Bronchiolitis in Early Infancy Is Associated With Irreversible Airway Obstruction in Young Adulthood.

BACKGROUND

Childhood risk factors, such as bronchiolitis, have been associated with airway obstruction later in life. However, assessing childhood risk factors for airway obstruction in adulthood requires long follow-ups with carefully gathered data. Our long-term follow-up represents lung function in early adulthood after infant bronchiolitis with evaluation of asthma and tobacco smoke exposure as childhood risk factors.

METHODS

We prospectively followed 166 term children hospitalized for bronchiolitis under 6 months of age. Lung function was measured at the mean age of 18.3 years by spirometry on 72 former bronchiolitis patients and 28 controls. We compared z-scores of FEV1 (forced expiratory volume in first second), FVC (forced vital capacity), and FEV1/FVC before and after bronchodilation. Reversibility was tested as FEV1 change in the bronchodilation test. The roles of asthma and smoke exposure were controlled in the analysis.

RESULTS

FEV1/FVC was lower in cases versus controls at baseline (mean z-score -0.90, SD 1.40 vs 0.10 SD 1.17; p = 0.001) and after bronchodilatation (0.54, SD 1.06 vs. -0.05, SD 1.22; p = 0.028). FEV1 increase in the bronchodilation test was greater in cases versus controls (6.3%, SD 5.3 vs. 2.3%, SD 3.7; p = 0.001). After excluding subjects with current asthma, the differences remained significant in baseline and post-bronchodilator FEV1/FVC and in FEV1 change in bronchodilation test, and after adjusting for previous asthma and household smoking, the differences remained significant in baseline and post-bronchodilator FEV1/FVC.

CONCLUSION

Lower FEV1/FVC after bronchodilation in cases suggests a risk of irreversible obstructive lung function in young adults after infant bronchiolitis.