The prevalence of food allergy is rising and etiologic factors remain uncertain. Evidence implicates a role of vitamin D in the development of atopic diseases. Based on seasonal patterns of UVB exposure (and consequent vitamin D status), we hypothesized that food allergy patients are more often born in fall or winter.
Investigate whether season of birth is associated with food allergy.
We performed a multicenter chart review of all patients presenting to three Boston emergency departments (EDs) for food-related acute allergic reactions between 1/1/01 and 12/31/06. Months of birth among food allergy patients were compared to those of patients visiting the ED for reasons other than food allergy.
We studied 1,002 food allergy patients. Among younger children with food allergy (age <5 years) – but not among older children or adults – 41% were born in spring/summer compared to 59% in fall/winter (P=0.002). This approximately 40/60 ratio differed from birth season of children treated in the ED for non-food allergy reasons (P=0.002). Children <5 years old born in fall/winter had a 53% higher odds of food allergy compared to controls. This finding was independent of the suspected triggering food and allergic comorbidities.
Food allergy is more common in Boston children who were born in the fall and winter seasons. We propose that these findings are mediated by seasonal differences in UVB exposure. These results add support to the hypothesis that seasonal fluctuations in sunlight and perhaps vitamin D may be involved in the pathogenesis of food allergy.