Geographical comparison of the prevalence of childhood asthma and allergies in Singapore.

Abstract

A previous study suggested that differences in the prevalence of respiratory illnesses such as asthma in school children in different regions of Singapore were not due to the influence of air pollution or environmental factors but possibly to cultural and socio-economic factors. The effects of socio-economic or demographic variables were, however, not shown in that study. In this study, we set out to discover whether regional differences in the prevalence of atopic diseases such as asthma, rhinitis and eczema in Singapore school children could be explained by different demographic profiles. The prevalence of asthma and allergies were evaluated in 6238 Singapore school children in two age groups (6-7 years [n = 2030] and 12-15 years [n = 4208]). They were from four regions, based on residential post codes. Demographic and socio-economic data were also obtained. The questionnaire of the International Study on Asthma and Allergies in Childhood (ISAAC) was used. The data showed that children residing in the northern regions of Singapore had a significantly lower prevalence of asthma and rhinitis than those in other regions. When controlled for demographic influences (age, sex and race) and socio-economic factors (type of housing), however, the differences between these regions were reduced. No geographical difference in the prevalence of eczema was observed. Thus, geographical differences in the prevalence of asthma and rhinitis in Singapore could in part be explained by demographic and socio-economic differences in the population.