Study reveals genetic links between oral and gut health

Dental Tribune International

Mon. 2. November 2026

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WUHAN, China: Growing evidence suggests that oral and gastro-intestinal diseases are interconnected, but the biological mechanisms underlying these associations are not well understood. A recent large-scale genetic study has examined whether common oral and gastro-intestinal diseases share a genetic susceptibility. The findings highlight immune-related pathways as potential links between oral and gut health and provide further evidence of a possible causal relationship between periodontitis and inflammatory bowel disease.

In the study, the researchers analysed genetic data on people of European ancestry using two large databases, the US Million Veteran Program and UK Biobank. They examined periodontitis, caries and temporomandibular disorder alongside five gastro-intestinal conditions: inflammatory bowel disease, irritable bowel syndrome, gastro-oesophageal reflux disease, peptic ulcer disease and diverticular disease.

Each oral condition was paired with each gastro-intestinal condition to look for shared genetic links. According to the findings, almost all the disease pairs shared genetic links, suggesting that shared genetic factors may contribute to the coexistence of oral and gastro-intestinal disease.

Additionally, the findings point to a potential causal association between genetic susceptibility to periodontitis and the development of inflammatory bowel disease. The study did not find evidence that genetic susceptibility to inflammatory bowel disease contributes to periodontitis. These findings add genetic evidence to prior clinical observations that periodontitis is more common among people with inflammatory bowel disease.

Shared genetic links involve immune pathways

Looking at the roles of the genes associated with both oral and gastro-intestinal diseases, the researchers found that many were involved in immune responses. This suggests that shared disturbances in immune regulation may contribute to the relationship between oral and gut health.

The researchers also identified several proteins in the blood associated with both inflammatory bowel disease and the three oral conditions studied. These findings provide potential targets for future investigation into how the diseases are connected.

Lifestyle and environmental associations

Using periodontitis as the representative oral condition, the researchers examined lifestyle and health factors associated with the coexistence of periodontal and gastro-intestinal disease. Smoking, higher body mass index, long-term or recurrent antibiotic use during childhood or adolescence, and poorer psychological health were associated with having both conditions, whereas the opposite was true for physical activity and fruit and vegetable intake.

The researchers also found that diet, alcohol consumption, smoking, physical activity and mental health indicators had different associations with coexisting periodontal and gastro-intestinal disease depending on people’s genetic variants. These findings suggest that lifestyle and mental health factors may influence genetic susceptibility, although further research is needed to establish their clinical significance.

Together with previous clinical evidence, the findings highlight the potential importance of considering periodontal health in patients with gastro-intestinal disorders, particularly inflammatory bowel disease. However, further research is needed to determine whether periodontal treatment can influence gastro-intestinal disease outcomes.

The study, titled “Shared genetic pathways linking oral diseases to gastrointestinal disorders: An integrative multi-omics study”, was published online on 8 October 2026 in iMetaMed, ahead of final publication.