title: Relationships between changes in time spent walking since middle age and incident functional disability.
abstract: OBJECTIVE
  To examine the relationship between changes in time spent walking since middle age and incident functional disability.
  
  
  METHODS
  In 2006, we conducted a prospective cohort study of 7177 disability-free Japanese individuals aged ≥65years 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 5years. 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.
  
  
  CONCLUSIONS
  An increase in time spent walking among sedentary adults is significantly associated with a lower risk of incident functional disability.
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Japan. Electronic address: cutewenty@gmail.com.
authors.forename: Wan-Ting
authors.initials: WT
authors.lastname: Chou
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Japan.
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Tomata
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Sugawara
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Kakizaki
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tsuji
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D002391:Catchment Area, Health; D002908:Chronic Disease / Q000453:epidemiology / Q000517:prevention & control / Q000523:psychology; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000523:psychology* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007353:Insurance, Long-Term Care; D007564:Japan; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data; D057185:Sedentary Behavior; D011795:Surveys and Questionnaires; D016138:Walking / Q000502:physiology* / Q000706:statistics & numerical data
keywords: ADL; Cohort study; Disability; LTCI; Long-term Care Insurance; Longitudinal study; Physical activity; Walking; activities of daily living