Table 4.
Baseline spirometry, lung function growth and airflow obstruction by study group
| Baseline | Group 1, mean (SD) | Group 2, mean (SD) | Group 3, mean (SD) | p Value |
|---|---|---|---|---|
| FEV1 (L) | 0.918 (0.2) | 0.911 (0.2) | 0.823 (0.2) | 0.19 |
| FVC (L) | 1.03 (0.2) | 1.01 (0.2) | 0.87 (0.2) | 0.16 |
| FEV1/FVC | 0.90 (0.06) | 0.90 (0.06) | 0.89 (0.06) | 0.56 |
| FEF25–75 (L) | 1.39 (0.4) | 1.42 (0.5) | 1.28 (0.4) | 0.08 |
| PEF (L) | 2.27 (0.5) | 2.30 (0.6) | 2.17 (0.5) | 0.22 |
| Per cent predicted lung function at baseline* | Mean (SD) | Mean (SD) | Mean (SD) | |
|
| ||||
| FEV1 (%) | 110 (20) | 108 (19) | 104 (16) | 0.15 |
| FVC (%) | 115 (23) | 112 (19) | 109 (16) | 0.16 |
| FEV1/FVC (%) | 95 (6) | 96 (6) | 95 (6) | 0.54 |
| FEF25–75 (%) | 109 (29) | 111 (36) | 101 (29) | 0.09 |
| Annual change† | Mean (95% CI) | Mean (95% CI) | Mean (95% CI) | |
|
| ||||
| FEV1 (mL/year) | 144 (114 to 176) | 100 (63 to 137) | 109 (67 to 152) | 0.14 |
| FVC (mL/year) | 172 (134 to 209) | 137 (96 to 177) | 146 (102 to 190) | 0.43 |
| FEV1/FVC (%/year) | −0.9 (−2.1 to 0.2) | −1.6 (−2.8 to −0.4) | −1.5 (−3.7 to 0.7) | 0.76 |
| FEF25–75 (mL/min/year) | 116 (31 to 202) | 91 (−16 to 198) | 89 (−38 to 217) | 0.91 |
| PEF (mL/min/year) | 405 (298 to 513) | 236 (108 to 365) | 272 (141 to 402) | 0.10 |
| Airflow obstruction | N (%) | N (%) | N (%) | |
|
| ||||
| Children with at least one FEV1/FVC <0.7 | 6 (3.4) | 5 (2.8) | 6 (4.0) | 0.83 |
*
Using the Global Lung Function Initiative predicted lung function equations; unavailable for PEF.
†
Calculations restricted to participants with two or more spirometry sessions.
PEF, peak expiratory flow.