Table 2.
Associations of residential radon exposure and cigarette smoking with lung cancer.
| Variables | Case, n | Control, n | Conditional Logistic Regression | Conventional Logistic Regression | ||
|---|---|---|---|---|---|---|
| OR (95% CI) * | p-Value | OR (95% CI) † | p-Value | |||
| Residential radon | ||||||
| Low (< 100 Bq/m3) | 448 | 427 | 1.00 (reference) | 1.00 (reference) | ||
| High (≥ 100 Bq/m3) | 71 | 92 | 1.56 (1.03–2.37) | 0.037 | 1.52 (1.00–2.31) | 0.048 |
| Cigarette smoking | ||||||
| Non-smokers | 297 | 338 | 1.00 (reference) | 1.00 (reference) | ||
| Smokers | 222 | 181 | 2.53 (1.60–3.99) | <0.001 | 2.50 (1.59–3.94) | <0.001 |
| Tobacco consumption | ||||||
| Never-smoker | 297 | 338 | 1.00 (reference) | 1.00 (reference) | ||
| Light smokers | 9 | 7 | 3.05 (0.81–11.43) | 0.739 | 2.47 (0.68–8.56) | 0.797 |
| Moderate smokers | 32 | 34 | 2.65 (1.32–5.30) | 0.934 | 2.03 (1.11–3.71) | 0.847 |
| Heavy smokers | 178 | 85 | 5.56 (3.31–9.35) | <0.001 | 4.24 (2.92–6.15) | <0.001 |
| Radon and smoking | ||||||
| Low-radon non-smokers | 262 | 282 | 1.00 (reference) | 1.00 (reference) | ||
| High-radon non-smokers | 35 | 56 | 1.40 (0.81–2.43) | 0.231 | 1.40 (0.81–2.44) | 0.230 |
| Low-radon smokers | 186 | 145 | 2.42 (1.49–3.92) | <0.001 | 2.42 (1.50–3.91) | <0.001 |
| High-radon smokers | 36 | 36 | 4.27 (2.14–8.52) | <0.001 | 4.02 (2.03–7.97) | <0.001 |
* Conditional logistic regression was adjusted for second-hand smoking, sleeping hours, indoor hours, housing type, floor, presence of house cracks, and green ratio. CI, confidence interval; OR, odds ratio. † Conventional logistic regression was further adjusted for age and sex.