General and abdominal adiposity and risk of death in Europe

Optimal body weight for the prevention of coronary heart disease in normal-weight physically active men

Although 36% of US men are normal weight (BMI <25 kg/m(2)), the health benefits of greater leanness in normal-weight individuals are seldom acknowledged. To assess the optimal body weight with respect to minimizing coronary heart disease (CHD) risk, we applied Cox proportional hazard analyses of 20,525 nonsmoking, nondiabetic, normal-weight men followed prospectively for 7.7 years, including 20,301 who provided follow-up questionnaires. Two-hundred and forty two men reported coronary artery bypass graph (CABG) or percutaneous transluminal coronary angioplasty (PTCA) and 82 reported physician-diagnosed incident myocardial infarction (267 total). The National Death Index identified 40 additional ischemic heart disease deaths. In these normal-weight men, each kg/m(2) decrement in baseline BMI was associated with 11.2% lower risk for total CHD (P = 0.005), 13.2% lower risk for nonfatal CHD (P = 0.002), 19.0% lower risk for nonfatal myocardial infarction (P = 0.01), and 12.2% lower risk for PTCA or CABG (P = 0.007). Compared to men with BMI between 22.5 and 25 kg/m(2), those <22.5 kg/m(2) had 24.1% lower total CHD risk (P = 0.01), 27.9% lower nonfatal CHD risk (P = 0.01), 37.8% lower nonfatal myocardial infarction risk (P = 0.05), and 27.8% lower PTCA or CABG risk (P = 0.02). In nonabdominally obese men (waist circumference <102 cm), CHD risk declined linearly with declining waist circumference. CHD risk was unrelated to change in waist circumference between 18 years old and baseline except as it contributed to baseline circumference. These results suggest that the optimal BMI for minimizing CHD risk lies somewhere <22.5 kg/m(2), as suggested from our previous analyses of incident diabetes, hypertension, and hypercholesterolemia in these men.

Overweight and obesity among Dutch workers: differences between occupational groups and sectors

PURPOSE

To describe the prevalence of overweight and obesity among different occupational groups and sectors in a representative sample of the Dutch working population, and to test whether these differences still exist after adjustment for socio-demographic variables.

METHODS

Cross-sectional data among 7,588 working adults were used. Univariate analyses of variance was performed to test differences in body mass index (BMI) values between occupational groups (n = 7) and sectors (n = 28). Adjusted analyses were carried out to examine the role of socio-demographic factors in the differences in overweight and obesity between occupational groups and sectors.

RESULTS

On average, the mean BMI was 24.3 kg/m(2) with 31% being overweight and 6% being obese. Those working in trade, industrial, or transportation occupations as well as the legislators and senior managers had the highest BMI and a relatively high prevalence of overweight (36.7 and 35.5%, respectively) and obesity (6.9 and 7.5%, respectively). In contrast, those working in scientific and artistic professions had the most favorable BMI profile with 25.7% being overweight and 4.2% being obese. After adjusting for sex, age, and education, the proportion of variance changed from about 0.01 to 0.10 with age being the main contributor of the differences in overweight and obesity.

CONCLUSIONS

BMI profile and prevalence of overweight and obesity differs between occupations and sectors. Despite the differences are explained partly by socio-demographic factors, based on a given distribution of age, sex, and education within each occupational group and sector, occupational group- and sector-specific strategies to prevent and reduce overweight are recommended.

Improvement of metabolic syndrome following intragastric balloon: 1 year follow-up analysis

OBJECTIVE

This study aimed to assess the impact of intragastric balloon (IGB)-induced body weight loss on metabolic syndrome in obese patients and evaluate what happens during 1-year follow-up.

METHODS

To this end, data were collected on 143 obese patients (body mass index (BMI) 36.2+/-5.7 kg/m2) who underwent IGB insertion between January 2000 and December 2005. Outcomes were recorded at BioEnterics Intragastric Balloon removal time (t0) and at 6-month (t6) and 12-month (t12) follow-up.

RESULTS

Significant BMI, excess body weight loss percentage, and body weight loss percentage (BWL%) were observed at t0 (29.6+/-4.6 kg/m2; 29.3+/-4.8%; 14.1+/-5.7%), followed by partial weight regain at t12 (32.4+/-4.3 kg/m2; 26.1+/-4.9%; 11.2+/-4.6%). Incidence of metabolic syndrome dropped from 34.8% (pre-IGB value) to 14.5% (t0) and 11.6% (t12). Likewise, type 2 diabetes mellitus (DM), hypertriglyceridemia, hypercholesterolemia, and blood hypertension (BH) incidence decreased from 32.6%, 37.7%, 33.4%, and 44.9% (pre-IGB values) to 20.9%, 14.5%, 16.7%, and 30.4% at t0 and 21.3%, 17.4%, 18.9%, and 34.8% at t12. HbA1c blood concentration shifted from an initial value of 7.5+/-2.1% to 5.7+/-1.9% (t0), 5.6+/-0.7% (t6), and 5.5+/-0.9% (t12). Patients suffering from DM or BH stopped or diminished relative drug consumption at t12. Negligible modifications were reported as regards HDL cholesterol and hyperuricemia.

CONCLUSION

Weight regain is commonly observed during long-term follow-up after IGB removal. Nevertheless, the maintenance of at least 10% of the BWL%, as reported at 1-year follow-up, is associated with an improvement in metabolic syndrome.

Genome-wide association scan meta-analysis identifies three Loci influencing adiposity and fat distribution

To identify genetic loci influencing central obesity and fat distribution, we performed a meta-analysis of 16 genome-wide association studies (GWAS, N = 38,580) informative for adult waist circumference (WC) and waist-hip ratio (WHR). We selected 26 SNPs for follow-up, for which the evidence of association with measures of central adiposity (WC and/or WHR) was strong and disproportionate to that for overall adiposity or height. Follow-up studies in a maximum of 70,689 individuals identified two loci strongly associated with measures of central adiposity; these map near TFAP2B (WC, P = 1.9x10(-11)) and MSRA (WC, P = 8.9x10(-9)). A third locus, near LYPLAL1, was associated with WHR in women only (P = 2.6x10(-8)). The variants near TFAP2B appear to influence central adiposity through an effect on overall obesity/fat-mass, whereas LYPLAL1 displays a strong female-only association with fat distribution. By focusing on anthropometric measures of central obesity and fat distribution, we have identified three loci implicated in the regulation of human adiposity.

Obesity and cardiovascular disease: risk factor, paradox, and impact of weight loss

Obesity has reached global epidemic proportions in both adults and children and is associated with numerous comorbidities, including hypertension (HTN), type II diabetes mellitus, dyslipidemia, obstructive sleep apnea and sleep-disordered breathing, certain cancers, and major cardiovascular (CV) diseases. Because of its maladaptive effects on various CV risk factors and its adverse effects on CV structure and function, obesity has a major impact on CV diseases, such as heart failure (HF), coronary heart disease (CHD), sudden cardiac death, and atrial fibrillation, and is associated with reduced overall survival. Despite this adverse association, numerous studies have documented an obesity paradox in which overweight and obese people with established CV disease, including HTN, HF, CHD, and peripheral arterial disease, have a better prognosis compared with nonoverweight/nonobese patients. This review summarizes the adverse effects of obesity on CV disease risk factors and its role in the pathogenesis of various CV diseases, reviews the obesity paradox and potential explanations for these puzzling data, and concludes with a discussion regarding the current state of weight reduction in the prevention and treatment of CV diseases.

Effects of ethnicity and socioeconomic status on body composition in an admixed, multiethnic population in Hawaii

This study determined ethnic differences in anthropometric measures of a sample of adults in Hawaii, examining the effects of differing degrees of ethnic admixing and socioeconomic status (SES) on the measures. Adults who had attended elementary school in Hawaii underwent anthropometric measurements and answered questionnaires about their educational attainment, income, age, cultural identity, ethnic ancestry, and health. Individuals reporting Asian American cultural identity had significantly lower mean body mass index (BMI) and waist circumference (WC) than others, whereas those with Hawaiian/Pacific Islander cultural identity had significantly higher BMI and WC. Educational attainment, but not reported family income and age, was significantly related to BMI and WC, and differences in educational attainment accounted for the increased mean BMI and WC in Hawaiian/Pacific Islanders, but did not account for the lower mean BMI and WC among Asian Americans. Higher percentage of Asian ancestry was significantly correlated with lower BMI and WC, whereas higher percentage of Hawaiian/Pacific Islander ancestry was significantly correlated with increased BMI and WC. Differences in education accounted for the significantly increased BMI in participants with a higher percentage of Hawaiian/Pacific Islander ancestry, but did not entirely account for the lower BMI in individuals with a higher percentage of Asian American ancestry. These results suggest that the high rate of obesity and its sequelae seen in Pacific Islanders may be more a result of socioeconomic status and lifestyle than of genetic propensity, whereas the lower rates of obesity observed in Asian American populations are less directly influenced by socioeconomic factors.

Predictive models of insulin resistance derived from simple morphometric and biochemical indices related to obesity and the metabolic syndrome in baboons

Background

Non-human primates are valuable models for the study of insulin resistance and human obesity. In baboons, insulin sensitivity levels can be evaluated directly with the euglycemic clamp and is highly predicted by adiposity, metabolic markers of obesity and impaired glucose metabolism (i.e. percent body fat by DXA and HbA_1c). However, a simple method to screen and identify obese insulin resistant baboons for inclusion in interventional studies is not available.

Methods

We studied a population of twenty baboons with the euglycemic clamp technique to characterize a population of obese nondiabetic, insulin resistant baboons, and used a multivariate linear regression analysis (adjusted for gender) to test different predictive models of insulin sensitivity (insulin-stimulated glucose uptake = Rd) using abdominal circumference and fasting plasma insulin. Alternatively, we tested in a separate baboon population (n = 159), a simpler model based on body weight and fasting plasma glucose to predict the whole-body insulin sensitivity (Rd/SSPI) derived from the clamp.

Results

In the first model, abdominal circumference explained 59% of total insulin mediated glucose uptake (Rd). A second model, which included fasting plasma insulin (log transformed) and abdominal circumference, explained 64% of Rd. Finally, the model using body weight and fasting plasma glucose explained 51% of Rd/SSPI. Interestingly, we found that percent body fat was directly correlated with the adipocyte insulin resistance index (r = 0.755, p < 0.0001).

Conclusion

In baboons, simple morphometric measurements of adiposity/obesity, (i.e. abdominal circumference), plus baseline markers of glucose/lipid metabolism, (i.e. fasting plasma glucose and insulin) provide a feasible method to screen and identify overweight/obese insulin resistant baboons for inclusion in interventional studies aimed to study human obesity, insulin resistance and type 2 diabetes mellitus.

Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies

BACKGROUND

The main associations of body-mass index (BMI) with overall and cause-specific mortality can best be assessed by long-term prospective follow-up of large numbers of people. The Prospective Studies Collaboration aimed to investigate these associations by sharing data from many studies.

METHODS

Collaborative analyses were undertaken of baseline BMI versus mortality in 57 prospective studies with 894 576 participants, mostly in western Europe and North America (61% [n=541 452] male, mean recruitment age 46 [SD 11] years, median recruitment year 1979 [IQR 1975-85], mean BMI 25 [SD 4] kg/m(2)). The analyses were adjusted for age, sex, smoking status, and study. To limit reverse causality, the first 5 years of follow-up were excluded, leaving 66 552 deaths of known cause during a mean of 8 (SD 6) further years of follow-up (mean age at death 67 [SD 10] years): 30 416 vascular; 2070 diabetic, renal or hepatic; 22 592 neoplastic; 3770 respiratory; 7704 other.

FINDINGS

In both sexes, mortality was lowest at about 22.5-25 kg/m(2). Above this range, positive associations were recorded for several specific causes and inverse associations for none, the absolute excess risks for higher BMI and smoking were roughly additive, and each 5 kg/m(2) higher BMI was on average associated with about 30% higher overall mortality (hazard ratio per 5 kg/m(2) [HR] 1.29 [95% CI 1.27-1.32]): 40% for vascular mortality (HR 1.41 [1.37-1.45]); 60-120% for diabetic, renal, and hepatic mortality (HRs 2.16 [1.89-2.46], 1.59 [1.27-1.99], and 1.82 [1.59-2.09], respectively); 10% for neoplastic mortality (HR 1.10 [1.06-1.15]); and 20% for respiratory and for all other mortality (HRs 1.20 [1.07-1.34] and 1.20 [1.16-1.25], respectively). Below the range 22.5-25 kg/m(2), BMI was associated inversely with overall mortality, mainly because of strong inverse associations with respiratory disease and lung cancer. These inverse associations were much stronger for smokers than for non-smokers, despite cigarette consumption per smoker varying little with BMI.

INTERPRETATION

Although other anthropometric measures (eg, waist circumference, waist-to-hip ratio) could well add extra information to BMI, and BMI to them, BMI is in itself a strong predictor of overall mortality both above and below the apparent optimum of about 22.5-25 kg/m(2). The progressive excess mortality above this range is due mainly to vascular disease and is probably largely causal. At 30-35 kg/m(2), median survival is reduced by 2-4 years; at 40-45 kg/m(2), it is reduced by 8-10 years (which is comparable with the effects of smoking). The definite excess mortality below 22.5 kg/m(2) is due mainly to smoking-related diseases, and is not fully explained.

Preventive cardiology and cardiac rehabilitation programmes in women

Cardiovascular diseases are the most common cause of death among women. Women historically under-appreciate these risks. There are key differences in terms of the relative importance of risk factors, particularly in the age of presentation. The female 'gender advantage' previously felt to be due to female sex hormones remains unexplained. The effects of post-menopausal hormone replacement also remain controversial. Risk can be reduced by sensible risk-factor control, but there is an ongoing imbalance between calculated risk and evidence of subclinical atherosclerosis and in women, in particular, a more proactive approach to risk reduction may be required. The controversy surrounding the effectiveness of statins in women is probably more due to problems with meta-analyses than from gender dimorphism. Cardiac rehabilitation reduces cardiac risk but women have previously been under-referred, although the benefits are equally great in both genders.

The association between BMI value and long-term mortality

OBJECTIVES

To study total mortality in different categories of BMI values, with adjustments for important covariates in a population-based 26-year mortality follow-up. Special interest will be given to gender differences and low BMI values.

METHODS

From a stratified sample in 1969 of 32 185 individuals aged 18-64 years from Stockholm County, 2422 underwent a health examination, with complete data obtained for 1020 subjects. BMI was classified as underweight (<20), normal (20-24.9), overweight (25-29.9) or obesity (> or =30). Participants were followed up in the National Cause of Death Register until the end of 1996. Multivariate analysis was performed by Cox regression for men and women separately, with different models, with step-wise adjustment for age, care need category, heart rate, hypertension, blood glucose, alcohol intake and smoking, with hazard ratios (HR) and 95% confidence interval (CI) and with normal weight as reference.

RESULTS

Among men, the age-adjusted HR was 1.68 (95% CI 1.10-2.57) for underweight and 1.62 (95% CI 1.08-2.43) for obesity, and among women it was 0.93 (95% CI 0.58-1.51) for underweight and 1.88 (95% CI 1.26-2.82) for obesity. In men, the significantly increased mortality remained when also adjusting for care need category, but not when adjusting for other factors, whereas the opposite was found regarding obesity. For women, underweight was significantly associated with decreased mortality when adjusting for smoking and for all factors together, whereas obesity was associated with increased mortality when adjusting for the different factors except for all factors together.

CONCLUSIONS

Underweight was associated with higher mortality among men, but not when adjusting for covariates, whereas underweight was associated with lower mortality among women when adjusting for smoking.

Lung function impairment and metabolic syndrome: the critical role of abdominal obesity

RATIONALE

Increased risk for cardiovascular morbidity and mortality has been related to both lung function impairment and metabolic syndrome. Data on the relationship between lung function and metabolic syndrome are sparse.

OBJECTIVES

To investigate risk for lung function impairment according to metabolic syndrome traits.

METHODS

This cross-sectional population-based study included 121,965 men and women examined at the Paris Investigations Préventives et Cliniques Center between 1999 and 2006. The lower limit of normal was used to define lung function impairment (FEV(1) or FVC < lower limit of normal). Metabolic syndrome was assessed according to the American Heart Association/National Heart, Lung, and Blood Institute statement.

MEASUREMENTS AND MAIN RESULTS

We used a logistic regression model and principal component analysis to investigate the differential associations between lung function impairment and specific components of metabolic syndrome. Lung function impairment was associated with metabolic syndrome (prevalence = 15.0%) independently of age, sex, smoking status, alcohol consumption, educational level, body mass index, leisure-time physical activity, and cardiovascular disease history (odds ratio [OR] [95% confidence interval], 1.28 [1.20-1.37] and OR, 1.41 [1.31-1.51] for FEV(1) and FVC, respectively). Three factors were identified from factor analysis: "lipids" (low high-density lipoprotein cholesterol, high triglycerides), "glucose-blood pressure" (high fasting glycemia, high blood pressure), and "abdominal obesity" (large waist circumference). All factors were inversely related to lung function, but abdominal obesity was the strongest predictor of lung function impairment (OR, 1.94 [1.80-2.09] and OR, 2.11 [1.95-2.29], for FEV(1) and FVC, respectively). Similar results were obtained for women and men.

CONCLUSIONS

We found a positive independent relationship between lung function impairment and metabolic syndrome in both sexes, predominantly due to abdominal obesity. Further studies are required to clarify the underlying mechanisms.

Adding biomeasures relating to fatness and obesity to the Panel Study of Income Dynamics

The pace of research on the causes and consequences of obesity has increased dramatically since the late 1990s. However, a great chasm exists between the high-quality measurements of fatness used in the medical literature and the mostly self-reported height and weight data found in social science surveys. This article discusses the scientific value of including more accurate measures of fatness in the Panel Study of Income Dynamics (PSID). It describes why fatness and obesity are of interest to PSID users, the concepts they measure, the strengths and weaknesses of alternative biomeasures for these concepts, the value added of including each in the PSID, and their synergies with the PSID structure. Although no single measure of fatness is ideal for every situation, given scarce PSID resources we recommend adding waist circumference, percentage of body fat, total body fat, and fat free mass through a method such as bioelectrical impedance analysis, as well as determining genetic predisposition to obesity.

BMI, weight stability and mortality among adults without clinical co-morbidities: a 22-year mortality follow-up in the Finnish twin cohort

AIM AND METHOD

Cause-specific mortality was studied in relation to body mass index (BMI) and weight stability (defined as less than 1 BMI unit change during a 6-year period) in 15,424 initially healthy twin subjects from the Finnish Twin Cohort, first examined in 1975, re-examined in 1981, and then followed over 22 years (1982-2003). Additionally, death discordant twin pairs were studied to assess whether body weight differences are associated with mortality independent of childhood factors and genetic background. Deaths and cause of death were ascertained from national registries. Associations with mortality were estimated by Cox proportional hazards model for all individuals and conditional logistic regression analysis for pairwise analyses.

RESULTS

Mortality increased with increasing BMI for all causes and coronary heart disease (CHD) in men, and there were no associations for all natural causes, cerebrovascular disease, and violent deaths. After adjustment for multiple co-variates and changes in co-variates between 1975 and 1981, BMI was associated with CHD mortality in all men (hazard ratio (HR) = 1.22, 95% CI 1.06-1.41) and in men with stable weight between 1975 and 1981 (HR = 1.26, 95% CI 1.03-1.55). Overall risk of death and cause-specific mortality was not associated with BMI in women.

CONCLUSION

Among clinically healthy subjects at low risk of death, BMI appears to be associated with CHD risk in men.