Abstract
BACKGROUND: Life-space mobility captures the daily, enacted mobility of older adults. We determined cross-sectional associations between life-space mobility and cognitive impairment (CI) among community-dwelling women in the 9th and 10th decades of life. METHODS: A total of 1375 (mean age 88 years; 88% White) community-dwelling women enrolled in a prospective cohort of older women. Life-space score was calculated with range 0 (daily restriction to one's bedroom) to 120 (daily trips leaving town without assistance) and categorized (0-20, 21-40, 41-60, 61-80, 81-120). The primary outcome was adjudicated CI defined as mild cognitive impairment or dementia; scores on a 6-test cognitive battery were secondary outcomes. RESULTS: Compared to women with life-space scores of 81-120 and after adjustment for demographics and depressive symptoms, the odds of CI was 1.4-fold (OR 1.36, 95% CI 0.91-2.03) higher for women with life-space scores of 61-80, twofold (OR 1.98, 95% CI 1.33-2.94) higher for women with life-space scores of 41-60, 2.6-fold (OR 2.62, 95% CI 1.71-4.01) higher for women with life-space scores of 21-40, and 2.7-fold (OR 2.71, 95% CI 1.27-5.79) higher for women with life-space scores of 0-20. The association of life-space scores with adjudicated CI was primarily due to higher odds of dementia; the odds of dementia versus normal cognition was eightfold (OR 8.63, 95% CI 3.20-23.26) higher among women with life-space scores of 0-20 compared to women with life-space scores of 81-120. Lower life-space scores were associated in a graded manner with lower mean scores on tests of delayed recall (California Verbal Learning Test-II delayed recall) and language and executive function (phonemic fluency, category fluency, and Trails B). Life-space score was not associated with scores on tests of attention and working memory (forward and backward digit span). CONCLUSIONS: Lower life-space mobility is associated in a graded manner with CI among community-dwelling White women in the 9th and 10th decades of life.