A Prospective Study of Asthma Prevalence and Atopy Rate in Children Living in Rural Area of Cheju Island for 3 Years / 소아알레르기및호흡기학회지

ABSTRACT

PURPOSE: Asthma has been increasing due to changes in life style and indoor environments. Manifestations of asthma and atopy varies according to age. The purpose of this study was to elucidate the changing prevalence of asthma and atopy in children living in rural area of Cheju island via three year prospective study. METHODS: A total of 314 subjects aged from 7 to 12 years was followed up for three years. They responded a ISAAC questionnare, underwent allergy skin prick test with common aeroallergens and methacholine bronchial provocation test. Children with asthma symptoms on a questionnaire and positive methacholine bronchial provocation test were diagnosed as bronchial asthma. Skin prick test was regarded as positive when the size of wheal caused by allergens was same or larger than that caused by histamine. RESULTS: The prevalence of bronchial asthma has a tendency to increase from 4.1 % to 7.3% three years later(P=0.08). The atopy rate has significantly increased from 34.1% to 49.2% in both girls and boys(P<0.001), from 35.0% to 46.9% in girls(P< 0.05), and from 33.3% to 51.3% in boys(P<0.05). The positive skin responses to Dermatophagoides pteronyssinus, D. farinae(P=0.36), Japanese cedar and cockroach were not changed between the three years. However, the postive skin reponse to citrus red mite was significantly increased three years later(from 10.7% to 31.1%, P<0.001). CONCLUSION: The asthma prevalence has a tendency to increase in children living in rural area with citrus farms. The atopy rate has been also increasing in the rural children. These phenomena may be explained by the fact that sensitization to citrus red mite has been increasing when they are getting older.