Bronchiolitis and asthma in infancy and early childhood.

Background. Many young children wheeze during respiratory infections, but the pathogenesis of these episodes and their relation to the development of asthma later in life are not well understood. Methods. In a prospective study, we investigated the factors affecting wheezing before the age of three years and their relation to wheezing at six years of age. Of 1246 newborns in the Tucson, Arizona area enrolled between May 1980 and October 1984, follow-up data at both three and six years of age was available for 826. For these children, assessments in infancy included measurement of cord-serum IgE levels (measured in 750 children), pulmonary-function testing before any lower respiratory illness had occurred (125), measurement of serum IgE levels at nine months of age (672), and questionnaires completed by the children's parents when the children were one year old (800). Assessments at six years of age included measurement of serum IgE levels (in 460), pulmonary-function testing (526), and skin allergy testing (629). Results. At the age of six years, 425 children (51 5 percent) had never wheezed, 164 (19.9 percent) had had at least one lower respiratory illness with wheezing during the first three years of life but had no wheezing at six years of age, 124 (15 0 percent) had no wheezing before the age of three years but had wheezing at the age of six years, and 113 (13 7 percent) had wheezing both on July 18, 2023 by guest.