Achievement of near-normal body weight as the prerequisite to normalize sex hormone-binding globulin concentrations in massively obese men

OBJECTIVE: To investigate the effects of weight loss on sex hormone-binding globulin (SHBG) in massively obese males and whether normal SHBG concentrations could be obtained regardless or not of the achievement of normal body weight values. DESIGN AND SUBJECTS: Sera were collected for SHBG determination from 63 massively obese men, partly before they underwent biliopancreatic diversion (pre-op group=11) and partly during the post-surgical follow up (post-op group=52), and twenty normal weight healthy control men. MEASUREMENTS: Serum SHBG was measured using a noncompetitive liquid-phase immunoradiometric assay, RESULTS: Baseline general characteristics were similar in both obese groups. Obese patients in the post-op group had lost 46.4 +/- 2.9 kg since they had undergone operation, namely during a mean period of 14.9+/-13.8 (range 1-58) months follow up. Obese groups had significantly lower SHBG than normal weight controls (66.2+/-18.6 nmol/l). However, preop obese (19.9+/-5.5 nmol/l) had significantly lower values than post-op obese subjects (45.5+/-24.8 nmol/l; P<0.001). There were a highly significant correlation between SHBG and individual BMI values (r=-0.629; P<0.001). Moreover, the post-op obese with BMI values lower or equal to 28 had significantly higher SHBG concentrations than those with BMI greater than 28 (62.8+/-22.2nmol/l vs 32.1+19.6nmol/l; P<0.001), but not significantly different with respect to normal weight controls. CONCLUSIONS: Massively obese men weight loss can completely reverse SHBG abnormalities, which can be restored to the normal range when near-normal body weight is achieved. Since reduced SHBG concentrations can be an independent risk factor for the development of diabetes and cardiovascular disease, this represents an additional benefit of weight loss program in massively obese individuals.