Endogenous estrogen levels and calcium intakes in postmenopausal women. Relationships with cortical bone measures.

To examine the interactions between hormone levels and calcium with cortical bone, we have attempted to combine risk factors for the development of peak skeletal mass with factors that may be related to the maintenance of bone integrity after menopause. A total of 174 postmenopausal women participated in our study. There was little relationship found between androgen hormones and radial bone density. Estrone levels were independently related to radial bone density. Examination of the relationship of calcium intake to bone revealed a protective effect solely in women who reported high "lifetime" calcium intakes. Taking calcium and estrone together revealed an additive relationship between the two factors, in that women with high estrone and high calcium levels had significantly greater bone density than women with less calcium and/or estrone. The results suggest that a lifetime of adequate calcium intake coupled with adequate levels of serum estrogens could maximize bone density after menopause.