AnaphylaxisExposure to sunlight

The epidemiological evidence for a role of vitamin D comes largely from studies of the geographical variations in anaphylactic symptoms and seasonality of births among children with food allergies.

The first epidemiological study was ecology-based on regional differences in EpiPen prescriptions in the United States in 20041. The highest rates were in the northeast (8–12 prescriptions/1000 people), while the lowest rates were in the southwest (2–3 prescriptions/1000 people). Based on Figure 2 in this paper, the variation seems to be related to summertime solar UVB doses, which are highest in the southwest and lowest in the northeast234. The distribution is highly asymmetric due to two reasons: higher surface elevations in the western states and thinner stratospheric ozone layer in the west. The thin ozone layer is due to the prevailing westerly winds crossing the Rocky Mountains and pushing the tropopause higher.

Solar UVB is the primary source of vitamin D for most Americans.

A similar study in Australia found a significant increase in EpiPen prescription rates going from 20º S to 45º S5. Because there are no mountain ranges in Australia, solar UVB doses decrease with increasing latitude. Other factors did not significantly affect the finding. A related study in Australia also found higher use rates of hypoallergenic formula for infants in that country’s southern and eastern regions6.

A study of U.S. emergency department visits for acute allergic reactions found the highest rates in the northeast, with a stronger association seen when the reactions were limited to those caused by food allergy7.

Two studies of season of birth and food allergy in Boston children found higher rates for those born in fall or winter compared to spring and summer. The first such study was conducted in the United States. It found a seasonal pattern with lowest rates for emergency department patients under the age of 5 years born in April to July and highest rates in December and January8. There was no apparent seasonality for older children or adults. In a second study involving 3792 patients in Boston found the lowest rate for those under the age of 18 years born in spring, with increasing relative ratio for summer, fall, and winter births9

A related paper found maternal diet to affect risk of food allergies among children up to the age of five years. This study, in Finland, found mothers who consumed more vitamin D during pregnancy delivered children who had reduced sensitivity to food allergens, even though the intake levels were rather low, with a mean value of 208.

Page last edited: 17 May 2011

References

  1. Camargo, C. A., Jr. Clark, S. Kaplan, M. S. Lieberman, P. Wood, R. A. Regional differences in EpiPen prescriptions in the United States: the potential role of vitamin D. The Journal of allergy and clinical immunology. 2007 Jul; 120 (1): 131-6.
  2. Leffell, D. J. Brash, D. E. Sunlight and skin cancer. Sci Am. 1996 Jul; 275 (1): 52-3, 56-9.
  3. Fioletov, V. E. McArthur, L. J. Mathews, T. W. Marrett, L. Estimated ultraviolet exposure levels for a sufficient vitamin D status in North America. J Photochem Photobiol B. 2010 Aug 2; 100 (2): 57-66.
  4. Fioletov, V. E. McArthur, L. J. Mathews, T. W. Marrett, L. Estimated ultraviolet exposure levels for a sufficient vitamin D status in North America. J Photochem Photobiol B. 2010 Aug 2; 100 (2): 57-66.
  5. Mullins, R. J. Clark, S. Camargo, C. A., Jr. Regional variation in epinephrine autoinjector prescriptions in Australia: more evidence for the vitamin D-anaphylaxis hypothesis. Ann Allergy Asthma Immunol. 2009 Dec; 103 (6): 488-95.
  6. Mullins, R. J. Clark, S. Camargo, C. A., Jr. Regional variation in infant hypoallergenic formula prescriptions in Australia. Pediatr Allergy Immunol. 2010 Mar; 21 (2 Pt 2): e413-20.
  7. Rudders, S. A. Espinola, J. A. Camargo, C. A., Jr. North-south differences in US emergency department visits for acute allergic reactions. Ann Allergy Asthma Immunol. 2010 May; 104 (5): 413-6.
  8. Vassallo, M. F. Banerji, A. Rudders, S. A. Clark, S. Mullins, R. J. Camargo, C. A., Jr. Season of birth and food allergy in children. Ann Allergy Asthma Immunol. 2010 Apr; 104 (4): 307-13.
  9. Vassallo, M. F. Camargo, C. A., Jr. Potential mechanisms for the hypothesized link between sunshine, vitamin D, and food allergy in children. J Allergy Clin Immunol. 2010 Aug; 126 (2): 217-22.