Impact of Weight Loss on the Metabolic Syndrome

Suzanne Phelan, Brown University
T. A. Wadden, University of Pennsylvania
R. I. Berkowitz, University of Pennsylvania
D. B. Sarwer, University of Pennsylvania
L. G. Womble, University of Pennsylvania
R. K. Cato, University of Pennsylvania
R. Rothman, University of Pennsylvania

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Copyright © 2007 Nature Publishing Group. The definitive version is available at http://dx.doi.org/10.1038/sj.ijo.0803606.

NOTE: At the time of publication, the author Suzanne Phelan was not yet affiliated with Cal Poly.

Abstract

Objective:
To evaluate the effects of weight loss on the risk of having metabolic syndrome after 1 year of treatment with lifestyle modification alone, pharmacotherapy alone (sibutramine) or the combination of the two.

Design:
Randomized, controlled, 1-year clinical trial.

Patients:
One hundred and eighty women and 44 men, 18–65 years of age, with a body mass index of 30–45 kg/m2, free of uncontrolled hypertension or type 1 or 2 diabetes.

Intervention:
Fifteen milligrams of sibutramine per day alone, lifestyle modification counseling alone, sibutramine plus lifestyle modification counseling or sibutramine plus brief lifestyle modification counseling.

Measurements:
The metabolic syndrome, as defined by the Adult Treatment Panel III.

Results:
Before treatment, 34.8% of the participants had the metabolic syndrome. Metabolic syndrome was more prevalent in Caucasians than African Americans (42.5 vs 20.3%; P<0.03), in males than females (65.1 vs 34.9%; P<0.002) and in older (>44 years) than younger (less than or equal to44 years) participants (47.5 vs 20.8%; P<0.0001). After 1 year of treatment, a moderate decrease in weight (8.0plusminus8.7 kg) resulted in significant reductions in the prevalence of metabolic syndrome from 34.8 to 27.2% of all participants (P<0.02). Logistic regression analyses indicated that for each 1 kg of weight lost, the odds of metabolic syndrome were reduced by 8% (CI=0.89–0.97; P<0.003). Lifestyle modification either alone (P<0.04), or in combination with sibutramine (P<0.05), significantly reduced the prevalence of metabolic syndrome compared with sibutramine alone. The group effect was removed after controlling for weight loss.

Conclusions:
The metabolic syndrome was prevalent in over one-third of obese individuals who sought weight loss treatment, and the prevalence differed by age, sex and ethnicity. Moderate weight loss markedly reduced the odds of metabolic syndrome in this sample.