Studying thousands of patients, Japanese researchers
have found a strong link between tooth loss and increased risk of three
cancers – esophageal, head and neck, and lung. They suggest that
preservation of teeth may decrease risk of developing these diseases.
In the May issue of Cancer Epidemiology, Biomarkers and Prevention, a
journal of the American Association for Cancer Research, scientists from
Aichi Cancer Center in Nagoya and Nagoya University Graduate School of
Medicine speculate that bacterial infection and inflammation resulting
from poor oral care that leads to tooth loss could also be driving
development of these cancers. Periodontal disease is known to increase
risk for stroke and heart disease.
“Tooth loss is a common consequence of chronic bacterial infection and
may, therefore, serve as a surrogate for chronic infection and
inflammation, which in turn may be important to the pathogenesis of
cancer,” said the study’s lead author, Akio Hiraki, Ph.D., a researcher
at the Aichi Cancer Center.
Researchers measured rates of 14 different cancers and rates of tooth loss
in 5,240 cancer patients in Japan, and compared those rates among 10,480
matched cancer-free participants. The researchers specifically found that
people with tooth loss were 136 percent more likely to develop esophageal
cancer, had a 68 percent increased risk of developing head and neck cancer
and a 54 percent greater chance of developing lung cancer. The researchers
also found that the rate of cancer increased proportionally to the number of
teeth a patient had lost.
These increased risks were seen after researchers took into account a
patient’s history of smoking and alcohol use.
Smaller studies have linked tooth loss to different cancers, but this is the
largest study to date, and the first conducted within an Asian population,
the researchers say. This is also the first study to show a link to lung
cancer, they add.
The researchers noted that age and gender affected the associations between
tooth loss and cancer risk. For head and neck and esophageal cancers, there
were clear associations between tooth loss and cancer risk in women and
patients younger than 70 years old, but a less clear link in men and older
patients.
The researchers say that while widespread inflammation could explain the
link between tooth loss and cancer risk, they also note that tooth loss in
the cancer patients may simply reflect unhealthy behaviors that contribute
to cancer risk. Furthermore, people who have lost teeth may not be able to
eat a healthy diet, and diet is also a factor in cancer development.
Whatever the mechanism, the researchers stress that oral care is critical to
good health.
“The oral cavity is a gateway between the external environment and the
gastrointestinal tract and acts in both food ingestion and digestion,” the
researchers wrote. “Oral hygiene potentially affects gastrointestinal flora
and nutritional status and may thus have implications for the development of
chronic disease.”-American Association for Cancer Research
