Walking Speed Is Better Than Hand Grip Strength as an Indicator of Early Decline in Physical Function with Age in Japanese Women Over 65: A Longitudinal Analysis of the Tanno-Sobetsu Study Using Linear Mixed-Effects Models

The decline in physical function with age is a major contributor to the need for long-term care. Age-related changes in hand grip strength, knee extension, and walking speed have been reported in cross-sectional studies, but longitudinal data are needed. This longitudinal study measured changes in these three measures among community-dwelling adults aged 65–89 years who participated in general health examinations between 2017 and 2019. Analyses were stratified by sex. Linear mixed-effects models adjusted for confounding factors were used to examine the interaction of different patterns of change with age of the three measures. A total of 284 participants were included in the analysis. The interaction term of age × walking speed, with age × handgrip strength as the reference, was statistically significant in women and showed different patterns in walking speed and hand grip strength. In men, none of the age × physical function interaction terms were significant in any model. For early recognition of the onset of physical function decline in older adults, any of the three measures may be used in men, but walking speed may be more suitable than hand grip strength in women. These findings may be useful in devising sex-specific screening strategies.