PURPOSE OF THE STUDY.
To determine the predictive value of lung function and airway pathology in infancy for asthma, lung function, airway responsiveness, and purchase of asthma medications at 8 years of age.
The study included 47 of 53 children who had undergone pulmonary function testing and bronchoscopy in infancy because of recurrent lower respiratory tract symptoms who were available for follow-up at 8 years of age, compared with 63 healthy, age-matched controls who were able to perform spirometry.
Current or past symptoms, physician-diagnosed asthma, use of inhaled corticosteroids (ICS) or leukotriene receptor antagonists (LTRA), current lung function (in 42/47), bronchodilator responsiveness (BDR), airway responsiveness (AR) (in 38/47), fraction of exhaled nitric oxide (FeNO), and atopy as manifest by positive skin tests, elevated immunoglobulin E, or peripheral eosinophilia were assessed in the children at age 8 years who had been evaluated in infancy. Results were compared with lung function and bronchoscopy findings in infancy, and lung function in healthy controls.
Physician-diagnosed asthma ever was present in 39 of the 47 study children, current asthma in 25. Reduced lung function in infancy was associated with physician-diagnosed asthma ever, current asthma, reduced lung function, purchase of ICS, LTRA ever and in past 2 years but not with AR or FeNO at age 8. Recurrent lower respiratory tract symptoms in infancy was associated with AR. Children in the study group who had normal lung function in infancy also had lower lung function at age 8 compared with healthy children. Infant smoke exposure and early onset of symptoms was also associated with lung function at age 8. The thickness of the reticular basement membrane, fraction of airway smooth muscle, and presence of endobronchial inflammatory cells in infancy did not correlate with asthma or lung function at age 8.
Reduced lung function in infancy is associated with asthma and treatment needs at age 8. Recurrent lower respiratory tract symptoms, even with normal infant lung function, exposure to smoking, and very early onset of symptoms were also associated with reduced lung function at age 8. The pathology on bronchoscopy in these infants, however, did not correlate with lung function or asthma at school age.
Limitations of this study include the difficulty in getting adequate biopsy specimens in infants, but the results do reaffirm the importance of early onset of lower respiratory symptoms, smoke exposure, and lung function in infancy in predicting the likelihood of asthma at school age. The lack of correlation with pathologic findings suggests that other mechanisms may be in play than what were originally thought.
- Copyright © 2015 by the American Academy of Pediatrics