Number of participants grouped according to smoking status and time
| Smokers | Ex-smokers | Non-smokers | |
|---|---|---|---|
| Before quitting smoking | 298 | 0 | 136 |
| Cigarette smokers | 237 | — | — |
| Never ceased smoking | 30 | — | — |
| 26 weeks after quitting day | 138 | 160 | — |
| 52 weeks after quitting day | — | 92 | 136 |