| Genotype | Healthy smokers | COPD | OR (95% CI) | p-value | Emphysema | OR (95% CI) | p-value |
| C | 264 (54.8) | 457 (60.8) | 0.78 (0.62–0.98) | 0.037 | 365 (62.5) | 1.38 (1.08–1.76) | 0.010 |
| A | 218 (45.2) | 295 (39.2) | 219 (37.5) | ||||
| CC | 69 (28.6) | 147 (39.1) | 1.82 (1.24–2.69) | 0.002# | 123 (42.1) | 2.04 (1.41–2.94) | 1.73×10−4# |
| CA | 126 (52.3) | 163 (43.4) | 119 (40.8) | ||||
| AA | 46 (19.1) | 66 (17.6) | 50 (17.1) |
Data are presented as n (%), unless otherwise stated. Percentages represent row percentages. Allele and genotype frequencies of rs31489 in COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage II or higher; n=408) and emphysema patients (n=318) were compared with frequencies in healthy smokers (forced expiratory volume in 1 s (FEV1)/forced vital capacity ratio of >0.70 and FEV1 >80% predicted; n=245). #: under the assumption of a recessive genetic model as assessed by logistic regression and after correction for covariates.