Walking Speed, Cognitive Function, and Dementia Risk in the English Longitudinal Study of Ageing.

Ruth A Hackett,Dorina Cadar,Andrew Steptoe,Hilary Davies‐Kershaw,Martin Orrell

doi:10.1111/jgs.15312

Abstract

ObjectivesTo determine the relationships between walking speed, cognitive function, and the interaction between changes in these measures and dementia risk.DesignLongitudinal observational study.SettingEnglish Longitudinal Study of Ageing.ParticipantsIndividuals aged 60 and older (N=3,932).MeasurementsWalking speed and cognition were assessed at Waves 1 (2002–03) and 2 (2004–05) of the English Longitudinal Study of Ageing. New dementia cases were assessed from Wave 3 (2006–07) to Wave 7 (2014–15). The associations were modelled using Cox proportional hazards regression.ResultsParticipants with faster baseline walking speeds were at lower risk of developing dementia (hazard ratio (HR)=0.36, 95% confidence interval (CI)=0.22–0.60). Those with a greater decline in walking speed from Wave 1 to 2 were at greater risk of developing dementia (HR=1.23, 95% CI=1.03–1.47). Participants with better baseline cognition (HR=0.42, 95% CI=0.34–0.54) were at lower risk of developing dementia. Those with a greater decline in cognition from Wave 1 to 2 were at greater risk of developing dementia (HR=1.78, 95% CI=1.53–2.06). Change in walking speed and change in cognition did not have an interactive effect on dementia risk (HR=1.01, 95% CI=0.88–1.17).ConclusionIn this community‐dwelling sample of English adults, those with slower walking speeds and a greater decline in speed over time were at greater risk of developing dementia independent of changes in cognition. Further research is required to understand the mechanisms that may drive these associations.

Highlights

The evidence is mixed as to whether changes in cognition are associated with changes in walking speed,[18,19,20] and these associations have not been examined in relation to dementia risk
We evaluated whether changes in cognition and walking speed have an interactive effect on dementia risk
We only considered new events from Wave 4 to 7, omitting any that occurred within 2 years of Wave 2. This reduced the number of cases from 289 to 225 (Supplementary Table S2), but walking speed at Wave 1 remained a predictor of dementia (HR50.33)

Summary

OBJECTIVES

To determine the relationships between walking speed, cognitive function, and the interaction between changes in these measures and dementia risk. J1A6G71S executive function (but no other domains) was associated with a decrease in walking speed.[19] An analysis from the Women’s Health Initiative Memory Study failed to detect any association.[20] Overall, it appears that slow walking speed[9] is associated with greater dementia risk, with more-limited evidence that faster decline in walking speed is relevant.[10,11,12] The evidence is mixed as to whether changes in cognition are associated with changes in walking speed,[18,19,20] and these associations have not been examined in relation to dementia risk. We evaluated whether changes in cognition and walking speed have an interactive effect on dementia risk

METHODS

RESULTS

DISCUSSION