Deaths averted by small changes in physical activity and sedentary time: individual participant data meta-analysis

Background: Previous studies have calculated preventable deaths using self-report physical activity (PA) data to estimate the effects of participants changing from not meeting to meeting the current PA recommendations. This approach may not be feasible for all individuals and fails to capture improvements at the lower end of moderate-to-vigorous-intensity (MVPA) distribution.
Purpose: To estimate the proportion of preventable deaths associated with realistically increases in MVPA and reductions in sedentary time while accounting for the non-linear, dose-response associations between these exposures and risk for mortality.
Methods: Individual participant data meta-analysis of seven prospective cohorts from Norway, Sweden, and the US (N=40,327; 4895 deaths) with device-measured physical activity and sedentary time. The potential impact fraction was calculated from adjusted hazard ratios estimated for five min increases in MVPA and 30 min reductions in sedentary time from observed levels across the activity distribution.
Results: A five-minute increase in MVPA per day in the least active ~20% of participants may prevent 6.0% (95% CI: 4.3%-7.4%) of all deaths. A similar increase in MVPA in the bottom ~80% participants (excluding the most active 20%) may prevent 10.0% (95% CI 6.3% to 13.4%) of all deaths. Reducing sedentary time by 30 minutes per day may prevent 3.0% (2.0% to 4.1%) and 7.3% (4.8% to 9.6%) of all deaths in the two groups, respectively
Conclusion: Small and realistically achievable increases in MVPA of five minutes per day may prevent up to 6% and 10% of all deaths when targeted in a ‘high-risk’ and a ‘population’ approach, respectively. Reducing sedentary time by 30 min per day prevented a smaller proportion of deaths in two risk scenarios, respectively.
Practical implications: Public health professionals and practitioners should consider promoting small increases in daily MVPA especially in the least active proportion of the population.
Funding: NA