People who have periodontal (gum) disease may have a higher risk of developing some forms of cancer, suggests a letter published in the journal Gut detailing a prospective study.

US researchers found that a history of periodontal disease appeared to be associated with a raised risk of esophageal (gullet) cancer and gastric (stomach) cancer and this risk was also higher among people who had lost teeth previously.

Previous findings on the relationship of periodontal disease and tooth loss with esophageal and gastric cancer have been inconsistent.

Therefore, a team of researchers from Harvard T.H. Chan School of Public Health, in Boston, USA, carried out a study of data on patients over decades of follow up.

They examined the association of history of periodontal disease and tooth loss with the risk of esophageal and gastric cancer in 98,459 women from the Nurses' Health Study (1992-2014) and 49,685 men from the Health Professionals Follow-up Study (1988-2016).

Dental measures, demographics, lifestyle, and diet were assessed using follow-up questionnaires and self-reported cancer diagnosis was confirmed after reviewing medical records.

The results showed that during 22-28 years of follow-up, there were 199 cases of esophageal cancer and 238 cases of gastric cancer.

A history of periodontal disease was associated with a 43% and 52% increased risk of esophageal cancer and gastric cancer, respectively.

Compared to people with no tooth loss, the risks of esophageal and gastric cancer for those who lost two or more teeth were also modestly higher -- 42% and 33%, respectively.

In addition, among individuals with a history of periodontal disease, no tooth loss and losing one or more teeth were equally associated with a 59% increased risk of esophageal cancer compared to those with no history of periodontal disease and no tooth loss.

Similarly, the same group of individuals had 50% and 68% greater risk of gastric cancer, respectively.