A study, by researchers at Queen‘s University Belfast, analysed a large cohort of over 469,000 people in the UK, investigated the association between oral health conditions and the risk of a number of gastrointestinal cancers, including liver, colon, rectum and pancreatic cancer. Models were applied to estimate the relationship between cancer risk and self-reported oral health conditions, such as painful or bleeding gums, mouth ulcers and loose teeth.
Whilst no significant associations were observed on the risk of the majority gastrointestinal cancers and poor oral health, a substantial link was found for hepatobiliary cancer.
“Poor oral health has been associated with the risk of several chronic diseases, such as heart disease, stroke and diabetes,” explained Dr Haydée WT Jordão, from the Centre of Public Health at Queen’s University Belfast and lead author of the study. “However, there is inconsistent evidence on the association between poor oral health and specific types of gastrointestinal cancers, which is what our research aimed to examine.”
Of the 469,628 participants, 4,069 developed gastrointestinal cancer during the (average) six-year follow up. In 13% of these cases, patients reported poor oral health. Participants with poor oral health were more likely to be younger, female, living in deprived socioeconomic areas and consumed less than two portions of fruit and vegetables per day.
The biological mechanisms by which poor oral health may be more strongly associated with liver cancer, rather than other digestive cancers, is currently uncertain. One explanation is the potential role of the oral and gut microbiome in disease development. “The liver contributes to the elimination of bacteria from the human body,” stated Jordão. “When the liver is affected by diseases, such as hepatitis, cirrhosis or cancer, its function will decline and bacteria will survive for longer and therefore have the potential to cause more harm. One bacteria, Fusobacterium nucleatum, originates in the oral cavity but its role in liver cancer is unclear. Further studies investigating the microbiome and liver cancer are therefore warranted.”
Another theory in explaining the higher cancer risk due to poor oral health suggests that participants with a high number of missing teeth may alter their diet, consuming softer and potentially less nutritious foods, which in turn influence the risk of liver cancer.
Liver cancer is the sixth bigger cancer killer in the EU, claiming the lives of almost 60,000 people per year. The five-year survival rate for the disease across Europe is just 11%4 and approximately 9 in 10 cases are in individuals over the age of 55. It is believed that up to half of cases of liver cancer are preventable, with risk factors often relating to lifestyle, such as overweight or obesity, smoking and alcohol consumption.
Background: Controversy remains as to whether poor oral health is independently associated with gastrointestinal cancers, due to potential confounding by smoking, alcohol and poor nutrition. The aim of this study was to investigate the association between oral health conditions and gastrointestinal cancer risk.
Methods: Data from the large, prospective UK Biobank cohort, which includes n = 475,766 participants, were analysed. Cox proportional hazard models were applied to estimate the relationship between gastrointestinal cancer risk and self-reported poor oral health (defined as painful gums, bleeding gums and/or having loose teeth), adjusting for confounders.
Results: During an average six years of follow-up, n = 4069 gastrointestinal cancer cases were detected, of which 13% self-reported poor oral health. Overall, there was no association between self-reported poor oral health and risk of gastrointestinal cancer detected (hazard ratio 0.97, 95% confidence interval 0.88–1.07). In site-specific analysis, an increased risk of hepatobiliary cancers was observed in those with self-reported poor oral health (hazard ratio 1.32, 95% confidence interval 0.95–1.80), which was stronger for hepatocellular carcinoma (hazard ratio 1.75, 95% confidence interval 1.04–2.92).
Conclusion: Overall there was no association between self-reported poor oral health and gastrointestinal cancer risk. However, there was a suggestion of an increased risk of hepatobiliary cancer, specifically hepatocellular carcinoma.
Haydée WT Jordão, Gerry McKenna, Úna C McMenamin, Andrew T Kunzmann, Liam J Murray, Helen G Coleman