Abstract P139: Changes In Sex Hormones In Premenopausal Black And White Women Associated With Childbearing: The Cardia Women’s Study.

Abstract

Introduction: Sex hormone binding globulin (SHBG) levels in blood are associated with bioavailability of sex hormones, glucose metabolism, and cardiometabolic health of premenopausal women. Low SHBG levels are associated with insulin resistance in women. Pregnancy is characterized by 6-10-fold increase in SHBG levels. This study is designed to evaluate the long-term associations among pregnancy, and SHBG, free and total testosterone levels in premenopausal women. Methods: Premenopausal women, aged 20-32 years, from the CARDIA Women’s Study cohort were tested for levels of serum SHBG, free testosterone, and total testosterone. Hormonal, anthropometric, socio-demographic, and behavioral data, along with self-reported pregnancy and birth data, were collected at baseline (1987-88 [Y0]; n=1,191) and after eight years (Y8; n=809) and 14 years (Y14; n=474) for follow-up. Participants who were pregnant, breastfeeding, had diabetes, hysterectomy, or were using oral contraceptive at any time point were excluded. Participants were divided in parity groups of 0, 1, and 2+births for analyses. Eight-year decrements of SHBG, free and total testosterone were used for primary analyses and 14-year decrements were used for secondary analyses Results: SHBG levels decreased more in parous than nulliparous women in a fully adjusted model including race, CARDIA field center, age, education, alcohol, smoking status, baseline BMI, weight gain and change in waist girth. Total testosterone decreased more in parous women between Y0-Y10 but not thereafter. No significant differences in free testosterone levels were observed among parity change groups in fully adjusted models. Hormone decrement analyses from fully adjusted model Conclusion: Childbearing is associated with a more pronounced long term decrease in SHBG but not with free testosterone levels in premenopausal women. A strong association was observed among parity and total testosterone decrements at 8-year but not 14-year follow-up.