Patients with COPD (n=262) | Healthy smokers (n=152) | |
Demographics | ||
Age† (years) | 66 (60–72) | 61 (58–65)* |
Gender (M/F) | 215/49 | 120/32 |
Body mass index (kg/m2) | 25.3±4.8 | 26.9±4.1* |
Previous steroid use, n (%) | 81 (31) | 0 |
Current steroids, n (%) | 35 (13) | 0 |
Smoking | ||
Current smoker, n (%) | 125 (47) | 68 (44) |
Pack-years† | 47 (33–63) | 39 (30–52)* |
Quit-years† | 1 (0–8) | 2 (0–8) |
Pulmonary function tests | ||
FEV1, litres | 1.8±0.9 | 3.2±0.8* |
FEV1, % predicted | 61±27 | 104±15* |
FVC, litres | 3.4±1.0 | 4.1±0.9* |
FVC, % predicted | 93±22 | 110±14* |
DLCO, % predicted | 60±21 | 85±15* |
KCO, % predicted | 78±23 | 96±16* |
25-OHD (ng/ml) | 19.9±8.2 | 24.6±8.7* |
COPD | ||
GOLD class 1, n (%) | 70 (27) | 0 |
GOLD class 2, n (%) | 87 (33) | 0 |
GOLD class 3, n (%) | 75 (29) | 0 |
GOLD class 4, n (%) | 30 (11) | 0 |
Demographic, smoking and pulmonary function characteristics of patients with COPD and smoking controls are shown. Data are expressed as numbers (group percentages in parentheses) for categorical variables and mean values±SD for continuous variables. When variables were not normally distributed, median values (Q1–Q3 IQR in parentheses) are given instead (indicated by †). Significant p values are indicated by an asterisk (*p<0.05).
COPD, chronic obstructive pulmonary disease; DLCO, diffusing capacity of the lung for carbon monoxide; F, female; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; GOLD, Global Initiative for Obstructive Lung Disease; KCO, alveolar ventilation; M, male; 25-OHD, 25-hydroxyvitamin D.