Crude and adjusted associations between wood and charcoal smoke exposure and chronic obstructive pulmonary disease(COPD)
| Controls | COPD patients | Univariate logistic regression | Multivariate logistic regression# | |||
| OR (95% CI) | p-value | OR (95% CI) | p-value | |||
| Subjects n | 60 | 60 | ||||
| Wood or charcoal smoke exposure | 43 (72) | 55 (92) | ||||
| Exposure length yrs | 11±10 | 21±18 | 1.1 (1.0–1.1) | 0.003 | 1.1 (1.0–1.1)¶ | 0.001 |
| Exposure length quartiles | ||||||
| 0–7 yrs | 22 (37) | 8 (13) | 1 | 1¶ | ||
| 7–15 yrs | 12 (20) | 16 (27) | 3.7 (1.2–11.0) | 0.02 | 3.8 (1.2–12.1) | 0.02 |
| 15–20 yrs | 15 (25) | 16 (27) | 2.9 (1.0–8.6) | 0.05 | 3.7 (1.2–11.5) | 0.02 |
| >20 yrs | 11 (18) | 20 (33) | 5.0 (1.0–14.9) | 0.004 | 6.7 (2.1–21.5) | 0.001 |
| Time from exposure yrs | 58±10 | 52±17 | 0.97 (0.94–1.00) | 0.03 | 0.97 (0.94–1.00) | 0.02 |
| Time from exposure in quartiles | ||||||
| 0–49 yrs | 11 (18) | 17 (28) | 1 | |||
| 50–55 yrs | 17 (28) | 12 (20) | 0.5 (0.2–1.3) | 0.15 | ||
| 56–63 yrs | 13 (22) | 17 (28) | 0.8 (0.3–2.4) | 0.76 | ||
| >63 yrs | 19 (32) | 14 (23) | 0.5 (0.2–1.3) | 0.16 | ||
| Exposure intensity in summer h·day−1 | 6±4 | 11±7 | 1.4 (1.2–1.7) | <0.0001 | ||
| Exposure intensity in summer in tertiles | ||||||
| 0–6 h·day−1 | 33 (55) | 9 (17) | 1 | 1¶ | ||
| 7–11 h·day−1 | 23 (38) | 18 (34) | 2.9 (1.1–7.5) | 0.03 | 2.9 (1.1–7.7) | 0.03 |
| 12–24 h·day−1 | 4 (7) | 26 (49) | 23.8 (6.6–86.2) | 0.001 | 23.3 (6.3–85.7) | 0.00 |
| Exposure intensity in winter h·day−1 | 8±8 | 15±7 | 1.1 (1.0–1.2) | 0.002 | ||
| Exposure intensity in winter in tertiles | ||||||
| 0–6 h·day−1 | 29 (48) | 9 (17) | 1 | 1¶ | ||
| 7–11 h·day−1 | 18 (30) | 11 (21) | 2.0 (0.7–5.7) | 0.21 | 1.8 (0.6–5.4) | 0.28 |
| 12–24 h·day−1 | 13 (22) | 33 (62) | 8.2 (3.1–21.9) | 0.00 | 8.1 (3.0–22.3) | 0.00 |
| Working as a cook+ | 9 (15) | 14 (25) | 1.9 (0.7–4.8) | 0.18 | ||
| Indoor location of kitchen+ | 44 (73) | 49 (89) | 3.0 (1.1–8.3) | 0.04 | ||
| Type of exposure | ||||||
| Not exposed | 17 (28) | 9 (15) | 1 | 1§ | ||
| Wood smoke | 13 (22) | 11 (18) | 1.6 (0.5–5.0) | 0.42 | 1.8 (0.6–6.0) | 0.33 |
| Charcoal smoke | 20 (33) | 15 (25) | 1.4 (0.5–4.1) | 0.52 | 1.5 (0.5–4.6) | 0.48 |
| Wood and charcoal smoke | 10 (17) | 25 (42) | 4.7 (1.6–14.1) | 0.01 | 4.5 (1.4–14.2) | 0.01 |
Data are presented as n (%), unless otherwise indicated. OR: odds ratio; CI: confidence interval. #: each line is a single adjusted model; ¶: adjusted by smoking (since age was highly correlated with yrs of exposure); +: five values were missing from “working as a cook” and five from “indoor location of kitchen”; §: adjusted by age and smoking.