INFLUENCE OF BODY-WEIGHT ON RATES OF CHANGE IN BONE-DENSITY OF THE SPINE, HIP, AND RADIUS IN POSTMENOPAUSAL WOMEN

Interrelationships between percent of ideal body weight (%IBW), serum estrogen levels, and change in bone mineral density (DELTA-BMD) and bone mineral content (DELTA-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 dual-photon 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 DELTA-BMD and DELTA-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 DELTA-BMD or DELTA-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 DELTA-BMD and DELTA-BMC at the femoral neck only.