Table 3:

Associations of death from natural causes with habitual exercise and exposure to air pollution (PM2.5) among adults in Taiwan, stratified by categories of PM2.5 or habitual exercise*

ModelHazard ratiop valueHazard ratiop valueHazard ratiop value
Stratified by PM2.5Low PM2.5Moderate PM2.5High PM2.5
InactiveReferenceReferenceReference
Moderate exercise0.81 (0.74–0.87)< 0.0010.87 (0.81–0.95)0.0010.84 (0.78–0.90)< 0.001
High exercise0.59 (0.55–0.64)< 0.0010.71 (0.65–0.77)< 0.0010.67 (0.62–0.72)< 0.001
Test for trend0.77 (0.74–0.80)< 0.0010.84 (0.81–0.88)< 0.0010.82 (0.79–0.85)< 0.001
Stratified by exerciseInactiveModerate exerciseHigh exercise
Low PM2.5ReferenceReferenceReference
Moderate PM2.50.93 (0.86–1.00)0.041.02 (0.94–1.11)0.71.15 (1.07–1.25)< 0.001
High PM2.50.99 (0.91–1.07)0.71.13 (1.03–1.24)0.0081.34 (1.22–1.47)< 0.001
Test for trend0.98 (0.94–1.02)0.31.06 (1.01–1.11)0.011.16 (1.11–1.21)< 0.001
Per 10 μg/m31.06 (1.01–1.11)0.021.10 (1.04–1.16)0.0011.44 (1.34–1.55)< 0.001
  • * The models fully adjusted for age, sex, educational level, body mass index, physical labour at work, cigarette smoking, alcohol drinking, vegetable intake, fruit intake, occupational exposure, season, and year of enrolment. The tertile cut-off points for exercise volume using the metabolic equivalent (MET) value and duration (h): inactive (MET-h = 0), moderate (MET-h = 0 to 8.75) and high (MET-h > 8.75). The tertile cut-off points for PM2.5: low (< 22.4 μg/m3), moderate (22.4 to 26.0 μg/m3) and high (≥ 26.0 μg/m3).