Table 2.
Spirometry results by age group
| Overall cohort n = 427 |
Adolescents 10 – 19 years old n = 52 |
Adults ≥20 years old n = 375 |
p-value | |
|---|---|---|---|---|
| Abnormal spirometry*, n (%, 95% CI) | 85 (20, 16 – 24) | 21 (40, 28 – 54) | 64 (17, 14 −21) | <0.001 |
| Airflow limitation (FEV1/FVC<LLN), n (%, 95% CI) | ||||
| Pre-bronchodilator (pre-BD) | 51 (12, 9 – 15) | 12 (23, 14 – 37) | 39 (10, 8 – 14) | 0.008 |
| Post-bronchodilator (post-BD) | 42 (10, 7 – 13) | 14 (27, 17 – 41) | 28 (7, 5 – 11) | <0.001 |
| FEV1 in L, pre-BD, mean (SD) | 2.62 (0.71) | 1.83 (0.55) | 2.73 (0.66) | -- |
| FEV1, % predicted pre-BD, mean (SD) | 95 (16) | 88 (18) | 96 (16) | 0.001 |
| FEV1 < LLN, n (%, 95% CI) | 55 (13, 10 – 16) | 14 (27, 17 – 41) | 41 (11, 8 – 15) | 0.001 |
| FVC in L, pre-BD, mean (SD) | 3.26 (0.85) | 2.20 (0.54) | 3.41 (0.77) | -- |
| FVC, % predicted pre-BD, mean (SD) | 98 (15) | 94 (15) | 98 (15) | 0.05 |
| FVC < LLN, n (%, 95% CI) | 38 (9, 7 – 12) | 9 (17, 9 – 30) | 29 (8, 5 – 11) | 0.02 |
| Bronchodilator responsiveness†, n (%, 95% CI) | 73 (17, 14 – 21) | 11 (21, 12 – 34) | 62 (17, 13 – 21) | 0.4 |
| Bronchodilator responsiveness in abnormal spirometry, n (%, 95% CI) | 29/85 (34, 25 – 45) | 7/21 (33, 16 – 56) | 22/64 (34, 24 – 47) | 1.0 |
| Bronchodilator responsiveness in normal spirometry, n (%, 95% CI) | 44/342 (13, 10 – 17) | 4/31 (13, 5 – 30) | 40/311 (13, 10 – 17) | 1.0 |
*
Abnormal spirometry includes pre-BD FEV1/FVC<LLN, FEV1<LLN and FVC<LLN.
†
Bronchodilator responsiveness present if FEV1 and/or FVC increased by ≥12% and 200 mL after bronchodilator administration.