Highlights

► IL-18 is hypothesized to destabilise atherosclerotic plaques, leading to thrombotic events. ► We prospectively studied serum IL-18 and CHD or stroke onset in older men and women. ► IL-18 was positively associated with adverse lipid and inflammatory profile. ► Results did not suggest independent associations between IL-18 and CHD or stroke risk.

Aim

IL-18 is hypothesized to destabilise atherosclerotic plaques, leading to thrombotic events and epidemiologic studies suggest that IL-18 may increase risk of CHD or CVD.

We examined prospective associations between levels of serum IL-18 and new CHD and stroke events in older men and women from a general population.

Methods

A case-control study was nested within a prospective cohort of men and women aged 60–79 years recruited from general practices in 25 British towns in 1998–2000 and followed-up for 7.5 years for fatal and non-fatal MI and stroke. Baseline IL-18 was measured in stored serum samples of incident cases of MI (n = 364) or stroke (n = 300) and two controls per case.

Results

Geometric mean IL-18 levels were higher among the 364 MI cases than the 706 controls; 417.84 pg/mL (IQR 316.25, 537.44) compared to 386.90 pg/mL (IQR 296.54, 482.33), p(difference) = 0.002. IL-18 was positively associated with adverse lipid and inflammatory profiles. Men and women in the top third of baseline IL-18 levels had an age and sex-adjusted odds ratio (OR) for MI of 1.31 (95%CI 0.92, 1.85) compared with those in the lowest third; this attenuated to 1.05 (95%CI 0.72, 1.53) after additional adjustment for established vascular and inflammatory risk factors. Each doubling of IL-18 level was associated with an increased OR for MI 1.34 (95%CI 1.04, 1.72), which was attenuated on adjustment for established vascular and inflammatory risk factors; 1.09 (95%CI 0.83, 1.44).

Geometric mean IL-18 levels did not differ between stroke cases and controls. The OR for stroke associated with the highest compared to the lowest tertile of IL-18 was 1.24 (95%CI 0.84, 1.84). Results for MI and stroke did not differ by presence of pre-existing CVD, gender or age.

Conclusions

Circulating IL-18 levels were strongly associated with a range of established and novel risk factors but were not independently associated with risk of MI or stroke in our study.

In a prospective Australian population-based study linking questionnaire data from 2006–2009 with hospitalisation and death data to June 2010 for 95,038 men aged ≥45 years, Banks and colleagues found that more severe erectile dysfunction was associated with higher risk of cardiovascular disease.

Background

Erectile dysfunction is an emerging risk marker for future cardiovascular disease (CVD) events; however, evidence on dose response and specific CVD outcomes is limited. This study investigates the relationship between severity of erectile dysfunction and specific CVD outcomes.

Methods and Findings

We conducted a prospective population-based Australian study (the 45 and Up Study) linking questionnaire data from 2006–2009 with hospitalisation and death data to 30 June and 31 Dec 2010 respectively for 95,038 men aged ≥45 y. Cox proportional hazards models were used to examine the relationship of reported severity of erectile dysfunction to all-cause mortality and first CVD-related hospitalisation since baseline in men with and without previous CVD, adjusting for age, smoking, alcohol consumption, marital status, income, education, physical activity, body mass index, diabetes, and hypertension and/or hypercholesterolaemia treatment. There were 7,855 incident admissions for CVD and 2,304 deaths during follow-up (mean time from recruitment, 2.2 y for CVD admission and 2.8 y for mortality). Risks of CVD and death increased steadily with severity of erectile dysfunction. Among men without previous CVD, those with severe versus no erectile dysfunction had significantly increased risks of ischaemic heart disease (adjusted relative risk [RR] = 1.60, 95% CI 1.31–1.95), heart failure (8.00, 2.64–24.2), peripheral vascular disease (1.92, 1.12–3.29), “other” CVD (1.26, 1.05–1.51), all CVD combined (1.35, 1.19–1.53), and all-cause mortality (1.93, 1.52–2.44). For men with previous CVD, corresponding RRs (95% CI) were 1.70 (1.46–1.98), 4.40 (2.64–7.33), 2.46 (1.63–3.70), 1.40 (1.21–1.63), 1.64 (1.48–1.81), and 2.37 (1.87–3.01), respectively. Among men without previous CVD, RRs of more specific CVDs increased significantly with severe versus no erectile dysfunction, including acute myocardial infarction (1.66, 1.22–2.26), atrioventricular and left bundle branch block (6.62, 1.86–23.56), and (peripheral) atherosclerosis (2.47, 1.18–5.15), with no significant difference in risk for conditions such as primary hypertension (0.61, 0.16–2.35) and intracerebral haemorrhage (0.78, 0.20–2.97).

Conclusions

These findings give support for CVD risk assessment in men with erectile dysfunction who have not already undergone assessment. The utility of erectile dysfunction as a clinical risk prediction tool requires specific testing.

Please see later in the article for the Editors' Summary

Editors' Summary

Background

Erectile dysfunction is the medical term used when a man is unable to achieve or sustain an erection of his penis suitable for sexual intercourse. Although a sensitive topic that can cause much embarrassment and distress, erectile dysfunction is very common, with an estimated 40% of men over the age of 40 years experiencing frequent or occasional difficulties. The most common causes of erectile dysfunction are medications, chronic illnesses such as diabetes, and drinking too much alcohol. Stress and mental health problems can also cause or worsen erectile dysfunction. There is also increasing evidence that erectile dysfunction may actually be a symptom of cardiovascular disease—a leading cause of death worldwide—as erectile dysfunction could indicate a problem with blood vessels or poor blood flow commonly associated with cardiovascular disease.

Why Was This Study Done?

Although previous studies have suggested that erectile dysfunction can serve as a marker for cardiovascular disease in men not previously diagnosed with the condition, few studies to date have investigated whether erectile dysfunction could also indicate worsening disease in men already diagnosed with cardiovascular disease. In addition, previous studies have typically been small and have not graded the severity of erectile dysfunction or investigated the specific types of cardiovascular disease associated with erectile dysfunction. In this large study conducted in Australia, the researchers investigated the relationship of the severity of erectile dysfunction with a range of cardiovascular disease outcomes among men with and without a previous diagnosis of cardiovascular disease.

What Did the Researchers Do and Find?

The researchers used information from the established 45 and Up Study, a large cohort study that includes 123,775 men aged 45 and over, selected at random from the general population of New South Wales, a large region of Australia. A total of 95,038 men were included in this analysis. The male participants completed a postal questionnaire that included a question on erectile functioning, which allowed the researchers to define erectile dysfunction as none, mild, moderate, or severe. Using information captured in the New South Wales Admitted Patient Data Collection—a complete record of all public and private hospital admissions, including the reasons for admission and the clinical diagnosis—and the government death register, the researchers were able to determine health outcomes of all study participants. They then used a statistical model to estimate hospital admissions for cardiovascular disease events for different levels of erectile dysfunction.

The researchers found that the rates of severe erectile dysfunction among study participants were 2.2% for men aged 45–54 years, 6.8% for men aged 55–64 years, 20.2% for men aged 65–74 years, 50.0% for men aged 75–84 years, and 75.4% for men aged 85 years and over. During the study period, the researchers recorded 7,855 hospital admissions related to cardiovascular disease and 2,304 deaths. The researchers found that among men without previous cardiovascular disease, those with severe erectile dysfunction were more likely to develop ischemic heart disease (risk 1.60), heart failure (risk 8.00), peripheral vascular disease (risk 1.92), and other causes of cardiovascular disease (risk 1.26) than men without erectile dysfunction. The risks of heart attacks and heart conduction problems were also increased (1.66 and 6.62, respectively). Furthermore, the combined risk of all cardiovascular disease outcomes was 1.35, and the overall risk of death was also higher (risk 1.93) in these men. The researchers found that these increased risks were similar in men with erectile dysfunction who had previously been diagnosed with cardiovascular disease.

What Do These Findings Mean?

These findings suggest that compared to men without erectile dysfunction, there is an increasing risk of ischemic heart disease, peripheral vascular disease, and death from all causes in those with increasing degrees of severity of erectile dysfunction. The authors emphasize that erectile dysfunction is a risk marker for cardiovascular disease, not a risk factor that causes cardiovascular disease. These findings add to previous studies and highlight the need to consider erectile dysfunction in relation to the risk of different types of cardiovascular disease, including heart failure and heart conduction disorders. However, the study's reliance on the answer to a single self-assessed question on erectile functioning limits the findings. Nevertheless, these findings provide useful information for clinicians: men with erectile dysfunction are at higher risk of cardiovascular disease, and the worse the erectile dysfunction, the higher the risk of cardiovascular disease. Men with erectile dysfunction, even at mild or moderate levels, should be screened and treated for cardiovascular disease accordingly.

Additional Information

Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001372.

Wikipedia defines erectile dysfunction (note that Wikipedia is a free online encyclopedia that anyone can edit)

MedlinePlus also has some useful patient information on erectile dysfunction

The Mayo Clinic has patient-friendly information on the causes of, and treatments for, erectile dysfunction, and also includes information on the link with cardiovascular disease

The National Heart Foundation of Australia provides information for health professionals, patients, and the general public about how to prevent and manage cardiovascular disease, including assessment and management of cardiovascular disease risk

Shah Ebrahim and colleagues argue that more research on non-communicable diseases (NCDs) in both high-income countries and low- and middle-income countries can result in mutual benefits and will help better address the growing burden of NCDs.

Obesity is an established risk factor for type 2 diabetes (T2D) and they are metabolically related through the mechanism of insulin resistance. In order to explore how common genetic variants associated with T2D correlate with body mass index (BMI), we examined the influence of 25 T2D associated loci on obesity risk. We used 5056 individuals (2528 sib-pairs) recruited in Indian Migration Study and conducted within sib-pair analysis for six obesity phenotypes. We found associations of variants in CXCR4 (rs932206) and HHEX (rs5015480) with higher body mass index (BMI) (β = 0.13, p = 0.001) and (β = 0.09, p = 0.002), respectively and weight (β = 0.13, p = 0.001) and (β = 0.09, p = 0.001), respectively. CXCR4 variant was also strongly associated with body fat (β = 0.10, p = 0.0004). In addition, we demonstrated associations of CXCR4 and HHEX with overweight/obesity (OR = 1.6, p = 0.003) and (OR = 1.4, p = 0.002), respectively, in 1333 sib-pairs (2666 individuals). We observed marginal evidence of associations between variants at six loci (TCF7L2, NGN3, FOXA2, LOC646279, FLJ3970 and THADA) and waist hip ratio (WHR), BMI and/or overweight which needs to be validated in larger set of samples. All the above findings were independent of daily energy consumption and physical activity level. The risk score estimates based on eight significant loci (including nominal associations) showed associations with WHR and body fat which were independent of BMI. In summary, we establish the role of T2D associated loci in influencing the measures of obesity in Indian population, suggesting common underlying pathophysiology across populations.

Summary

The association between functioning of the hypothalamic pituitary adrenal (HPA) axis and physical performance at older ages remains poorly understood. We carried out meta-analyses to test the hypothesis that dysregulation of the HPA axis, as indexed by patterns of diurnal cortisol release, is associated with worse physical performance. Data from six adult cohorts (ages 50–92 years) were included in a two stage meta-analysis of individual participant data. We analysed each study separately using linear and logistic regression models and then used meta-analytic methods to pool the results. Physical performance outcome measures were walking speed, balance time, chair rise time and grip strength. Exposure measures were morning (serum and salivary) and evening (salivary) cortisol. Total sample sizes in meta-analyses ranged from n = 2146 for associations between morning Cortisol Awakening Response and balance to n = 8448 for associations between morning cortisol and walking speed. A larger diurnal drop was associated with faster walking speed (standardised coefficient per SD increase 0.052, 95% confidence interval (CI) 0.029, 0.076, p < 0.001; age and gender adjusted) and a quicker chair rise time (standardised coefficient per SD increase −0.075, 95% CI −0.116, −0.034, p < 0.001; age and gender adjusted). There was little evidence of associations with balance or grip strength. Greater diurnal decline of the HPA axis is associated with better physical performance in later life. This may reflect a causal effect of the HPA axis on performance or that other ageing-related factors are associated with both reduced HPA reactivity and performance.

Objective

Abdominal adiposity is an important risk factor for diabetes and cardiovascular disease in Indians. Dual energy X-ray absorptiometry (DXA) can be used to determine abdominal fat depots, being more accessible and less costly than gold standard measures such as magnetic resonance imaging (MRI). DXA has not been fully validated for use in South Asians. Here, we determined the accuracy of DXA for measurement of abdominal fat in an Indian population by comparison with MRI.

Design

146 males and females (age range 18–74, BMI range 15–46 kg/m2) from Hyderabad, India underwent whole body DXA scans on a Hologic Discovery A scanner, from which fat mass in two abdominal regions was calculated, from the L1 to L4 vertebrae (L1L4) and from the L2 to L4 vertebrae (L2L4). Abdominal MRI scans (axial T1-weighted spin echo images) were taken, from which adipose tissue volumes were calculated for the same regions.

Results

Intra-class correlation coefficients between DXA and MRI measures of abdominal fat were high (0.98 for both regions). Although at the level of the individual, differences between DXA and MRI could be large (95% of DXA measures were between 0.8 and 1.4 times MRI measures), at the sample level, DXA only slightly overestimated MRI measures of abdominal fat mass (mean difference in L1L4 region: 2% (95% CI:0%, 5%), mean difference in L2L4 region:4% (95% CI: 1%, 7%)). There was evidence of a proportional bias in the association between DXA and MRI (correlation between difference and mean −0.3), with overestimation by DXA greater in individuals with less abdominal fat (mean bias in leaner half of sample was 6% for L1L4 (95%CI: 2, 11%) and 7% for L2L4 (95% CI:3,12%).

Conclusions

DXA measures of abdominal fat are suitable for use in Indian populations and provide a good indication of abdominal adiposity at the population level.

Background

Genome wide association studies (GWAS), mostly in Europeans have identified several common variants as associated with key lipid traits. Replication of these genetic effects in South Asian populations is important since it would suggest wider relevance for these findings. Given the rising prevalence of metabolic disorders and heart disease in the Indian sub-continent, these studies could be of future clinical relevance.

Methods

We studied seven common variants associated with a variety of lipid traits in previous GWASs. The study sample comprised of 3178 sib-pairs recruited as participants for the Indian Migration Study (IMS). Associations with various lipid parameters and quantitative traits were analyzed using the Fulker genetic association model.

Results

We replicated five of the 7 main effect associations with p-values ranging from 0.03 to 1.97x10-7. We identified particularly strong association signals at rs662799 in APOA5 (beta=0.18 s.d, p=1.97 x 10-7), rs10503669 in LPL (beta =−0.18 s.d, p=1.0 x 10-4) and rs780094 in GCKR (beta=0.11 s.d, p=0.001) loci in relation to triglycerides. In addition, the GCKR variant was also associated with total cholesterol (beta=0.11 s.d, p=3.9x10-4). We also replicated the association of rs562338 in APOB (p=0.03) and rs4775041 in LIPC (p=0.007) with LDL-cholesterol and HDL-cholesterol respectively.

Conclusions

We report associations of five loci with various lipid traits with the effect size consistent with the same reported in Europeans. These results indicate an overlap of genetic effects pertaining to lipid traits across the European and Indian populations.

Background

Socioeconomic influences over a lifetime impact on health and may contribute to poor physical functioning in old age.

Methods

We examined the impact of both childhood and adulthood socioeconomic factors on locomotor function at 63-86 years (measured with the get up and go timed walk and flamingo balance test), in the UK-based Boyd Orr (n=405) and Caerphilly (n=1,196) prospective cohorts.

Results

There was a marked reduction in walking speed and balance time with increasing age. Each year of age was associated with a 1.7% slower walk time and a 14% increased odds of poor balance. Participants who moved from a low socioeconomic position in childhood to a high socioeconomic position in adulthood had walking times 3% slower (95% CI: -2%, 8%) than people with high socioeconomic position in both periods. Participants who moved from a high socioeconomic position in childhood to a low adulthood socioeconomic position had walking times 5% slower (95% CI: -2%, 12%). Participants with a low socioeconomic position in both periods had walking times 10% slower (95% CI: 5%, 16%; P for trend <0.001).

In Boyd Orr, low socioeconomic position in childhood was associated with poor balance in old age (OR per worsening category = 1.26; 95% CI 1.01, 1.57; P=0.043), as was socioeconomic position in adulthood (OR = 1.71; 95% CI 1.20, 2.45; P=0.003). Similar associations were not observed in Caerphilly.

Conclusion

Accumulating socioeconomic disadvantage from childhood to adulthood is associated with slower walking time in old age, with mixed results for balance ability.

Objective

We examined the distribution of diabetes and modifiable risk factors to provide data to aid diabetes prevention programmes in India.

Design

Population-based cross-sectional survey of men and women included in India's third National Family Health Survey (NFHS-3, 2005–2006).

Setting

The sample is a multistage cluster sample with an overall response rate of 98 %. All states of India are represented in the sample (except the small Union Territories), covering more than 99 % of the country's population.

Subjects

Women (n 99 574) and men (n 56 742) aged 20–49 years residing in the sample households.

Results

Prevalence of diabetes was 1598/100 000 (95 % CI 1462, 1735) among men and 1054/100 000 (95 % CI 974, 1134) among women in India. Rural–urban and marked geographic variation were found with higher rates in south and north-eastern India. Weekly and daily fish intake contributed to a significantly higher risk of diabetes among both women and men. Risks of diabetes increased with increased BMI, age and wealth status of both women and men, but no effects of the consumption of milk/curd, vegetables, eggs, television watching, alcohol consumption or smoking were found. Daily consumption of pulse/beans or fruits was associated with a significantly reduced risk of diabetes among women, whereas non-significant inverse associations were observed in the case of men.

Conclusions

Prevalence was underestimated using self-reports. The wide variation in self-reported diabetes is unlikely to be due entirely to reporting biases or access to health care, and indicates that modifiable risk factors exist. Prevention of diabetes should focus on obesity and target specific socio-economic groups in India.

Background

Reducing salt intake has been proposed to prevent cardiovascular disease in India. We sought to determine whether salt reductions would be beneficial or feasible, given the worry that unrealistically large reductions would be required, worsening iodine deficiency and benefiting only urban subpopulations.

Methods and Results

Future myocardial infarctions (MI) and strokes in India were predicted with a Markov model simulating men and women aged 40 to 69 in both urban and rural locations, incorporating the risk reduction from lower salt intake. If salt intake does not change, we expect ∼8.3 million MIs (95% CI: 6.9–9.6 million), 830,000 strokes (690,000–960,000) and 2.0 million associated deaths (1.5–2.4 million) per year among Indian adults aged 40 to 69 over the next three decades. Reducing intake by 3 g/day over 30 years (−0.1 g/year, 25% reduction) would reduce annual MIs by 350,000 (a 4.6% reduction; 95% CI: 320,000–380,000), strokes by 48,000 (−6.5%; 13,000–83,000) and deaths by 81,000 (−4.9%; 59,000–100,000) among this group. The largest decline in MIs would be among younger urban men, but the greatest number of averted strokes would be among rural men, and nearly one-third of averted strokes and one-fifth of averted MIs would be among rural women. Only under a highly pessimistic scenario would iodine deficiency increase (by <0.0001%, ∼1600 persons), since inadequate iodized salt access—not low intake of iodized salt—is the major cause of deficiency and would be unaffected by dietary salt reduction.

Conclusions

Modest reductions in salt intake could substantially reduce cardiovascular disease throughout India.

Maternal smoking during pregnancy is associated with low birth weight. Common variation at rs1051730 is robustly associated with smoking quantity and was recently shown to influence smoking cessation during pregnancy, but its influence on birth weight is not clear. We aimed to investigate the association between this variant and birth weight of term, singleton offspring in a well-powered meta-analysis. We stratified 26 241 European origin study participants by smoking status (women who smoked during pregnancy versus women who did not smoke during pregnancy) and, in each stratum, analysed the association between maternal rs1051730 genotype and offspring birth weight. There was evidence of interaction between genotype and smoking (P = 0.007). In women who smoked during pregnancy, each additional smoking-related T-allele was associated with a 20 g [95% confidence interval (95% CI): 4–36 g] lower birth weight (P = 0.014). However, in women who did not smoke during pregnancy, the effect size estimate was 5 g per T-allele (95% CI: −4 to 14 g; P = 0.268). To conclude, smoking status during pregnancy modifies the association between maternal rs1051730 genotype and offspring birth weight. This strengthens the evidence that smoking during pregnancy is causally related to lower offspring birth weight and suggests that population interventions that effectively reduce smoking in pregnant women would result in a reduced prevalence of low birth weight.

In an article that forms part of the PLoS Medicine series on Big Food, David Stuckler and colleagues report that unhealthy packaged foods are being consumed rapidly in low- and middle-income countries, consistent with rapid expansion of multinational food companies into emerging markets and fueling obesity and chronic disease epidemics.

Objectives

To evaluate effectiveness of a structured one-to-one behaviour change programme on weight loss in obese and overweight individuals.

Design

Randomised controlled trial.

Setting

23 general practices in Camden, London.

Participants

381 adults with body mass index ≥25 kg/m2 randomly assigned to intervention (n=191) or control (n=190) group.

Interventions

A structured one-to-one programme, delivered over 14 visits during 12 months by trained advisors in three primary care centres compared with usual care in general practice.

Outcome measures

Changes in weight, per cent body fat, waist circumference, blood pressure and heart rate between baseline and 12 months.

Results

217/381 (57.0%) participants were assessed at 12 months: missing values were imputed. The difference in mean weight change between the intervention and control groups was not statistically significant (0.70 kg (0.67 to 2.17, p=0.35)), although a higher proportion of the intervention group (32.7%) than the control group (20.4%) lost 5% or more of their baseline weight (OR: 1.80 (1.02 to 3.18, p=0.04)). The intervention group achieved a lower mean heart rate (mean difference 3.68 beats per minute (0.31 to 7.04, p=0.03)) than the control group. Participants in the intervention group reported higher satisfaction and more positive experiences of their care compared with the control group.

Conclusions

Although there is no significant difference in mean weight loss between the intervention and control groups, trained non-specialist advisors can deliver a structured programme and achieve clinically beneficial weight loss in some patients in primary care. The intervention group also reported a higher level of satisfaction with the support received. Primary care interventions are unlikely to be sufficient to tackle the obesity epidemic and effective population-wide measures are also necessary.

Clinical trial registration number

Trial registrationClincaltrials.gov NCT00891943.

Article summary

Article focus

Evaluated structured one-to-one weight management programme.

Delivery by trained non-specialists.

Primary care setting.

Key messages

Clinically important level of weight loss achieved by higher proportion of participants in the intervention (33%) compared with the control group (20%).

Intervention group reported higher level of satisfaction with support received.

Primary care interventions are unlikely to be sufficient to tackle the obesity epidemic.

Strengths and limitations of this study

Relatively low threshold of body mass index ≥25 for inclusion, with few exclusions, so wide applicability of findings.

High loss to follow-up (43%), although similar to other studies in the area; used multiple imputation to counter any biases.

Background

Two single-nucleotide polymorphisms, rs1051730 and rs16969968, located within the nicotinic acetylcholine receptor gene cluster on chromosome 15q25 locus, are associated with heaviness of smoking, risk for lung cancer, and other smoking-related health outcomes. Previous studies have typically relied on self-reported smoking behavior, which may not fully capture interindividual variation in tobacco exposure.

Methods

We investigated the association of rs1051730 and rs16969968 genotype (referred to as rs1051730–rs16969968, because these are in perfect linkage disequilibrium and interchangeable) with both self-reported daily cigarette consumption and biochemically measured plasma or serum cotinine levels among cigarette smokers. Summary estimates and descriptive statistical data for 12 364 subjects were obtained from six independent studies, and 2932 smokers were included in the analyses. Linear regression was used to calculate the per-allele association of rs1051730–rs16969968 genotype with cigarette consumption and cotinine levels in current smokers for each study. Meta-analysis of per-allele associations was conducted using a random effects method. The likely resulting association between genotype and lung cancer risk was assessed using published data on the association between cotinine levels and lung cancer risk. All statistical tests were two-sided.

Results

Pooled per-allele associations showed that current smokers with one or two copies of the rs1051730–rs16969968 risk allele had increased self-reported cigarette consumption (mean increase in unadjusted number of cigarettes per day per allele = 1.0 cigarette, 95% confidence interval [CI] = 0.57 to 1.43 cigarettes, P = 5.22 × 10−6) and cotinine levels (mean increase in unadjusted cotinine levels per allele = 138.72 nmol/L, 95% CI = 97.91 to 179.53 nmol/L, P = 2.71 × 10−11). The increase in cotinine levels indicated an increased risk of lung cancer with each additional copy of the rs1051730–rs16969968 risk allele (per-allele odds ratio = 1.31, 95% CI = 1.21 to 1.42).

Conclusions

Our data show a stronger association of rs1051730–rs16969968 genotype with objective measures of tobacco exposure compared with self-reported cigarette consumption. The association of these variants with lung cancer risk is likely to be mediated largely, if not wholly, via tobacco exposure.

Background

Evidence on economically efficient strategies to lower blood pressure (BP) from low- and middle-income countries remains scarce. The Control of Blood Pressure and Risk Attenuation (COBRA) trial randomized 1341 hypertensive subjects in 12 randomly selected communities in Karachi, Pakistan, to three intervention programs: combined home health education (HHE) plus trained general practitioner (GP); 2) HHE only; 3) trained GP only. The comparator was no intervention (or usual care). The reduction in BP was most pronounced in the combined group. The present study examined the cost-effectiveness of these strategies.

Methods and Results

Total costs were assessed at baseline and 2 years to estimate incremental cost effectiveness ratios (ICER) based on (a) intervention cost; b) cost of physician consultation, medications and diagnostics, changes in lifestyle, and productivity loss and (c) change in systolic BP. Precision of the ICER estimates was assessed by 1000 bootstrapping replications. Bayesian probabilistic sensitivity analysis was also performed.

The annual per participant cost associated with the combined HHE plus trained GP, HHE alone, and trained GP alone were $3.99, $3.34, and $0.65, respectively.

HHE plus trained GP was the most cost effective intervention with an ICER of $ 23 (6 to 99) per mm Hg reduction in systolic BP compared to usual care and remained so in 97.7% of 1000 bootstrapped replications.

Conclusions

The combined intervention of HHE plus trained GP is potentially affordable and more cost effective for BP control than usual care or either strategy alone in some communities in Pakistan, and possibly other countries in Indo-China with similar healthcare infrastructure.

Rationale: Genomic loci are associated with FEV1 or the ratio of FEV1 to FVC in population samples, but their association with chronic obstructive pulmonary disease (COPD) has not yet been proven, nor have their combined effects on lung function and COPD been studied.

Objectives: To test association with COPD of variants at five loci (TNS1, GSTCD, HTR4, AGER, and THSD4) and to evaluate joint effects on lung function and COPD of these single-nucleotide polymorphisms (SNPs), and variants at the previously reported locus near HHIP.

Methods: By sampling from 12 population-based studies (n = 31,422), we obtained genotype data on 3,284 COPD case subjects and 17,538 control subjects for sentinel SNPs in TNS1, GSTCD, HTR4, AGER, and THSD4. In 24,648 individuals (including 2,890 COPD case subjects and 13,862 control subjects), we additionally obtained genotypes for rs12504628 near HHIP. Each allele associated with lung function decline at these six SNPs contributed to a risk score. We studied the association of the risk score to lung function and COPD.

Measurements and Main Results: Association with COPD was significant for three loci (TNS1, GSTCD, and HTR4) and the previously reported HHIP locus, and suggestive and directionally consistent for AGER and TSHD4. Compared with the baseline group (7 risk alleles), carrying 10–12 risk alleles was associated with a reduction in FEV1 (β = –72.21 ml, P = 3.90 × 10−4) and FEV1/FVC (β = –1.53%, P = 6.35 × 10−6), and with COPD (odds ratio = 1.63, P = 1.46 × 10−5).

Conclusions: Variants in TNS1, GSTCD, and HTR4 are associated with COPD. Our highest risk score category was associated with a 1.6-fold higher COPD risk than the population average score.

OBJECTIVE

The causal nature of associations between circulating triglycerides, insulin resistance, and type 2 diabetes is unclear. We aimed to use Mendelian randomization to test the hypothesis that raised circulating triglyceride levels causally influence the risk of type 2 diabetes and raise normal fasting glucose levels and hepatic insulin resistance.

RESEARCH DESIGN AND METHODS

We tested 10 common genetic variants robustly associated with circulating triglyceride levels against the type 2 diabetes status in 5,637 case and 6,860 control subjects and four continuous outcomes (reflecting glycemia and hepatic insulin resistance) in 8,271 nondiabetic individuals from four studies.

RESULTS

Individuals carrying greater numbers of triglyceride-raising alleles had increased circulating triglyceride levels (SD 0.59 [95% CI 0.52–0.65] difference between the 20% of individuals with the most alleles and the 20% with the fewest alleles). There was no evidence that the carriers of greater numbers of triglyceride-raising alleles were at increased risk of type 2 diabetes (per weighted allele odds ratio [OR] 0.99 [95% CI 0.97–1.01]; P = 0.26). In nondiabetic individuals, there was no evidence that carriers of greater numbers of triglyceride-raising alleles had increased fasting insulin levels (SD 0.00 per weighted allele [95% CI −0.01 to 0.02]; P = 0.72) or increased fasting glucose levels (0.00 [−0.01 to 0.01]; P = 0.88). Instrumental variable analyses confirmed that genetically raised circulating triglyceride levels were not associated with increased diabetes risk, fasting glucose, or fasting insulin and, for diabetes, showed a trend toward a protective association (OR per 1-SD increase in log10 triglycerides: 0.61 [95% CI 0.45–0.83]; P = 0.002).

CONCLUSIONS

Genetically raised circulating triglyceride levels do not increase the risk of type 2 diabetes or raise fasting glucose or fasting insulin levels in nondiabetic individuals. One explanation for our results is that raised circulating triglycerides are predominantly secondary to the diabetes disease process rather than causal.

Background

Socio-cultural differences for country-specific activities are rarely addressed in physical activity questionnaires. We examined the reliability and validity of the Indian Migration Study Physical Activity Questionnaire (IMS-PAQ) in urban and rural groups in India.

Methods

A sub-sample of IMS participants (n = 479) was used to examine short term (≤1 month [n = 158]) and long term (> 1 month [n = 321]) IMS-PAQ reliability for levels of total, sedentary, light and moderate/vigorous activity (MVPA) intensity using intraclass correlation (ICC) and kappa coefficients (k). Criterion validity (n = 157) was examined by comparing the IMS-PAQ to a uniaxial accelerometer (ACC) worn ≥4 days, via Spearman's rank correlations (ρ) and k, using Bland-Altman plots to check for systematic bias. Construct validity (n = 7,000) was established using linear regression, comparing IMS-PAQ against theoretical constructs associated with physical activity (PA): BMI [kg/m2], percent body fat and pulse rate.

Results

IMS-PAQ reliability ranged from ICC 0.42-0.88 and k = 0.37-0.61 (≤1 month) and ICC 0.26 to 0.62; kappa 0.17 to 0.45 (> 1 month). Criterion validity was ρ = 0.18-0.48; k = 0.08-0.34. Light activity was underestimated and MVPA consistently and substantially overestimated for the IMS-PAQ vs. the accelerometer. Criterion validity was moderate for total activity and MVPA. Reliability and validity were comparable for urban and rural participants but lower in women than men. Increasing time spent in total activity or MVPA, and decreasing time in sedentary activity were associated with decreasing BMI, percent body fat and pulse rate, thereby demonstrating construct validity.

Conclusion

IMS-PAQ reliability and validity is similar to comparable self-reported instruments. It is an appropriate tool for ranking PA of individuals in India. Some refinements may be required for sedentary populations and women in India.

Objective

Insulin and the insulin-like growth factor (IGF) system regulate growth and are involved in determining muscle mass, strength and body composition. We hypothesised that IGF-I and IGF-II are associated with improved, and insulin with worse, physical performance in old age.

Methods

Physical performance was measured using the get-up and go timed walk and flamingo balance test at 63–86 years. We examined prospective associations of insulin, IGF-I, IGF-II and IGFBP-3 with physical performance in the UK-based Caerphilly Prospective Study (CaPS; n = 739 men); and cross-sectional insulin, IGF-I, IGF-II, IGFBP-2 and IGFBP-3 in the Boyd Orr cohort (n = 182 men, 223 women).

Results

In confounder-adjusted models, there was some evidence in CaPS that a standard deviation (SD) increase in IGF-I was associated with 1.5% faster get-up and go test times (95% CI: −0.2%, 3.2%; p = 0.08), but little association with poor balance, 19 years later. Coefficients in Boyd Orr were in the same direction as CaPS, but consistent with chance. Higher levels of insulin were weakly associated with worse physical performance (CaPS and Boyd Orr combined: get-up and go time = 1.3% slower per SD log-transformed insulin; 95% CI: 0.0%, 2.7%; p = 0.07; OR poor balance 1.13; 95% CI; 0.98, 1.29; p = 0.08), although associations were attenuated after controlling for body mass index (BMI) and co-morbidities. In Boyd Orr, a one SD increase in IGFBP-2 was associated with 2.6% slower get-up and go times (95% CI: 0.4%, 4.8% slower; p = 0.02), but this was only seen when controlling for BMI and co-morbidities. There was no consistent evidence of associations of IGF-II, or IGFBP-3 with physical performance.

Conclusions

There was some evidence that high IGF-I and low insulin levels in middle-age were associated with improved physical performance in old age, but estimates were imprecise. Larger cohorts are required to confirm or refute the findings.

Objective

To investigate the relationship between rural to urban migration and physical activity (PA) in India.

Methods

6,447 (42% women) participants comprising 2077 rural, 2,094 migrants and 2,276 urban were recruited. Total activity (MET hr/day), activity intensity (min/day), PA Level (PAL) television viewing and sleeping (min/day) were estimated and associations with migrant status examined, adjusting for the sib-pair design, age, site, occupation, education, and socio-economic position (SEP).

Results

Total activity was highest in rural men whereas migrant and urban men had broadly similar activity levels (p<0.001). Women showed similar patterns, but slightly lower levels of total activity. Sedentary behaviour and television viewing were lower in rural residents and similar in migrant and urban groups. Sleep duration was highest in the rural group and lowest in urban non-migrants. Migrant men had considerably lower odds of being in the highest quartile of total activity than rural men, a finding that persisted after adjustment for age, SEP and education (OR 0.53, 95% CI 0.37, 0.74). For women, odds ratios attenuated and associations were removed after adjusting for age, SEP and education.

Conclusion

Our findings suggest that migrants have already acquired PA levels that closely resemble long-term urban residents. Effective public health interventions to increase PA are needed.

Objective

The causal nature of associations between circulating triglycerides, insulin resistance and type 2 diabetes is unclear. We aimed to use Mendelian randomization to test the hypothesis that raised circulating triglyceride levels causally influence the risk of type 2 diabetes, raised normal fasting glucose levels, and hepatic insulin resistance.

Research design and methods

We tested 10 common genetic variants robustly associated with circulating triglyceride levels against type 2 diabetes status in 5637 cases, 6860 controls, and four continuous outcomes (reflecting glycemia and hepatic insulin resistance) in 8271 non-diabetic individuals from four studies.

Results

Individuals carrying greater numbers of triglyceride-raising alleles had increased circulating triglyceride levels (0.59 SD [95% CI: 0.52, 0.65] difference between the 20% of individuals with the most alleles and the 20% with the fewest alleles). There was no evidence that carriers of greater numbers of triglyceride-raising alleles were at increased risk of type 2 diabetes (per weighted allele odds ratio (OR) 0.99 [95% CI: 0.97, 1.01]; P = 0.26). In non-diabetic individuals, there was no evidence that carriers of greater numbers of triglyceride-raising alleles had increased fasting insulin levels (0.00 SD per weighted allele [95% CI: −0.01, 0.02]; P = 0.72) or increased fasting glucose levels (0.00 SD per weighted allele [95% CI: −0.01, 0.01]; P = 0.88). Instrumental variable analyses confirmed that genetically raised circulating triglyceride levels were not associated with increased diabetes risk, fasting glucose or fasting insulin, and, for diabetes, showed a trend towards a protective association (OR per 1 SD increase in log10-triglycerides: 0.61 [95% CI: 0.45, 0.83]; P = 0.002).

Conclusion

Genetically raised circulating triglyceride levels do not increase the risk of type 2 diabetes, or raise fasting glucose or fasting insulin levels in non-diabetic individuals. One explanation for our results is that raised circulating triglycerides are predominantly secondary to the diabetes disease process rather than causal.

Background Cross-sectional studies have suggested that elevated cortisol is associated with worse physical performance, a surrogate of ageing. We examined the relationship between repeat cortisol measures over 20 years and physical performance in later life.

Methods Middle-aged men (45–59 years) were recruited between 1979 and 1983 (Phase 1) from the Caerphilly Prospective Study (CaPS) and re-examined 20 years later at 65–83 years of age (Phase 5). Participants included 750 and 898 subjects with either Phase 1 and/or Phase 5 data on exposure and outcomes. Outcome measures were walking speed and balance time and exposures included morning fasting serum cortisol (Phase 1) and four salivary samples on 2 consecutive days (Phase 5).

Results Faster walking speed was associated with higher morning cortisol at Phase 1 [coefficient per standard deviation (SD) increase 0.68, 95% confidence interval (95% CI) 0.09–1.27; P = 0.02] though this was attenuated after adjustment for covariates (coefficient per SD increase 0.45; 95% CI –0.16 to 1.07; P = 0.15). Higher night-time cortisol at Phase 5 was associated with slower speed (coefficient per SD increase –1.06; 95% CI –1.60 to –0.52; P < 0.001) and poorer balance (odds ratio of top tertile vs bottom 2.49; 95% CI 1.63–3.81; P < 0.001). Worst performance was seen for men with a poor morning response (Phase 1) and less nocturnal decline (Phase 5).

Conclusions Dysregulation of the hypothalamic pituitary adrenal (HPA) axis is associated with worse physical performance in later life. This may reflect a causal effect of the HPA axis on ageing or that ageing itself is associated with reduced HPA reactivity.

Aims

To determine the effect of exercise training on clinical events and health-related quality of life (HRQoL) of patients with systolic heart failure.

Methods and results

We searched electronic databases including Medline, EMBASE, and Cochrane Library up to January 2008 to identify randomized controlled trials (RCTs) comparing exercise training and usual care with a minimum follow-up of 6 months. Nineteen RCTs were included with a total of 3647 patients, the majority of whom were male, low-to-medium risk, and New York Heart Association class II–III with a left ventricular ejection fraction of <40%. There was no significant difference between exercise and control in short-term (≤12 months) or longer-term all-cause mortality or overall hospital admissions. Heart failure-related hospitalizations were lower [relative risk: 0.72, 95% confidence interval (CI): 0.52–0.99] and HRQoL improved (standardized mean difference: −0.63, 95% CI: −0.80 to −0.37) with exercise therapy. Any effect of cardiac exercise training on total mortality and HRQoL was independent of degree of left ventricular dysfunction, type of cardiac rehabilitation, dose of exercise intervention, length of follow-up, trial quality, and trial publication date.

Conclusion

Compared with usual care, in selected heart failure patients, exercise training reduces heart failure-related hospitalizations and results in clinically important improvements in HRQoL. High-quality RCT and cost-effectiveness evidence is needed for the effect of exercise training in community-based settings and in more severe heart failure patients, elderly people, and women.

Background

Migration from rural areas of India contributes to urbanisation and lifestyle change, and dietary changes may increase the risk of obesity and chronic diseases. We tested the hypothesis that rural-to-urban migrants have different macronutrient and food group intake to rural non-migrants, and that migrants have a diet more similar to urban non-migrants.

Methods and findings

The diets of migrants of rural origin, their rural dwelling sibs, and those of urban origin together with their urban dwelling sibs were assessed by an interviewer-administered semi-quantitative food frequency questionnaire. A total of 6,509 participants were included. Median energy intake in the rural, migrant and urban groups was 2731, 3078, and 3224 kcal respectively for men, and 2153, 2504, and 2644 kcal for women (p<0.001). A similar trend was seen for overall intake of fat, protein and carbohydrates (p<0.001), though differences in the proportion of energy from these nutrients were <2%. Migrant and urban participants reported up to 80% higher fruit and vegetable intake than rural participants (p<0.001), and up to 35% higher sugar intake (p<0.001). Meat and dairy intake were higher in migrant and urban participants than rural participants (p<0.001), but varied by region. Sibling-pair analyses confirmed these results. There was no evidence of associations with time in urban area.

Conclusions

Rural to urban migration appears to be associated with both positive (higher fruit and vegetables intake) and negative (higher energy and fat intake) dietary changes. These changes may be of relevance to cardiovascular health and warrant public health interventions.

Urban living is associated with an increase in cardiometabolic risks, but the speed at which these risks are accrued over time is unknown. Using a cross-sectional sibling-pair design, the authors surveyed migrant factory workers and their spouses from 4 cities in India together with their rural-dwelling siblings and examined the associations between urban life-years and cardiometabolic risk factors. Data on 4,221 participants (39% women; mean age = 41 years) were available (2005–2007). In regression models, a 2-slope pattern for body fat (with a marked shift at 10 years) was found, whereas a common slope could be accepted for other risk factors. In men, the regression coefficients (per decade of urban life) were 2.5% in the first decade and 0.1% thereafter for body fat; 1.4 mm Hg for systolic blood pressure; and 7% for fasting insulin. Age, gender, marital status, household structure, and occupation did not influence the patterns appreciably; however, stronger gradients for adiposity were noted in migrants from lower socioeconomic positions. The findings suggest that body fat increases rapidly when one first moves to an urban environment, whereas other cardiometabolic risk factors evolve gradually. Public health interventions focused on the control of obesity in newer migrants to urban areas, particularly those from lower socioeconomic positions, may be beneficial.