Midlife Risk Factors for Impaired Physical and Cognitive Functioning at Older Ages: A Cohort Study

Background: Previous studies examined midlife risk factors separately for old-age impaired physical and cognitive functioning. We determined the overlap of risk factors for both domains of functioning within the same setting. Methods: Biological and behavioral risk factors at age 50 years and cognitive and physical functioning were assessed 18 (SD = 5) years later in the Whitehall II study (N = 6,316). Impaired physical functioning was defined as = 1 limitation on the activities of daily living scale. Impaired cognitive functioning was defined as Mini-Mental State Examination score <27. Two statistical analyses were employed: minimally adjusted analysis (for age, sex, and ethnicity) and mutually adjusted analysis (including all risk factors). Missing data on risk factors were imputed. Results: After confounder adjustment, impaired physical and cognitive functioning at older ages were predicted by hypertension (odds ratios [ORs] 1.80 95% confidence interval [CI] 1.39-2.33 and 1.57 95% CI 1.07-2.31, respectively), poor lung function (1.51 95% CI 1.28-1.78 and 1.31 95% CI 1.08-1.59), and physical inactivity, marginally in the case of cognitive function (1.50 95% CI 1.19-1.90 and 1.27 95% CI 0.99-1.62) at age 50 years. Impaired physical functioning but not cognitive functioning was additionally predicted by depression and higher body mass index (1.72 95% CI 1.46-2.03 and 1.29 95% CI 1.16-1.44, respectively). Conclusions: Several midlife risk factors are associated with impaired physical and cognitive functioning in old age, supporting a unified prevention policy. Analysis of 12 risk factors at age 50 suggests that strategies targeting physical inactivity, hypertension, and poor lung function will reduce impairments in both cognitive and physical functioning in old age.