Relationship between Bone Mineral Content and Frequency of Postmenopausal Fractures

Abstract

To elucidate the relationship between bone mineral content (BMC) and the frequency of postmenopausal fractures, an epidemiologic investigation in a representative sample of 70-yr-old women was performed. Anamnestic data concerning postmenopausal fractures due to minor trauma were recorded, and lateral X-rays of the spine were taken for evaluation of spinal fractures. BMC was measured by 125I photon absorptionmetry. The 285 women studied were allocated into quintiles according to their BMC value. In 77 women, there were 131 definite osteoporotic fractures (i.e., spinal crush and fracture of the hip, proximal humerous and distal forearm), and, in 48 women, there were 162 other nonviolent fractures (i.e., spinal wedge and other long bone fractures). The frequencies of osteoporotic fractues varied inversely with the mean BMC values for each quintile (r = 0.959, P < 0.01). The difference in frequency of osteoporotic fractures between the 1st and 5th quintiles was highly significant (P < 0.001). Other nonviolent fractures appeared to be unrelated to BMC. Low BMC levels may predispose to osteoporotic fractures.