Abstract
BACKGROUND: The association of pulmonary function (PF) with motor function and disability remains unclear. We investigate the association of PF with motor function trajectories and disability progression, and explore the role of social activity, cognitive function, and cardiovascular diseases (CVDs) in this relationship. METHODS: Within the Rush Memory and Aging Project, 1 403 disability-free participants (mean age: 79.28 years) were followed for up to 22 years. PF was measured with a composite score based on peak expiratory flow, forced expiratory volume in 1 second, and forced vital capacity at baseline. Global motor function including dexterity, gait, and hand strength was assessed annually using 10 motor tests. Disability was evaluated according to the basic activities of daily living. Social activity was defined as the frequency of common types of social interaction. Global cognitive function was assessed using a battery of 19 cognitive performance tests. CVDs (including stroke, congestive heart failure, and heart diseases) were ascertained at baseline. Linear mixed-effects models were used. RESULTS: Compared to high PF, low PF was related to faster decline in global motor function (β = -0.005, 95% confidence interval [CI]: -0.008 to -0.001) and all 3 specific motor abilities (p < .05), as well as faster progression of disability (β = 0.012, 95% CI: 0.009 to 0.014). There was a statistically significant interaction between PF and social activity/cognitive function on disability progression (β = 0.005, 95% CI: 0.001 to 0.009, p = .010/β = 0.004, 95% CI: 0.001 to 0.009, p = .025). CONCLUSION: Poor PF accelerates motor function decline and the progression of disability. A high level of social activity and cognitive function appear to decelerate disability progression related to poor PF.