RT Journal Article
SR Electronic
T1 Effects of air pollution and habitual exercise on the risk of death: a longitudinal cohort study
JF Canadian Medical Association Journal
JO CMAJ
FD Canadian Medical Association
SP E1240
OP E1249
DO 10.1503/cmaj.202729
VO 193
IS 32
A1 Cui Guo
A1 Tsung Yu
A1 Ly-yun Chang
A1 Changqing Lin
A1 Hsiao Ting Yang
A1 Yacong Bo
A1 Yiqian Zeng
A1 Tony Tam
A1 Alexis K.H. Lau
A1 Xiang Qian Lao
YR 2021
UL http://www.cmaj.ca/content/193/32/E1240.abstract
AB Background: Exercise may exacerbate the adverse health effects of air pollution by increasing the inhalation of air pollutants. We investigated the combined effects of long-term exposure to fine particle matter (PM2.5) and habitual exercise on deaths from natural causes in Taiwan.Methods: We recruited 384 130 adults (aged ≥ 18 yr) with 842 394 medical examination records between 2001 and 2016, and followed all participants until May 31, 2019. We obtained vital data from the National Death Registry of Taiwan. We estimated PM2.5 exposure using a satellite-based spatiotemporal model, and collected information on exercise habits using a standard self-administered questionnaire. We analyzed the data using a Cox regression model with time-dependent covariates.Results: A higher level of habitual exercise was associated with a lower risk of death from natural causes, compared with inactivity (hazard ratio [HR] 0.84, 95% confidence interval [CI] 0.80–0.88 for the moderate exercise group; HR 0.65, 95% CI 0.62–0.68 for the high exercise groups), whereas a higher PM2.5 exposure was associated with a higher risk of death from natural causes compared with lower exposure (HR 1.02, 95% CI 0.98–1.07, and HR 1.15, 95% CI 1.10–1.20, for the moderate and high PM2.5 exposure groups, respectively). Compared with inactive adults with high PM2.5 exposure, adults with high levels of habitual exercise and low PM2.5 exposure had a substantially lower risk of death from natural causes. We found a minor, but statistically significant, interaction effect between exercise and PM2.5 exposure on risk of death (HR 1.03 95% CI 1.01–1.06). Subgroup analyses, stratified by PM2.5 categories, suggested that moderate and high levels of exercise were associated with a lower risk of death in each PM2.5 stratum, compared with inactivity.Interpretation: Increased levels of exercise and reduced PM2.5 exposure are associated with a lower risk of death from natural causes. Habitual exercise can reduce risk regardless of the levels of PM2.5 exposure. Our results suggest that exercise is a safe health improvement strategy, even for people residing in relatively polluted regions.See related article at www.cmaj.ca/lookup/doi/10.1503/cmaj.211282