[Respiratory symptoms in young adulthood in relation to the results of a house dust skin test during childhood--a 20 year follow-up survey].

Beginning in 1972, a survey of respiratory symptoms and allergic skin tests in school children from an agricultural area in the Hokuriku region has been continuing. A higher prevalence of respiratory symptoms in school children with positive house dust skin test has been previously reported. In order to elucidate the relationship between results of a house dust skin test during childhood and manifestation of respiratory symptoms thereafter, an examination of respiratory symptoms was conducted in 1991, of the portion of the 5,334 subjects who participated in the earlier survey during childhood, who still live in the same town after leaving junior high school. The results are as follows: 1) During childhood (school-age), prevalence of respiratory symptoms (subacute cough, wheezing when having a cold, wheezing attack) was higher in the positive skin test group (612 subjects) compared to the negative group (856 subjects). There were no significant differences between the two groups in the prevalence of respiratory symptoms (subacute phlegm, wheezing when not having a cold). 2) In young adulthood, prevalence of respiratory symptoms (subacute cough, subacute phlegm) was higher in the negative skin test group compared to the positive group. There were no significant differences between the two groups in the prevalence of respiratory symptoms (wheezing when not having a cold, wheezing attack). The prevalence of wheezing when having a cold was higher in the positive group compared to the negative group. 3) The paradoxical results in young adulthood was due to a marked decline in the prevalence ratio of the high positive rate skin test group (184 subjects) to the negative skin test group. This suggested a decline in contribution of serum IgE to manifestation of respiratory symptoms in young adulthood compared to childhood, with the result that the positive skin test group had a higher prevalence of respiratory symptoms during childhood, but lower in young adulthood.