Characteristics of adults with suspected non-coeliac gluten sensitivity as compared to patients with coeliac disease

Background: In contrast to coeliac disease (CD), the mechanism behind non-coeliac gluten sensitivity (NCGS) is unclear. As intestinal and extraintestinal symptoms largely overlap, it is difficult to distinguish these patient groups clinically. Aims: The overall aim of this thesis was to obtain a better understanding of the general characteristics, symptoms and health complaints experienced by adults with self-reported NCGS compared with CD patients. The primary outcome was to compare the level of gastrointestinal symptoms, fatigue, depression and health-related quality of life (HRQOL) on a gluten free diet (GFD). The secondary outcomes were to compare the proportion of NCGS adults to CD patients who retrospectively reported gastrointestinal symptoms and tiredness prior to a GFD, and further, to assess the symptom changes within the groups after treatment with a GFD. Methods: We compared baseline characteristics between 20 patients with CD and 66 patients with NCGS participating in two separate gluten challenge studies at Oslo University Hospital, Rikshospitalet. Symptoms on a GFD were reported via the completion of 5 questionnaires regarding gastrointestinal symptoms, fatigue, depression, HRQOL and general health complaints. Symptoms experienced prior to a GFD were reported retrospectively during the baseline interview. Results: The NCGS group experienced more gastrointestinal symptoms (p= 0.01), fatigue (p= 0.002), dizziness (p= 0.01) and depression (p= 0.002) on a GFD compared to the CD group. They also reported a lower level of HRQOL, particularly for the Bodily Pain (p= 0.01), General Health (p= 0.001), and Social Functioning (p= 0.01) scales. In regards to gastrointestinal symptoms reported prior to a GFD, a larger proportion of NCGS patients experienced abdominal pain (p= 0.02) and diarrhoea (p= 0.02). They did however report an improvement in all gastrointestinal symptoms on a GFD (p < 0.001). The CD group only experienced improvements in abdominal pain (p= 0.02). Furthermore, a larger percentage of NCGS patients reported tiredness (p= 0.02) prior to a GFD compared to CD patients. Both groups however, did report a considerable improvement in tiredness on a GFD (CD p= 0.03; NCGS p < 0.001). Conclusion: Compared to patients with CD, adults with self-reported NCGS reported a significantly higher level of symptoms both on a GFD and prior to treatment with a GFD based on the measures conducted.