Relationships between changes in time spent walking since middle age and incident functional disability

Objective: To examine the relationship between changes in time spent walking since middle age and incident functional disability. Method: In 2006, we conducted a prospective cohort study of 7177 disability-free Japanese individuals aged ≥. 65. years who lived in Ohsaki City, Miyagi Prefecture, Japan. Participants were categorized into four groups according to changes in time spent walking based on two questionnaire surveys conducted in 1994 and in 2006. Incident functional disability was retrieved from the public Long-term Care Insurance database, and the subjects were followed up for 5. years. The Cox proportional hazards model was used to investigate the association between changes in time spent walking and the risk of incident functional disability. Results: Compared with subjects who remained sedentary, the multivariate-adjusted hazard ratios (95% confidence intervals) were 0.69 (0.49-0.98) among those who became active and 0.64 (0.50-0.82) among those who remained active. These results did not alter when analyses were stratified by gender, age and motor function status. Conclusion: An increase in time spent walking among sedentary adults is significantly associated with a lower risk of incident functional disability.