María Catalina Vespa^{1, 2}, Amaya Oyarzún Arancibia¹, Jimena Ayala Cid², Magdalena Araya Quezada^{1, 2,}

To date the only efficient treatment of celiac disease is a lifelong gluten-free diet (GFD), which involves relevant lifestyle changes. Numerous methods measure adherence to GFD, but none is completely reliable. The aim of the study was to compare three frequently used methods to measure adherence to GFD and study factors that influence adherence to GFD. Eighty-one celiac patients 15 years or older, on GFD were evaluated by dietitian interview, a Celiac Dietary Adherence Test (CDAT) and blood antitransglutaminase antibodies (tTG). Factors influencing adherence were assessed by an ad-hoc questionnaire following WHO criteria. Adherent and non-adherent patients were classified in the same category in 44.4% of cases (n=36), (non-adherent=35.8% and adherent= 8.6%). In general, methods identified better non-adherent than adherent individuals. Among the 5 realms defined by WHO, when tTG (positive/negative) defined adherence, logistic regression identified ten significant variables (information about disease, income, education, cost of gluten-free products, eating in restaurants, time on GFD, symptoms at diagnosis, number of symptoms at time of diagnosis, other chronic diseases present, allergy/food intolerance plus a chronic disease and CD). Using the interview as reference, two variables were significant (self-perception of knowledge of the GFD, and presence of gastrointestinal symptoms when gluten is consumed). Results illustrate the difficulties of measuring both adherence to GFD and the factors that influences it. Further studies should explore new markers able to measure the amount of gluten necessary to activate autoantibodies production and the time they take to stop their production once the patient stops gluten ingestion.

celiac disease, adherence, CDAT, serum antitransglutaminase antibodies, interview