Contribution of body fatness and adipose tissue distribution to the age variation in plasma steroid hormone concentrations in men: The HERITAGE family study

Obesity has been associated with alterations in plasma steroid hormone conc entrations in men. Older men present an altered steroid hormone profile com pared to younger individuals, and an increase in body fatness and changes i n adipose tissue (AT) distribution are noted with advancing age. Thus, ther e is a need to examine the relative importance of increased body fatness an d changes in AT distribution with advancing age to plasma steroid hormone a nd sex hormone-binding globulin levels in men. We, therefore, investigated the relationships among age, body fatness, AT distribution, and the plasma steroid hormone profile in a group of 217 Caucasian men (mean age +/- so, 3 6.2 +/- 14.9 yr) who covered a wide age range (17-64 yr), Compared to young adult men, older men were characterized by increased adiposity (P < 0.0001 ) expressed either as body mass index or total body fat mass assessed by un derwater weighing. Differences in AT distribution were also noted with a pr eferential accumulation of abdominal fat as indicated by a larger waist gir th (P < 0.0001) and higher visceral AT accumulation (P < 0.0001), measured by computed tomography, in older subjects. Age was associated with decrease s (P < 0.0001) in C-19 adrenal steroid levels, namely reduced dehydroepiand rosterone (DHEA), DHEA fatty acid ester, DI-IEA sulfate, as well as androst enedione levels. Androgens, i.e. dihydrotestosterone and testosterone, were also affected by age, with lower levels of both steroids being found in ol der individuals (P < 0.0005). When statistical adjustment for body fatness and AT distribution was performed, differences in C-19 adrenal steroids bet ween the age groups remained significant, whereas differences in androgens and sex hormone-binding globulin concentrations were no longer significant. The present study suggests that age-related differences in plasma steroid hormone levels, especially androgens, are partly mediated by concomitant va riation in adiposity in men.