As if gum disease is not a painful enough experience, a Harvard study shows the disease can more than double the risk of pancreatic cancer. Additionally, those with a history of gum disease and recent tooth loss have a 2.7-fold increase in risk.

Previous studies have linked gum disease and pancreatic cancer, but smoking -- which contributes to both diseases -- has never been taken into consideration.

Researchers in this study, who controlled for smoking, followed 51,529 men for 16 years and found those who reported gum disease were 64 percent more likely to have pancreatic cancer. Nonsmokers with gum disease were twice as likely to develop the disease.

It was also determined in the study, published in the January 17 issue of the Journal of the National Cancer Institute, that the more severe the gum disease, the higher the cancer risk.

While it is not clear why gum disease is linked to cancer risk, researchers believe perhaps long-term gum infections trigger body-wide inflammation -- and inflamed tissues send chemical signals that promote tumor growth.