1. Wellington Asthma Research Group; Department of Medicine; University of Otago; Wellington New Zealand
2. He Kainga Oranga/Housing and Health Research Group; Department of Public Health; University of Otago; Wellington New Zealand
3. Centre for Public Health Research; Massey University; Wellington New Zealand
4. Department of Paediatrics and Child Health; University of Otago; Wellington New Zealand
5. Department of Health Protection; National Institute for Health and Welfare (THL); Kuopio Finland