Background The relation between central obesity and survival in community-dwelling adults with a normal body mass index (BMI) is not well known. Objectives To examine the risk of total and cardiovascular mortality associated with central obesity but normal BMI Design Stratified multistage probability design Setting Third National Health and Nutrition Examination Survey Participants We analyzed data on 15,184 people (52.3% women) aged 18 to 90 years.. Measurements We used multivariable Cox proportional hazards model to evaluate the relation of obesity patterns defined by BMI and WHR and total and cardiovascular mortality risk after adjustment for confounding factors. Results Persons with normal-weight central obesity had the worst long-term survival: a man with a normal BMI (22 kg/m2) and central obesity had greater total mortality risk than one with similar BMI but no central obesity (hazard ratio [HR], 1.87 [95% CI, 1.53–2.29]) and twice the mortality risk of participants who were overweight or obese by BMI only (HR, 2.24 [95% CI,1.52–3.32] and HR, 2.42 [95% CI, 1.30–4.53], respectively). Similarly, women with normal weight and central obesity had higher mortality risk than both women with similar BMI but no central obesity (HR, 1.48 [95% CI, 1.35–1.62]) and women who were obese by BMI only (HR, 1.32 [95% CI, 1.15–1.51]). Expected survival estimates were consistently lower for those with central obesity when controlled for age and BMI. Limitations Body fat distribution was assessed based on anthropometric indicators alone. Information on comorbidities was collected by self-report. Conclusion Normal-weight central obesity defined by WHR is associated with higher mortality than BMI–defined obesity, particularly in the absence of central fat distribution.
Background Body composition changes with aging lead to increased adiposity and decreased muscle mass, making the diagnosis of obesity challenging. Conventional anthropometry, including body mass index (BMI), while easy to use clinically may misrepresent adiposity. We determined the diagnostic accuracy of BMI using dual energy x-ray absorptiometry (DEXA) in assessing the degree of obesity in older adults. Methods The National Health and Nutrition Examination Surveys 1999–2004 were used to identify adults aged ≥60years with DEXA measures. They were categorized (yes/no) as having elevated body fat by gender (men≥25%; females ≥35%) and by body mass index (BMI) ≥25 and ≥30kg/m2. The diagnostic performance of BMI was assessed. Metabolic characteristics were compared in discordant cases of BMI/body fat. Weighting and analyses were performed per NHANES guidelines. Results We identified 4,984 subjects (men:2,453; female:2,531). Mean BMI and % body fat was 28.0kg/m2 and 30.8% in men, and 28.5kg/m2 and 42.1% in females. A BMI ≥30kg/m2 had a low sensitivity and moderately high specificity (men:32.9% and 80.8%, concordance index 0.66; females:38.5% and 78.5%, concordance 0.69) correctly classifying 41.0 and 45.1% of obese subjects. A BMI ≥25kg/m2 had a moderately high sensitivity and specificity (men:80.7% and 99.6%, concordance 0.81;females:76.9% and 98.8%, concordance 0.84) correctly classifying 80.8 and 78.5% of obese subjects. In subjects with BMI<30kg/m2 body fat was considered elevated in 67.1% and 61.5% of males and females, respectively. For a BMI≥30kg/m2, sensitivity drops from 40.3 to 14.5% and 44.5 to 23.4%, while specificity remains elevated (>98%),in males and females, respectively in those 60–69.9years to subjects aged ≥80years. Correct classification of obesity using a cutoff of 30kg/m2 drops from 48.1 to 23.9% and 49.0 to 19.6%, in males and females in these two age groups. Conclusions Traditional measures poorly identify obesity in the elderly. In older adults, BMI may be a suboptimal marker for adiposity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.