Dental Disease Linked to Pancreatic Cancer

August 24, 2010
A Prospective Study of Periodontal Disease and Pancreatic Cancer

Can diseased gums increase the risk of pancreatic cancer?

Epidemiologists at the Harvard School of Public Health in Boston think it could, at least according to the findings of a study analyzing 16 years of health data on more than 52,000 men.
Dominique Michaud, Sc.D., assistant professor of epidemiology in the Harvard School of Public Health in Boston, and colleagues at Dana-Farber Cancer Institute and the University of Puerto Rico wanted to know if inflammation, and specifically, systemic inflammation from periodontal disease, might be related to pancreatic cancer.
According to Michaud, several studies have linked inflammation and cancer, and researchers have found a high risk of developing pancreatic cancer among individuals with pancreatitis, or inflammation of the pancreas. But the ties between periodontal disease and cancer have been more tenuous.
Previous studies have shown associations between tooth loss and cancer, and pancreatic cancer as well. But the validity of such studies was questionable because of confounding factors, including smoking, which contributes to both periodontal disease and cancer. An association with periodontal disease and heart disease has also been examined, with systemic inflammation being a potential mechanism behind the connection. Periodontal disease results in chronic inflammation over many years, both in the mouth and potentially, systemically, as well.
The researchers analyzed the health records of a fairly homogenous group of about 52,000 highly educated, male health professionals between ages 40 and 75 who participated in the Health Professionals Follow-up Study, which was created in 1986 to look at lifestyle factors related to cancer and other chronic diseases. They continue to be followed at present through mailed questionnaires, with a greater than 95 percent follow-up rate, Michaud said.
The researchers recorded 216 cases of pancreatic cancer in the 16 years of follow-up between 1986 and 2002. Men who reported having periodontal disease had a 63 percent higher risk of developing pancreatic cancer compared to those who did not report periodontal disease, after the team adjusted for smoking, diabetes, age, physical activity and diet. Those men who never smoked fared even worse, with a two-fold increase in risk. Men who reported a history of periodontal disease and tooth loss in the last four years showed a more than a 2.5-fold increase in the risk of developing pancreatic cancer compared to those without periodontal disease and recent tooth loss.
In a secondary analysis, the team looked at tooth loss at both the beginning of the study (baseline) and during the follow-up period. While tooth loss at baseline was not associated with a risk of pancreatic cancer, those who lost teeth during follow up showed an increased, albeit lesser, risk for pancreatic cancer. Tooth loss among older individuals is likely due to periodontal disease, Michaud explained, whereas tooth loss at enrollment in the study is more likely to reflect teeth that were lost or removed because of cavities.
"The results confirm our hypothesis that pancreatic cancer is related to periodontal disease, not merely tooth loss," Michaud said.
Other potential mechanisms, she said, include the fact that those with periodontal disease have high amounts of bacteria in the mouth and in the gut, and also tend to have higher amounts of nitrosamines, which have been proposed to increase pancreatic cancer risk.
"The work might provide new insights in understanding the role of systemic inflammation on initiation or promotion of pancreatic cancer," she said. Smoking, she noted, is a risk factor that could be acting as a promoter by causing inflammation.
"Establishing whether periodontal disease increases the risk and understanding the mechanisms behind these associations are important because we know so little about pancreatic cancer."
Pancreatic cancer, the fourth-leading cause of cancer death in this country, takes some 30,000 lives a year.

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