Cumulative Associations Between Midlife Health Behaviors and Physical Functioning in Early Old Age: A 17-Year Prospective Cohort Study

ObjectivesTo examine cumulative associations between midlife health behaviors and walking speed and upper-limb strength in early old age. DesignProspective cohort study. SettingWhitehall II Study. ParticipantsIndividuals (mean age 49.15.9 in 1991-93) with health behavior data for at least two of the three assessments (1991-93, 1997-99, 2002-04) and physical functioning measures in 2007-09 (mean age 65.95.9) (N=5,671). MeasurementsA trained nurse assessed walking speed and upper-limb strength. Unhealthy behaviors were defined as current or recent smoking, nonmoderate alcohol consumption (abstinence or heavy drinking), fruit and vegetable consumption less than twice per day, and physical inactivity (<1h/wk of moderate and <1h/wk of vigorous physical activity). For each unhealthy behavior, a cumulative score was calculated as the number of times a person reported the behavior over the three assessments divided by 3. The score ranged between 0 (never) and 1 (all three times). ResultsIn linear regression models adjusted for age, sex, education, marital status, and height, all unhealthy behaviors in 1991-93 were associated with slower walking speed in 2007-09, with differences ranging from 0.10 (nonmoderate alcohol consumption) to 0.25 (physical inactivity) of a standard deviation between participants with and without the unhealthy behavior (Pt-test<.001). For walking speed, the accumulation-of-risk model provided the best fit for unhealthy diet ( for a 1-point increment in the low fruit and vegetable consumption score=-0.29, 95% confidence interval (CI)=-0.36 to -0.22) and physical inactivity (=-0.37, 95% CI=-0.45 to -0.29). For smoking and nonmoderate alcohol consumption, a cumulative effect was also observed, but partial F-tests did not suggest that it provided a better fit than models with behaviors in 1991-93, 1997-99, or 2002-04. All behavioral scores except smoking were associated with grip strength, but F-tests supported the accumulation-of-risk hypothesis only for physical inactivity. ConclusionThese findings highlight the importance of duration of unhealthy behaviors, particularly for diet and physical activity, when examining associations with physical functioning.