Obesity and overweight in relation to disease-specific mortality in men with and without existing coronary heart disease in London: the original Whitehall study

Impact of body mass index in patients with tricuspid regurgitation after transcatheter edge-to-edge repair

BACKGROUND

Obesity and underweight represent classical risk factors for outcome in patients treated for cardiovascular disease. This study describes the impact of different body mass index (BMI) categories on 1-year clinical outcome in patients with tricuspid regurgitation (TR) undergoing transcatheter-edge-to-edge repair (TEER).

METHODS

We analyzed 211 consecutive patients (age 78.3 ± 7.2 years, 55.5% female, median EuroSCORE II 9.6 ± 6.7) with tricuspid regurgitation undergoing TEER from June 2015 until May 2021. Patients were prospectively enrolled in our single center registry and were retrospectively analyzed. Patients were stratified according to body mass index (BMI) into 4 groups: BMI < 20 kg/m2 (underweight), BMI 20.0 to < 25.0 kg/m2 (normal weight), BMI 25.0 to > 30.0 kg/m2 (overweight) and BMI ≥ 30 kg/m2 (obese).

RESULTS

Kaplan-Meier survival curves demonstrated inferior survival for underweight and obese patients, but comparable outcomes for normal and overweight patients (global log rank test, p < 0.01). Cardiovascular death was significantly higher in underweight patients compared to the other groups (24.1% vs. 7.0% vs. 6.3% vs. 6.4%; p < 0.01). Over all, there were comparable rates of bleeding, stroke and myocardial infarction. Multivariable Cox regression analysis (adjusted for age, gender, coronary artery disease, chronic obstructive pulmonary disease, tricuspid annular plane systolic excursion, left-ventricular ejection fraction) confirmed underweight (HR 3.88; 95% CI 1.64-7.66; p < 0.01) and obesity (HR 3.24; 95% CI 1.37-9.16; p < 0.01) as independent risk factors for 1-year all-cause mortality.

CONCLUSIONS

Compared to normal weight and overweight patients, obesity and underweight patients undergoing TEER display significant higher 1-year all-cause mortality.

Contribution of obesity and cardiometabolic risk factors in developing cardiovascular disease: a population-based cohort study

This study aims to assess the effects of central and general adiposity on development of cardiovascular diseases (CVDs) mediated by cardiometabolic risk factors and to analyze their degree of dependency for mediating their effects. To this end, data from the the Tehran Lipid and Glucose Study cohort with 6280 participants were included in this study. The hazard ratios were calculated using a 2-stage regression model in the context of a survival model. Systolic blood pressure (BP), total serum cholesterol, and fasting plasma glucose were designated as mediators. Assessing the interactions revealed that BP was the most important mediator for general ( (HR_NIE: 1.11, 95% CI 1.17–1.24) and central obesity (CO) (HR_NIE: 1.11, 95% CI 1.07–1.15) with 60% and 36% proportion of the effects mediated in the total population, respectively. The proportion of mediated risk for all three metabolic risk factors was 46% (95% CI 31–75%) for overweight, 66% (45–100%) for general obesity and 52% (39–87%) for central obesity. BP was the most important mediator for overweight and central obesity in men, comprising 29% and 36% of the risk, respectively. The proportion of the risk mediated through all three metabolic risk factors in women was 23% (95% CI 13–50%) for overweight, 36% (21–64%) for general obesity and 52% (39–87%) for central obesity. Based on the results of this study, cardiometabolic mediators have conciliated more than 60% of the adverse effects of high BMI on CVDs in men. Controlling the metabolic risk factors in women does not efficiently contribute to decreasing CVDs as effectively.

Stroke and death-findings from a 25-year follow-up of a cohort of employed Swedish middle-aged men of the Coeur study

Aim

In 1993, a study of 1000 automotive workers in Sweden and France looked into national differences of cardiovascular disease. Here, we evaluate the proportion of the Swedish cohort that suffered a stroke or died over a 25-year period and associated risk factors.

Subject and methods

Data from 1993 included a life-style questionnaire, a health examination and laboratory data. Figures on stroke and survival status up until the end of 2018 were collected from national registers. Survival analysis was used for both univariable and multivariable analyses to study associations between potential risk factors and stroke and death, respectively.

Results

By the end of 2018, 65 individuals had suffered a stroke and 160 had died. In the univariable analysis, we found age, systolic blood pressure, Framingham risk index and diabetes at baseline to be significantly associated with stroke during follow-up.

For death, most of the traditional risk factors were significantly associated with the outcome, as was blue-collar work and living alone. In the multivariable analysis, age and diabetes at baseline remained significantly associated with stroke, whereas eight factors (age, blue-collar work, living alone, systolic blood pressure, waist–hip ratio, smoking habits, diabetes and hypertension at baseline) were significantly associated with death during follow-up.

Conclusion

Few of the traditional risk factors were significantly associated with stroke possibly explained by low power and/or different pathogenetic mechanism than for myocardial infarction.

Partly because death occurred more often, we did find a number of potential risk factors to be significantly associated with this outcome.

Contemporary Results of Transcatheter Aortic Valve Replacement in Obese Patients

Background. Little research has been conducted to explore the postoperative outcomes of obese patients after transfemoral transcatheter aortic valve replacement (TF-TAVR). Objective. We investigated the influence of body mass index (BMI) on 1-year outcomes after TF-TAVR. Methods. We included retrospectively 1609 high- and intermediate-risk TAVR patients (mean EuroSCORE II 21 ± 11) operated under general anesthesia between March 2014 and March 2018 in central hospital, Bad Berka, Germany. We stratified the patients according to BMI. Results. Our demographic data analysis showed 41% of patients were male and the mean age was 78 (range, 61–92 years). According to the WHO classification, 33% patients had normal weight, 42% were defined as overweight, and 22% were obese. Obese patients showed statistically significant difference in their clinical parameters as having higher incidence of hypertension, diabetes mellitus, pulmonary hypertension, and chronic obstructive pulmonary disease; on the contrary, obese patients were found to be younger than others. We found no differences in valve types and sizes among the different BMI categories. Our mortality rate during the 1-year follow-up period was 17.8% (287 patients). Mortality was significantly higher in patients with BMI < 25 kg/m2 (1 year mortality 149 patients 28.2% in patients with BMI < 25 kg/m2 vs. 138 patients 12.6% in patients with BMI ≥ 25 kg/m2; P=0.0001). Even after considering the confounding risk factors, BMI ≥ 25 kg/m2 was independently associated with reduced 1 year mortality (odds ratio (OR): 0.36, 95% confidence interval (CI): 0.21–0.6; P=0.01) in multivariate logistic regression analysis. The rate of vascular complication was higher in patients with BMI ≥ 25 kg/m2. However, the rate of blood transfusion was higher in patients with BMI < 25 kg/m2. All other serious complications occurred with equal distribution in both groups. Conclusion. In our single-center study, BMI ≥ 25 kg/m2 was independently associated with lower 1 year mortality after TF-TAVR.

Gender-modulated risk of coronary heart disease, diabetes and coronary mortality among Turks for three major risk factors, and residual adiposity risk

BACKGROUND

We determined the proportion of the effects of body mass index (BMI) or its categories on cardiometabolic outcomes mediated through systolic blood pressure (SBP), total cholesterol and fasting glucose.

METHODS

Cox regression analyses were performed for incident outcomes among Turkish Adult Risk Factor study participants in whom the three mediators had been determined (n = 2158, age 48.5 ± 11 years). Over a mean 10.2-years' follow-up, new coronary heart disease (CHD) developed in 406, diabetes in 284 individuals, and 149 CHD deaths occurred.

RESULTS

Hazard ratios (HR) of BMI for incident diabetes were no more than marginally attenuated by the 3 mediators including glucose, irrespective of gender. Compared to "normal-weight", sex- and age-adjusted RRs for incident CHD of overweight and obesity were 1.40 and 2.24 (95 % CI 1.68; 2.99), respectively, in gender combined. Only three-tenths of the excess risk was retained by BMI in men, six-tenths in women. No mediation of glycemia was discerned in males, in contrast to greatest mediation in females. HR of age-adjusted continuous BMI was a significant but modest contributor to CHD mortality in each gender. While the BMI risk of CHD death was abolished by mediation of SBP in men, HR strengthened to over two-fold in women through mediation of fasting glucose.

CONCLUSIONS

Mediation of adiposity by 3 traditional factors exhibited among Turkish adults strong gender dependence regarding its magnitude for CHD risk and the mediation by individual risk factors. Retention of the large part of risk for diabetes in each sex and for CHD in women likely reflects underlying autoimmune activation.

The obesity paradox in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Obesity is a major risk factor for cardiovascular morbidity and mortality. A considerable number of studies, however, showed better outcomes for overweight patients undergoing cardiovascular interventions-the so called obesity paradox.

HYPOTHESIS

Increased body mass index (BMI) is independently associated with improved survival following transcatheter aortic valve implantation (TAVI).

METHODS

We analyzed the data of 409 consecutive patients undergoing TAVI in our medical center. Patients were categorized into 4 groups according to BMI: underweight (≤18.4 kg/m(2) ), normal weight (18.5-24.9 kg/m(2) ), overweight (25-29.9 kg/m(2) ), and obese (≥30 kg/m(2) ). Procedure-related complications were recorded, as well as 30-day and 1-year all-cause mortality rates.

RESULTS

Obese patients had a higher prevalence of comorbidities and higher incidence of vascular complications compared with the normal-weight patients (16% vs 7%, P = 0.013). Nevertheless, 30-day mortality was similar among the groups, whereas 1-year mortality was lower among the overweight and obese patients (BMI >25) (P = 0.038). After adjusting for differences in baseline characteristics, increase in BMI was found to be independently associated with improved survival following TAVI (hazard ratio: 0.94, confidence interval: 0.89-0.99, P = 0.043).

CONCLUSIONS

In our single-center study, obesity and overweight were independently associated with better outcome, supporting the obesity paradox in the TAVI population.

Long term risk factors for coronary heart disease and stroke: influence of duration of follow-up over four decades of mortality surveillance

AIM

While cohort studies have revealed a range of risk factors for coronary heart disease and stroke, the extent to which the strength of these associations varies according to duration of follow-up in studies with extended disease surveillance is unclear. This was the aim of the present study.

METHODS AND RESULTS

Initiated in 1967/70, the original Whitehall study is an on-going cohort study of 15,402 male UK government workers free of coronary heart disease when they took part in a baseline medical examination during which a range of standard risk factors was measured. In analyses in which we stratified by duration of follow-up, there was evidence of time-dependency for most risk factor-disease relationships. Thus, the associations of systolic and diastolic blood pressure, total cholesterol and cigarette smoking with coronary heart disease and stroke diminished in strength with increasing duration of follow-up, whereas the magnitude of the body mass index-coronary heart disease relation was unchanged. For example, the age-adjusted hazard ratios (95% confidence interval) for cigarette smoking (versus never smoked) in relation to coronary heart disease were: 2.49 (1.80, 3.44), 1.65 (1.34, 2.03), 1.36 (1.15, 1.61) and 1.32 (1.10, 1.58) for follow-up periods 0-10, 10-20, 20-30 and 30+ years, respectively.

CONCLUSION

Despite a general diminution in the strength of effect over time, even in the fourth decade of follow-up, classic risk factors retained some predictive capacity for coronary heart disease and, to a lesser degree, stroke.

Metabolic mediators of the effects of body-mass index, overweight, and obesity on coronary heart disease and stroke: a pooled analysis of 97 prospective cohorts with 1·8 million participants

BACKGROUND

Body-mass index (BMI) and diabetes have increased worldwide, whereas global average blood pressure and cholesterol have decreased or remained unchanged in the past three decades. We quantified how much of the effects of BMI on coronary heart disease and stroke are mediated through blood pressure, cholesterol, and glucose, and how much is independent of these factors.

METHODS

We pooled data from 97 prospective cohort studies that collectively enrolled 1·8 million participants between 1948 and 2005, and that included 57,161 coronary heart disease and 31,093 stroke events. For each cohort we excluded participants who were younger than 18 years, had a BMI of lower than 20 kg/m(2), or who had a history of coronary heart disease or stroke. We estimated the hazard ratio (HR) of BMI on coronary heart disease and stroke with and without adjustment for all possible combinations of blood pressure, cholesterol, and glucose. We pooled HRs with a random-effects model and calculated the attenuation of excess risk after adjustment for mediators.

FINDINGS

The HR for each 5 kg/m(2) higher BMI was 1·27 (95% CI 1·23-1·31) for coronary heart disease and 1·18 (1·14-1·22) for stroke after adjustment for confounders. Additional adjustment for the three metabolic risk factors reduced the HRs to 1·15 (1·12-1·18) for coronary heart disease and 1·04 (1·01-1·08) for stroke, suggesting that 46% (95% CI 42-50) of the excess risk of BMI for coronary heart disease and 76% (65-91) for stroke is mediated by these factors. Blood pressure was the most important mediator, accounting for 31% (28-35) of the excess risk for coronary heart disease and 65% (56-75) for stroke. The percentage excess risks mediated by these three mediators did not differ significantly between Asian and western cohorts (North America, western Europe, Australia, and New Zealand). Both overweight (BMI ≥25 to <30 kg/m(2)) and obesity (BMI ≥30 kg/m(2)) were associated with a significantly increased risk of coronary heart disease and stroke, compared with normal weight (BMI ≥20 to <25 kg/m(2)), with 50% (44-58) of the excess risk of overweight and 44% (41-48) of the excess risk of obesity for coronary heart disease mediated by the selected three mediators. The percentages for stroke were 98% (69-155) for overweight and 69% (64-77) for obesity.

INTERPRETATION

Interventions that reduce high blood pressure, cholesterol, and glucose might address about half of excess risk of coronary heart disease and three-quarters of excess risk of stroke associated with high BMI. Maintenance of optimum bodyweight is needed for the full benefits.

FUNDING

US National Institute of Health, UK Medical Research Council, National Institute for Health Research Comprehensive Biomedical Research Centre at Imperial College Healthcare NHS Trust, Lown Scholars in Residence Program on cardiovascular disease prevention, and Harvard Global Health Institute Doctoral Research Grant.

Variation in the relationship between BMI and survival by socioeconomic status in Great Britain

We investigate the relationship between obesity and survival, and the extent to which this relationship varies by socioeconomic status (SES). The underlying model is based on the "Pathways to health" framework in which SES affects health by modifying the relationship between lifestyles and health. We use data from the British Health and Lifestyle Survey (1984-1985) and the longitudinal follow-up in June 2009, and run parametric Gompertz survival models to investigate the association between obesity and survival, also accounting for interactions between obesity and both age and SES. Generally we find that obesity is negatively associated with survival, and that SES is positively associated with survival, in both men and women. The interactions between obesity and SES predict survival among women but not among men. Obesity compared with normal weight is associated with a reduction in survival of 3.3, 3.2 and 2.8 years in men aged 40, 50 and 60 years, respectively. Corresponding numbers among women in the lowest SES group are 13.1, 9.7 and 6.1 years, respectively; in the highest SES group they are 6.2, 3.1 and 0.1 years, respectively, a difference of approximately 6 years between the highest and lowest SES groups.

Factors influencing the decline in stroke mortality: a statement from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

Stroke mortality has been declining since the early 20th century. The reasons for this are not completely understood, although the decline is welcome. As a result of recent striking and more accelerated decreases in stroke mortality, stroke has fallen from the third to the fourth leading cause of death in the United States. This has prompted a detailed assessment of the factors associated with the change in stroke risk and mortality. This statement considers the evidence for factors that have contributed to the decline and how they can be used in the design of future interventions for this major public health burden.

METHODS

Writing group members were nominated by the committee chair and co-chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council's Scientific Statements Oversight Committee and the American Heart Association Manuscript Oversight Committee. The writers used systematic literature reviews, references to published clinical and epidemiological studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize evidence and to indicate gaps in current knowledge. All members of the writing group had the opportunity to comment on this document and approved the final version. The document underwent extensive American Heart Association internal peer review, Stroke Council leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee.

RESULTS

The decline in stroke mortality over the past decades represents a major improvement in population health and is observed for both sexes and for all racial/ethnic and age groups. In addition to the overall impact on fewer lives lost to stroke, the major decline in stroke mortality seen among people <65 years of age represents a reduction in years of potential life lost. The decline in mortality results from reduced incidence of stroke and lower case-fatality rates. These significant improvements in stroke outcomes are concurrent with cardiovascular risk factor control interventions. Although it is difficult to calculate specific attributable risk estimates, efforts in hypertension control initiated in the 1970s appear to have had the most substantial influence on the accelerated decline in stroke mortality. Although implemented later, diabetes mellitus and dyslipidemia control and smoking cessation programs, particularly in combination with treatment of hypertension, also appear to have contributed to the decline in stroke mortality. The potential effects of telemedicine and stroke systems of care appear to be strong but have not been in place long enough to indicate their influence on the decline. Other factors had probable effects, but additional studies are needed to determine their contributions.

CONCLUSIONS

The decline in stroke mortality is real and represents a major public health and clinical medicine success story. The repositioning of stroke from third to fourth leading cause of death is the result of true mortality decline and not an increase in mortality from chronic lung disease, which is now the third leading cause of death in the United States. There is strong evidence that the decline can be attributed to a combination of interventions and programs based on scientific findings and implemented with the purpose of reducing stroke risks, the most likely being improved control of hypertension. Thus, research studies and the application of their findings in developing intervention programs have improved the health of the population. The continued application of aggressive evidence-based public health programs and clinical interventions is expected to result in further declines in stroke mortality.

New insights into the true nature of the obesity paradox and the lower cardiovascular risk

Obesity is considered a major risk factor for cardiovascular disease, hypertension, and diabetes by National and International Committees. For this reason, they advocate weight loss and prevention of obesity. However, several studies in patients with established coronary artery disease (CAD), congestive heart failure, and hypertension have shown an inverse relationship between obesity and mortality, the so called "obesity paradox," whereas other studies have not shown such a relationship. In studies showing the obesity paradox (OP), body mass index (BMI) was used, almost exclusively as an index of obesity, although is a poor discriminator of total body fatness. Recent studies using better indices of obesity such as waist circumference (WC) and waist to hip ratio (WHR) have shown that high WC and WHR were directly and positively associated with higher event rate and total mortality in these patients. Because the OP could convey the wrong message in obese patients, the validity and true nature of the OP will be examined in this concise review. A Medline search of the English literature was performed between 2000 and September 2012, and 46 pertinent articles were selected for this review. The majority of these studies do not support an OP and those that do have used almost exclusively BMI as an index of obesity. Therefore, based on recent studies using other indices of body fat distribution, such as WC and WHR, besides BMI, the true existence of OP has been questioned and needs to be confirmed by future studies.

Are current UK National Institute for Health and Clinical Excellence (NICE) obesity risk guidelines useful? Cross-sectional associations with cardiovascular disease risk factors in a large, representative English population

The National Institute for Health and Clinical Excellence (NICE) has recently released obesity guidelines for health risk. For the first time in the UK, we estimate the utility of these guidelines by relating them to the established cardiovascular disease (CVD) risk factors. Health Survey for England (HSE) 2006, a population-based cross-sectional study in England was used with a sample size of 7225 men and women aged ≥35 years (age range: 35–97 years). The following CVD risk factor outcomes were used: hypertension, diabetes, total and high density lipoprotein cholesterol, glycated haemoglobin, fibrinogen, C-reactive protein and Framingham risk score. Four NICE categories of obesity were created based on body mass index (BMI) and waist circumference (WC): no risk (up to normal BMI and low/high WC); increased risk (normal BMI & very high WC, or obese & low WC); high risk (overweight & very high WC, or obese & high WC); and very high risk (obese I & very high WC or obese II/III with any levels of WC. Men and women in the very high risk category had the highest odds ratios (OR) of having unfavourable CVD risk factors compared to those in the no risk category. For example, the OR of having hypertension for those in the very high risk category of the NICE obesity groupings was 2.57 (95% confidence interval 2.06 to 3.21) in men, and 2.15 (1.75 to 2.64) in women. Moreover, a dose-response association between the adiposity groups and most of the CVD risk factors was observed except total cholesterol in men and low HDL in women. Similar results were apparent when the Framingham risk score was the outcome of interest. In conclusion, the current NICE definitions of obesity show utility for a range of CVD risk factors and CVD risk in both men and women.

Association of obesity with cardiovascular disease mortality in the PLCO trial

OBJECTIVE

Obesity is a risk factor for cardiovascular disease (CVD) mortality, but the association between obesity and specific causes of CVD mortality is still under investigation.

METHOD

We prospectively examined body-mass index (BMI) in relation to CVD-specific causes of death in approximately 86,000 US men and women in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, followed for up to 13 years. BMI was calculated from self-reported weight and height at baseline. Hazard ratios (HRs) were calculated overall and stratified by sex, smoking status, and educational level.

RESULT

Overweight non-obese participants (BMI: 25.0-29.9) were not at excess risk for CVD mortality (HR and CIs are 1.02 [0.92-1.13]), compared to participants of normal BMI (18.5-24.9). Excess CVD mortality was observed for participants of BMI 30.0-34.9 (HR and CIs: 1.29 [1.13-1.48]), BMI 35.0-39.9 (HR and CIs: 1.87 [1.51-2.32]) and BMI 40.0+ (HR and CIs: 2.21 [1.57-3.21]) (p<0.001 for trend). BMI was unrelated to mortality due to stroke. The observed association of BMI with CVD was independent of gender, smoking status and educational level.

CONCLUSION

Obesity is associated with increased mortality due to CVD.

The interaction of exercise ability and body mass index upon long-term outcomes among patients undergoing stress-rest perfusion single-photon emission computed tomography imaging

BACKGROUND

The obesity paradox has been reported in several populations of patients with cardiovascular disease. Recent data have shown that physical fitness may attenuate the obesity paradox. Patients who undergo pharmacologic stress testing are known to have a higher risk of mortality than those who can exercise. The purpose of this study is to determine the interaction of obesity and exercise ability on survival among patients with a normal stress-rest single-photon emission computed tomography (SPECT).

METHODS

A total of 5,203 (60 ± 13 years, male 37%) patients without a history of heart disease and a normal stress-rest SPECT between the years 1995 and 2010 were included in this analysis. Body mass index categories were defined according to the World Health Organization classification: normal weight, 18.5 to 24.9 kg/m(2); overweight, 25 to 29.9 kg/m(2); and obese, ≥30 kg/m(2). Patients were divided into 3 groups based on their ability to exercise: those who reached ≥6 METs on exercise, those who attained a level of <6 METs, and those who required pharmacologic stress. Patients in each of these fitness groups were further divided into 3 subgroups based on their body mass index.

RESULTS

There were 939 (18%) deaths during a mean follow-up of 8.1 ± 4.1 years, for an overall event rate of 2.3%/y. Both exercise to ≥6 METs and being obese were associated with lower mortality. Adjusted multivariate analysis using the obese high-fit patients as the reference showed a wide heterogeneity in annualized mortality rates according to exercise and weight status, with annualized event rates which varied from 0.6%/y in the obese subjects who were physically fit to 5.3%/y among healthy subjects who underwent pharmacologic stress testing (P < .001).

CONCLUSIONS

Stress mode and body weight impacted long-term survival in patients with a normal stress SPECT. The benefit of being physically fit was evident in all weight groups, as was the adverse effect of being unable to exercise. However, with regard to body weight, there was a paradoxical survival advantage for those patients who were overweight and obese, regardless of their exercise ability.

Influence of calendar period on the association between BMI and coronary heart disease: a meta-analysis of 31 cohorts

OBJECTIVE

The association between obesity and coronary heart disease (CHD) may have changed over time, for example due to improved pharmacological treatment of CHD risk factors. This meta-analysis of 31 prospective cohort studies explores the influence of calendar period on CHD risk associated with body mass index (BMI).

DESIGN AND METHODS

The relative risks (RRs) of CHD for a five-BMI-unit increment and BMI categories were pooled by means of random effects models. Meta-regression analysis was used to examine the influence of calendar period (>1985 v ≤1985) in univariate and multivariate analyses (including mean population age as a covariate).

RESULTS

The age, sex, and smoking adjusted RR (95% confidence intervals) of CHD for a five-BMI-unit increment was 1.28(1.22:1.34). For underweight, overweight and obesity, the RRs (compared to normal weight) were 1.11(0.91:1.36), 1.31(1.22:1.41), and 1.78(1.55:2.04), respectively. The univariate analysis indicated 31% (95%CI: -56:0) lower RR of CHD associated with a five-BMI-unit increment and a 51% (95%CI: -78: -14)) lower RR associated with obesity in studies starting after 1985 (n = 15 and 10, respectively) compared to studies starting in or before 1985 (n = 16 and 10). However, in the multivariate analysis, only mean population age was independently associated with the RRs for a five-BMI-unit increment and obesity (-29(95%CI: -55: -5)) and -31(95%CI: -66:3), respectively) per 10-year increment in mean age).

CONCLUSION

This study provides no consistent evidence for a difference in the association between BMI and CHD by calendar period. The mean population age seems to be the most important factor that modifies the association between the risk of CHD and BMI, in which the RR decreases with increasing age.

Association of all-cause mortality with overweight and obesity using standard body mass index categories: a systematic review and meta-analysis

IMPORTANCE

Estimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting.

OBJECTIVE

To perform a systematic review of reported hazard ratios (HRs) of all-cause mortality for overweight and obesity relative to normal weight in the general population.

DATA SOURCES

PubMed and EMBASE electronic databases were searched through September 30, 2012, without language restrictions.

STUDY SELECTION

Articles that reported HRs for all-cause mortality using standard body mass index (BMI) categories from prospective studies of general populations of adults were selected by consensus among multiple reviewers. Studies were excluded that used nonstandard categories or that were limited to adolescents or to those with specific medical conditions or to those undergoing specific procedures. PubMed searches yielded 7034 articles, of which 141 (2.0%) were eligible. An EMBASE search yielded 2 additional articles. After eliminating overlap, 97 studies were retained for analysis, providing a combined sample size of more than 2.88 million individuals and more than 270,000 deaths.

DATA EXTRACTION

Data were extracted by 1 reviewer and then reviewed by 3 independent reviewers. We selected the most complex model available for the full sample and used a variety of sensitivity analyses to address issues of possible overadjustment (adjusted for factors in causal pathway) or underadjustment (not adjusted for at least age, sex, and smoking).

RESULTS

Random-effects summary all-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured.

CONCLUSIONS AND RELEVANCE

Relative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.

The epidemiological Boehringer Ingelheim Employee study--part I: impact of overweight and obesity on cardiometabolic risk

OBJECTIVE

Obesity-dependent diseases cause economic burden to companies. Large-scale data for working populations are lacking. Prevalence of overweight and obesity in the Boehringer Ingelheim (BI) Employee cohort and the relationship between body mass index (BMI) and cardiometabolic risk factors and diseases were estimated.

DESIGN AND METHODS

Employees (≥38 years, employed in Ingelheim ≥2 years; n = 3151) of BI Pharma GmbH & Co. KG were invited by the medical corporate department to participate in intensive health checkups. Cross-sectional analysis of baseline data collected through 2006-2011 was performed.

RESULTS

90% of eligible subjects participated (n = 2849). Prevalences of overweight and obesity were 40% and 18% and significantly higher in men and participants ≥50 years. Cardiometabolic risk factor levels and prevalences of cardiometabolic diseases significantly increased with BMI and were higher in overweight and obese participants. Cut-points for increased risk estimated from ROC curves were ≈ 25 kg/m(2) for hypertension, hypercholesterolemia, arteriosclerosis, and hypertriglyceridemia and 26.7-28.0 kg/m(2) for the metabolic syndrome, insulin resistance, hyperinsulinemia, increased intima media thickness, and type 2 diabetes.

CONCLUSION

This is the first large-scale occupational health care cohort from a single company. Cardiometabolic risk factors and diseases accumulate with increasing BMI. Occupational weight reduction programs seem to be reasonable strategies.

Interaction of body mass index and diabetes as modifiers of cardiovascular mortality in a cohort study

OBJECTIVES

Diabetes and obesity each increases mortality, but recent papers have shown that lean Asian persons were at greater risk for mortality than were obese persons. The objective of this study is to determine whether an interaction exists between body mass index (BMI) and diabetes, which can modify the risk of death by cardiovascular disease (CVD).

METHODS

Subjects who were over 20 years of age, and who had information regarding BMI, past history of diabetes, and fasting blood glucose levels (n=16 048), were selected from the Korea Multi-center Cancer Cohort study participants. By 2008, a total of 1290 participants had died; 251 and 155 had died of CVD and stroke, respectively. The hazard for deaths was calculated with hazard ratio (HR) and 95% confidence interval (95% CI) by Cox proportional hazard model.

RESULTS

Compared with the normal population, patients with diabetes were at higher risk for CVD and stroke deaths (HR, 1.84; 95% CI, 1.33 to 2.56; HR, 1.82; 95% CI, 1.20 to 2.76; respectively). Relative to subjects with no diabetes and normal BMI (21 to 22.9 kg/m(2)), lean subjects with diabetes (BMI <21 kg/m(2)) had a greater risk for CVD and stroke deaths (HR, 2.83; 95% CI, 1.57 to 5.09; HR, 3.27; 95% CI, 1.58 to 6.76; respectively), while obese subjects with diabetes (BMI ≥25 kg/m(2)) had no increased death risk (p-interaction <0.05). This pattern was consistent in sub-populations with no incidence of hypertension.

CONCLUSIONS

This study suggests that diabetes in lean people is more critical to CVD deaths than it is in obese people.

Predicting prediabetes in a rural community: a survey among the Karen ethnic community, Thasongyang, Thailand

Background

Diabetes is a growing epidemic in both urban and rural communities worldwide.

Aim

We aimed to survey fasting plasma glucose (FPG) status and awareness of diabetes in the rural Karen ethnic community. We investigated the predictors of impaired fasting plasma glucose (IFG) status, which would be easily applicable for prevention of diabetes in a rural community.

Materials and methods

This was a community-based cross-sectional study conducted at Thasongyang, the most north-western district in Thailand. A total of 299 Karen ethnic rural residents were included in the study. FPG, body mass index, and waist circumference were prospectively measured. We assessed the awareness of diabetes and lifestyle-related health behavior with closed questionnaires in a rural community setting.

Results

On screening for FPG, 16.72% of the Karen ethnic residents had hyperglycemia: 3.68% in the diabetic range and 13.04% in the prediabetic range respectively. After adjustment for age, sex, and BMI, waist circumference (adjusted odds ratio [aOR] 3.5, 95% confidence interval [CI] 1.29–9.57), and having a diabetic blood relative (aOR 4.6, CI 1.81–11.71) are significant predictors of IFG status.

Conclusion

It is necessary to promote awareness of diabetes among the Karen ethnic community. Application of simple evidence-based predictors of the prediabetic state may lead to timely and effective prevention of diabetes in rural settings.

Birthweight and mortality in adulthood: a systematic review and meta-analysis

BACKGROUND

Small birth size may be associated with increased risk of cardiovascular diseases (CVD), whereas large birth size may predict increased risk of obesity and some cancers. The net effect of birth size on long-term mortality has only been assessed in individual studies, with conflicting results.

METHODS

The Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines for conducting and reporting meta-analysis of observational studies were followed. We retrieved 22 studies that assessed the association between birthweight and adult mortality from all causes, CVD or cancer. The studies were systematically reviewed and those reporting hazard ratios (HRs) and 95% confidence intervals (95% CIs) per kilogram (kg) increase in birthweight were included in generic inverse variance meta-analyses.

RESULTS

For all-cause mortality, 36,834 deaths were included and the results showed a 6% lower risk (adjusted HR = 0.94, 95% CI: 0.92-0.97) per kg higher birthweight for men and women combined. For cardiovascular mortality, the corresponding inverse association was stronger (HR = 0.88, 95% CI: 0.85-0.91). For cancer mortality, HR per kg higher birthweight was 1.13 (95% CI: 1.07-1.19) for men and 1.04 (95% CI: 0.98-1.10) for women (P(interaction) = 0.03). Residual confounding could not be eliminated, but is unlikely to account for the main findings.

CONCLUSION

These results show an inverse but moderate association of birthweight with adult mortality from all-causes and a stronger inverse association with cardiovascular mortality. For men, higher birthweight was strongly associated with increased risk of cancer deaths. The findings suggest that birthweight can be a useful indicator of processes that influence long-term health.

Body mass index and attempted suicide: Cohort study of 1,133,019 Swedish men

Associations between body mass index (BMI) and attempted (nonfatal) suicide have recently been reported. However, the few existing studies are relatively small in scale, the majority cross-sectional, and results contradictory. The authors have explored BMI-attempted suicide associations in a large cohort of 1,133,019 Swedish men born between 1950 and 1976, with BMI measured in early adulthood. During a mean follow-up of 23.9 years, a total of 18,277 (1.6%) men had at least 1 hospital admission for attempted suicide. After adjustment for confounding factors, there was a stepwise, linear decrease in attempted suicide with increasing BMI across the full BMI range (per standard deviation increase in BMI, hazard ratio = 0.93, 95% confidence interval: 0.91, 0.94). Analyses excluding men with depression at baseline were essentially identical to those based on the complete cohort. In men free from depression at baseline, controlling for subsequent depression slightly attenuated the raised risk of attempted suicide, particularly in lower weight men. This study suggests that lower weight men have an increased risk of attempted suicide and that associations may extend into the "normal" BMI range.

Impact of weight on long-term survival among patients without known coronary artery disease and a normal stress SPECT MPI

BACKGROUND

While obesity has been shown to be associated with a worse mortality, an "obesity paradox"--lower mortality in obese patients--has been noted among many patients with coronary artery disease (CAD). The extent to which an obesity paradox operates among patients with only suspected CAD, is not well determined.

METHODS AND RESULTS

A total of 3,673 patients (60 +/- 13 years, 36% males) with no history of heart disease and a normal stress SPECT were included in this study. Normal weight was defined as BMI of 18.5-24.9 kg x m(2); overweight 25-29.9 kg . m(2), obese >30 kg x m(2). The baseline clinical risk factors were recorded for each patient. The end point of the study was all-cause mortality. Of patients 942 (26%) were normal weight, 1,261 (34%) were overweight, and 1,470 (40%) were obese. Mean patient follow-up was 7.5 +/- 3 years. When compared to normal weight patients (event rate 3.2%/year), there was a lower incidence of death in the overweight (event rate 1.5%/year, P < .0001) and the obese (event rate 1.2%/year, P < .0001) groups. After controlling for baseline risk factors, using a reference HR = 1 for normal weight patients, there was a lower risk of death in the overweight (HR = .54, 95% CI .43-.7) and the obese groups (HR = .49, 95% CI .38-.63).

CONCLUSION

In patients without known cardiac disease and a normal stress SPECT, overweight and obese patients had a lower rate of all-cause mortality compared to normal weight patients over long-term follow-up. This study substantially extends the spectrum of patients in whom the obesity paradox is present.

Excess body weight and incidence of stroke: meta-analysis of prospective studies with 2 million participants

BACKGROUND AND PURPOSE

A systematic review of the prospective studies addressing the relationship of overweight and obesity to major stroke subtypes is lacking. We evaluated the occurrence of a graded association between overweight, obesity, and incidence of ischemic and hemorrhagic stroke by a meta-analysis of cohort studies.

METHODS

A search of online databases and relevant reviews was performed. Inclusion criteria were original article in English, prospective study design, follow-up > or = 4 years, indication of number of subjects exposed, and number of events across body mass index categories. Crude unadjusted relative risk (RR) and 95% CI were calculated for each study for overweight or obese compared with normal-weight categories. Log-transformed values and SE were used to calculate the pooled RR with random effects models; publication bias was checked. Additional analyses were performed using the multivariate estimates of risk reported in the individual studies.

RESULTS

Twenty-five studies were included, with 2 274 961 participants and 30 757 events. RR for ischemic stroke was 1.22 (95% CI, 1.05-1.41) for overweight and 1.64 (95% CI, 1.36-1.99) for obesity, whereas RR for hemorrhagic stroke was 1.01 (95% CI, 0.88-1.17) and 1.24 (95% CI, 0.99-1.54), respectively. Subgroup and meta-regression analyses ruled out gender, population average age, body mass index and blood pressure, year of recruitment, year of study publication, and length of follow-up as significant sources of heterogeneity. The additional analyses relying on the published multivariate estimates of risk provided qualitatively similar results.

CONCLUSIONS

Overweight and obesity are associated with progressively increasing risk of ischemic stroke, at least in part, independently from age, lifestyle, and other cardiovascular risk factors.

What is the predictive value of established risk factors for total and cardiovascular disease mortality when measured before middle age? Pooled analyses of two prospective cohort studies from Scotland

AIMS

To examine the association of physiological, behavioural and social characteristics in pre-middle age with future total and cardiovascular disease (CVD) mortality.

METHODS AND RESULTS

Risk factor data on 1503 individuals aged 16-35 years at baseline were collected in two prospective cohort studies using standard protocols. Their association with total and CVD mortality ascertained during 40 years of follow-up was summarized using Cox proportional hazards regression. A median follow-up of 39.6 years gave rise to 255 deaths (103 from CVD). In age-adjusted and sex-adjusted analyses, impaired lung function [one standard deviation increases in forced expiratory volume in 1 s: hazards ratio 0.69; 95% confidence interval 0.55, 0.86; and in forced vital capacity: 0.76; 0.59, 0.98], current cigarette smoking (4.16; 2.22, 7.80) and higher alcohol consumption (one standard deviation increase in standard units consumed: 1.20; 1.02, 1.41) were associated with CVD. In fully adjusted analyses associations generally held. For total mortality, these factors and obesity and socioeconomic disadvantage were predictive.

CONCLUSION

A range of risk factors measured before middle age were related to risk of total and CVD mortality up to four decades later, indicating that public health interventions should be implemented earlier in the life course than is currently the case.

Maternal high-fat diet promotes body length increases and insulin insensitivity in second-generation mice

Maternal obesity and diet consumption during pregnancy have been linked to offspring adiposity, cardiovascular disease, and impaired glucose metabolism. Furthermore, nutrition during development is clearly linked to somatic growth. However, few studies have examined whether phenotypes derived from maternal high-fat diet exposure can be passed to subsequent generations and by what mechanisms this may occur. Here we report the novel finding of a significant body length increase that persisted across at least two generations of offspring in response to maternal high-fat diet exposure. This phenotype is not attributable to altered intrauterine conditions or maternal feeding behavior because maternal and paternal lineages were able to transmit the effect, supporting a true epigenetic manner of inheritance. We also detected a heritable feature of reduced insulin sensitivity across two generations. Alterations in the GH secretagogue receptor (GHSR), the GHSR transcriptional repressor AF5q31, plasma IGF-I concentrations, and IGF-binding protein-3 (IGFBP3) suggest a contribution of the GH axis. These studies provide evidence that the heritability of body length and glucose homeostasis are modulated by maternal diet across multiple generations, providing a mechanism where length can increase rapidly in concert with caloric availability.

Does greater adiposity increase blood pressure and hypertension risk?: Mendelian randomization using the FTO/MC4R genotype

Elevated blood pressure increases the risk of experiencing cardiovascular events like myocardial infarction and stroke. Current observational data suggest that body mass index may have a causal role in the etiology of hypertension, but this may be influenced by confounding and reverse causation. Through the use of instrumental variable methods, we aim to estimate the strength of the unconfounded and unbiased association between body mass index/adiposity and blood pressure. We explore these issues in the Copenhagen General Population Study. We used instrumental variable methods to obtain estimates of the causal association between body mass index and blood pressure. This was performed using both rs9939609 (FTO) and rs17782313 (MC4R) genotypes as instruments for body mass index. Avoiding the epidemiological problems of confounding, bias, and reverse causation, we confirmed observational associations between body mass index and blood pressure. In analyses including those taking antihypertensive drugs, but for whom appropriate adjustment had been made, systolic blood pressure was seen to increase by 3.85 mm Hg (95% CI: 1.88 to 5.83 mm Hg) for each 10% increase in body mass index (P=0.0002), with diastolic blood pressure showing an increase of 1.79 mm Hg (95% CI: 0.68 to 2.90 mm Hg) for each 10% increase in body mass index (P=0.002). Observed associations are large and illustrate the considerable benefits in terms of reductions in blood pressure-related morbidity that could be achieved through a reduction in body mass index.

Body mass index and risk of all-cause and cardiovascular mortality in hospitalized elderly patients with diabetes mellitus

AIMS

Obesity is linked to increased morbidity and mortality risk in both the general population and in patients with diabetes mellitus; however, recent reports suggest that, in hospitalized elderly individuals, the association between body mass index (BMI) and mortality may be inverse. The present study sought to investigate the association between BMI and survival in hospitalized elderly individuals with diabetes mellitus.

METHODS

The medical records of 470 patients (226 males, mean age of 81.5 +/- 7.0 years) admitted to an acute geriatric ward between 1999 and 2000 were reviewed. Of the 140 patients with diabetes mellitus, 122 had more than 6 months of follow-up and were included in this analysis. Patients were followed up until 31 August 2004. Mortality data were extracted from death certificates.

RESULTS

During a mean follow-up of 3.7 +/- 1.6 years, 69 (56.6%) subjects died, 31 (25.4%) from cardiovascular causes. Those who died from any cause had lower baseline BMI than those who survived (24.0 +/- 4.0 vs. 27.1 +/- 4.3 kg/m(2); P < 0.0001). Similarly, those who died of cardiovascular causes had lower baseline BMI than those who did not (23.7 +/- 3.6 vs. 25.9 +/- 4.5, P = 0.01). BMI was inversely associated with all-cause [relative risk (RR) 0.89, 95% confidence interval (CI) 0.83-0.96, P = 0.002] and cardiovascular death (RR 0.83, 95% CI 0.74-0.93, P = 0.002) even after controlling for age, sex, smoking, dyslipidaemia and reason for hospital admission.

CONCLUSIONS

In very elderly subjects with diabetes mellitus, increased BMI was associated with reduced mortality risk.

Physical fitness and physical activity at age 13 years as predictors of cardiovascular disease risk factors at ages 15, 25, 33, and 40 years: extended follow-up of the Oslo Youth Study

OBJECTIVE

Few studies have examined the association of childhood physical activity and physical fitness with cardiovascular disease risk factors in adulthood. Furthermore, interpretation of these findings is hampered by methodologic shortcomings. In a population-based cohort study, we explored the influence, if any, of childhood physical activity and physical fitness on later cardiovascular disease risk factors.

METHODS

Data were taken from the Oslo Youth Study, a prospective cohort study that began in 1979, when 1016 students (mean age: 13 years; range: 11-15 years) who were attending 6 schools were invited to participate in a health education intervention. Cardiovascular disease risk factor data were collected at baseline and again in 1981 (mean age: 15 years; range: 13-17 years), 1991 (mean age: 25; range: 23-27 years), 1999 (mean age: 33; range: 31-35 years), and 2006 (mean age: 40; range: 38-42 years).

RESULTS

At baseline, physical fitness was inversely related to BMI, triceps skinfold thickness, and blood pressure (systolic and diastolic; N = 716). These associations were also present in prospective analyses at ages 15 (N = 472), 25 (N = 280; except for systolic blood pressure), and 33 years (N = 410, only BMI measured)-albeit with progressively diminishing magnitude-but were lost at 40 years (N = 294). There were fewer relationships with cardiovascular disease risk factors when physical activity was the exposure of interest. Controlling for educational attainment of both the parent and the study member had little impact on these associations.

CONCLUSIONS

Although childhood physical fitness seems to reveal some inverse associations with obesity and blood pressure in early adulthood, these effects diminished markedly into middle age.

A 6-month exercise intervention among inactive and overweight favela-residing women in Brazil: the Caranguejo Exercise Trial

OBJECTIVES

We examined the viability and efficacy of a known quantity of exercise in facilitating weight loss among previously sedentary or irregularly active overweight and obese adult women residing in a slum (favela) in Brazil.

METHODS

In this randomized controlled trial, 156 women were randomized to a control or intervention group (78 in each group). Exercise was supervised, consisting of three 50-minute aerobic sessions each week for 6 months.

RESULTS

Ninety-one percent (71) of the participants in the intervention group completed 6 months of the exercise program. At 6 months, women in the treatment group showed significant reduction in weight (mean=-1.69 kg; 95% confidence interval [CI]=-2.36,-1.03) and body mass index (mean=-0.63 kg/m2; 95% CI=-0.97, -0.30) compared with controls (P for both<.001).

CONCLUSIONS

A moderately intense, structured exercise program resulted in modest weight loss in women when sustained for 6 months.

Abdominal obesity and the spectrum of global cardiometabolic risks in US adults

OBJECTIVE

To compare the association of obesity and abdominal obesity with cardiometabolic risk factor burden and global estimated coronary heart disease (CHD) risk among multiethnic US adults.

DESIGN

Cross-sectional, survey study.

SUBJECTS

A total of 4456 participants (representing 194.9 million adults) aged 20-79 years in the 2003-2004 National Health and Nutrition Examination Survey (NHANES).

MEASUREMENTS

Body mass index (BMI) and waist circumference (WC) measures, CHD risk factors and a 10-year estimated CHD risk based on Framingham algorithms. Obesity was defined as a BMI >or=30 kg/m(2) and abdominal obesity as a WC >88 cm in women and >102 cm in men. High CHD risk status included diabetes, cardiovascular disease (CVD) or a 10-year Framingham risk score of >20%.

RESULTS

Overall, abdominal obesity was present in 42.3% of men and 62.5% of women and in 53.6% of whites, 56.9% of blacks and 50.5% of Hispanics (P<0.001 between gender and ethnicity). However, using International Diabetes Federation (IDF)-recommended WC cut points for Hispanics, the prevalence of abdominal obesity was 78.3%. Mean levels of low-density lipoprotein cholesterol (LDL-C), systolic and diastolic blood pressure, fasting glucose and C-reactive protein increased, and high-density lipoprotein cholesterol (HDL-C) decreased (P<0.001) according to BMI and WC categories, although these associations were attenuated in blacks for blood pressure, LDL-C, HDL-C and triglycerides. Of those with high WC, 25-35% had >or=3 cardiometabolic risk factors. High CHD risk among those with high WC was most common in men (27.9%) and non-Hispanic whites (23.9%). Persons with a high vs normal WC, adjusted for age, gender, ethnicity and BMI were more likely to have >or=3 cardiometabolic risk factors (odds ratio (OR)=5.1, 95% confidence interval (CI)=3.9-6.6) and were classified as high CHD risk (OR=1.5, 95% CI=1.1-2.0).

CONCLUSION

The association of abdominal obesity with risk factors varies by ethnicity and is independently associated with high CHD risk status, further validating its clinical significance.

Optimal form of operationalizing BMI in relation to all-cause and cause-specific mortality: the original Whitehall study

OBJECTIVE

The shape of the association between BMI (kg/m(2)) and mortality has important methodological implications as it partially determines the optimal form for operationalizing BMI for use in analyses. We examined various BMI operationalizations in relation to mortality from all causes and specific causes.

METHODS AND PROCEDURES

A clinical examination with measurements of height and weight was conducted at baseline (1967-1970) for 18,860 working men aged 40-69, in the total cohort and 7,865 men in the healthy subcohort, that is, those who had no unexplained weight loss, no cardiovascular (CVD) or respiratory disease, were nonsmokers and did not die during the first 5 years of follow-up (the original Whitehall study). A mean follow-up of 35 years for mortality gave rise to 13,498 deaths of which 4,766 were in the healthy subcohort.

RESULTS

There was a dose-response relation between BMI and CVD and coronary heart disease (CHD) mortality in the total cohort and healthy subcohort, with an increasingly steep slope at the high end of the BMI distribution. For noncardiovascular, cancer, and respiratory mortality, an excess risk was also associated with a BMI <18.5; in the healthy subcohort, this was true only for respiratory deaths. The association between BMI and all-cause mortality was J-shaped in the total cohort and healthy subgroup and even after excluding underweight participants.

DISCUSSION

For associations with all-cause and cause-specific mortality, a linear and quadratic term in combination provided a more parsimonious BMI operationalization than the WHO definition, obese-nonobese dichotomy or BMI treated as a continuous linear variable.

The epidemiology of obesity: the size of the problem

The epidemic of obesity took off from about 1980 and in almost all countries has been rising inexorably ever since. Only in 1997 did WHO accept that this was a major public health problem and, even then, there was no accepted method for monitoring the problem in children. It was soon evident, however, that the optimum population body mass index is about 21 and this is particularly true in Asia and Latin America where the populations are very prone to developing abdominal obesity, type 2 diabetes and hypertension. These features are now being increasingly linked to epigenetic programming of gene expression and body composition in utero and early childhood, both in terms of fat/lean tissue ratios and also in terms of organ size and metabolic pathway regulation. New Indian evidence suggests that insulin resistance at birth seems linked to low birth weight and a higher proportion of body fat with selective B12 deficiency and abnormalities of one carbon pool metabolism potentially responsible and affecting 75% of Indians and many populations in the developing world. Biologically there are also adaptive biological mechanisms which limit weight loss after weight gain and thereby in part account for the continuing epidemic despite the widespread desire to slim. Logically, the burden of disease induced by inappropriate diets and widespread physical inactivity can be addressed by increasing physical activity (PA), but simply advocating more leisure time activity is unrealistic. Substantial changes in urban planning and diet are needed to counter the removal of any every day need for PA and the decades of misdirected food policies which with free market forces have induced our current 'toxic environment'. Counteracting this requires unusual policy initiatives.

Mental ability across childhood in relation to risk factors for premature mortality in adult life: the 1970 British Cohort Study

OBJECTIVE

To examine the relation of scores on tests of mental ability across childhood with established risk factors for premature mortality at the age of 30 years.

METHODS

A prospective cohort study based on members of the British Cohort Study born in Great Britain in 1970 who had complete data on IQ scores at five (N = 8203) or 10 (N = 8171) years of age and risk factors at age 30 years.

RESULTS

In sex-adjusted analyses, higher IQ score at age 10 years was associated with a reduced prevalence of current smoking (OR(per 1 SD advantage in IQ) 0.84; 95% CI 0.80, 0.88), overweight (0.88; 0.84, 0.92), obesity (0.84; 0.79, 0.92), and hypertension (0.90; 0.83, 0.98), and an increased likelihood of having given up smoking by the age of 30 years (1.25; 1.18, 1.24). These gradients were attenuated after adjustment for markers of socioeconomic circumstances across the life course, particularly education. There was no apparent relationship between IQ and diabetes. Essentially the same pattern of association was evident when the predictive value of IQ scores at five years of age was examined.

CONCLUSIONS

The mental ability-risk factor gradients reported in the present study may offer some insights into the apparent link between low pre-adult mental ability and premature mortality.

Obesity paradox in patients with hypertension and coronary artery disease

PURPOSE

An obesity paradox, a "paradoxical" decrease in morbidity and mortality with increasing body mass index (BMI), has been shown in patients with heart failure and those undergoing percutaneous coronary intervention. However, whether this phenomenon exists in patients with hypertension and coronary artery disease is not known.

METHODS

A total of 22,576 hypertensive patients with coronary artery disease (follow-up 61,835 patient years, mean age 66+/-9.8 years) were randomized to a verapamil-SR or atenolol strategy. Dose titration and additional drugs (trandolapril and/or hydrochlorothiazide) were added to achieve target blood pressure control according to the Sixth Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure targets. Patients were classified into 5 groups according to baseline BMI: less than 20 kg/m2 (thin), 20 to 25 kg/m2 (normal weight), 25 to 30 kg/m2 (overweight), 30 to 35 kg/m2 (class I obesity), and 35 kg/m2 or more (class II-III obesity). The primary outcome was first occurrence of death, nonfatal myocardial infarction, or nonfatal stroke.

RESULTS

With patients of normal weight (BMI 20 to<25 kg/m2) as the reference group, the risk of primary outcome was lower in the overweight patients (adjusted hazard ratio [HR] 0.77, 95% confidence interval [CI], 0.70-0.86, P<.001), class I obese patients (adjusted HR 0.68, 95% CI, 0.59-0.78, P<.001), and class II to III obese patients (adjusted HR 0.76, 95% CI, 0.65-0.88, P <.001). Class I obese patients had the lowest rate of primary outcome and death despite having smaller blood pressure reduction compared with patients of normal weight at 24 months (-17.5+/-21.9 mm Hg/-9.8+/-12.4 mm Hg vs -20.7+/-23.1 mm Hg /-10.6+/-12.5 mm Hg, P<.001).

CONCLUSION

In a population with hypertension and coronary artery disease, overweight and obese patients had a decreased risk of primary outcome compared with patients of normal weight, which was driven primarily by a decreased risk of all-cause mortality. Our results further suggest a protective effect of obesity in patients with known cardiovascular disease in concordance with data in patients with heart failure and those undergoing percutaneous coronary intervention.