Objective: To determine the risk factors and short-term outcome until 3 years of age for subsequent wheezing in children with early childhood bronchiolitis or pneumonia.
Design: Prospective follow-up of a patient group.
Setting: University hospital providing primary care for all pediatric patients of a defined area.
Patients: One hundred twenty-seven children under 2 years of age hospitalized owing to wheezing (n = 83) or pneumonia (n = 44) during 12 months in 1981 to 1982. One hundred eight children completed the prospective follow-up until 3 years of age.
Main results: The wheezing and pneumonia groups had equal viral and bacterial etiologic findings. History of wheezing, atopic eczema, and elevated serum IgE levels were more common in patients with wheezing than with pneumonia. Subsequent wheezing was seen after bronchiolitis in 76% (61 of 80) of the children at 1 to 2 years of age and in 58% (44 of 76) at 2 to 3 years of age. The respective figures were significantly lower, 9% (three of 33) and 16% (five of 32), in patients with pneumonia. An analysis of risk factors did not reveal any with a significant effect on subsequent wheezing.
Conclusions: Subsequent wheezing is common after bronchiolitis, but rare after early childhood pneumonia, although caused by the same viruses or bacteria. Atopic diathesis is the host factor associated with initial wheezing. No genetic or environmental risk factor had significant association with later wheezing.