New Zealand’s hospital admission rates for food-induced anaphylaxis – the most severe form of allergic reaction – have increased threefold in Pacific peoples over a 10-year period, according to a recently published study.
The study, which was published online last month in the peer-reviewed Postgraduate Medical Journal, investigated the incidence of adults and adolescents admitted to hospital in New Zealand with food-induced anaphylaxis from 2002 to 2011 using Ministry of Health hospital discharge data.
These data revealed that rates of food-induced anaphylaxis in Pacific peoples were more than twice that of Māori and Asian population rates, and three times that of those who identified as ‘New Zealand European and other’.
During the 10-year period, rates per 100,000 people rose from 6.0 to 20.6 for Pacific peoples in New Zealand, compared to the more moderate increase from 3.5 to 5.2 for New Zealand Europeans.
The study confirms that food-induced anaphylaxis is an increasing problem in New Zealand with an overall 1.7-fold increase over the 10-year period, mainly attributable to the increase in rates in the Pacific population.
University of Auckland medical student Devika Chandra and her supervisor Dr Bridget Kool from the university’s School of Population Health were co-authors on the study, which was funded through a Health Research Council of New Zealand (HRC) summer studentship grant to Miss Chandra. Dr Penny Fitzharris, Director of the Clinical Immunology and Allergy Service at Auckland District Health Board, was the clinical expert on the study and also a co-author.
Although anaphylaxis admission rates vary between countries, there has been an upward trend in New Zealand consistent with findings in the UK, USA, Italy, and Australia.
In addition to differences in ethnicity, the study also found significant differences in admission rates by gender and age group, with notably higher rates in females – almost two-thirds of cases – and younger adults (15–34 years).
The most common allergens reported were seafood followed by nuts.
The reasons for the differences in food-induced anaphylaxis by gender and ethnicity observed in this study could potentially include genetics, dietary food patterns, and environmental factors such as vitamin D exposure. However, the authors note that the presence of cause-and-effect relationships would need to be confirmed by controlled trials.
This is Allergy NZ's Anaphylaxis Awareness Week, which aims to bring attention to the increasing prevalence of serious allergies in New Zealand.