Asthma and airway hyper-responsiveness in adults who required hospital admission for bronchiolitis in early childhood

Viral respiratory infections in infancy may contribute to the development o f airway hyper-responsiveness (AHR) in childhood but their effects on respi ratory function at the adult age are still uncertain. A group of 42 subject s aged 17-35 with a pediatrician-made diagnosis of severe bronchiolitis in infancy (Br) were compared for the presence of asthma and AHR to a control group (C) paired far age and gender, without evidence of lower respiratory disease in infancy. All had a respiratory and environmental questionnaire, allergy skin prick tests, blood eosinophil count, total serum IgE determina tion and measurements of expiratory flows and airway response to methacholi ne. In Br and C groups, respectively, 38 and 12% of subjects had a physicia n-made diagnosis of asthma, 26 and 7% used bronchodilators and 12 and 0% an inhaled corticosteroid; 71 and 67%, respectively, were atopic, 50 and 24% were smokers and 43 and 17% had a first-degree relative with asthma. Mean b aseline FEV1 and FEV1/FVC ratio were lower in the Br than in the C group, w ith 94/103% (P=0.002) and 80/87 (P<0.0001) of the predicted value, respecti vely. Geometric mean PC20 methacholine was significantly lower in the Br th an in the C group 3.9/20.3 mg ml(-1) (P<0.0001). Mean blood eosinophil coun t and serum IgE levels were similar in both groups (P>0.05). In conclusion, asthma and AHR were found more frequently in young adults wi th a past history of bronchiolitis, suggesting that this type of respirator y infection may contribute to altered pulmonary function in adulthood, alth ough it may also represent an early manifestation of asthma. The influence of potential confounding factors, such as familial predisposition and expos ure to cigarette smoke on the development of asthma and AHR in the Br group , cannot be excluded.