From: Lifetime environmental tobacco smoke exposure and the risk of chronic obstructive pulmonary disease
Source of ETS exposure | COPD (n = 386) | No COPD (n = 1,727) | P value |
---|---|---|---|
Prenatal ETS* | 32 (8.3%) | 96 (5.6%) | 0.051 |
Cumulative lifetime home ETS | Â | Â | <0.0001 |
   Quartile 1 (0–9 yrs) | 70 (18%) | 443 (26%) |  |
   Quartile 2 (10–21 yrs) | 72 (19%) | 461 (27%) |  |
   Quartile 3 (22–41 yrs) | 86 (22%) | 451 (26%) |  |
   Quartile 4 (≥42 yrs) | 158 (41%) | 372 (22%) |  |
Cumulative lifetime work ETS | Â | Â | 0.0002 |
   Quartile 1 & 2 (0–5 yrs)†| 163 (42%) | 881 (51%) |  |
   Quartile 3 (6–22 yrs) | 93 (24%) | 440 (25%) |  |
   Quartile 4 (≥23 yrs) | 130 (34%) | 406 (24%) |  |