A prospective study on a weight control program and its impact on regional and total body composition in post-menopausal women

Abstract

Forty-five obese postmenopausal Caucasian women were treated with phentermine hydrochloride (Fastin®) and a 1200 kcal diet for weight reduction. Total and regional body composition changes were measured by dual-energy X-ray absorptiometry (DXA) and by anthropometry at 3-mo intervals over 9 mo. Plasma lipids, and serum insulin and leptin were measured. After 3 mo, Fastin® therapy produced a 6.8 kg weight loss (P < 0.01), and DXA-assessed fat and lean mass losses (P < 0.01) of 11.9 and 3.0%. respectively. DXA-estimated regional composition revealed respective fat mass losses of 14.1 and 11.9%. From abdomen and thighs, suggesting primarily subcutaneous and central fat depot losses. DXA reliability was assessed by same-day duplicate measurements (n = 10) calculated using old (version 8.1a) and new (version 8.21) analysis software. A 1.5% between-duplicate difference in lean mass was obtained with the old software; the new software yielded 1.1, 1.4 and 1.6% differences between duplicates for fat, lean and leg lean masses, respectively. CVs ranged from 1.7% for bone mineral content to 12.0% for arm fat mass for both versions. The new software produced higher values for all variables, except arm fat and lean masses than the old software. Except for a 1.9% trunk fat loss detected with the old software, magnitude of body composition changes over 3 mo in 21 weight-stable subjects was the same. The new software estimated total weight more accurately and with less variability than the old software. Fastin®-treated women lost (P < 0.01) 10% of their baseline body weight over 9 mo which correlated with a 20% reduction (P < 0.01) in serum leptin concentration. Plasma HDL-cholesterol concentration increased (P < 0.01) by 15% over 9 mo while total- and LDL-cholesterol and triglycerides decreased 14.2 (P < 0.01), 25.4 (P < 0.01) and 12.2% (P < 0.05), respectively. Serum insulin was unaffected by weight reduction. These data suggest that FastinRTM therapy was effective in reducing weight, and in producing a healthier body fat distribution and plasma lipid profile, thereby lowering cardiovascular disease risk in obese postmenopausal women. The DXA instrument (Holologic QDR-4500A. Hologic Inc. Waltham, MA) gave reproducible estimates of composition change in this population regardless of the software version used.