Background: Gluten free diet (GFD) is the only treatment for celiac disease (CD). Adherence to the GFD is highly important to reduce the risk of complications. It has been found that adherence to the GFD is reduced over time. In addition it has been indicated that persons with CD living on a GFD for over ten years may not have a nutritionally balanced diet. It is essential to be able to accurately assess GFD adherence, and there is currently no consensus regarding any method to best describe this.
Aim: The main aim of the study was to validate objective methods for assessing adherence to the GFD in Norwegian CD patients. Furthermore, the aim was to study micronutrient status.
Method: The Martine questionnaire was developed to assess GFD adherence. In addition previously developed methods for GFD assessment; the Celiac Disease Adherence Test (CDAT) and Biagi’s test were used. The different questionnaires were validated against the Marsh criteria. A four day weighed food record was used to obtain micronutrient intake. In addition serum micronutrient level was measured.
Results: A total of 58 participants were included in the study. Mean years on GFD was 21.2 years. The majority of participants had a Marsh grade 0, indicating a normal mucosa. According to Marsh grades, 82.8% of participants were adherent to the GFD. None of the GFD assessment methods performed satisfactory when compared to Marsh grades. According to the Martine questionnaire 89.7% of participants were adherent. The method will however need further re-evaluation and testing. Interestingly, the previously developed and validated CDAT and Biagi’s test showed a discrepancy in amount of non-adherence. According to Biagi’s test 86.2% were adherent, compared to 58.6% by CDAT, suggesting that these will also need further evaluation for use in Norway. All micronutrient serum levels were within respective reference ranges, both for adherent and non-adherent participants. For females, intake of iron, folate, calcium, magnesium, vitamin D and potassium were below the recommendations. For males, intake of folate, thiamine, magnesium, selenium, vitamin A, D and E were below the recommendations.
Conclusions: Further studies are needed to obtain a simple, objective method to assess adherence to the GFD. Furthermore, micronutrient intake in Norwegian CD patients may be inadequate.