Calcium, FSH, and the changing bones of menopause: A longitudinal look at the silent transformation

Osteoporosis poses a health risk to post-menopausal females. The menopause transition is associated with hormone fluctuations (e.g., follicle-stimulating hormone (FSH), estrogen), and other biochemical and physiological changes that contribute a decline in bone mineral density (BMD). This will investigate the relationship between biochemical and physiological markers of BMD across the menopause transition.

Fifty-six middle-aged females who completed their menopause transition were included in this longitudinal sub-analysis. Participants were recruited from the Ottawa/Gatineau region. Menopause status was classified using menstrual history and FSH plasma levels. BMD and body composition were assessed using dual-energy x-ray absorptiometry (DXA). Additional measures included BMI, cardiorespiratory fitness (VO_2max), diet calcium and Vitamin D, and biochemical markers (i.e., FSH, cortisol, calcium). Statistical analysis included repeated measures analysis of variance, linear mixed modeling, and group-based trajectory modeling to identify distinct FSH trajectory groups and their associations with BMD changes over time.

Serum calcium was negatively associated with BMD at the lumbar spine [β: -0.0799, 95% confidence interval (CI): -0.139; -0.020, p = 0.009]. Further, the high FSH trajectory group experienced a greater decrease in BMD across the 5-year period, at the femur neck [β: 0.067, CI: 0.050; 0.084 vs. β: 0.035, CI: 0.021; 0.048; p = 0.003] and total body [β: 0.045, CI: 0.035; 0.055 vs. β: 0.028, CI: 0.020; 0.036; p = 0.007] than the low FSH trajectory group.

Associations between serum calcium and lumbar spine BMD, and a greater BMD decline in individuals with high FSH levels were revealed. This information suggests that serum calcium and FSH should be monitored throughout the menopause transition to protect BMD.