Changes in calcanean bone mineral occurring spontaneously and during hormone replacement therapy in early post-menopausal women.

The spontaneous calcanean bone loss occurring in healthy early post-menopausal women and the effect of two hormone replacement therapies (HRT's) were investigated in a longitudinal study. There was no difference between the right and left calcanean BMC or BMD (p > 0.15). The spontaneous bone loss was similar at all the skeletal sites measured, with a mean spontaneous loss in calcanean BMD of 1.6% over one year. Both HRT's significantly (p < 0.01) prevented the bone loss from all skeletal sites irrespective of the weight-bearing or content of trabecular bone, and (for the weight-bearing bones) there was even a gain in calcanean BMC and BMD and spinal BMD (p < 0.01). Bone mineral of the calcaneus and the spine correlated equally to body weight (r approximately 0.4, p < 0.001), whereas bone mineral in the forearm was not correlated to body weight. The correlations between the changes in bone mineral at the sites measured were all significant (r approximately 0.2-0.4).