A surprising, but unambiguous link has been detected between tooth loss and an increased risk of three different kinds of cancer — of the esophagus, head and neck, and lung.
During 2008, two separate and unrelated studies — one conducted in Japan and the other in Iran — both found a significant relationship between tooth loss and esophageal cancer, while the larger Japanese study also identified a connection between tooth loss and head/neck and lung cancer.
The Iranian study was conducted by researchers from the National Cancer Institute in Maryland, the International Agency for Research on Cancer in France and Tehran University of Medical Sciences in Iran. They found a significant correlation between tooth loss/poor oral hygiene and the risk of one specific cancer — esophageal squamous cell carcinoma.
The Aichi Cancer Center in Nagoya, Japan, conducted a large-scale (15,000-person) study to examine the role of oral health in common cancers. Two groups of subjects, one with newly diagnosed cancer and an age- and sex-matched control group without cancer, were grouped by number of remaining teeth. The researchers discovered that the fewer remaining teeth, the greater the likelihood of esophageal, lung and head/neck cancer. They speculated that the reasons could include that cancers were not detected in the early, precancerous stages as they might have been among people who see their dentist regularly, and also that their poor dental hygiene likely was a factor that increased risk. Another possibility is that saliva may carry bacteria from chronic inflammation (periodontal disease) and recurrent infections, possibly inducing tissue changes and perhaps even cancer, in those particular body parts.
Does this mean that poor oral hygiene causes cancer? Not necessarily, but Dr. Keitaro Matsuo, Division of Epidemiology and Prevention at the Aichi Cancer Center of Nagoya University in Japan and one of the authors of the Japanese study, says that people should practice good oral hygiene to prevent decay and infection that leads to tooth loss, other inflammatory conditions and potentially cancer.
Dr. Matsuo also noted another interesting finding: The associations between tooth loss and head/neck and esophageal cancer were not as clear among men and older subjects as among women and younger (less than 70 years) subjects, although he acknowledges that this difference may reflect other factors not considered in the analysis. Nonetheless, he says it makes sense for all, but especially for women who’ve already lost teeth, to be extra-attentive to following a cancer preventive lifestyle.
