CHILDHOOD ASTHMA IN 4 COUNTRIES - A COMPARATIVE SURVEY

Background. Asthma mortality among young people varies widely between different countries. Geographical differences in asthma prevalence are also believed to exist, but evidence is sparse owing to the lack of m ulticentre surveys using common protocols. A survey was conducted of 1 2-year-old children living in defined areas of New Zealand, Wales, Sou th Africa and Sweden, in order to see whether asthma prevalence and mo rtality rates in children show parallel differences. Methods. Question naires enquiring about a history of asthma and respiratory symptoms we re issued to the parent. The children performed a simple exercise chal lenge test. Results. Information was obtained for 4353 children. A his tory of asthma at any time was reported for 16.8% of children in New Z ealand, 12.0% in Wales, 11.5% in South Africa and 4.0% of Sweden, and a similar pattern was shown by several other indices of asthma (variou s relevant symptoms, inhaler use, response to exercise challenge, and asthma mortality at ages 5-19 years). In Sweden wheezing was negativel y associated with pet ownership; elsewhere there was a positive (thoug h non-significant) association. Cat ownership was highest in New Zeala nd and lowest in Sweden. Conclusions. The prevalence of asthma in chil dren shows geographical variation which is parallel to that of asthma mortality, being high in New Zealand and low in Sweden. Differential e xposure to animal allergens is a possible factor in this variation.