Mean % predicted FEV1compared between non-smokers and smokers currently working, asymptomatic and symptomatic current workers, and current and ex-employees
| Compared categories (actual number) |
Mean % predicted FEV1 | 95% CI |
| Non-smokers (n=197) | 104.73 | 102.62 to 106.94 |
| Smokers (n=104) | 102.86 | 100.25 to 105.47 |
| Current workers with no WRSs of the lower respiratory tract (n=275) | 104.54 | 102.84 to 106.24 |
| Current workers with WRSs of the lower respiratory tract (n=26) | 99.26 | 92.85 to 105.93 |
| Current workers (n=301) | 104.08 | 102.35 to 105.73 |
| Ex-employees (n=14) | 93.82 | 88.53 to 99.11 |