Open Access Research article

The New Zealand Asthma and Allergy Cohort Study (NZA2CS): Assembly, Demographics and Investigations

Michael J Epton1*, George I Town1, Tristram Ingham2, Kristin Wickens2, David Fishwick3, Julian Crane2 and the New Zealand Asthma and Allergy Cohort Study Group123

Author Affiliations

1 Canterbury Respiratory Research Group, Department of Medicine, Christchurch School of Medicine and Health Sciences, University of Otago, PO Box 4345, Christchurch, New Zealand

2 Wellington Asthma Research Group, Department of Medicine, Wellington School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand

3 Centre for Workplace Health, University of Sheffield, Sheffield, UK

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BMC Public Health 2007, 7:26  doi:10.1186/1471-2458-7-26

Published: 28 February 2007



Asthma and allergy are highly prevalent in industrialised countries. Longitudinal and cross-sectional studies have identified a number of potential risk factors for these conditions, including genetic and environmental factors, with significant gene-environment relationships. Birth cohort studies have been proposed as an important tool to explore these risk factors, particularly exposures in early life that are associated with later disease or protection from disease. This paper describes the establishment of a birth cohort in New Zealand.


A birth cohort was established in 1996 in Christchurch and Wellington and infants recruited between 1997–2001. Expectant mothers were recruited by midwives. Children and mothers have undergone assessment by serial questionnaires, environmental assessment including mould and allergen exposure, skin-prick testing, and at age six years are undergoing full assessment for the presence of asthma, atopy and allergic disease, including genetic assessment.


A total of 1105 children have been recruited, and the retention rate at fifteen months was 91.4%. 15.2% of the children at recruitment have been identified as Maori. A positive family history of asthma, eczema or hay fever has been reported in 84% of children. All children have now been assessed at fifteen months and 685 children from the cohort have reached age six years and have completed the six year assessment.


The cohort is fully assembled, and assessment of children is well advanced, with good retention rates. The study is well placed to address many current hypotheses about the risk factors for allergic disease and asthma.