Racial Differences in the Association Between Sex Hormone–Binding Globulin and Adiposity in Premenopausal Women: The BioCycle study

OBJECTIVE: To assess the associations between measures of adiposity and sex hormone– binding globulin (SHBG) and to evaluate whether such associations differ by race. RESEARCH DESIGN AND METHODS: Adiposity was measured by anthropometry and dual-energy X-ray absorptiometry among women (146 white, 50 black, and 25 Asian) aged 18–44 years in the BioCycle study. SHBG was repeatedly measured over one to two menstrual cycles. The ratio of trunkal to leg fat (T/L) was used to assess upper to lower body adiposity. RESULTS: Among whites, all adiposity measures were significantly and inversely associated with SHBG. Among blacks, BMI (β = −0.032), waist circumference (β = −0.016), and T/L (β = −0.033) were significantly associated with SHBG, whereas total and trunkal fat were not (P interaction with race <0.04). Among Asians, measures of central and upper body fat were significantly associated with SHBG (e.g., T/L, β = −0.84) but not BMI. CONCLUSIONS: Associations between SHBG and adiposity differ by race among premenopausal women.