Joint associations of accelerometer-measured physical activity and BMI with mortality: harmonized meta-analysis of cohort studies

Background: What are the joint associations of physical activity/sedentary time and adiposity with mortality risk? Purpose: Determine the joint associations of total, light intensity physical activity (LPA), moderate-to-vigorous physical activity (MVPA), and sedentary time with BMI in relation to all-cause mortality risk. Methods: Harmonized meta-analysis of 34,492 participants (2034 deaths) with a median age of 62.1 years from 8 population-based prospective cohort studies with device-measured physical activity and sedentary time. Follow-up ranged from 6.0 to 14.5 years. Standard BMI-based categories of weight-status were combined with tertiles of total, LPA, MVPA and sedentary time, yielding 9 combinations of weight status and physical activity for each activity exposure. All studies used multivariable-adjustment and excluded individuals with prevalent cardiovascular disease or cancer. Results: There was an inverse dose-response relationship between higher levels of total and intensity-specific physical activity and lower mortality within the normal- and overweight categories, but a clear dose-response relationship within the obese category was only observed for total physical activity. Sedentary time was not associated with mortality risk in individuals with obesity. Compared with the obese-low total activity reference, the HRs (95%CI) were 0.67 (0.48 to 0.94), 0.56 (0.40 to 0.79), and 0.59 (0.44 to 0.79) for the obese-high total activity, overweight-high total activity, and normal weight-high total activity groups. There was no difference in mortality risk between normal weight-low active and obese-low active individuals. Conclusions: Higher physical activity was associated with lower risk of mortality irrespective of weight status. Funding: No funding directly supported this work. Jakob Tarp was funded by the Research Council of Norway (249932/F20).
The Health & Fitness Journal of Canada, Vol. 14 No. 3 (2021): Proceedings from the 8th International Society for Physical Activity and Health Congress