Reallocation time of accelerometer-measured movement behaviours, genetic susceptibility, and incident chronic obstructive pulmonary disease

INTRODUCTION: Little is known about the associations between reallocating time from one movement behaviour to another within 24 h with the risk of chronic obstructive pulmonary disease (COPD), particularly in the context of genetics. METHODS: This study included 87 656 participants from the UK Biobank with valid wrist-worn accelerometer data and without prevalent COPD for the primary analysis. The isotemporal substitution model was used to evaluate the potential impact on COPD incidence of replacing one behaviour with an equivalent duration of another. RESULTS: Our study showed that replacing 1 h/day of sleep, sedentary behaviours (SB), or light-intensity physical activity (LIPA) with an equal amount of time spent in moderate-to-vigorous physical activity (MVPA) was associated with 40%, 43%, and 39% lower risk of incident COPD, respectively. Stratified by genetic risk, within each subgroup, the inverse relationship between replacing sleep, SB, and LIPA with MVPA and COPD remained significant. In the joint association analysis of genetic susceptibility and MVPA duration with COPD, participants with intermediate and low genetic predisposition plus low MVPA duration were significantly associated with a 1.72- (95% CI: 1.32-2.24) and 1.39- (95% CI: 1.04-1.87) fold higher risk of incident COPD, respectively, compared to those with a high genetic predisposition and high MVPA duration. CONCLUSION: Irrespective of genetic susceptibility, substituting MVPA for other movement behaviours was associated with a lower risk of incident COPD. More MVPA involvement seemed to be able to mitigate the genetic risk of COPD.