Variables | Without chronic bronchitis | With chronic bronchitis | p-value¶ |
Subjects n | 663 | 96 | |
Age yrs | 64.6±0.47 | 60.6±1.16 | 0.0009 |
Female | 319 (48.1) | 43 (44.8) | 0.5276 |
Body mass index kg·m−2 | 26.8±0.19 | 27.2±0.53 | 0.5244 |
Smoking pack-yrs | 17.9±0.96 | 30.1±3.43 | 0.0006 |
Smoking status | |||
Current | 227(34.2) | 46 (47.9) | 0.0025 |
Former | 216 (32.6) | 31 (32.3) | 0.0025 |
Never | 220 (33.2) | 19 (19.8) | |
Self-reported diagnosis | |||
COPD | 60 (9.1) | 26 (27.1) | <0.0001 |
Asthma | 137 (20.7) | 36 (37.5) | 0.0003 |
Tuberculosis | 30 (4.5) | 9 (9.4) | 0.0494 |
Lung cancer | 6 (0.9) | 2 (2.1) | 0.2948 |
Respiratory symptoms | |||
Wheeze | 229 (34.5) | 66 (68.8) | <0.0001 |
Dyspnoea | 307 (47.0) | 72 (75.8) | <0.0001 |
Exposures | |||
No occupational dust | 322 (48.6) | 34 (35.4) | 0.0344 |
<10 yrs | 168 (25.3) | 32 (33.3) | |
≥10 yrs | 173 (26.1) | 30 (31.3) | |
Any occupational dust exposure | 341 (51.4) | 62 (64.6) | 0.0249 |
Domestic exposure to coal or biomass | 421 (63.5) | 68 (70.8) | 0.1666 |
Childhood pulmonary hospitalisation | 16 (2.4) | 3 (3.1) | 0.6813 |
Any respiratory medication | 81 (12.2) | 32 (33.3) | <0.0001 |
Any bronchodilator | 77 (11.6) | 30 (31.3) | <0.0001 |
Chronic bronchodilator >3 months | 28 (4.2) | 23 (24.0) | <0.0001 |
Any corticosteroid | 25 (3.8) | 17 (17.7) | <0.0001 |
Chronic corticosteroid >3 months | 12 (1.8) | 11 (11.5) | <0.0001 |
Comorbidity score | 1.1±0.04 | 1.4±0.11 | 0.575 |
Exacerbations in the past year | 2.1±0.95 | 5.3±3.83 | 0.4258 |
Short Form-12 physical score | 49.5±0.36 | 44.6±1.01 | <0.0001 |
Limitation due to physical health | 148 (22.4) | 39 (40.6) | 0.0001 |
Work limitation due to physical health | 135 (20.4) | 38 (39.6) | <0.0001 |
Leisure impairment due to physical health | 62 (9.4) | 19 (19.8) | 0.0029 |
Pre-bronchodilator FEV1 % pred | 81.0±0.93 | 67.6±2.10 | <0.0001 |
Post-bronchodilator FEV1 % pred | 84.9±0.85 | 73.0±2.10 | <0.0001 |
Absolute FEV1 change mL | 107.0±7.7 | 135.5±17.6 | 0.1196 |
Relative FEV1 change % | 6.9±0.53 | 9.5±1.37 | 0.0654 |
Pre-bronchodilator FVC % pred | 99.6±0.90 | 90.5±2.18 | 0.0001 |
Post-bronchodilator FVC % pred | 104.0±0.82 | 96.0±2.32 | 0.0013 |
Absolute FVC change mL | 144.5±14.8 | 160.4±41.2 | 0.7102 |
Relative FVC change % | 5.86±0.54 | 6.81±1.54 | 0.5487 |
Pre-bronchodilator FEV1/FVC | 62.1±0.39 | 57.3±0.97 | <0.0001 |
Post-bronchodilator FEV1/FVC | 62.5±0.32 | 58.6±1.02 | 0.0003 |
Data are presented as mean±se or n (%), unless otherwise stated. FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity. #: defined as phlegm on most days, at least 3 months per year for ≥2 yrs; ¶: statistical tests for nominal variables: Pearson Chi-squared (adjusted for survey design); for ordinal variables: Mann-Whitney test; for continuous variables: Wald test (adjusted for survey design).