Cognitive impairment in coeliac disease improves on a gluten-free diet and correlates with histological and serological indices of disease severity

Background Mild impairments of cognition or Brain fog' are often reported by patients with coeliac disease but the nature of these impairments has not been systematically investigated. Aim This longitudinal pilot study investigated relationships between cognitive function and mucosal healing in people with newly diagnosed coeliac disease commencing a gluten-free diet. Methods Eleven patients (8 females, 3 males), mean age 30 (range 22-39) years, were tested with a battery of cognitive tests at weeks 0, 12 and 52. Information processing efficacy, memory, visuospatial ability, motoric function and attention were tested. Small bowel biopsies were collected via routine gastroscopy at weeks 12 and 52 and were compared to baseline Marsh scores. Cognitive performance was compared to serum concentrations of tissue transglutaminase antibodies, biopsy outcomes and other biological markers. Results All patients had excellent adherence to the diet. Marsh scores improved significantly (P=0.001, Friedman's test) and tissue transglutaminase antibody concentrations decreased from a mean of 58.4 at baseline to 16.8U/mL at week 52 (P=0.025). Four of the cognitive tests assessing verbal fluency, attention and motoric function showed significant improvement over the 12months and strongly correlated with the Marsh scores and tissue transglutaminase antibody levels (r=0.377-0.735; all P<0.05). However, no meaningful patterns of correlations were found for nutritional or biochemical markers, or markers of intestinal permeability. Conclusions In newly diagnosed coeliac disease, cognitive performance improves with adherence to the gluten-free diet in parallel to mucosal healing. Suboptimal levels of cognition in untreated coeliac disease may affect the performance of everyday tasks.