Regular dental flossing may lower risk of stroke from blood clots, irregular heartbeats

(Press-News.org) Research Highlights:

People who regularly floss their teeth (one or more times per week) may lower their risk of stroke caused by a blood clot traveling from the heart and a stroke associated with an irregular heartbeat such as atrial fibrillation (AFib). The benefits of regular flossing may be independent of tooth brushing and other oral hygiene behaviors. Researchers suggest that flossing is a healthy habit that is affordable, easy to adopt and accessible everywhere. Note: The study featured in this news release is a research abstract. Abstracts presented at the American Heart Association’s scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as full manuscripts in a peer-reviewed scientific journal. Embargoed until 4 a.m. CT/5 a.m. ET, Thursday, Jan. 30, 2025

DALLAS, Jan. 30, 2025 — Flossing your teeth at least once a week may be linked to a lower risk of stroke caused by a blood clot blocking brain blood flow and irregular heartbeats, according to a preliminary study to be presented at the American Stroke Association’s International Stroke Conference 2025. The meeting is in Los Angeles, Feb. 5-7, 2025, and is a world premier meeting for researchers and clinicians dedicated to the science of stroke and brain health.

“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, M.D., M. S., M.P.H, 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 behavior — 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 U.S., assessed the home use of dental floss through a structured questionnaire of more than 6,000 people. Among those who reported flossing, 4,092 had not experienced a stroke, and 4,050 had not been diagnosed with an irregular heartbeat known as atrial fibrillation (AFib).

Participants were asked about their status regarding high blood pressure, diabetes, high cholesterol, smoking, body mass index, education, regular brushing and dentist visits. During the 25 years of follow-up, 434 participants were identified as having strokes, of which 147 were larger artery brain clots, 97 were heart-driven clots and 95 were hardening of the smaller arteries. Additionally, 1,291 participants were noted to have experienced AFib.

The analysis found:

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 behaviors. Increasing the frequency of flossing had 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 irregular heartbeats, or AFib. AFib is the most common form of irregular heartbeat. It can lead to stroke, heart failure or other cardiovascular complications. More than 12 million people are projected to have AFib in the United States by 2030, according to the American Heart Association’s 2025 Heart Disease and Stroke Statistics.

“Oral health behaviors are linked to inflammation and artery hardening. Flossing may reduce stroke risk by lowering oral infections and inflammation and encouraging other healthy habits,” Sen said. “Many people have expressed that dental care is costly. Flossing is a healthy habit that is easy to adopt, affordable and accessible everywhere.”

Study limitations include that data were based on answers to a questionnaire, and the 25-year follow-up appears to have focused on stroke and heart outcomes only. There was no follow-up concerning flossing or other oral behaviors over the years, Sen said.

“This study offers more insights into the specific dental health behaviors that may be linked to stroke risks and potential risk reduction. With further research, dental health practices could possibly be incorporated into the "Life's Essential 8" risk factors, which include diet, physical activity, nicotine exposure, sleep, body mass index, blood pressure, blood glucose and blood lipids,” said Daniel T. Lackland, Dr.P.H., FAHA, American Heart Association EPI and Stroke Council member and professor of epidemiology and director of the Division of Translational Neurosciences and Population Studies in the department of neurology at the Medical University of South Carolina in Charleston. Lackland was not involved in this study.

Study background, and details:

The study began in 1987 and is ongoing. Of the 6,258 participants, 82% were self-reported white adults and 18% Black adults. Their average age was 62 years and 55% were women. Potential participants were excluded if they had total tooth loss, dental implants, heart disease, organ transplant, artificial joints, implanted heart valve or stent or major surgery. Co-authors, disclosures and funding sources are listed in the manuscript.

Statements and conclusions of studies that are presented at the American Heart Association’s scientific meetings are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association’s scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

The Association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific Association programs and events. The Association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance providers and the Association’s overall financial information are available here.

Additional Resources:

Multimedia is available on the right column of the release link Spanish news release Link to Abstract 19; and ASA International Stroke Conference 2025 Online Program Planner AHA news release: Treating gum disease after heart rhythm ablation reduced risk of AFib recurrence (April 2024) AHA news release: New initiative focuses on oral health clinicians in prevention and early detection of heart disease (Jan. 2024) AHA news release: Poor oral health may contribute to declines in brain health (Feb 2022) AHA health information: Oral Health For more news at ASA International Stroke Conference 2025, follow us on X @HeartNews #ISC25 ###

About the American Stroke Association

The American Stroke Association is devoted to saving people from stroke — the No. 2 cause of death in the world and a leading cause of serious disability. We team with millions of volunteers to fund innovative research, fight for stronger public health policies and provide lifesaving tools and information to prevent and treat stroke. The Dallas-based association officially launched in 1998 as a division of the American Heart Association. To learn more or to get involved, call 1-888-4STROKE or visit stroke.org. Follow us on Facebook, X.

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