Characteristics of participants by group
| Case | Control | |
| Subjects n (% males) | 150 (68) | 116 (56) |
| Age yrs | 71 (9) | 63 (9) |
| BMI kg·m−2 | 26.0 (4.2) | 28.0 (4.3) |
| FEV1 % pred | 54.4 (18.3) | 95.8 (17.4) |
| FEV1/FVC ratio % | 50.4 (11.5) | 77.1 (7.0) |
| Pack-yrs (IQ range) | 41 (28–56) | 35 (22–49) |
| Current smokers % | 30.7 | 35.3 |
Data are presented as mean (sd) unless otherwise stated
Case: smokers and exsmokers with chronic obstructive pulmonary disease (COPD)
Control: smokers and exsmokers without COPD
BMI: body mass index
% pred: % predicted
FEV1: forced expiratory volume in one second
PVC: forced vital capacity
IQ: interquartile