Approved research

Associations of oral and gut microbiome-related exposures with cancer risk and mortality

Lay summary

Both the oral and gut microbiome (i.e., the collection of microbes including bacteria, archaea, fungi, viruses, and other eukaryotic microbes found in the oral cavity or the gut) are likely to be involved in the development of leading causes of mortality in developed countries, such as cardiovascular disease, diabetes, and cancers; however, associations between the microbiome and cancer or mortality risk remain unclear. This is mostly due to the lack of large prospective studies with oral and/or fecal samples available for the assessment of the microbiome with adequate follow-up to observe microbiome-disease associations. In the meantime, it is informative to assess associations of established microbiome-related exposures with cancer and mortality risk to provide a better understanding of the mechanisms underlying microbiome-disease associations. Therefore, our objective is to investigate the associations of exposures related to oral and gut microbiome composition with overall and site-specific cancer risk, as well as overall and cause-specific mortality in the large, prospective UK Biobank study. We will characterize oral microbiota-related metrics by assessing oral health, including history of mouth ulcers, gingivitis and periodontal disease, loose teeth, dental caries, and denture use. Exposures related to the gut microbiome will include long-term antibiotic use, birth by cesarean section, inflammatory and irritable bowel syndromes, Celiac disease, appendicitis, and average number of bowel movements. To assess these associations, we will use statistical models which take into account variables that may affect the microbiome and/or cancer risk and mortality, such as smoking, alcohol consumption, and diet. These findings could provide evidence and further insight into the role of exposures related to the microbiome in cancer risk and premature mortality, and provide evidence for the continuing exploration into the etiology of microbial-related health states. Findings from this study may also provide insight into prevention strategies and translate into public health and clinical recommendations for oral and gut health.