Lung function indices (with 95% CI) of non-smoking catering workers for different ranges of urinary cotinine (ng/ml)
| Cotinine (ng/ml) | n0 | n1 | FEV1 (l) | FEF25–75 (l/s−1) | FEV1/FVC (%) |
| ≤0.8 | 37 | 1 | 0 | 0 | 0 |
| 0.8–1.6 | 27 | 2 | −0.067 (−0.197 to 0.063) | −0.065 (−0.389 to 0.260) | 0.019 (−0.007 to 0.044) |
| 1.6–3.2 | 46 | 1 | −0.093 (−0.235 to 0.049) | −0.329 (−0.659 to 0.000)* | −0.011 (−0.041 to 0.019) |
| >3.2 | 30 | 42 | −0.143 (−0.260 to −0.026)* | −0.335 (−0.635 to −0.036)* | −0.001 (−0.028 to 0.026) |
| p for trend=0.017 | p for trend=0.015 | p for trend=0.528 | |||
↵* p<0.05.
Estimates were adjusted for gender, age, height, duration from the last shift of work, exposure to co-workers' SHS, daily duration of SHS exposure at home and in other places, education and income.
FEV1, forced expiratory volume in 1 s; FEF25–75, forced expiratory flow as 25–75% of FVC; FVC, forced vital capacity; n0, number of workers from non-smoking premises; n1, number of workers from smoking premises; SHS, second-hand smoke.