Gait speed and cognitive performance in older adult women: the Study of Women’s Health Across the Nation

TL;DR

This study finds that faster walking speed in older women is linked to better future thinking speed, but not the other way around.

Contribution

The study provides longitudinal evidence that gait speed predicts future processing speed, but not vice versa, in older women.

Findings

Faster gait speed at V13 predicted better processing speed at V15 (β = 4.19).

Processing speed at V13 did not significantly predict gait speed at V15.

No significant associations were found between gait speed and working or verbal memory.

Abstract

Cross-sectional studies show a bi-directional association between gait speed and cognitive function; longitudinal studies are needed to determine the true causal directionality. However, longitudinal studies, particularly of older adults, are prone to selection bias due to differential loss to follow-up. This analysis leverages longitudinal data from the Study of Women’s Health Across the Nation to explore relationships between gait speed and cognitive function, accounting for meaningful loss-to-follow-up. We hypothesize that gait speed predicts cognitive functioning and vice-versa. SWAN is a multi-ethnic, community-based cohort of women followed through menopause and into older adulthood. At study visits in 2012-13 (V13) and 2015-16 (V15), 1,258 participants completed: a four-meter timed walk to quantify gait speed and tests of working memory, processing speed, and verbal memory. Linear regressions predicted V15 cognitive test scores from V13 gait speed and vice-versa. Inverse probability weights for missingness due to death, stroke, poor physical function, and other missingness adjusted for differential loss-to-follow-up from baseline. In models including weights to account for differential loss-to-follow-up and adjusting for race and ethnicity, education, age, and financial strain, faster gait speeds at V13 were associated with better processing speed at V15 (β = 4.19,95%CI:1.69,6.70) but processing speed at V13 was not statistically significantly associated with gait speed at V15 (β = 0.0010,95%CI:-0.0002,0.0022). No statistically significant associations were observed between gait speed and working or verbal memory. These results suggest the relationship between gait speed and cognitive function is not bi-directional, but that gait speed may have an effect on future processing speed and not the reverse.