Does season of birth affect the likelihood of being sensitized to food allergens?
The number of children with food allergies is increasing and the reason for this increase is not well understood. Likely several factors contribute, and previous studies have examined the influence of vitamin D status, timing of food introduction, and season of birth. However, previous investigators have focused primarily on Caucasian children. As a result, reports of the influence of either season of birth or vitamin D status on the development of food allergy in African American children are lacking. In a Letter to the Editor recently published in The Journal of Allergy and Clinical Immunology (JACI), Bird and colleagues report their results from an analysis of serum and historical information collected from a previously conducted trial focusing on inner city African American asthmatic children.
Specifically, they looked for a relationship between the season in which children were born and the likelihood they were sensitized to milk, egg, peanut, wheat, soy, codfish, shrimp, or various indoor allergens. They also analyzed the data looking for a relationship in food or indoor allergen sensitization to vitamin D status at the time of enrollment into the study. Children in the study were mostly male (64%), ranged from 5 to 8 years of age (average age of 6 years), and lived primarily in Northern latitudes (e.g. Boston, Chicago, or Bronx). They found that African American children born in the winter were more likely to be sensitized to egg, peanut or soy allergens.
They also looked at vitamin D status at the time of enrollment in the study and did not find a relationship with regards to sensitization to food or indoor allergens. Winter birth did not have any influence on the development of sensitization to indoor allergens.
The authors’ results from studying this African American population support findings from previous studies in Caucasian children showing a correlation between the season of birth and the likelihood of being sensitized to food allergens. Other factors which may influence sensitization to food allergens during winter include winter virus exposure and indoor allergen exposure. Breast feeding, Caesarian delivery, and vitamin D status during the first year of life may also impact the likelihood of developing food allergy, and the authors were not able to analyze these variables. Results from this study further support the role of winter birth in sensitization to food allergens.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.
Posted with permission from the American Academy of Allergy, Asthma & Immunology (AAAAI)