UCSF

Objectives

To evaluate the relationship between life-space mobility (extent, frequency, independence of movement) and mortality in older women.

Design

Prospective cohort study.

Setting

Four U.S. clinical sites.

Participants

Women (N = 1,498) aged 75 to 102 (mean 87.6) followed from 2006 to 2015.

Measurements

Life-space during the past 4 weeks was assessed in an interview, scored from 0 (daily restriction to bedroom) to 120 (daily trips outside town without assistance), and categorized (0-20, 21-40, 41-60, 61-80, 81-120). All-cause mortality was the primary outcome; noncancer, cardiovascular, cancer, and noncardiovascular noncancer mortality were secondary outcomes.

Results

Over a mean 5.2 years, 842 (56.2%) women died. Unadjusted risk of all-cause mortality was 82.6% in women with the lowest level of life-space (0-20 points) and 36.2% in those with the highest level (81-120 points). In multivariable proportional hazards models, there was a strong relationship between less life-space and greater risk of all-cause mortality (P_trend < .001). Women with the lowest level of life-space (0-20 points) had a risk of all-cause mortality that was 2.4 times as high (95% confidence interval (CI) = 1.5-4.0) as that of women with the highest level (81-120 points); women with life-space scores between 21 and 60 had a risk of all-cause mortality that was 1.5 times as high as that of women with the highest level. Each standard deviation decrease in life-space was associated with a 1.2 times greater (95% CI = 1.1-1.4) risk of all-cause mortality. Women unable to travel beyond their neighborhood without assistance had a risk of all-cause mortality that was 1.4 times (95% CI = 1.1-1.7) as high as that of women who could travel beyond their neighborhood without assistance. Results were similar for noncancer, cardiovascular, and other mortality and did not change after controlling for underlying disease or living arrangement.

Conclusion

Life-space scores of 60 or less were associated with mortality in older women independent of other strong risk factors.