Usual Walking Speed Predicts Decline of Functional Capacity among Community-Dwelling Older Japanese Women: a 4-year Longitudinal Study

Abstract

[Purpose] In this study, we examined the physical predictors of the decline of functional capacity among community-dwelling older Japanese individuals. [Methods] A total of 265 Japanese individuals aged 68-96 years participated in a baseline survey and a follow-up 4 years later. In this survey, participants performed tests for grip strength, one-legged standing, and 5-m walking. At baseline and the follow-up survey, we measured functional capacity using the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC), which consists of the instrumental self-maintenance scale, the intellectual activity scale, and the social role scale. [Results] There was only a weak association between physical performance and the decline of functional status in men. The 5-m walking time was most sensitive at predicting the future decline of the instrumental self-maintenance scale in women. Even after controlling for age, body mass index, grip strength, and one-legged standing, a slower 5-m walking time (greater than 4.6 sec) indicated an increased risk of future decline in instrumental self-maintenance in women (odds ratio = 5.31, p<0.01). [Conclusions] The usual walking speed is the best performance measure for predicting the decline of instrumental self-maintenance among Japanese older women.