Sedentary Time in US Older Adults Associated With Disability in Activities of Daily Living Independent of Physical Activity

Background: The harmful relationship of sedentary behavior to health may reflect an exchange of sedentary activity for moderate-to-vigorous physical activity (MVPA), or sedentary behavior may be a separate risk factor. We examined whether time spent in sedentary behavior is related to disability in activities of daily living (ADL), independent of time spent in MVPA in older adults. Methods: The nationally representative 2003-2006 National Health and Nutrition Examinations Surveys (NHANES) included 2286 adults aged 60 years and older in whom physical activity was assessed by accelerometer. The association between ADL task disability and the daily percentage of sedentary time was evaluated by multiple logistic regression. Results: These adults on average spent 9h/d being sedentary during waking hours and 4.5% reported ADL disability. The odds of ADL disability were 46% greater (odds ratio, 1.46; 95% confidence interval, 1.07-1.98) for each daily hour spent in sedentary behavior, adjusted for MVPA and socioeconomic and health factors. Conclusion: These US national data show a strong relationship between greater time spent in sedentary behavior and the presence of ADL disability, independent of time spent in moderate or vigorous activity. These findings support programs encouraging older adults to decrease sedentary behavior regardless of their engagement in moderate or vigorous activity.