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).