Associations of death from natural causes with habitual exercise and exposure to air pollution (PM2.5 ) among adults in Taiwan*
| Model† | Hazard ratio | p value | Hazard ratio‡ | p value |
|---|---|---|---|---|
| Main effects of exercise | ||||
| Model 1 | ||||
| Inactive | Reference | – | Reference | – |
| Moderate exercise | 0.79 (0.75–0.82) | < 0.001 | 0.79 (0.75–0.82) | < 0.001 |
| High exercise | 0.59 (0.56–0.61) | < 0.001 | 0.59 (0.57–0.62) | < 0.001 |
| Test for trend | 0.77 (0.75–0.78) | < 0.001 | 0.77 (0.75–0.79) | < 0.001 |
| Model 2 | ||||
| Inactive | Reference | – | Reference | – |
| Moderate exercise | 0.84 (0.80–0.88) | < 0.001 | 0.84 (0.80–0.88) | < 0.001 |
| High exercise | 0.65 (0.62–0.68) | < 0.001 | 0.65 (0.62–0.68) | < 0.001 |
| Test for trend | 0.81 (0.79–0.82) | < 0.001 | 0.81 (0.79–0.83) | < 0.001 |
| Main effects of PM2.5 exposure | ||||
| Model 1 | ||||
| Low PM2.5 | Reference | – | Reference | – |
| Moderate PM2.5 | 1.03 (0.99–1.08) | 0.1 | 1.02 (0.97–1.06) | 0.5 |
| High PM2.5 | 1.14 (1.09–1.19) | < 0.001 | 1.13 (1.08–1.18) | < 0.001 |
| Test for trend | 1.07 (1.05–1.09) | < 0.001 | 1.06 (1.04–1.09) | < 0.001 |
| Per 10 μg/m3 of exposure | 1.26 (1.20–1.31) | < 0.001 | 1.21 (1.16–1.26) | < 0.001 |
| Model 2 | ||||
| Low PM2.5 | Reference | – | Reference | – |
| Moderate PM2.5 | 1.04 (0.99–1.08) | 0.1 | 1.02 (0.98–1.07) | 0.4 |
| High PM2.5 | 1.17 (1.12–1.22) | < 0.001 | 1.15 (1.10–1.20) | < 0.001 |
| Test for trend | 1.08 (1.06–1.10) | < 0.001 | 1.07 (1.04–1.09) | < 0.001 |
| Per 10 μg/m3 of exposure | 1.22 (1.17–1.27) | < 0.001 | 1.18 (1.14–1.23) | < 0.001 |
↵* The tertile cut-off points for exercise volume using the metabolic equivalent (MET) value and duration (h): inactive (0 MET-h), moderate (0 to 8.75 MET-h) and high ( > 8.75 MET-h). 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).
↵† Model 1 adjusted for age, sex and education; Model 2 further adjusted for body mass index, physical labour at work, cigarette smoking, alcohol drinking, vegetable intake, fruit intake, occupational exposure, season, and year of enrolment.
↵‡ Further adjusted for exercise (for the association between PM2.5 and death from natural causes) or PM2.5 (for the association between exercise and death from natural causes).