Chronic inflammation could be the link, experts say
TUESDAY, May 27 (HealthDay News) -- There may be another good reason to floss each day: A new study finds that gum disease could raise the risk for cancer.
"Men with history of periodontal disease had a 14 percent higher risk of cancer than those who did not have periodontal disease, and the increase persisted among never smokers," said lead researcher Dominique Michaud, a cancer epidemiologist at Imperial College London, in the U.K.
People with gum infections do have an increased amount of inflammatory markers circulating in their blood, and inflammation has been linked to cancer, experts say. But the exact link, if any, between gum disease and cancer remains unclear.
This new finding needs to be examined in other populations and among women, but it at least suggests that oral health may have some impact on cancer risk, Michaud said.
"If other data can support this association, then it will have implications for prevention and may provide some new clues on the role of the immune function in cancer development," Michaud said.
The report is published in the June edition of the journal The Lancet Oncology.
In the study, Michaud's team collected data on more than 48,000 American men who participated in the Health Professionals Follow-Up study, which included health professionals aged 40 to 75.
During an average of 17.7 years of follow-up, 5,720 cancer cases were reported. These cases excluded non-melanoma skin cancer and non-aggressive prostate cancer. The most common cancers reported were colorectal, melanoma, lung and bladder and advanced prostate cancer, Michaud's group found.
After taking into account other risk factors, such as smoking and diet, the researchers found that men with a history of gum disease had a 14 percent higher risk of developing cancer compared with men did not have a history of the condition.
While the overall risk was 14 percent, the risk for specific cancers was typically higher. Compared to men with healthy gums, men with a history of gum disease had a 36 percent increased risk of lung cancer, a 49 percent hike in risk of kidney cancer, a 54 percent higher risk of pancreatic cancer, and a 30 percent increased risk of white blood cell cancers.
In addition, men who had fewer teeth at the beginning of the study had a 70 percent increased risk of developing lung cancer, compared with men who had 25 to 32 teeth, Michaud's team found.
However, the association between gum disease and lung cancer disappeared among men with gum disease who had never smoked, the team noted. Men with gum disease who did not smoke still had a 35 percent increased risk for blood cancers, however, and a 21 percent overall increased risk for cancer.
One expert believes that the increased risk found in the study is too small to conclude that gum disease is a major risk factor for cancer.
"I am not very impressed with the finding," said Dr. Eva S. Schernhammer, an assistant professor, medicine and public health at Harvard Medical School and School of Public Health. "It's a really modest increased risk. I am not sure I would make too much out of it," she said.
"If this is a true association, it could be a marker of socioeconomic status, or a marker for some inflammatory process that leads to cancer," Schernhammer reasoned. "Given the small increase in risk, I'm not sure it would lead to major, dramatic changes in anything" in terms of public health policy, she said.
For more on cancer risk, visit the American Cancer Society.
SOURCES: Dominique Michaud, Sc.D., reader in cancer epidemiology, Imperial College London, U.K.; Eva S. Schernhammer, M.D., Dr.P.H., assistant professor, medicine and public health, Harvard Medical School and School of Public Health, Boston; June 2008 The Lancet Oncology
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