Periodontal Disease Associated
With Increased Cancer Risk
Roxanne Nelson
May 28, 2008 — 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.