Table 1.
Comparison of baseline characteristics between never-smokers without COPD and those with COPD.a
| Total (n = 131) | Never-smokers without COPD (n = 54; 41.2%) | Never-smokers with COPD (n = 77; 58.8%) | p | |
|---|---|---|---|---|
| Age | 73.0 (70.0, 77.0) | 73.0 (69.0, 77.0) | 74.0 (71.0, 78.0) | 0.314 |
| Female | 95 (72.5) | 38 (70.4) | 57 (74.0) | 0.793 |
| BMI (kg m−2) | 24.0 ± 3.1 | 23.9 ± 3.2 | 24.1 ± 3.1 | 0.682 |
| Extra-pulmonary comorbidities | ||||
| Diabetes mellitus | 16 (12.2) | 7 (13.0) | 9 (11.7) | 1.0 |
| Cerebrovascular disease | 12 (9.2) | 5 (9.3) | 7 (9.1) | 1.0 |
| Malignancy | 6 (4.6) | 3 (5.6) | 3 (3.9) | 0.976 |
| Chronic liver disease | 5 (3.8) | 2 (3.7) | 3 (3.9) | 1.0 |
| Chronic kidney disease | 3 (2.3) | 2 (3.7) | 1 (1.3) | 0.772 |
| Pulmonary comorbidities | ||||
| Asthma | 30 (22.9) | 11 (20.4) | 19 (24.7) | 0.575 |
| Bronchiectasis | 4 (3.1) | 1 (1.9) | 3 (3.9) | 0.782 |
| CAT score | 18.0 (9.0, 26.0) | 18.0 (9.0, 24.0) | 19.0 (8.0, 26.0) | 0.830 |
| mMRC dyspnea scale | 0.536 | |||
| 0 | 25 (19.1) | 13 (24.1) | 12 (15.6) | |
| 1 | 56 (42.8) | 22 (40.7) | 34 (44.1) | |
| 2 | 16 (12.2) | 8 (14.8) | 8 (10.4) | |
| 3 | 26 (19.8) | 9 (16.7) | 17 (22.1) | |
| 4 | 8 (6.1) | 2 (3.7) | 6 (7.8) | |
| Severity of airflow limitations | <0.001 | |||
| Mild | 46 (35.1) | — | 46 (59.7) | |
| Moderate | 30 (22.9) | — | 30 (39.0) | |
| Severe | 1 (0.8) | — | 1 (1.3) | |
| Post-BD spirometry | ||||
| FVC (L) | 2.6 (2.1, 3.1) | 2.7 (2.2, 3.1) | 2.4 (2.1, 3.4) | 0.510 |
| FVC (% predicted) | 103.0 (93.5, 114.0) | 100.5 (93.0, 113.0) | 104.0 (94.0, 115.0) | 0.583 |
| FEV1 (L) | 1.7 (1.4, 2.1) | 2.1 (1.7, 2.3) | 1.5 (1.2, 1.9) | <0.001 |
| FEV1 (% predicted) | 94.0 (80.6, 104.5) | 99.5 (94.0, 115.0) | 86.0 (72.0, 96.0) | <0.001 |
| FEV1/FVC (%) | 66.7 ± 9.4 | 75.5 ± 3.7 | 60.6 ± 6.6 | <0.001 |
COPD: chronic obstructive pulmonary disease; BMI: body mass index; mMRC: modified Medical Research Council; BD: bronchodilator; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 s; CAT: COPD assessment test.
aCategorical variables are presented as number (%) and continuous variables are presented as mean and standard deviation or median and interquartile range, as appropriate.