Socio-economic status, geographic remoteness and childhood food allergy and anaphylaxis in Australia

Background: The risk factors for food allergy (FA) and anaphylaxis remain uncertain.

Objective: We examined the association between socio-economic status (SES), geographic remoteness and childhood FA and anaphylaxis in Australia.

Methods: Sales of infant hypoallergenic formulae (IHF; 2008-2009) and EpiPens (2006-2007) in children aged 0-4 years and hospital anaphylaxis admission rates (2002-2006) in age groups 0-4, 5-14, 15-24, 25-64 and 65+ years were used as proxy markers of FA and anaphylaxis in Australia. Government and commercially derived data were analysed by SES and geographic remoteness (very remote, remote, outer regional, inner regional and major cities).

Results: Annual IHF sales rates were higher in those with the greatest compared with the least socio-economic advantage (47,830 vs. 21,384 tins/100,000 population; P<0.001). EpiPen sales trends were also higher in those with the greatest socio-economic advantage in all age groups, most marked in those aged 0-4 (1713 vs. 669/100,000; P=0.002) and 5-14 years (1628 vs. 600/100,000; P=0.001). Formula sales rates were higher in major cities than remote/very remote regions (37,421 vs. 6704/100,000; P<0.001) with similar EpiPen sales trends, particularly in ages 0-4 (1166 vs. 601/100,000; P=0.045) and 5-14 years (1099 vs. 588/100,000; P<0.001). Socio-economic advantage and geographic remoteness remained statistically significant in multivariable analysis of prescription rates (P<0.01) and were unchanged by adjustment for health services access. While anaphylaxis admission rates were higher in those with the greatest compared with the least socio-economic advantage in children aged 0-4 years (129 vs. 92/100,000 population/year; P=0.03), the opposite was observed in older age groups (e.g. aged 25-64 years: 43 vs. 76, P=0.01). There was no association between geographic remoteness and anaphylaxis admissions.

Conclusion: Socio-economic advantage and residence in major cities may be risk factors for developing childhood FA and anaphylaxis. Further study will determine the extent to which economic factors and location of residence also influence access to health services.