A case-control study of risk factors for asthma in New Zealand children

Objective: As in other English-speaking countries, asthma is a major and in creasing health problem in New Zealand. This study examined the risk factor s for asthma in children aged 7-9. Methods: Cases and controls were randomly selected from participants in the Wellington arm of the international Study of Asthma and Allergies in Child hood (ISAAC). Cases were children with a previous diagnosis of asthma and c urrent medication use (n=233), and controls were children with no history o f wheezing and no diagnosis of asthma (n=241). Results: After controlling for confounders, factors significantly associate d with asthma were maternal (OR=3.36, 95% CI 1.88- 5.99) and paternal asthm a (OR=2.67, 95% CI 1.42-5.02), and male sex (OR=1.81, 95% CI 1.17-2.81). Ch ildren from social classes 5 and 6 or with unemployed parents (OR=2.32, 95% CI 1.22-4.44) were significantly more likely to have asthma than children in social classes 1 and 2. There was no significant association between hav ing polio vaccination (OR=2.48, 95% CI 0.83-7.41), hepatitis B vaccination (OR-0.66, 95% CI 0.42-1.04) or measles/mumps/rubella vaccination (OR=1.43, 95% CI 0.85-2.41) and asthma. Conclusions: This study has confirmed the associations of family history an d lower socio-economic status with current asthma in 7-9 year old children. The role of vaccinations requires further research.