| Subjects | Mean ± s.e.a | *p | ||
| WCWs | Non-smokers | 8.60 ± 0.60 | <0.05 | |
| Smokers | 13.00 ± 0.93 | |||
| BCWs | Non-smokers | 12.64 ± 0.64 | <0.05 | |
| Smokers | 17.96 ± 1.10 | |||
| WCWs / BCWs | Non-smokers | 8.60 ± 0.60 | <0.05 | |
| 12.64 ± 0.64 | ||||
| Smokers | 13.00 ± 0.93 | <0.05 | ||
| 17.96 ± 1.10 | ||||