Life-Space Mobility and Mortality in Older Men: A Prospective Cohort Study

OBJECTIVES: To evaluate the relationship between life-space (the extent, frequency, and independence of an individual's movement) and mortality in older men. DESIGN: Prospective cohort study. SETTING: Six U. S. clinical sites. PARTICIPANTS: Men aged 71 to 98 followed from 2007 to 2011 (N = 3,892). MEASUREMENTS: Life-space during the past month was assessed as 0 (daily restriction to one's bedroom) to 120 (daily trips outside one's town without assistance) and categorized into 20-point intervals. The primary outcome was noncancer mortality, and secondary outcomes were all-cause, cardiovascular, cancer, and non-cardiovascular noncancer mortality. RESULTS: Over 2.7 years (2007-2011), 373 (9.6%) men died, 230 from noncancer causes. Unadjusted risk of noncancer mortality was 41.2% in men with the lowest level of life-space (0-20 points, n = 34) and 2.4% in men with the highest level of life-space (101-120 points, n = 868), a 17 times difference. In multivariable-adjusted models, there was a strong linear trend between decreasing life-space and increasing risk of noncancer mortality (P =.005). Risk of noncancer mortality was 3.8 times higher (95% confidence interval (CI)= 1.3,11.5) in men with the lowest life-space than in those with the highest life-space. Risk of noncancer mortality was 1.3 times higher (95% CI=1.1-1.5) for each standard-deviation (24 point) decrease in life-space. Risk of noncancer mortality was 1.5 times higher (95% CI= 1.0-2.3) in men who did not travel beyond their neighborhood without assistance (n = 471). Results were similar for all-cause mortality and did not change after control for chronic disease burden. CONCLUSION: Life-space predicted a variety of mortality endpoints in older men; scores of 40 or less were associated with mortality independent of other risk factors.