Poole JA, Barriga K, Leung DYM, et al. Pediatrics. 2006;117:2175–2182
PURPOSE OF THE STUDY. To ascertain the relationship between cereal-grain exposure, wheat, barley, rye, and oats in the infant diet and the subsequent development of wheat allergy.
STUDY POPULATION. A birth cohort of 1612 children followed to a mean age of 4.7 years.
METHODS. A total of 1612 children were enrolled in a birth cohort with questionnaire data, and dietary exposures were determined at 3, 6, 9, 15, and 24 months and annually thereafter. The primary outcome measure was apparent report of wheat allergy. Wheat-specific immunoglobulin E (IgE) levels in children reported to have wheat allergy were obtained. Children with celiac disease with autoimmunity were excluded.
RESULTS. Sixteen children (1%) noted wheat allergy. Children who were first exposed to cereal after 6 months of age had a >4 times prevalence of wheat allergy when compared with children who were first exposed to cereals before 6 months of age, after controlling for family history and allergic disorder and history of food allergy before 6 months of age. All 4 children with detectable wheat-specific IgE were initially given cereal grains after 6 months. Having a first-degree relative with a history of atopy (ie, asthma, eczema, or hives) was also independently associated with an enhanced risk of subsequent development of wheat allergy.
CONCLUSIONS. Delaying first exposure to cereal grains until after 6 months enhanced the risk of subsequent development of wheat allergy. These results do not support delaying introduction of cereal grains for protection against food allergy.
REVIEWER COMMENTS. This study was limited by its dependence of parental report of wheat allergy, although IgE was obtained as well. No formal diagnostic oral food challenges were performed. The possibility of reverse causality was addressed by eliminating confounding factors related to history of food allergy but could still be a potential explanation. The birth cohort also was selected on the basis of HLA-genotype screening and family history of diabetes, which may limit its generalizability. However, the results, that delaying exposure to cereal grains until after 6 months is associated with increased risk of wheat allergy, not a protective outcome, are still provocative. Additional large prospective studies using double-blind, placebo-controlled food challenge to confirm these findings are needed.