Gum disease may raise the risk of developing gastric cancer by up to 25 per cent, according to a large-scale study published in BMC Medicine.
The research, led by Southeast University’s School of Public Health in China, analysed health data from nearly six million adults in Sweden. It is the first study to use sibling-controlled comparisons to examine the link between poor dental health and gastric cancer risk.
“Promoting dental health in the general population could have significant public health implications in preventing this disease,” the authors wrote.
Researchers followed 5.8 million Swedish adults aged 19 and older who had visited a dentist between 2009 and 2016. Over an average follow-up of 6.4 years, 3,993 cases of gastric cancer were diagnosed, including 1,241 cases of cardia gastric cancer, which affects the upper part of the stomach.
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Compared to individuals with healthy teeth, those with periodontitis, or gum disease, had an 11 per cent higher risk of developing gastric cancer. For cardia gastric cancer specifically, the risk increased by 25 per cent.
To account for shared genetic and early-life environmental factors, researchers also conducted sibling-controlled analyses, which confirmed the positive association between gum disease and gastric cancer.
The study also observed a dose-response relationship between tooth loss and gastric cancer risk. Individuals with fewer teeth had a higher likelihood of developing the disease. However, having both gum disease and fewer teeth did not appear to compound the risk.
Unlike previous studies, which were often limited by small sample sizes and retrospective designs, this research combined nationwide health and dental records with a robust study design, providing stronger evidence of the oral-systemic health connection.
Gastric cancer remains one of the leading causes of cancer-related deaths globally. The researchers say maintaining good oral hygiene may be an important step in reducing this risk.