“Individuals with increased birth order have a smaller risk of allergy," explained Takashi Kusunoki, MD, PhD, of the Shiga Medical Center for Children in Moriyama, Japan, in a news release. "However, the significance of the effect may differ by allergic diseases.”
Prenatal Origins of Allergies?
The study also showed that in infancy symptoms such as wheezing increased and food allergies decreased as birth order increased.
Researchers say these findings suggest that food allergies may have their origins in the prenatal period in the womb.
The results were presented at the Annual Meeting of the American Academy of Asthma, Allergy and Immunology in San Francisco.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.