A Longitudinal Study of Bone Turnover, Menopause, Aging, and Ethnicity as Risk Factors for Osteoporosis.

This four-year study is a very cost-efficient and timely longitudinal study of bone turnover markers in an ethnically diverse sample of mid-aged women as they experience the menopause transition. Building on the multisite Study of Women's Health Across the Nation (SWAN), already funded by the National Institutes of Aging and Nursing Research at the National Institutes of Health, this study proposes to analyze already collected and stored specimens of serum to measure bone formation (using an immunoradiometric assay of osteocalcin) and stored urine specimens to measure bone resorption (using urinary N-telopeptide of type I collagen). These two measures will be combined with data from SWAN on bone density (spine, hip and total body), ovarian aging (endogenous sex hormones and menstrual bleeding), medications, medical history, social and psychological assessments, and life style factors (exercise, diet, smoking, body mass) to address four research aims. For each of these aims, specific hypotheses will be investigated using data collected at up to four annual visits as well as menstrual bleeding data collected annually from monthly calendars kept by the subjects. To date, major progress on the study includes completion of bone marker assays for two of the three planned study visits, specification of priority manuscripts and conduct of preliminary analyses of the relation of bone markers and bone density to ethnicity, menopause status, and the correlation of bone density to bone turnover markers.