Association between change in bone mineral density and decline in usual walking speed in elderly community-dwelling Japanese women during 2 years of follow-up.

摘要

OBJECTIVES: To investigate the association between change in bone mineral density (BMD) and change in usual walking speed in elderly community-living Japanese women during 2 years of follow-up. DESIGN: Longitudinal cohort study. SETTING: Community-based. PARTICIPANTS: A total of 182 women aged 70 to 84 who completed a baseline survey and a follow-up survey 2 years later. MEASUREMENTS: An interview, anthropometric measurements, blood analysis, and physical performance tests were performed at baseline and at follow-up 2 years later. BMD was evaluated using dual-energy X-ray absorptiometry measured at the forearm. Annual percentage changes in BMD and usual walking speed during the 2-year follow-up period were calculated; annual percentage changes in BMD were summarized in quartiles. The association between annual bone loss rate and decline in usual walking speed was analyzed using multiple linear regression adjusted for changes in muscle strength, balance capability, and other potential confounders. RESULTS: Change in BMD was significantly related to change in usual walking speed during the 2-year follow-up. After multivariate adjustment, usual walking speed declined significantly more in elderly women whose BMD decreased (-3.5% change in walking speed in the first quartile of percentage change in BMD and -3.1% in the second quartile) than in women whose BMD increased (+1.5% in fourth quartile). CONCLUSION: Elderly women whose BMD decreased had a significantly greater decline in usual walking speed than women whose BMD increased, even after multivariate adjustment of potential confounders.