Total and local bone mineral during estrogen treatment: a placebo controlled trial

103 healthy postmenopausal women with a natural menopause 0.5-2 years previously were randomized to either estrogen (n = 52) or placebo (n = 51) treatment. Total body bone mineral (TBBM) was measured by dual photon absorptiometry and forearm bone mineral content (BMC) by single photon absorptiometry before and after one year. Both TBBM and forearm BMC fell significantly (P less than 0.001) in the placebo group, but were unchanged after estrogen treatment. The loss of bone mineral in the placebo group during one year was 5% (TBBM) and 3% (forearm BMC). A significant correlation (r = 0.53; P less than 0.001) was found between the fractional percent change in forearm BMC and TBBM. It is concluded, that both the forearm BMC and the TBBM measurements are suitable for following changes in bone mass postmenopausally. The almost equal relative amount of cortical bone in the total skeleton and in the forearm BMC may explain that longitudinally performed forearm BMC measurements are indicative of average changes in the total skeletal status.