19/05/2025
Two recent studies presented at the American Stroke Association’s International Stroke Conference 2025 have highlighted the role of oral health in cardiovascular disease. A study in Japan found elevated levels of Streptococcus anginosus, a common mouth and gut bacterium, in the gut of recent stroke survivors. Over two years, stroke patients with high levels of this bacteria had a greater risk of death or another major cardiovascular event. The findings suggest that analysing oral and gut bacteria could help assess stroke risk, and that targeting harmful bacteria through new treatments and better dental hygiene may aid in stroke prevention.
“In the future, if there was a quick test to detect harmful bacteria in the mouth and gut, we could use the information to help calculate stroke risk. Targeting these specific harmful oral bacteria may help prevent stroke,” said Shuichi Tonomura, lead author of the study and staff physician in the department of neurology at the National Cerebral and Cardiovascular Centre in Osaka, Japan.
Previously, these researchers found that a different bacterium, the one that causes tooth decay, Streptococcus mutans, was associated with a higher risk of bleeding inside the brain.
The second study suggests that flossing at least once a week may lower the risk of stroke and atrial fibrillation (AFib), independent of other oral hygiene habits. Researchers believe the benefits stem from reduced inflammation and infection, though further studies are needed. However, while the study found a correlation between flossing and lower stroke risk, this does not prove that flossing directly causes the reduction.
“A recent global health report revealed that oral diseases, such as untreated tooth decay and gum disease, affected 3.5 billion people in 2022, making them the most widespread health conditions,” said study lead author Souvik Sen, chair of the Department of Neurology, Prisma Health Richland Hospital and the University of South Carolina School of Medicine in Columbia, South Carolina. “We aimed to determine which oral hygiene behaviour, dental flossing, brushing, or regular dentist visits, has the greatest impact on stroke prevention.”
The Atherosclerosis Risk in Communities (ARIC) study, one of the first large-scale investigations of this kind in the US, assessed the home use of dental floss through a structured questionnaire of more than 6,000 people over 25 years. Flossing was associated with a 22% lower risk of ischemic stroke, 44% lower risk of cardioembolic stroke (blood clots traveling from the heart), and 12% lower risk of AFib. The associated lower risk was independent of regular brushing and routine dental visits or other oral hygiene behaviours. Increasing the frequency of flossing conferred a greater chance of stroke risk reduction. Flossing was also associated with a lower chance of cavities and periodontal disease. Researchers were surprised by the reduction of AFib associated with flossing.
For more information see: https://scitechdaily.com/common-mouth-bacteria-linked-to-higher-stroke-risk/
and
https://scitechdaily.com/new-study-reveals-that-flossing-could-reduce-your-risk-of-stroke-by-22/