Thursday, July 19, 2007

Abdominal Adiposity Has Adverse Effects, Regardless of BMI

Abdominal Adiposity Has Adverse Effects, Regardless of BMI

With fat distribution, it's location, location, location.

In general, evidence implicates body-fat distribution as a risk factor for morbidity and mortality. To evaluate the link between abdominal adiposity and premature death in lean populations, trained interviewers measured baseline weight, height, and waist and hip circumferences (according to a standard protocol) for more than 72,000 nonsmoking participants in the Shanghai Women's Health Study, a population-based, prospective cohort study (age range, 40–70). Mortality data were verified via registries and death certificates. Mean age at enrollment was 52. Mean BMI was normal (24 kg/m2); 35.2% were overweight or obese (BMI >=25), and 5% were obese (BMI >=30). Mean waist-hip ratio (WHR) was 0.81.

During a mean follow-up of 5.7 years, 1456 women died. WHR was positively associated, in dose-response fashion, with all-cause, cardiovascular, stroke, and diabetes mortality (P<0.01 for trend). After adjusting for BMI and other possible confounders, women in the highest WHR quintile had higher risks for death from all causes (relative risk, 1.79), cardiovascular disease (RR, 2.41), and stroke (RR, 2.23) compared with those in the lowest quintile. When stratified for BMI, women with lower BMIs had an even greater risk for death with increasing WHR.

Comment: In less than 6 years, WHR predicted higher mortality in this lean (compared with U.S. women) Chinese population. But an editorialist cautions that, because of time constraints, lack of standardization, and questions about whether abdominal obesity increases risk for all or some populations, fat-distribution measurement in clinical practice is unlikely to become part of routine clinical practice any time soon. What we can do is explain to our patients that BMI is not the whole story. Women with normal BMI but increased abdominal girth can be advised to exercise (which has been shown to decrease waist circumference [Journal Watch Women’s Health Jun 21 2007] and to improve on other modifiable risk factors.

Diane E. Judge, APN/CNP

Published in Journal Watch Women's Health June 21, 2007

Citations

Zhang X et al. Abdominal adiposity and mortality in Chinese women. Arch Intern Med 2007 May 14; 167:886-92. [Medline® abstract]

Hu FB. Obesity and mortality: Watch your waist, not just your weight. Arch Intern Med 2007 May 14; 167:875-6. [Medline® abstract]

Copyright © 2007. Massachusetts Medical Society. All rights reserved.

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