MODULE SUPPLEMENT: MUSCULO-SKELETAL SYSTEM
General Changes in the Bone with Age

Peak bone density may be achieved somewhere between the ages of 20-30, although data are somewhat conflicting (Recker, et al., 1992). However, beginning around the age of 30, the balance between bone formation and bone resorption is altered so that resorption begins to exceed deposition. The rate of loss is accelerated in women at the time of menopause. It then stabilizes and the rate of loss again parallels the rate of loss in men. This is schematically presented in the figure below.

Both compact and trabecular bone are affected by age but at different rates and at different starting times. Bone loss by itself would not be a problem--one doesn't die directly from bone loss. The problem is reaching fracture threshold. Thus one of the most important factors in bone health with age is peak bone density at age of maturity. If peak bone density is great, then a great deal of bone can be lost before fracture threshold is reached. While good bone density does not prevent fracture, it is an extremely important protective factor.