The Role of Age in Moderating the Association between Disability and Light-Intensity Physical Activity

Abstract

Purpose. There's a lack of evidence on the association between light-intensity physical activity and disability. This study examines the relationships in activity by self-reported physical function in five domains (i.e., activities of daily living [ADL], instrumental ADL, leisure activities, lower extremity, and general activities), and whether this association varies by age. Design. Cross-sectional. Setting. Data from National Health and Nutrition Examination Survey 2003–2004 and 2005–2006 waves. Subjects. Participants included 5700 men and women ages 20 to 85 years. Measures. Difficulty with various activities was measured with the Physical Functioning Questionnaire, accelerometer-measured physical activity, demographics, and self-rated health. Analysis. Ordinary least squares regression models were run to examine the relationship between physical function in each domain, light-intensity activity, and the moderating effect of age. Analyses controlled for body mass index, moderate-to-vigorous–intensity activity, self-reported health, accelerometer wear time, and gender. Results. Little variation was seen in light-intensity physical activity among younger adults regardless of disability status. Older adults reporting difficulty with activities engaged in significantly less light-intensity physical activity compared to those with no disability (271.8 vs. 316.5 minutes). Age significantly moderated the association between light-intensity physical activity and leisure activities (p = .048), and lower extremity mobility (p = .039). Age did not moderate other domains of disability. Conclusion. Younger age may be protective regarding the influence of disability on light-intensity activity. In addition, disability may be more debilitating for some older individuals. Interventions to increase light-intensity activity should aim to address disability at all ages, with increased attention for older adults.