Heart attack (FDA picture)

A new study suggests that brushing your teeth might reduce your risk of stroke and heart attack. Researchers say people who suffer gum disease are more likely to have narrowing of their arteries and blood vessels.

Scientists at Columbia University in New York report that older adults who have higher than normal amounts of gum disease bacteria also tend to have thicker carotid arteries. These are the four main arteries in the neck and head, and their narrowing, called atherosclerosis, is a strong predictor of stroke and heart attack.

The researchers reveal their findings in the American Heart Association journal Circulation after measuring mouth bacteria levels and carotid artery thickness in nearly 700 white, black and Hispanic New Yorkers aged 55 or older.

This is the first direct association between cardiovascular disease and gum inflammation. Previous studies have suggested a link, but they relied on indirect markers of gum disease, such as tooth loss. The Columbia team is the first to measure the four key bacteria involved in gum disease and positively relate them to atherosclerosis.

But the work does not prove gum disease causes cardiovascular illness.

Moise Desvarieux

"Because we measured both the bacteria and atherosclerosis at the same time, it's the chicken and the egg. We don't know which one comes first," says Moise Desvarieux, a Columbia University infectious disease specialist.

He says it is important to determine the actual relationship between the two conditions because gum disease is very common.

"So many people have it that if it becomes clearer that there is an implication for atherosclerosis, at a population level it would be very important because it would be something that could be acted upon. But we do not know yet as of now whether it is a cause, either partial or not," he said.

Dr. Desvarieux, a native of Haiti, says if gum disease bacteria do cause thickening of the arteries, it could be because the organisms migrate through the bloodstream and stimulate the immune system, causing inflammation that results in the clogging of arteries with fatty deposits.

However, he notes that the gum bacteria could be acting jointly with other cardiovascular disease risk factors, such as diabetes, high cholesterol and blood pressure, and smoking. But he says the findings make this possibility less likely because the relationship between the two diseases held, even after the researchers statistically controlled for those factors.

"In that sense, it seems to suggest that it is not simply the joint risk factors, but we still have to await further studies," he said.

The Columbia University researchers plan to track the study participants over time to see whether their initial findings hold up and translate into cardiovascular disease.