Association of Gait Speed, Psychomotor Speed, and Dementia.

Abstract

Gait speed (GS) and psychomotor speed (PS) could be considered as two different dimensions of age-related slowness and both measures are associated with higher risk of adverse health-related outcomes among elderly people. To determine the association between GS, PS, and incident dementia among community-dwelling older adults. Twelve-year longitudinal study of 1,265 participants in the Bordeaux Three-City Study, a French prospective cohort designed to determine the risk of dementia and cognitive impairment attributable to cardiovascular risk factors. Participants completed a battery of cognitive tests, including time to complete the Trail Making Test A, and a walking speed test. The incidence of dementia was determined over the 12-year follow-up period. Cox proportional hazards models with delayed entry were used to estimate the cumulative risk of dementia and were adjusted for sex, education, and ApoE4 genotype. Mean age of participants was 74.0 years (SD 4.8). Over the 12-year follow-up, 203 participants developed dementia. GS and PS were both independent predictors of incident all-cause dementia after 12 years of follow-up. For a one SD increase of either GS or PS, the hazard ratio (HR) for Alzheimer's disease was 1.2 (95% CI = 1.02-1.32) and 1.4 (95% CI = 1.2-1.61), respectively; whereas for incident vascular dementia, the HR was 1.3 (95% CI = 1.05-1.71) and 1.5 (95% CI = 1.16-2.08), respectively. No significant interaction between GS and PS was observed. In older French people aged 65+, our findings showed that both low GS and PS were independently associated with risk of incident Alzheimer's disease and vascular dementia.