Relative strength of association between chronic bronchitis and long term occupational exposure to physical and chemical factors adjusted for social class and age
| OR (95% CI) | p Value | |
| Cold and draught exposure v not | 1.4 (1.1 to 1.7) | 0.002 |
| Dust exposure v not | 1.5 (1.1 to 2.0) | 0.020 |
| Social class IV/V v I, II, III | 1.2 (0.99 to 1.5) | 0.063 |
| Organic solvent exposurev not | 1.3 (0.99 to 1.8) | 0.066 |
Not in the final model (p>0.10): age, plastic (manufacture of or exposure to vapours), strong variations of temperature, strong heat, moist and humidity, asbestos, soldering fumes, welding fumes, vapours (from lacquer, paint, and varnish), glass fibre.
Variables are ordered according to strength of association with bronchitis after multivariate adjustment in a logistic regression model with backward elimination of variables.