ORLANDO – Vitamin D insufficiency at age 1 year was associated with a nearly fourfold increased prevalence of a food allergy in a case-control study of 269 children.
The finding appears consistent with prior reports that linked the prevalence of food allergies to the latitude gradients for where people lived, Dr. Katrina J. Allen and her associates reported in a poster at the annual meeting of the American Academy of Allergy, Asthma, and Immunology. Those reports had suggested that the further people lived from the equator, the higher their rate of hospitalizations for food-allergy related events, said Dr. Allen, a pediatric allergist and gastroenterologist at Royal Children’s Hospital Melbourne, and her associates.
The study involved 5,276 12-month old infants from the Melbourne area enrolled in the Health Nuts population-based study. All infants had skin prick tests to egg white, peanut, and sesame; 1,005 developed at least a 1 mm wheal to at least one of these foods. Of the 834 food-sensitized infants who returned to the clinic for an oral food challenge with egg, peanut, and sesame, 351 were identified as food allergic with at least three non-contact hives or areas of urticaria that persisted for at least 5 minutes; perioral or periorbital angioedema; or severe and persistent vomiting or anaphylaxis (J. Allergy Clin. Immunol. 2012;129[suppl.]:AB141).
The researchers then drew blood specimens from 165 of the food-allergic infants and 104 control infants without food allergy or sensitivity, and measured their serum level of 25-hydroxyvitamin D.
In all, 92 of the control infants (88%) were vitamin D sufficient, with a serum level greater than 50 nM, corresponding to a level greater than 20 ng/mL. Among the infants with a food allergy, 118 (72%) were vitamin D sufficient (N. Engl. J. Med. 2011;364:248-54).
Vitamin D insufficiency, defined as a serum level of 26-50 nM (10 ng/mL to 20 ng/mL), occurred in 11% (11) of the control infants and in 25% (42) of the infants with a food allergy.
The remainder of the infants in the study, one in the control group and five in the food-allergy group, were vitamin D deficient, with a serum level of 25 nM or less (less than 10 ng/mL), but the numbers in this subgroup were too limited to allow a meaningful statistical analysis.
In a multiple logistical regression model that adjusted for diet (breast fed or formula fed), level of prior egg consumption, number of siblings, the presence of a pet dog, and ambient UV radiation exposure at the time of the blood draw, vitamin D insufficiency was linked with a statistically significant, 3.8-fold increased rate of food allergy, compared with the infants who were vitamin D sufficient, the researchers reported.
Dr. Allen and her associates said that they had no relevant financial disclosures.