Atopy and coeliac disease: bias or true relation?

Several reports have suggested a relationship between atopy and coeliac disease and atopy has also been linked to the pathogenesis of the mucosal damage. Conclusive epidemiological evidence of the relationship has not been satisfactorily established. The case-control study reported here was undertaken to test the hypothesis that coeliac disease is linked to atopy. Eighty-two coeliac disease cases and a group of 180 age matched controls and all their first degree relatives were investigated for atopy. Siblings of cases reported an increased prevalence of food intolerance, compared to siblings of controls. No increase in asthma, eczema, rhinitis, conjunctivitis, cow's milk protein allergy (CMPA) were detected in relatives of cases, compared to those of controls. When each index case and each control were investigated no increased prevalence of atopic conditions was found. Skin prick testing to major allergens was positive in a similar proportion of cases and controls. Serum total IgE of a random sample of cases and controls showed no difference in mean values. This study supports the null hypothesis: there is no difference in the prevalence of atopy in cases affected by coeliac disease and their relatives, compared to controls and their relatives. The sources of possible bias in previous reports are discussed.