Study participant characteristics and lung function (n=767)
| Study characteristics | 2002–2008 follow-up | 2010–2012 follow-up |
| Age, (mean, SD) | 44.8 (0.8) | 49.6 (0.6) |
| Sex, n (%) | ||
| Men | 382 (49.9) | |
| Women | 385 (50.0) | |
| Height, cm (mean, SD) | 170.4 (8.7) | |
| Smoking history | ||
| Never, n (%) | 345 (47.1) | 345 (46.2) |
| Past, n (%) Pack-years, median (Q1, Q3) | 243 (32.7) 6.3 (1.8 to 17.8) | 284 (38.9) 6.3 (1.4 to 18) |
| Current, n (%) Pack-years, median (Q1, Q3) | 179 (20.2) 21 (7.5 to 30) | 138 (14.9) 24.5 (12.6 to 33) |
| Prebronchodilator lung function | ||
| FEV1, mean decline (mL/year, 95% CI) | −27.8 (−31.3 to −24.2) | |
| FVC, mean decline (mL/year, 95% CI) | −33.4 (-39.0 to −27.7) | |
| FEV1/FVC, mean decline (%/year, 95% CI) | −0.6 (−0.7 to −0.6) | |
| Current asthma, n (%) | 203 (17.5) | 177 (14.9) |
Q1, 25th centile; Q3, 75th centile.