Common Gut Bacteria Linked to Increased Stroke Risk and Mortality, Japanese Study Finds

Researchers at Japan's National Cerebral and Cardiovascular Center have uncovered a potential connection between a specific gut bacteria and increased stroke risk, offering new insights into stroke prevention and prognosis.

The study, set to be presented at the American Stroke Association's International Stroke Conference, found that Streptococcus anginosus was significantly more abundant in stroke patients' saliva and gut compared to individuals without stroke. Notably, patients with this bacteria in their gut had 20% higher odds of stroke and a significantly increased risk of death and major cardiovascular events over a two-year period.

The research analyzed 250 participants, including 200 stroke patients and 50 non-stroke controls, examining their oral and gut microbiomes. The findings suggest that the delicate balance of bacteria in the human microbiome could play a crucial role in cardiovascular health.

Lead researcher Dr. Shuichi Tonomura emphasized the potential future implications, stating that a quick test to detect harmful bacteria could help calculate stroke risk. The study also highlighted the importance of oral hygiene, noting that both Streptococcus mutans and Streptococcus anginosus contribute to tooth decay and potentially cardiovascular complications.

Interestingly, the research found that certain bacteria like Anaerostipes hadrus and Bacteroides plebeius were associated with reduced stroke risk, indicating the complex relationship between microbiome composition and cardiovascular health.

The researchers acknowledged limitations in the study, including its focus on a Japanese population with a relatively small sample size. Dr. Tonomura noted that the oral and gut microbiome is strongly influenced by lifestyle, and bacteria's role in stroke risk might vary across different populations.

Dr. Louise D. McCullough, who was not involved in the study, praised the research's potential to enhance stroke prevention strategies. She suggested that future studies should examine populations at risk of stroke to better understand the broader implications of bacterial interactions.

While the findings are preliminary and require further validation through peer-reviewed research, they represent a promising avenue for understanding stroke risk and developing targeted prevention strategies. The study underscores the growing recognition of the microbiome's significance in human health and disease.