Changes in Bone Mineral Density of the Proximal Femur and Spine with Aging DIFFERENCES BETWEEN THE POSTMENOPAUSAL AND SENILE OSTEOPOROSIS SYNDROMES

(BMD) of the proximal femur, lumbar spine, or both by dual photon absorptiometry in 205 normal volun-teers (123 women and 82 men; age range 20 to 92 yr) and in 31 patients with hip fractures (26 women and 5 men; mean age, 78 yr). For normal women, the regression of BMD on age was negative and linear at each site; overall decrease during life was 58 % in the femoral neck, 53 % in the intertrochanteric region of the femur, and 42 % in the lumbar spine. For normal men, the age regression was linear also; the rate of decrease in BMD was two-thirds of that in women for femoral neck and intertrochanteric femur but was only one-fourth of that in women for lumbar spine. This difference may explain why the female/male ratio is 2:1 for hip fractures but 8:1 for vertebral fractures