Association between lung cancer risk and exposure to organic dust, stratified by history of chronic obstructive pulmonary disease (COPD) or asthma
| Exposure to organic dust | Overall | No history of COPD or asthma | With history of COPD or asthma |
| n=21 655* | n=16 737 | n=4918 | |
| OR† (95% CI) | OR† (95% CI) | OR† (95% CI) | |
| Never | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) |
| First quartile | 1.08 (0.98 to 1.19) | 1.09 (0.86 to 1.22) | 1.04 (0.85 to 1.28) |
| Second quartile | 1.12 (1.02 to 1.23) | 1.06 (0.95 to 1.18) | 1.32 (1.08 to 1.62) |
| Third quartile | 1.12 (1.01 to 1.24) | 1.09 (0.97 to 1.22) | 1.27 (1.02 to 1.58) |
| Fourth quartile | 1.32 (1.19 to 1.46) | 1.27 (1.13 to 1.42) | 1.49 (1.18 to 1.87) |
| Test for trend, p value‡ | <0.001 | <0.001 | <0.001 |
* Subset of total study population for which information on non-malignant respiratory diseases was available.
† ORs are adjusted for age, sex, study, cigarette pack-years, time since quitting smoking, and ever employment in a ‘list A job’.
‡ p Values for trend result from a logistic regression model with exposure as a continuous variable.