Prevalence of Coeliac Disease in the General Population of Northern Spain: Strategies of Serologic Screening

Background: Coeliac disease (CD) is common in Western countries. In Spain, however, no studies exist on its prevalence. The best method for serologic screening is also unknown. Methods. We determined the IgA and IgG antigliadin antibodies (AGA) and IgA antiendomysium antibodies (AEA) in a sample of 1170 randomly selected subjects from a health area in northern Spain. The prevalence of CD was calculated with a two-step serologic screening method (first IgA and IgG AGA and then AEA in those positive for AGA) or with only one step with AEA determination. Diagnosis was confirmed by small-intestinal biopsy. Results: When using a two-step strategy, we found 174 (15%) subjects with AGA. Only one of these was confirmed by means of AEA (prevalence of CD = 0.9/1000). Two subjects were found to be positive when a one-step strategy was used (prevalence of CD = 1.7/1000). This yielded an economic saving of 19% with regard to the use of a two-step strategy. One new case of CD in a seronegative subject was diagnosed during the study (real prevalence of CD = 2.6/1000; 95% confidence interval = 0.7-8.2). Conclusions: The prevalence of CD in Northern Spain is 2.6/1000 (1:389). One-step serologic screening (AEA) is both more economical and more sensitive than the two-step procedure (first AGA and then AEA if AGA is positive).