Respiratory symptoms in recent quitters at baseline, by interval since the quit date
| Day since smoking cessation | Chi-squared | p-value | ||||
| 0–7 | 8–31 | 32–91 | 92–365 | |||
| Subjects n | 440 | 563 | 537 | 550 | ||
| Median age yrs | 32.0 | 35.0 | 38.0 | 39.0 | 123.8 | <0.001 |
| Males % | 35.0 | 41.4 | 47.5 | 49.5 | 25.8 | <0.001 |
| Do you often cough even without a cold? % | 34.1 | 24.0 | 13.8 | 14.9 | 78.1 | <0.001 |
| Do you expectorate when you cough in the morning? % | 36.8 | 30.9 | 21.0 | 20.4 | 46.9 | <0.001 |
| Are you out of breath after an effort like climbing stairs or a quick walk? % | 68.0 | 63.8 | 52.9 | 54.5 | 32.3 | <0.001 |
| Do you have a wheezing respiration? % | 25.2 | 16.3 | 14.9 | 14.9 | 23.3 | <0.001 |
| None of the above four symptoms % | 17.0 | 21.5 | 34.6 | 34.4 | 117.2 | <0.001 |