Sex steroids and bone density in premenopausal and perimenopausal women

Abstract

Bone density begins to decline in women before menopause, and the degree of bone loss is variable. We performed a cross-sectional analysis on the entry data of a 5-yr prospective study of risk factors for osteoporosis to determine the correlation of bone density with serum sex steroid concentrations and body weight. We studied 292 healthy white women, aged 35-50 yr, who were menstruating regularly or had had menses in the past 12 months. Blood samples were drawn in the early follicular phase for estradiol (E2), testosterone (T), dehydroepiandrosterone sulfate, and sex hormone-binding globulin (SHBG). Free levels of E2 (FE2) and T (FT) were calculated based on total T and E2, SHBG, and albumin levels. Women were classified as premenopausal (FSH, <12 U/L) and perimenopausal (FSH ≥12 U/L; n = 46; 16%). Bone density was measured by dual photon absorptiometry of the lumbar spine (L2-L4) and hip and by single photon absorptiometry of the wrist. Perimenopausal women were older than premenopausal women (45.5+−3.5...