Table 5. Prevalence rates of spirometric categories according to respiratory symptoms and age group.
| Respiratory Symptoms | N | Spiometric Category a | ||
|---|---|---|---|---|
| Normal | Airflow-obstruction | Restrictive-pattern | ||
| No. (%) | ||||
| Age 40-80 | ||||
| Dyspnea on exertion | 2,004 | 1,463 (73.0) | 344 (17.2) | 197 (9.8) |
| Chronic bronchitis | 876 | 599 (68.4) | 208 (23.7) | 69 (7.9) |
| Wheezing | 907 | 606 (66.8) | 218 (24.0) | 83 (9.2) |
| Age 40-64 | ||||
| Dyspnea on exertion | 1,168 | 874 (74.8) | 179 (15.3) | 115 (9.9) |
| Chronic bronchitis | 511 | 356 (69.7) | 118 (23.1) | 37 (7.2) |
| Wheezing | 601 | 414 (68.9) | 131 (21.8) | 56 (9.3) |
| Age 65-80 | ||||
| Dyspnea on exertion | 836 | 589 (70.5) | 165 (19.7) | 82 (9.8) |
| Chronic bronchitis | 365 | 243 (66.6) | 90 (24.7) | 32 (8.8) |
| Wheezing | 306 | 192 (62.8) | 87 (28.4) | 27 (8.8) |
Abbreviations: FEV1, forced expiratory volume in 1-second; FVC, forced vital capacity; GLI, Global Lung Function Initiative; GLI-LLN5, lower limit of normal at the 5th percentile distribution, as defined by a GLI-calculated Z-score of -1.64; SD, standard deviation.
a
Normal spirometry was defined by FEV1/FVC and FVC, both ≥GLI-LLN5; airflow-obstruction by FEV1/FVC<GLI-LLN5; and restrictive-pattern by FEV1/FVC≥GLI-LLN5 and FVC<GLI-LLN5.