Background: Coeliac disease is an immune-mediated intestinal disease characterised by lifelong intolerance to dietary gluten in genetically predisposed individuals. Microbial factors including infections or bacterial microbiota have long been suspected to be involved in the aetiology, but the scientific literature on the topic is scattered and heterogeneous.
Aims: To review human observational studies on microbes and coeliac disease METHODS: We identified 135 publications judged relevant. Most studies were cross-sectional, and prone to reverse causation and other biases. Only a few were prospective. Cohort studies and longitudinal studies that have sampled biological specimens before disease onset are emphasised in the review.
Results: Infections during early childhood were associated with an increased risk of subsequent coeliac disease in nine studies , whereas maternal infections during pregnancy did not show a clear association. For the most frequently studied microbial factors, some evidence for an association was found, including Helicobacter pylori (four out of 16 studies), adenovirus (two out of nine studies) and enterovirus (two out of six studies). Rotavirus infections have been associated with disease development, and rotavirus vaccination may reduce the risk. Among the many studies of gut microbiota, most were cross-sectional and, therefore, potentially influenced by reverse causation. Only two smaller prospective case-control studies with sampling before disease onset were identified; they reported inconsistent findings regarding the faecal microbiome.
Conclusions: Several microbes are potentially linked to coeliac disease. As microbial factors are amenable to interventions, larger prospective studies are still warranted.
© 2020 John Wiley & Sons Ltd.