Abstract
ObjectivesTo examine the joint associations of accelerometer-measured physical activity and sedentary time with all-cause mortality.MethodsWe conducted a harmonised meta-analysis including nine prospective cohort studies from four countries. 44 370 men and women were followed for 4.0 to 14.5 years during which 3451 participants died (7.8% mortality rate). Associations between different combinations of moderate-to-vigorous intensity physical activity (MVPA) and sedentary time were analysed at study level using Cox proportional hazards regression analysis and summarised using random effects meta-analysis.ResultsAcross cohorts, the average time spent sedentary ranged from 8.5 hours/day to 10.5 hours/day and 8 min/day to 35 min/day for MVPA. Compared with the referent group (highest physical activity/lowest sedentary time), the risk of death increased with lower levels of MVPA and greater amounts of sedentary time. Among those in the highest third of MVPA, the risk of death was not statistically different from the referent for those in the middle (16%; 95% CI 0.87% to 1.54%) and highest (40%; 95% CI 0.87% to 2.26%) thirds of sedentary time. Those in the lowest third of MVPA had a greater risk of death in all combinations with sedentary time; 65% (95% CI 1.25% to 2.19%), 65% (95% CI 1.24% to 2.21%) and 263% (95% CI 1.93% to 3.57%), respectively.ConclusionHigher sedentary time is associated with higher mortality in less active individuals when measured by accelerometry. About 30–40 min of MVPA per day attenuate the association between sedentary time and risk of death, which is lower than previous estimates from self-reported data.
Funder
National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care East Midlands
National Health and Medical Research Council of Australia
Health and Human Services
NIHR Biomedical Research Centre in Cambridge
UK Medical Research Council
National Institute on Aging
National Institute of Neurological Disorders and Stroke of the National Institutes of Health
American Heart Association
Research Council of Norway
Stockholms Läns Landsting
National Institutes of Health
Norwegian Directorate for Public Health
Centrum for Idrottsforskning
Cancer Research UK
The Coca-Cola Company
National Institutes of Health, National Heart, Lung, and Blood Institute
British Heart Foundation
Subject
Physical Therapy, Sports Therapy and Rehabilitation,Orthopedics and Sports Medicine,General Medicine