TABLE 3.
Lung function by the presence of chronic bronchitis symptoms, chronic airway obstruction (CAO) and self-reported asthma
| Mutually exclusive categories | p-value# | ||||||||
| Without CBS, CAO and asthma | CBS | CAO | CAO+CBS | Asthma | Asthma+CBS | CAO+asthma | CAO+asthma+CBS | ||
| Subjects n | 18 551 | 345 | 1192 | 129 | 746 | 121 | 257 | 77 | |
| FEV1 % pred¶ | 89.7±17.1 | 89.8±17.9 | 66.6±19.8 | 56.4±18 | 86.6±16.4 | 82.9±17.5 | 59.8±18.3 | 55.8±21 | <0.001 |
| FVC % pred¶ | 88.1±16.8 | 90.3±18 | 86.5±21.8 | 81.4±18.8 | 86.8±16 | 84.3±17.9 | 82.6±20.1 | 79.2±20.5 | <0.001 |
| FEV1/FVC¶ | 79.4±6.0 | 77.0±6.4 | 58.4±8.8 | 52.3±11 | 78.1±6.2 | 76.8±6.5 | 55.5±10.6 | 53.2±11.4 | <0.001 |
| ΔFEV1¶ mL | 67.9±14.2 | 93.7±184.5 | 110.2±171.0 | 131.0±141.1 | 113.9±176.7 | 127.8±192.8 | 177.3±184.7 | 154.9±169.4 | <0.001 |
|
ΔFEV1¶ % of initial value |
3.1±7.0 | 4.0±7.5 | 7.9±12.4 | 10.8±12.3 | 5.6±9.0 | 6.7±10.3 | 14±15.3 | 13.1±13.2 | <0.001 |
|
Proportion of subjects with ΔFEV1¶ ≥12% and >200 mL+ |
5.3 | 9.3 | 18.6 | 30.2 | 13.5 | 19.0 | 38.9 | 32.5 | <0.001 |
|
Proportion of subjects with ΔFEV1¶ >15% and >400 mL+ |
1.4 | 2.0 | 4.1 | 3.9 | 4.6 | 5.0 | 11.7 | 6.5 | <0.001 |
Data are presented as mean±sd or %, unless otherwise stated. n=21 418. CBS: chronic bronchitis symptoms; FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity; ΔFEV1: change in FEV1. #: comparison across mutually exclusive groups; ¶: post-bronchodilator; +: thresholds for significant bronchodilator response suggested in the Global Initiative for Asthma guidelines [28].