Menopause and age-related bone loss

This chapter focuses on two major factors that compromise bone strength in women: the occurrence of menopause and the effects of advancing age. Bone remodeling is balanced during young adulthood with equal volumes of bone resorbed and formed. The effect of bone remodeling partly depends upon the surface area/bone matrix volume configuration of the skeleton. Age-related bone loss is the result of a reduction in the volume of bone formed by each BMU. The mechanisms responsible for this reduction in bone formation are not understood but may involve a reduction in osteoblast numbers, their work capacity, or life span. Menopause-related bone loss is a result of four distinct mechanisms: a decline in the net amount of bone deposited by each BMU; a transitory increase in the volume of bone resorbed by each BMU; an increase in the rate of bone remodeling; and a reduction in periosteal apposition associated with intracortical, endocortical, and trabecular bone loss.