Association of gait speed with mortality among the Japanese elderly in the New Integrated Suburban Seniority Investigation Project: a prospective cohort study.

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. SUBJECTS 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. CONCLUSION 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.