Premenopausal Calcium with or Without Vitamin D Supplementation: A Critical Window of Opportunity for Preventing Bone Loss Across Menopause Transition (P18-049-19)

To estimate the annualized BMD changes of the lumbar spine and femoral neck by the use of calcium with or without vitamin D supplements in the Study of Women’s Health Across the Nation (SWAN), a multi-center, multi-ethnic, community-based longitudinal cohort across the menopause transition. Mixed model regression was used to estimate the 10 year annualized BMD change between the calcium with or without vitamin D supplements in SWAN women (n = 1564; aged 42 to 52 years at baseline) unadjusted and adjusted for time-varying covariates (age, menopausal status[pre-, early peri-, late peri- and post- menopausal], smoking, physical activity) and time-constant covariates (height, baseline alcohol). Models were also stratified by menopausal status at baseline. When combined by menopausal status, calcium with or without vitamin D supplement use was associated with less femoral neck BMD annualized loss across in all models (beta = 0.0038 vs −0.0048; P = 0.003). When stratified by pre- and peri- menopause at baseline, calcium with or without vitamin D supplement use was only significant in pre-menopausal women for both the lumbar spine (beta = 0.0067 vs −0.0082; P = 0.02) and femoral neck (beta = −0.0037 vs −0.0052; P = 0.002). The use of calcium with or without vitamin D supplements is associated with less BMD loss of the lumbar spine and femoral neck, especially in premenopausal women. Funding for this study was provided through an unrestricted educational grant from Pfizer. The funding body had no influence on the study design; the collection, analysis, and interpretation of data; the writing of the report; and the decision to submit the paper for publication.