Regular flossing may significantly reduce the risk of stroke, according to a new study drawing attention to the link between oral hygiene and cardiovascular health.
According to the Korea Disease Control and Prevention Agency on Tuesday, Korea recorded 113,098 stroke cases in 2024, or 221.1 cases per 100,000 people. The one-year mortality rate following a stroke has been rising again since 2020.
While chronic conditions such as hypertension, diabetes and hyperlipidemia, along with smoking and lack of exercise, are considered major risk factors, recent studies have increasingly linked oral health management to stroke prevention.
A new study has now quantified that connection. A research team led by Professor Souvik Sen at the Medical University of South Carolina tracked the association between flossing and the incidence of stroke and atrial fibrillation in 6,200 adults with no history of stroke over approximately 23.7 years. The study was published in the latest issue of Stroke, a journal of the American Heart Association.
The findings were clear. People who flossed had a 23% lower risk of ischemic stroke than those who did not.
The risk of cardioembolic stroke, which occurs when a blood clot formed in the heart travels to the brain's blood vessels, was about 40% lower, while the risk of atrial fibrillation was 12% lower. The risk of cerebral thrombosis, in which clots accumulate in brain vessels damaged by arteriosclerosis, was also 22% lower. In contrast, brushing alone did not show a notable effect in reducing stroke risk.
However, it would be premature to interpret these results as meaning that flossing prevents stroke. People who floss regularly tend to also practice other healthy habits, such as a balanced diet, not smoking, exercising and managing blood pressure.
The study is an observational study, not a clinical trial that establishes causation. The research team explained that flossing reduces oral bacteria and gum inflammation, which in turn may decrease vascular inflammation and lower stroke risk.
Domestic studies have also consistently reported a link between oral health and brain and cardiovascular health. A joint research team from Seoul National University and Korea University analyzed data on approximately 2.55 million people from the National Health Insurance Service and found that periodontal disease, cavities and tooth loss were associated with an increased risk of Alzheimer's disease and vascular dementia.
Since stroke is one of the major causes of vascular dementia, managing oral inflammation can be seen as an issue connected to brain health.
Using floss is not complicated. Cut a piece about 30 to 40 centimeters long, wrap it around the fingers of both hands, slowly insert it between the teeth, then wrap it in a C-shape around the side of the tooth at the gum line and gently rub it up and down.
Pressing down hard on the gums should be avoided. For wider gaps between teeth or for those with dental prosthetics, an interdental brush may work better, while a holder-type flosser can be an alternative for those who have difficulty with hand movement.
