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OBESITY: HEALTH IMPACT AND BENEFITS OF REDUCTION.

Two new studies in JAMA provide insights into obesity and weight reduction. The first was a cross-sectional study of 2792 adults in Manitoba, Canada, of whom 2339 underwent physical examinations. The authors used body mass index (BMI: weight divided by square of height) and waist-to-hip ratio (WHR) to categorize the subjects as nonobese, noncentral obese (high BMI, low WHR), and central obese (high BMI and WHR). The lipid profile, blood pressure, and glucose status of the noncentrally obese subjects were intermediate between those of the nonobese and centrally obese subjects. Multivariate analyses showed that BMI was as strongly -- and sometimes more strongly -- correlated with cardiac risk factors as WHR.

A second study randomly compared the benefits of nine months of diet-induced weight loss, aerobic exercise, or a weight maintenance program in 170 obese but otherwise healthy men over age 45. The weight loss program emphasized a reduction of 300 to 500 kcal per day. Twenty-nine of the 73 men in this group dropped out (versus 22 of 71 men assigned to exercise); the remaining 44 men had an average weight loss of 9.5 kilograms, and 20 (44 percent) met the goal of 10 percent reduction in weight. Weight loss improved glucose tolerance, high-density lipoprotein levels, and systolic and diastolic blood pressure significantly more than exercise.

Comment: Neither of these studies included "hard" cardiovascular outcomes, but the first study indicated that obesity itself is probably an important contributing factor to coronary disease, even if it is noncentral in distribution. The second study supports the health benefits of weight loss, even when it occurs within a brief time period.

— TH Lee

Published in Journal Watch General Medicine January 9, 1996

Citation(s):

Young TK; Gelskey DE. Is noncentral obesity metabolically benign? Implications for prevention from a population survey. JAMA 1995 Dec 27 274 1939-1941.

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Katzel LI et al. Effects of weight loss vs aerobic exercise training on risk factors for coronary disease in healthy, obese, middle- aged and older men: a randomized controlled trial. JAMA 1995 Dec 27 274 1915-1921.

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