title: Association of gait speed with mortality among the Japanese elderly in the New Integrated Suburban Seniority Investigation Project: a prospective cohort study.
abstract: BACKGROUND
  gait speed is associated with mortality among the elderly, but evidence for this in Japan is lacking. We investigated the impact of gait speed on mortality among younger-elderly people and determined whether daily walking modifies that association.
  
  
  METHODS
  data were obtained from 2,105 community-dwelling individuals (990 men, 1,025 women) approaching age 65 who were free of heart disease, cerebrovascular disease and cancer, and who were enrolled in the New Integrated Suburban Seniority Investigation Project between 1996 and 2003.
  
  
  METHODS
  Cox proportional hazard regression was applied to estimate hazard ratios (HRs) of all-cause mortality and 95% confidence intervals (CIs) according to gait speed and daily walking. We adjusted for potential confounders, including survey year, marital status, work status, education, smoking and drinking status, body mass index and medical history.
  
  
  RESULTS
  during the total 21,192 person-year follow-up to age 75, 188 participants (140 men, 48 women) died. Slow gait speed was significantly associated with increased all-cause mortality among men after full adjustment (HR, 1.72; 95% CI, 1.08-2.63). This association disappeared when men with slow gait speed walked ≥1 h/day (HR, 0.98; 95% CI, 0.34-2.25) compared with subjects with normal or fast gait speed walking >1 h/day. Slow gait speed yielded a threefold greater risk of mortality when women walked ≥1 h/day (HR, 3.04; 95% CI, 1.34-6.49), compared with the normal- or fast-gait group.
  
  
  CONCLUSIONS
  slow gait speed is associated with an increased risk of all-cause mortality among younger-elderly people. Daily walking was found to modify this association among men.
authors.affiliation: Public Health Department, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Public Health Department, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Ukawa
authors.affiliation: Comprehensive Health Science Center, Aichi Health Promotion Public Interest Foundation, Chita, Aichi, Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Tsushita
authors.affiliation: Kyoto University Health Service, Kyoto, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawamura
authors.affiliation: Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Wakai
authors.affiliation: Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, Nagoya, Aichi, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ando
authors.affiliation: Public Health Department, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Tamakoshi
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging; D002423:Cause of Death; D005260:Female; D005684:Gait; D015577:Geriatric Assessment / Q000379:methods; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D016138:Walking
keywords: daily walking; early old age; gait speed; mortality; older people