity suggests that, for the majority of individuals, the disorder arises from an interaction between genetic predisposition and lifestyle behaviors such as dietary intake and physical activity. Unravelling the molecular basis of such interactions is complex but is becoming a realistic proposition as evidence emerges from whole genome association studies of genetic variants that are definitively associated with obesity. A range of possible study designs is available for investigating gene–lifestyle interaction, and the strengths and weaknesses of each approach are discussed in this article. Given the likely small main effect of common genetic variants and the difficulties in demonstrating associations of lifestyle factors with future risk of obesity, we would favor an analytical approach based on the clear specification of prior probabilities to reduce the likelihood of false discovery. Mixed approaches combining data from large-scale observational studies with smaller intervention trials may be ideal. In designing new studies to investigate these issues, a key choice is how precisely to quantify the important, but difficult to measure lifestyle behaviors. It is clear from power calculations that an approach based on enhancing precision of measurement of diet and physical activity is critical.
The high heritability of obesity coupled with the rapid increase in prevalence suggests that a combination of genetic and behavioral factors is critical to the etiology of obesity (1). It is easy to propose such a model for the development of obesity, but it is altogether much harder to identify the molecular mechanisms that underlie such a model. In this article, we review overall strategies and possible epidemiological study designs for investigating how genetic and behavioral risk factors combine to lead to excess weight gain.
PMCID: PMC2703295  PMID: 19037217
23.  The EPIC-Norfolk Eye Study: rationale, methods and a cross-sectional analysis of visual impairment in a population-based cohort 
BMJ Open  2013;3(3):e002684.
To summarise the methods of the European Prospective Investigation of Cancer (EPIC)-Norfolk Eye Study, and to present data on the prevalence of visual impairment and associations with visual impairment in the participants.
A population-based cross-sectional study nested within an on-going prospective cohort study (EPIC).
East England population (the city of Norwich and its surrounding small towns and rural areas).
A total of 8623 participants aged 48–92 years attended the Eye Study and underwent assessment of visual acuity, autorefraction, biometry, tonometry, corneal biomechanical measures, scanning laser polarimetry, confocal scanning laser ophthalmoscopy, fundal photography and automated perimetry.
Outcome measures
Visual impairment was defined according to the WHO classification and the UK driving standard, and was based on presenting visual acuity. Summary measures of other ophthalmic measurements are also presented.
The prevalence (95% CI) of WHO-defined moderate-to-severe visual impairment and blindness was 0.74% (0.55% to 0.92%). The prevalence (95% CI) of presenting visual acuity worse than the UK driving standard was 5.87% (5.38% to 6.37%). Older age was significantly associated with visual impairment or blindness (p<0.001). Presenting visual acuity worse than UK driving standard was associated with older age (p<0.001), female sex (p=0.005) and lower educational level (p=0.022).
The prevalence of blindness and visual impairment in this selected population was low. Visual impairment was more likely in older participants, women and those with a lower educational level.
PMCID: PMC3612817  PMID: 23516272
24.  Seropositivity and Higher Immunoglobulin G Antibody Levels Against Cytomegalovirus Are Associated With Mortality in the Population-Based European Prospective Investigation of Cancer–Norfolk Cohort 
After adjustment for a range of possible confounders, cytomegalovirus seropositivity and cytomegalovirus immunoglobulin G antibody levels were associated with all-cause mortality in the EPIC-Norfolk population-based cohort study.
Background. The relationship between cytomegalovirus (CMV) infection and mortality among immunocompetent individuals is uncertain. We aimed to examine whether seropositivity for CMV and the level of CMV immunoglobulin G (IgG) antibody are associated with all-cause and cause-specific mortality.
Methods. We used data from a random sample of 13 090 participants aged 40–79 years at recruitment in 1993–1997 to the European Prospective Investigation of Cancer–Norfolk population-based cohort study. We measured baseline IgG antibody levels against CMV. Death certificates were obtained for all participants who died before 31 March 2011. Codes for the underlying cause of death were used to investigate cause-specific mortality.
Results. A total of 2514 deaths occurred during a mean follow-up of 14.3 years (SD, 3.3 years). Compared to seronegative participants (age- and sex-adjusted mortality rate, 12.4 [95% confidence interval {CI}, 11.3–13.2] per 1000 person-years at risk), rates increased across thirds of IgG antibody levels (score test of trend P < .0001). CMV seropositivity (prevalence 59%) was associated with increased all-cause mortality (age- and sex-adjusted hazard ratio [HR], 1.16 [95% CI, 1.07–1.26]), similarly in men and women (P for interaction = .52). The association persisted after additionally adjusting for measures of socioeconomic status and possible confounders. Cause-specific analyses suggested that increased mortality from cardiovascular disease (HR, 1.06 [95% CI, .91–1.24]), cancer (HR, 1.13 [95% CI, .98–1.31]), and other causes (HR, 1.23 [95% CI, 1.04–1.47) all appeared to contribute to the overall associations.
Conclusions. Seropositivity and higher IgG antibody levels against CMV are associated with increased mortality and after adjustment for a range of potential confounders in the general population.
PMCID: PMC3634310  PMID: 23442763
cytomegalovirus; cancer; mortality; cohort study; cardiovascular disease
25.  An Ensemble Learning Approach Jointly Modeling Main and Interaction Effects in Genetic Association Studies 
Genetic epidemiology  2008;32(4):285-300.
Complex diseases are presumed to be the results of interactions of several genes and environmental factors, with each gene only having a small effect on the disease. Thus, the methods that can account for gene-gene interactions to search for a set of marker loci in different genes or across genome and to analyze these loci jointly are critical. In this article, we propose an ensemble learning approach (ELA) to detect a set of loci whose main and interaction effects jointly have a significant association with the trait. In the ELA, we first search for “base learners” and then combine the effects of the base learners by a linear model. Each base learner represents a main effect or an interaction effect. The result of the ELA is easy to interpret. When the ELA is applied to analyze a data set, we can get a final model, an overall P-value of the association test between the set of loci involved in the final model and the trait, and an importance measure for each base learner and each marker involved in the final model. The final model is a linear combination of some base learners. We know which base learner represents a main effect and which one represents an interaction effect. The importance measure of each base learner or marker can tell us the relative importance of the base learner or marker in the final model. We used intensive simulation studies as well as a real data set to evaluate the performance of the ELA. Our simulation studies demonstrated that the ELA is more powerful than the single-marker test in all the simulation scenarios. The ELA also outperformed the other three existing multi-locus methods in almost all cases. In an application to a large-scale case-control study for Type 2 diabetes, the ELA identified 11 single nucleotide polymorphisms that have a significant multi-locus effect (P-value = 0.01), while none of the single nucleotide polymorphisms showed significant marginal effects and none of the two-locus combinations showed significant two-locus interaction effects.
PMCID: PMC3572743  PMID: 18205210
epistasis; association study; complex disease; Type 2 diabetes

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