The dynamic relationship between cognitive function and walking speed: the English Longitudinal Study of Ageing

Abstract Cross-sectional studies show that older peo-ple with better cognition tend to walk faster. Whether this association reflects an influence of fluid cognition upon walking speed, vice versa, a bidirectional relation-ship or the effect of common causes is unclear. We used linear mixed effects models to examine the dynamic relationship between usual walking speed and fluid cognition, as measured by executive function, verbal memory and processing speed, in 2,654 men and wom-en aged 60 to over 90 years from the English Longitu-dinal Study of Ageing. There was a bidirectional rela-tionship between walking speed and fluid cognition. After adjusting for age and sex, better performance on executive function, memory and processing speed was associated with less yearly decline in walking speed over the 6-year follow-up period; faster walking speed was associated with less yearly decline in each cognitive domain; and less yearly decline in each cognitive do-main was associated with less yearly decline in walking speed. Effect sizes were small. After further adjustment for other covariates, effect sizes were attenuated but most remained statistically significant. We found some evidence that walking speed and the fluid cognitive domains of executive function and processing speed may change in parallel with increasing age. Investiga-tion of the association between walking speed and cog-nition earlier in life is needed to better understand the origins of this relation and inform the development and timing of interventions