The microanatomy of trabecular bone loss in normal aging men and women.

Histomorphometric changes in normal bone were investigated using tissue from the ilium of 86 women and 98 men, aged 20-90 years. While loss of trabecular volume was common to both sexes, the histologic basis for the loss differed. Decreased formation (expressed primarily as static indices) seemed to be the principal factor in bone loss in men; in women these features remained unchanged, suggesting that increased resorption was the principal factor. Bone loss in women was principally attributable to the total removal of individual trabeculae; conversely in men, there was generalized attenuation of trabecular bone. Similar findings in bone tissues of vertebral bodies suggest that differences in bone remodelling between the sexes produce different patterns of bone loss as a sequence of aging.