Can flossing reduce your risk of a stroke?

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Can a simple habit like flossing really reduce your risk of stroke? In this episode, Dr. Bobby unpacks the headlines sparked by a recent presentation at the American Stroke Association’s International Conference that claimed regular flossing could reduce stroke risk by 20–50%. 

Dr. Bobby begins with a refresher on the importance of stroke prevention. From there, he explores the biological plausibility of a connection between oral health and cardiovascular events. While Americans are fairly diligent about brushing (with 90% brushing once daily and 60% brushing twice a day per YouGov data), flossing habits lag significantly (NIH Oral Health Study—highlighting a clear opportunity if the flossing-stroke link is real.

Dr. Bobby dives into the study behind the headlines, a new analysis from the long-running Atherosclerosis Risk in Communities (ARIC) study, which tracked over 6,000 individuals for 25 years. The preliminary finding: regular flossers had significantly lower risk of ischemic and cardioembolic strokes (Study Abstract). Surprisingly, brushing and dental visits showed no significant benefit in this analysis.

So why isn’t this flossing-stroke connection headline a "five-alarm fire" in medicine? Dr. Bobby explains the limitations: the results were shared via a conference abstract, not a peer-reviewed journal article. Without full access to the data or understanding how many other hypotheses were tested from this large dataset (which has already generated over 2,300 publications), we risk falling into the trap of correlation being mistaken for causation.

To further evaluate the credibility of this association, Dr. Bobby introduces the Bradford Hill criteria—nine principles to assess causality in observational studies. While the biological plausibility is strong and the effect size notable, the study fails on criteria like replication, dose-response, and publication rigor (Bradford Hill Overview).

In closing, Dr. Bobby affirms the benefits of flossing—not necessarily for stroke prevention, but for better oral health, which is valuable in its own right. He shares his personal oral care routine, including flossing nightly and using a water jet, while reminding listeners to stay evidence-informed in their health decisions.

Takeaways
Flossing likely improves oral health, but its role in stroke prevention remains unproven.

Be cautious with headlines drawn from unpublished conference abstracts—they’re a starting point for inquiry, not a reason to change behavior just yet.

"How to Live Long and Well" at DrBobbyLiveLongAndWell.com.