Influence of body weight on rates of change in bone density of the spine,hip, and radius in postmenopausal women

Summary Interrelationships between percent of ideal body weight (%IBW), serum estrogen levels, and change in bone mineral density (BMD) and bone mineral content (BMC) were studied in 288 postmenopausal women aged 41–71 years who participated in a 2-year calcium supplement trial. The spine (L2–L4) and femoral neck were measured by dualphoton absorptiometry, and the radius was measured by single-photon absorptiometry. Years since menopause, calcium intake, and initial BMD or BMC were included as independent variables in two-phase regressions of BMD and BMC on %IBW. Increased %IBW protected against loss of spine BMD regression slope estimate=0.05, 95% C.I.: (0.03, 0.26)] and BMC in women up through about 106 %IBW but not in heavier women. Increased %IBW was not significantly related to BMD or BMC at the femoral neck or radius. Women above 106%IBW had significant gains in spine and femoral neck area (P< 0.05). Serum estrone and estradiol were positively correlated with BMD and BMC at the femoral neck only.