Prevalence of Eczema and Food Allergy is Associated with Latitude in Australia

Abstract

RationaleRecent reports from both Australia and the US suggest that UVR might play a role in the recent rise in allergic disease in children, in particular food allergy. Previous studies have used proxy measured of allergy, rather than direct measures.MethodsWe examined this using the nationally representative epidemiological study - the Longitudinal Study of Australian Children - containing information about two cohorts of children age 4-5 years and 8-9 years, respectively (n∼5000 each) on States of domicile (spanning 33° latitude), parental report of food allergy, eczema and asthma, and potential confounders.ResultsA latitude gradient existed for both food allergy (peanut and egg) and eczema, but not for asthma, in each of the two cohorts. In the 4-5 year-old cohort, children in the central and southerly areas were 1.9 (95%CI;0.88-4.04) and 2.4 (95%CI;1.18-5.04) times at greater odds of peanut allergy when compared to the northern region; odds of egg allergy were 2.9 (0.97-8.49) and 3.1 (95%CI;1.04-9.01) greater, and eczema 1.8 (95%CI;1.34-2.29) and 2.6 (95%CI;2.00-3.32) times greater.In the 8-9 year-old cohort, the odds of having a peanut allergy were 4.0 (95%CI;0.89-17.83) and 6.1 (95%CI;1.42-24.27) times greater in the central and southern regions, and the odds of having eczema were 1.6 (95%CI;1.14-2.26) and 1.9 (95%CI;1.36-2.67) greater in children residing Central and South, respectively, compared to the North.ConclusionsThis provides stimulus for research into possible causal roles of ambient UVR and, potentially through vitamin D status, the impact on risk of food allergy and eczema in children. RationaleRecent reports from both Australia and the US suggest that UVR might play a role in the recent rise in allergic disease in children, in particular food allergy. Previous studies have used proxy measured of allergy, rather than direct measures. Recent reports from both Australia and the US suggest that UVR might play a role in the recent rise in allergic disease in children, in particular food allergy. Previous studies have used proxy measured of allergy, rather than direct measures. MethodsWe examined this using the nationally representative epidemiological study - the Longitudinal Study of Australian Children - containing information about two cohorts of children age 4-5 years and 8-9 years, respectively (n∼5000 each) on States of domicile (spanning 33° latitude), parental report of food allergy, eczema and asthma, and potential confounders. We examined this using the nationally representative epidemiological study - the Longitudinal Study of Australian Children - containing information about two cohorts of children age 4-5 years and 8-9 years, respectively (n∼5000 each) on States of domicile (spanning 33° latitude), parental report of food allergy, eczema and asthma, and potential confounders. ResultsA latitude gradient existed for both food allergy (peanut and egg) and eczema, but not for asthma, in each of the two cohorts. In the 4-5 year-old cohort, children in the central and southerly areas were 1.9 (95%CI;0.88-4.04) and 2.4 (95%CI;1.18-5.04) times at greater odds of peanut allergy when compared to the northern region; odds of egg allergy were 2.9 (0.97-8.49) and 3.1 (95%CI;1.04-9.01) greater, and eczema 1.8 (95%CI;1.34-2.29) and 2.6 (95%CI;2.00-3.32) times greater.In the 8-9 year-old cohort, the odds of having a peanut allergy were 4.0 (95%CI;0.89-17.83) and 6.1 (95%CI;1.42-24.27) times greater in the central and southern regions, and the odds of having eczema were 1.6 (95%CI;1.14-2.26) and 1.9 (95%CI;1.36-2.67) greater in children residing Central and South, respectively, compared to the North. A latitude gradient existed for both food allergy (peanut and egg) and eczema, but not for asthma, in each of the two cohorts. In the 4-5 year-old cohort, children in the central and southerly areas were 1.9 (95%CI;0.88-4.04) and 2.4 (95%CI;1.18-5.04) times at greater odds of peanut allergy when compared to the northern region; odds of egg allergy were 2.9 (0.97-8.49) and 3.1 (95%CI;1.04-9.01) greater, and eczema 1.8 (95%CI;1.34-2.29) and 2.6 (95%CI;2.00-3.32) times greater. In the 8-9 year-old cohort, the odds of having a peanut allergy were 4.0 (95%CI;0.89-17.83) and 6.1 (95%CI;1.42-24.27) times greater in the central and southern regions, and the odds of having eczema were 1.6 (95%CI;1.14-2.26) and 1.9 (95%CI;1.36-2.67) greater in children residing Central and South, respectively, compared to the North. ConclusionsThis provides stimulus for research into possible causal roles of ambient UVR and, potentially through vitamin D status, the impact on risk of food allergy and eczema in children. This provides stimulus for research into possible causal roles of ambient UVR and, potentially through vitamin D status, the impact on risk of food allergy and eczema in children.