Airway responsiveness in early infancy predicts asthma, lung function, andrespiratory symptoms by school age

Asthma is the most common chronic childhood disease in developed nations. L ittle is known about the relationship between airway responsiveness in infa ncy and the development of asthma later in life. The relationship of airway responsiveness at 1 mo with asthma, atopy, lower respiratory symptoms, and lung function at 6 yr of age was investigated prospectively in 95 white ch ildren from a randomly ascertained birth cohort. Baseline spirometry, airwa y responsiveness to histamine, and skin reactivity to common allergens were assessed at the age of 1 mo and 6 yr. Total serum immunoglobulin E (IgE) w as measured from cord blood and at 6 yr. Brood eosinophil counts were measu red at 6 yr only. Family, symptom, and exposure histories at both time poin ts were derived from questionnaire data. Independently of the other factors assessed, increased airway responsiveness at 1 mo was significantly associ ated with the following parameters measured at six yr: decreased FEV1 (p < 0.001); decreased FVC (p < 0.001); physician-diagnosed asthma (p < 0.001); and lower respiratory tract symptoms (p < 0.05). None of the other physiolo gic factors measured in infancy showed such consistent associations with im portant clinical and physiologic outcomes at age 6. These data suggest that airway responsiveness in early life defines a functional state that is ass ociated with abnormal airway function, lower respiratory symptoms, and the emergence of asthma by 6 yr of age.