Table 1.
Baseline characteristics of patients with COPD and control participants included in the study
| Patients with COPD | Controls | P value | |
|---|---|---|---|
| (n = 35) | (n = 34) | ||
| Gender | |||
| Male | 21 (60.0%) | 20 (58.8%) | 1 |
| Female | 14 (40.0%) | 14 (41.2%) | |
| Age | |||
| Mean (SD) | 61.5 (7.36) | 60.2 (7.82) | 0.473 |
| Median (min, max) | 62.6 (43.9, 71.6) | 62.7 (41.8, 70.6) | |
| BMI | |||
| Mean (SD) | 26.7 (4.15) | 27.5 (4.40) | 0.473 |
| Median (min, max) | 25.9 (20.1, 34.1) | 26.3 (21.4, 39.2) | |
| COPD GOLD grade | |||
| 0 | 0 (0%) | 34 (100%) | <0.001 |
| 1 | 18 (51.4%) | 0 (0%) | |
| 2 | 17 (48.6%) | 0 (0%) | |
| Childhood on farm | |||
| No | 22 (62.9%) | 22 (64.7%) | 1 |
| Yes | 13 (37.1%) | 12 (35.3%) | |
| Smoking status | |||
| Former smoker | 27 (77.1%) | 26 (76.5%) | 1 |
| Never | 8 (22.9%) | 8 (23.5%) | |
| Pack-years of cigarettes smoked | |||
| Mean (SD) | 16.8 (15.1) | 13.8 (22.0) | 0.506 |
| Median (min, max) | 16.7 (0, 54.6) | 7.25 (0, 117) | |
| Education level | |||
| No | 22 (62.9%) | 22 (64.7%) | 1 |
| Yes | 13 (37.1%) | 12 (35.3%) | |
| Number of farms within 3 km radius | |||
| Mean (SD) | 82.7 (30.1) | 90.0 (23.1) | 0.265 |
| Median (min, max) | 78.0 (13.0, 137) | 89.5 (20.0, 129) |
For continuous variables, data are presented as mean (SD) and median (min, max), and P values were derived from t tests between COPD and control groups. For categorical variables, data are presented as number (%) per category and P values were derived from the χ2 test of independence.