SEX-HORMONES AND AGE - A CROSS-SECTIONAL STUDY OF TESTOSTERONE AND ESTRADIOL AND THEIR BIOAVAILABLE FRACTIONS IN COMMUNITY-DWELLING MEN

The role of endogenous sex hormones in many diseases makes understandi ng factors that influence levels of these hormones increasingly import ant. This study examined age-associated variations in total and bioava ilable testosterone and estradiol levels among community-dwelling Cauc asian men in Rancho Bernardo, California. Plasma samples obtained from 810 men aged 24-90 years in 1984-1987 were analyzed in 1993 using rad ioimmunoassay. Analyses of age-hormone associations, adjusting for wei ght, body mass index, alcohol ingestion, smoking, physical activity, c affeine intake, specimen storage time, and disease status, were undert aken. Bioavailable testosterone and bioavailable estradiol levels decr eased significantly with age independently of covariates. Total testos terone and estradiol levels decreased with age only when analyses were controlled for confounders. The importance of the age-associated decl ine in endogenous sex hormone levels, particularly levels of bioavaila ble testosterone and bioavailable estradiol, and their relation to dis ease and function in men deserve further research.