Body fatness and sex steroid hormone concentrations in US men: results from NHANES III

Obesity is associated with a variety of chronic diseases, including cancer, which may partly be explained by its influence on sex steroid hormone concentrations. Whether different measures of obesity, i.e., body mass index (BMI), waist circumference, and percent body fat were differentially associated with circulating levels of sex steroid hormones was examined in 1,265 men, aged 20-90+ years old, attending the morning examination session of the Third National Health and Nutrition Examination Survey (NHANES III). Serum hormones were measured by immunoassay. Weight, height, and waist circumference were measured by trained staff. Percent body fat was estimated from bioelectrical impedance. Multivariate linear regression was used to estimate associations between body fatness measures and hormone levels. Total and free testosterone and sex hormone binding globulin concentrations decreased, whereas total and free estradiol increased with increasing BMI, waist circumference, and percent body fat (all p trend < 0.05). The magnitude of change in these hormones was similar for a one-quartile increase in each body fatness measure. Measured BMI, waist circumference, and percent body fat led to similar inferences about their association with hormone levels in men.