Epinephrine autoinjector (EpiPen) prescriptions (2006-2007) and anaphylaxis hospital admission rates (2002-2007) were used as surrogate markers of anaphylaxis. Australia is a particularly good place for vitamin D studies as it spans nearly 3000 miles from north to south (http://goo.gl/ZR7hM). Vitamin D is a steroid hormone and a component of a complex endocrine pathway sometimes called 'vitamin D endocrine system' (Medscape, 2012).
EpiPen prescription rates (per 100,000 population per year) were higher in children from birth to the age of 4 years than in the overall population. Decreasing latitude was associated with a decrease in EpiPen prescription rates - the rates were higher in southern compared with northern regions of Australia. There is more sun exposure in the northern regions (opposite of the U.S.).
Anaphylaxis admission rates showed a similar south-north gradient, such that admission rates were higher in southern compared with northern regions of Australia.
EpiPen prescription rates and anaphylaxis admissions are more common in southern regions of Australia. These data may support a possible role of vitamin D in the pathogenesis of anaphylaxis.
Regional variation in epinephrine autoinjector prescriptions in Australia: more evidence for the vitamin D-anaphylaxis hypothesis. Mullins, Raymond J.; Clark, Sunday; Camargo, Carlos A. Annals of Allergy, Asthma and Immunology, Volume 103, Number 6, December 2009 , pp. 488-495(8).
EpiPen prescriptions in the U.S. - click to see the results on a map.
Bacterial components plus vitamin D: The ultimate solution to the asthma (autoimmune disease) epidemic? JACI, 2011 (PDF).
Image source: Wikipedia, public domain.