Associations of gait speed and other measures of physical function with cognition in a healthy cohort of elderly persons

Background. Recent evidence suggests that physical decline and slower gait may be associated with early signs of dementia, but more information on healthy older adults is needed. Methods. We determined associations between cognitive function, gait speed, and self-reported measures of physical function in 3035 healthy mobile participants of the Ginkgo Evaluation of Memory Study evaluated in 2000-2001. Gait speed was measured over a 15-foot course with participants walking at both their usual and rapid pace. Self-reported difficulties with Activities of Daily Living (ADLs) and other physical function tasks were also collected. Results of the Modified Mini-Mental State Examination (3MSE) determined cognitive function. Results. The average age of the cohort was 78.6 years (standard deviation [SD] 3.3), and 53.9% of participants were men. Mean gait speed was 0.95 (SD 0.23) m/s at a usual pace and 1.35 (SD 0.58) m/s at a rapid pace. More than three-fourths of participants had 3MSE scores > 90. In multiple logistic models adjusted for demographics and comorbidities, risk of low cognition (defined as 3MSE score of 80-85) was almost twice as great for participants in the slowest quartile of the rapid-paced walking task than for the fastest walkers (odds ratio: 1.96, 95% confidence interval, 1.25-3.08). Associations between cognition and usual-paced walking were borderline, and no relationships were found with self-reported measures of physical function, including ADLs. Conclusions. In very healthy older adults, performance -based measures better predict early cognitive decline than do subjective measures, and tasks requiring greater functional reserve, such as fast-paced walking, appear to be the most sensitive in assessing these relationships.