From: Analysis and evaluation of environmental tobacco smoke exposure as a risk factor for chronic cough
 | ETS exposure (hours/week) |  |  | |||
---|---|---|---|---|---|---|
n = 808 female | Â | Â | Â | Â | Odds ratio (95% CI) | |
 | 0 | 1–9 | 10–39 | >40 | Heavy vs. no exposure | Any vs. no exposure |
at home | 2.9 | 3.2 | 4.2 | 3.0 | 0.93 (0.65, 1.28) | 1.14 (0.97, 1.34) |
Small spaces | 2.8 | 3.2 | 4.1 | 3.4* | 1.17 (0.89, 1.51) | 1.17 (1.01, 1.37) |
Large indoor areas | 2.9 | 3.1 | 3.6 | 5.1*** | 1.68 (1.17, 2.34) | 1.12 (0.96, 1.30) |
Total exposure | 2.7 | 2.8 | 3.8 | 3.3** | 1.14 (0.92, 1.42) | 1.12 (0.96, 1.32) |