Periodontal Disease Associated With Increased Cancer Risk

Periodontal Disease Associated With Increased Cancer Risk

Roxanne Nelson

Periodontal disease is associated with a small but significant increase in cancer risk, researchers report.

The association between periodontal disease and overall cancer risk was found in both smokers and nonsmokers, according to a study that appears in June issue of Lancet Oncology.

The authors note that periodontal disease might be a marker of a susceptible immune system or might directly affect cancer risk.

Periodontal infections have previously been found to have systemic implications; individuals with gum disease have increased concentrations of circulating inflammatory markers, and disease severity directly correlates with serum concentrations of inflammatory markers.

Treating periodontal infection can lower markers of systemic inflammatory and endothelial dysfunction, and data from multidisciplinary studies add strength to the possibility of causal associations for a number of health conditions, including diabetes, stroke, and cardiovascular disease.

However, there is no consensus on the relative roles of confounding and bias, or on the causal component of these associations.

In this study, Dominique Michaud, ScD, a cancer epidemiologist from the Imperial College London, United Kingdom, and colleagues assessed the role of oral health in cancer risk. Using data from the Health Professionals Follow-Up Study (HPFS), they examined whether there was an association between periodontal disease, number of teeth, tooth loss during follow-up, and cancer incidence.

The HPFS is a large prospective-questionnaire study of male health professionals that was started in 1986 and included 51,529 American men between the ages 40 to 75 years.

Participants have responded to subsequent surveys every 2 years since the initial questionnaire. In the current analysis, data were available for 48,375 men, with a median follow-up of 17.7 years.

Among this group, there were 5720 incident cancer cases documented, excluding nonmelanoma skin cancer and nonaggressive prostate cancer. The researchers found that the 5 most common cancers were colorectal (n = 1043), melanoma of the skin (n = 698), lung (n = 678), bladder (n = 543), and advanced prostate (n = 541).

Men who reported a history of periodontal disease at baseline had a slightly higher total cancer incidence than men without periodontal disease (unadjusted hazard ratio [HR], 1.28).

After controlling for known risk factors, including smoking and dietary factors, men with a history of periodontal disease had a higher risk for total cancer than men without such a history (HR, 1.14).

When they looked at specific cancer sites, the researchers noted significant associations between a history of periodontal disease and lung (HR, 1.36), kidney (HR, 1.49), pancreas (HR, 1.54), and hematological (HR, 1.30) cancers. Men with fewer teeth at baseline (0 to 16 teeth) had a higher risk for lung cancer (HR, 1.70) than men with 25 to 32 teeth.

Although periodontal disease was associated with significant increases in total (HR, 1.21) and hematological (HR, 1.35) cancers in men who never smoked, no association was observed for lung cancer.

The study had several limitations, the authors note: periodontal disease was self-reported and it had inadequate power to study less-common cancers. The cohort also consisted entirely of men; the findings might not be generalizable to women.

A small increase in the risk for total cancer was seen in men who reported having periodontal disease, compared with those who did not, the authors note. "The increase in risk persisted in never-smokers for total cancer, but not for lung cancer, suggesting that the increase in risk of malignant disease overall is not because of residual confounding by smoking."

"Given the systemic effects of periodontal disease and the potential involvement of the immune system, as a marker of susceptibility or through changes in immune surveillance, we believe that further research on the role of periodontal disease in cancer, especially hematological cancers, is warranted," they conclude.

The study was funded by the National Institutes of Health. The researchers have disclosed no relevant financial relationships.

Lancet Oncol. 2008;9:550-558.

Thanks to Medscape, May 2008

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