RADIAL BONE MASS IN POSTMENOPAUSAL WOMEN: A 10 YEAR FOLLOW-UP STUDY959

Abstract

We evaluated the effects of exercise (EXC) and estrogen replacement therapy(ERT) upon radial bone mass in 71 postmenopausal (PM) women followed for 10 yrs. Multiple regression (REG) equations predicted future bone levels in individual Ss under hypothetical interventions of all combinations of EXC and/or ERT. Radial bone mass at the 1/3 and 4mm sites were measured in 1984(BL=baseline), 1989 (BL+5), and 1994 (BL+10) using a Norland SPA Bone densitometer. EXC consisted of light weight lifting (40-60% of 1 RM for benchpress, military press, reverse fly, lat pull), heavy hands (1-5 lbs) during supervised aerobic exercise and walking. ERT consisted primarily of Premarin usage (0.625 mg). REG analyses showed ERT usage to be a significant predictor (p<0.05) of future bone mass at both sites at BL+5 and BL+10(adjusting for individual covariates such as years past menopause and pre-baseline history of EXC and/or ERT usage). EXC was a significant predictor of bone mass at both sites for BL+5, but not for BL+10. R2 values were 0.90 (1/3,BL+5), 0.92 (4mm,BL+5), 0.78 (1/3,BL+10), and 0.85 (4mm,BL+10). PM women should be educated regarding the usefulness of combinations of ERT and EXC as interventions for preserving bone mass. More importantly, the high R2 values suggest the equations can be used clinically for efficient individual predictions of bone levels that may indicate whether intervention(s) are warranted, depending on comparisons with known fracture thresholds.