Table 4 Multivariate logistic regression analyses of independent factors as predictors of PTB
Variables | OR | 95 % CI |
|---|---|---|
Age at certification | 1.1 | 1.0–1.1 |
Current smoker* | 4.3 | 1.9–9.9 |
Cumulative respirable silica dust exposure | ||
Low | 1 | |
Medium | 2.8 | 0.7–10.6 |
High** | 6.4 | 1.8–23.0 |