Accelerometer-measured physical activity and mortality risk in myocardial infarction survivors: a dose-response analysis
Tao Liu, Junlan Pu, Weijiao Zhou, Wei Luo, Dan Li, Baohua Li, Shaomei ShangAbstract
Objectives:
To examine dose-response associations of accelerometer-measured moderate-to-vigorous physical activity (MVPA), light-intensity physical activity (LIPA), and sedentary time (ST) with all-cause and ischemic heart disease (IHD) mortality among myocardial infarction (MI) survivors.
Methods:
UK Biobank participants with a confirmed history of MI were included. Wrist-worn accelerometers quantified daily MVPA, LIPA, and ST. Cox proportional hazards models estimated hazard ratios (HRs) and 95% CIs for each exposure (single-exposure models) and mutually adjusted partition models that included MVPA, LIPA, and ST simultaneously. Dose effects were modeled per 10 min/day higher MVPA and per 1 h/day higher LIPA and ST, and MVPA was also analyzed in 5 categories (0–<15, 15–<30, 30–<45, 45–<60, ≥60 min/day). Restricted cubic splines were used to visualize dose-response patterns.
Results:
A total of 2108 MI survivors were included (mean age 67.51 y; 79.13% men). During a median follow-up of 7.8 years (IQR: 7.3–8.4) and over 15,920.63 person-years, 295 all-cause deaths and 74 IHD deaths occurred. In partition models, higher MVPA was associated with lower all-cause mortality (per 10 min/day: HR: 0.93, 95% CI: 0.89–0.98) and lower IHD mortality (per 10 min/day: HR: 0.88, 95% CI: 0.80–0.98). Compared with MVPA 0–<15 min/day, MVPA ≥60 min/day was associated with lower all-cause mortality (HR: 0.50, 95% CI: 0.33–0.76) and lower IHD mortality (HR: 0.40, 95% CI: 0.17–0.92). Higher LIPA was inversely associated with all-cause mortality (per 1 h/day: HR: 0.85, 95% CI: 0.77–0.93), but not with IHD mortality (HR: 1.03, 95% CI: 0.85–1.24). ST was not independently associated with all-cause mortality (per 1 h/day: HR: 0.97, 95% CI: 0.90–1.04), or IHD mortality (HR: 1.03, 95% CI: 0.85–1.24).
Conclusions:
Among MI survivors, higher accelerometer-measured MVPA was consistently associated with lower all-cause and IHD mortality. LIPA showed an inverse association with all-cause mortality, whereas ST was not independently associated with mortality in mutually adjusted models.