Concentrations of endogenous sex steroid hormones and SHBG in healthy postmenopausal women

Studies reporting age-specific reference ranges of endogenous sex steroid hormones in postmenopausal women are relatively scarce. If levels differ by age, dosing and treatment regimens should vary among postmenopausal women accordingly. Our objective was to establish reference ranges for sex steroid hormones and sex hormone binding globulin (SHBG) by age group and overall, and to investigate their association with demographic characteristics. Serum samples were obtained from 1207 healthy postmenopausal women aged 41-92, not using hormone therapy, at the baseline visit of 3 clinical trials. Estrone (E1), estradiol (E2), and total testosterone (T) were measured by radioimmunoassay with preceding purification steps; SHBG was measured by direct chemiluminescent immunoassay. Free T (FT) was calculated. Women were categorized by 5-year age groups. There was little change in the mean estrogen levels among the different age groups (E2: 9-12 pg/mL; E1: 33-35 pg/mL). Mean total T levels increased gradually with age from 19.9-26.2 ng/dL, but FT mean levels were relatively constant (3.7-4.6 pg/mL). Mean SHBG levels increased with age from 43-68 nmol/L. A generalized linear model tested the association of each demographic characteristic with the hormones and SHBG. A significant association was derived. Our study provides valuable insight into the profiles of serum sex steroid hormones and SHBG in different healthy postmenopausal women aged 41-92 years.