For most of the last century, researchers believed that individuals who suffered from gum disease were at a higher risk of developing heart disease or suffering from a stroke. While no direct link between the two diseases was ever conclusively proven, studies showed that patients who suffered from periodontal disease were twice as likely to develop coronary disease, and that individual’s whose blood contained high levels of disease-causing bacteria in the mouth were at a higher risk of developing clogs in the carotid arteries, which can lead to stroke.

Despite these compelling statistics, finding a direct cause and effect between the two conditions had always eluded researchers, and apparently for good reason. In a report released earlier this year, the American Heart Association announced the findings of a study that concluded no compelling evidence exists that convincingly links gum disease to heart disease or stroke. Published in the journal Circulation, the report offers an explanation of why dentists, cardiologists, and the entire scientific community were misled about the effects of gum disease for so long.

Cause and Effect

Led by cardiologist at the University of California, San Francisco, the study examined over 500 studies that had previously explored the link between cardiovascular and gum disease that were conducted between 1950 to July of 2011. What researchers found was little cause and effect existed between the two diseases, but they did share several common risk factors.

Heart disease, gum disease, and stroke all produce inflammation in the body, and each share common risk factors, such as smoking, diabetes, and age. Individuals who possess these risk factors increase their chances of developing one or more of these conditions. So previous studies that drew a link between gum disease and heart disease were in essence seeing the disease in the same patients not because one led to the other, but because common risk factors led to patients developing both diseases. This information goes against the tenuous links that researchers used to link gum disease to cardiovascular disease.

Previously, researchers hypothesized that bacteria in the mouth entered the bloodstream through the gums, allowing it to travel throughout the body. When confronted with bacteria and infection, the body’s natural response is inflammation, and researchers suspected that oral bacteria traveling through the bloodstream caused blood cells to swell in response, which could narrow the arteries and lead to a blood clot.

Another theory stated that oral bacteria would stick to fatty plaques it encountered as it moved through a person’s bloodstream. These fatty deposits begin to line the walls of arteries in the heart and directly lead to blockages that cause heart attacks.

A New Understanding

Based on their review of existing research, it became clear to the study’s organizers that the link between the two diseases was more coincidence than hard science. Individuals at risk of developing gum disease are at just as big a risk of developing heart disease, so studies that found patients had both diseases mistakenly drew parallels where none existed. If a patient has gum disease and heart disease, they have two separate diseases, and the treating of one disease won’t help cure the other.

The study’s findings were backed by several prominent organizations, including the American Dental Association’s Council of Scientific Affairs, the World Heart Federation, and the American Academy of Periodontology. Just because no link exists between the two diseases, however, doesn’t mean a person’s risk of developing one or both has lessened. Patients diagnosed with gum disease should use their diagnosis as an early warning sign, and need to consult their doctor about undergoing treatments designed to help prevent heart disease.