Metabolically healthy obesity and risk of mortality Does the definition of metabolic health matter
TL;DR: For most definitions of metabolic health, both metabolically healthy and unhealthy obese patients carry an elevated risk of mortality.
Abstract: To assess the association of a "metabolically healthy obese" phenotype with mortality using five definitions of metabolic health. Adults (n = 5,269; 71.7% men) aged 39-62 years in 1991 through 1993 provided data on BMI and metabolic health, defined using data from the Adult Treatment Panel-III (ATP-III); criteria from two studies; and the Matsuda and homeostasis model assessment (HOMA) indices. Cross-classification of BMI categories and metabolic status (healthy/unhealthy) created six groups. Cox proportional hazards regression models were used to analyze associations with all-cause and cardiovascular disease (CVD) mortality during a median follow-up of 17.7 years. A total of 638 individuals (12.1% of the cohort) were obese, of whom 9-41% were metabolically healthy, depending on the definition. Regardless of the definition, compared with metabolically healthy, normal-weight individuals, both the metabolically healthy obese (hazard ratios [HRs] ranged from 1.81 [95% CI 1.16-2.84] for ATP-III to 2.30 [1.13-4.70] for the Matsuda index) and the metabolically abnormal obese (HRs ranged from 1.57 [1.08-2.28] for the Matsuda index to 2.05 [1.44-2.92] for criteria defined in a separate study) had an increased risk of mortality. The only exception was the lack of excess risk using the HOMA criterion for the metabolically healthy obese (1.08; 0.67-1.74). Among the obese, the risk of mortality did not vary as a function of metabolic health apart from when using the HOMA criterion (1.93; 1.15-3.22). Similar results were obtained for cardiovascular mortality. For most definitions of metabolic health, both metabolically healthy and unhealthy obese patients carry an elevated risk of mortality.
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TL;DR: Obesity is associated with a large decrease in life expectancy, but up to 30% of obese patients are metabolically healthy with insulin sensitivity similar to healthy normal weight individuals, lower visceral fat content, and lower intima media thickness of the carotid artery than the majority of metabolically "unhealthy" obese patients.
Abstract: Increase in prevalence of obesity has become a worldwide major health problem in adults, as well as among children and adolescents. Furthermore, total adiposity and truncal subcutaneous fat accumulation during adolescence are positively and independently associated with atherosclerosis at adult ages. Centrally accumulation of body fat is associated with insulin resistance, whereas distribution of body fat in a peripheral pattern is metabolically less important. Obesity is associated with a large decrease in life expectancy. The effect of extreme obesity on mortality is greater among younger than older adults. In this respect, obesity is also associated with increased risk of several cancer types. However, up to 30% of obese patients are metabolically healthy with insulin sensitivity similar to healthy normal weight individuals, lower visceral fat content, and lower intima media thickness of the carotid artery than the majority of metabolically “unhealthy” obese patients.
665 citations
TL;DR: There was a U shaped association between BMI and mortality in analyses with a greater potential for bias including all participants, current, former, or ever smokers, and in studies with a short duration of follow-up (<5 years or <10 years), or with moderate study quality scores.
Abstract: Objective To conduct a systematic review and meta-analysis of cohort studies of body mass index (BMI) and the risk of all cause mortality, and to clarify the shape and the nadir of the dose-response curve, and the influence on the results of confounding from smoking, weight loss associated with disease, and preclinical disease. Data sources PubMed and Embase databases searched up to 23 September 2015. Study selection Cohort studies that reported adjusted risk estimates for at least three categories of BMI in relation to all cause mortality. Data synthesis Summary relative risks were calculated with random effects models. Non-linear associations were explored with fractional polynomial models. Results 230 cohort studies (207 publications) were included. The analysis of never smokers included 53 cohort studies (44 risk estimates) with >738 144 deaths and >9 976 077 participants. The analysis of all participants included 228 cohort studies (198 risk estimates) with >3 744 722 deaths among 30 233 329 participants. The summary relative risk for a 5 unit increment in BMI was 1.18 (95% confidence interval 1.15 to 1.21; I 2 =95%, n=44) among never smokers, 1.21 (1.18 to 1.25; I 2 =93%, n=25) among healthy never smokers, 1.27 (1.21 to 1.33; I 2 =89%, n=11) among healthy never smokers with exclusion of early follow-up, and 1.05 (1.04 to 1.07; I 2 =97%, n=198) among all participants. There was a J shaped dose-response relation in never smokers (P non-linearity Conclusion Overweight and obesity is associated with increased risk of all cause mortality and the nadir of the curve was observed at BMI 23-24 among never smokers, 22-23 among healthy never smokers, and 20-22 with longer durations of follow-up. The increased risk of mortality observed in underweight people could at least partly be caused by residual confounding from prediagnostic disease. Lack of exclusion of ever smokers, people with prevalent and preclinical disease, and early follow-up could bias the results towards a more U shaped association.
583 citations
TL;DR: The observational studies that gave rise to the idea of metabolically healthy obesity are described and the key parameters that can help to distinguish it from the general form of obesity are discussed.
580 citations
TL;DR: The present narrative review summarizes the major pathophysiological links between obesity and CVD (traditional and novel concepts), analyses the heterogeneity of obesity-related cardiometabolic consequences, and provides an overview of the cardiovascular impact of weight loss interventions.
Abstract: A wealth of clinical and epidemiological evidence has linked obesity to a broad spectrum of cardiovascular diseases (CVD) including coronary heart disease, heart failure, hypertension, stroke, atrial fibrillation and sudden cardiac death. Obesity can increase CVD morbidity and mortality directly and indirectly. Direct effects are mediated by obesity-induced structural and functional adaptations of the cardiovascular system to accommodate excess body weight, as well as by adipokine effects on inflammation and vascular homeostasis. Indirect effects are mediated by co-existing CVD risk factors such as insulin resistance, hyperglycemia, hypertension and dyslipidemia. Adipose tissue (AT) quality and functionality are more relevant aspects for cardiometabolic risk than its total amount. The consequences of maladaptive AT expansion in obesity are local and systemic: the local include inflammation, hypoxia, dysregulated adipokine secretion and impaired mitochondrial function; the systemic comprise insulin resistance, abnormal glucose/lipid metabolism, hypertension, a pro-inflammatory and pro-thrombotic state and endothelial dysfunction, all of which provide linking mechanisms for the association between obesity and CVD. The present narrative review summarizes the major pathophysiological links between obesity and CVD (traditional and novel concepts), analyses the heterogeneity of obesity-related cardiometabolic consequences, and provides an overview of the cardiovascular impact of weight loss interventions.
359 citations
TL;DR: It is found that age, sex and ethnicity are major physiological modifiers of the risk of non-alcoholic fatty liver disease, along with belonging to "non- alcoholic fatty Liver disease families" and carrying risk alleles for selected genetic polymorphisms.
357 citations
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TL;DR: The correlation of the model's estimates with patient data accords with the hypothesis that basal glucose and insulin interactions are largely determined by a simple feed back loop.
Abstract: The steady-state basal plasma glucose and insulin concentrations are determined by their interaction in a feedback loop. A computer-solved model has been used to predict the homeostatic concentrations which arise from varying degrees beta-cell deficiency and insulin resistance. Comparison of a patient's fasting values with the model's predictions allows a quantitative assessment of the contributions of insulin resistance and deficient beta-cell function to the fasting hyperglycaemia (homeostasis model assessment, HOMA). The accuracy and precision of the estimate have been determined by comparison with independent measures of insulin resistance and beta-cell function using hyperglycaemic and euglycaemic clamps and an intravenous glucose tolerance test. The estimate of insulin resistance obtained by homeostasis model assessment correlated with estimates obtained by use of the euglycaemic clamp (Rs = 0.88, p less than 0.0001), the fasting insulin concentration (Rs = 0.81, p less than 0.0001), and the hyperglycaemic clamp, (Rs = 0.69, p less than 0.01). There was no correlation with any aspect of insulin-receptor binding. The estimate of deficient beta-cell function obtained by homeostasis model assessment correlated with that derived using the hyperglycaemic clamp (Rs = 0.61, p less than 0.01) and with the estimate from the intravenous glucose tolerance test (Rs = 0.64, p less than 0.05). The low precision of the estimates from the model (coefficients of variation: 31% for insulin resistance and 32% for beta-cell deficit) limits its use, but the correlation of the model's estimates with patient data accords with the hypothesis that basal glucose and insulin interactions are largely determined by a simple feed back loop.
29,217 citations
TL;DR: Dairy therapy remains the first line of treatment of high blood cholesterol, and drug therapy is reserved for patients who are considered to be at high risk for CHD, and the fundamental approach to treatment is comparable.
Abstract: THE SECOND report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II, or ATP II) presents the National Cholesterol Education Program's updated recommendations for cholesterol management. It is similar to the first in general outline, and the fundamental approach to treatment of high blood cholesterol is comparable. This report continues to identify low-density lipoproteins (LDL) as the primary target of cholesterol-lowering therapy. As in the first report, the second report emphasizes the role of the clinical approach in primary prevention of coronary heart disease (CHD). Dietary therapy remains the first line of treatment of high blood cholesterol, and drug therapy is reserved for patients who are considered to be at high risk for CHD. However, the second report contains new features that distinguish it from the first. These include the following: Increased emphasis on See also pp 3002 and 3009.
28,495 citations
01 Jan 2009
15,111 citations
Book•
01 Jan 2000
TL;DR: The fundamental causes of the obesity epidemic are sedentary lifestyles and high-fat energy-dense diets, both resulting from the profound changes taking place in society and the behavioural patterns of communities as a consequence of increased urbanization and industrialization and the disappearance of traditional lifestyles.
Abstract: This report issues a call for urgent action to combat the growing epidemic of obesity, which now affects developing and industrialized countries alike. Adopting a public health approach, the report responds to both the enormity of health problems associated with obesity and the notorious difficulty of treating this complex, multifactorial disease. With these problems in mind, the report aims to help policy-makers introduce strategies for prevention and management that have the greatest chance of success. The importance of prevention as the most sensible strategy in developing countries, where obesity coexists with undernutrition, is repeatedly emphasized. Recommended lines of action, which reflect the consensus reached by 25 leading authorities, are based on a critical review of current scientific knowledge about the causes of obesity in both individuals and populations. While all causes are considered, major attention is given to behavioural and societal changes that have increased the energy density of diets, overwhelmed sophisticated regulatory systems that control appetite and maintain energy balance, and reduced physical activity. Specific topics discussed range from the importance of fat content in the food supply as a cause of population-wide obesity, through misconceptions about obesity held by both the medical profession and the public, to strategies for dealing with the alarming prevalence of obesity in children. "...the volume is clearly written, and carries a wealth of summary information that is likely to be invaluable for anyone interested in the public health aspects of obesity and fatness, be they students, practitioner or researcher." - Journal of Biosocial Science
5,188 citations