Association of accelerometer-derived physical activity with all-cause and cause-specific mortality among individuals with cardiovascular diseases: a prospective cohort study

Aims To investigate the association of accelerometer-measured intensity-specific physical activity (PA) with all-cause and cause-specific mortality among individuals with cardiovascular disease (CVD).Methods and results In this prospective cohort study, 8024 individuals with pre-existing CVD (mean age: 66.6 years, female: 34.1%) from the UK Biobank had their PA measured using wrist-worn accelerometers over a 7-day period in 2013-2015. All-cause, cancer, and CVD mortality was ascertained from death registries. Cox regression modelling and restricted cubic splines were used to assess the associations. Population-attributable fractions (PAFs) were used to estimate the proportion of preventable deaths if more PA was undertaken. During a median follow-up of 6.8 years, 691 deaths (273 from cancer and 219 from CVD) were recorded. An inverse non-linear association was found between PA duration and all-cause mortality risk, irrespective of PA intensity. The hazard ratio (HR) of all-cause mortality plateaued at 1800 min/week for light-intensity PA (LPA), 320 min/week for moderate-intensity PA (MPA), and 15 min/week for vigorous-intensity PA (VPA). The highest quartile of PA was associated with lower risks for all-cause mortality, with HRs of 0.63 (95% confidence interval [CI]: 0.51-0.79), 0.42 (0.33-0.54), and 0.47 (0.37-0.60) for LPA, MPA, and VPA, respectively. Similar associations were observed for cancer and CVD mortality. Additionally, the highest PAFs were noted for VPA, followed by MPA.Conclusion We found an inverse non-linear association between all intensities of PA (LPA, MPA, VPA, and MVPA) and mortality risk in CVD patients using accelerometer-derived data, but with a larger magnitude of the associations than that in previous studies based on self-reported PA. This study investigated the associations of accelerometer-derived intensity-specific physical activity (PA) with the risks of all-cause and cause-specific mortality among individuals with cardiovascular disease (CVD). L-shaped dose-response relationships between PA duration and all-cause mortality were observed across all levels of PA intensities. The risk reduction for mortality exhibited a sharp decline from 0 to 1800 min/week of light-intensity PA, followed by reaching a plateau. Notably, the inflection points for moderate-intensity PA and vigorous-intensity PA were found at 320 and 15 min per week, respectively.The population-attributable fraction analysis indicated that a significant number of deaths could potentially be prevented if individuals with CVD engaged in more vigorous-intensity PA. Graphical Abstract The research design and key findings of the current study. LPA, light-intensity physical activity; MPA, moderate-intensity physical activity; VPA, vigorous-intensity physical activity; MVPA, moderate-to-vigorous-intensity physical activity; PA, physical activity; CVD, cardiovascular disease.