The Link Between Your Mouth and Your Stroke Risk

Stroke risk linked to presence of mouth bacteria

/ Author:  / Reviewed by: Jennifer Gershman, PharmD, CPh

(RxWiki News) Here's a reason to keep your mouth clean that you probably didn't expect: It might lower your risk of stroke.

That's what the findings of a new study suggest, anyway. The presence of S. mutans bacteria in the saliva was linked to hemorrhagic strokes in this study of 100 stroke patients hospitalized in Japan.

What's the best way to reduce the number of bacteria in your mouth? Keep it clean, the authors of this study said.

"This study shows that oral health is important for brain health," said lead study author Robert P. Friedland, MD, a professor of neurology at the University of Louisville, in a press release. "People need to take care of their teeth because it is good for their brain and their heart as well as their teeth. The study and related work in our labs have shown that oral bacteria are involved in several kinds of stroke, including brain hemorrhages and strokes that lead to dementia."

The patients in this study had hemorrhagic strokes, which are marked by ruptures in the brain that cause bleeding. Another common type of stroke is ischemic stroke, which is caused by a blood vessel blockage that keeps blood from reaching the brain.

Dr. Friedland and colleagues tested the saliva of the patients before they left the hospital. Twenty-six percent of these patients tested positive for S. mutans. This type of bacteria is thought to play a role in tooth decay, Dr. Friedland noted.

These researchers also observed the MRI brain scan images of these patients for microbleeds — small ruptures in brain blood vessels that may be linked to dementia — and found that patients who tested positive for S. mutans were more likely to have these microbleeds.

S. mutans bacteria may attach to weakened blood vessels and lead to ruptures, Dr. Friedland and team said. These researchers said they plan to conduct more research on this subject.

This study was published Feb. 16 in the journal Scientific Reports.

The Mitsui Sumitomo Insurance Welfare Foundation and SENSHIN Medical Research Foundation funded this research. The authors disclosed no conflicts of interest.

Review Date: 
February 18, 2016
Last Updated:
February 18, 2016