Association of toothbrushing, dental flossing, and interdental brushing with stroke risk

Stroke is the second leading cause of death globally. While daily toothbrushing is widely promoted for oral hygiene, the preventive impact of adjunctive oral hygiene practices, such as dental flossing and interdental brushing, on stroke risk remains unclear. This study aimed to investigate the association between comprehensive oral hygiene behaviors and the risk of stroke.

We conducted a population-based retrospective cohort study using data from the Korean National Health Insurance Service-Health Screening cohort. A total of 98,866 adults aged ≥40 years who underwent both general and oral health examinations during 2009-2010 were included. Participants were followed from January 2011 to December 2019. Individuals with pre-existing cardiovascular disease, death before baseline, or missing data were excluded. Oral hygiene behaviors, including daily toothbrushing frequency and weekly use of dental floss and interdental brushes, were self-reported. The primary outcome was incident stroke requiring hospitalization for ≥2 days and was classified as total, ischemic, or hemorrhagic stroke according to diagnostic codes. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

During follow-up, participants with favorable oral hygiene behaviors showed a lower risk of stroke compared with those with poor oral hygiene practices. In multivariable-adjusted analyses, individuals who brushed their teeth at least twice daily and regularly used dental floss and interdental brushes had a 23% lower risk of ischemic stroke (adjusted hazard ratio [aHR] 0.77, 95% CI 0.63-0.94). A significant dose-response relationship was observed across categories of oral hygiene behaviors.

Frequent toothbrushing combined with regular use of dental floss and interdental brushes was associated with a reduced risk of ischemic stroke. These findings suggest that comprehensive oral hygiene practices may provide additional benefits for stroke prevention.

Comprehensive oral hygiene behaviors, including regular toothbrushing, dental flossing, and interdental brushing, may contribute to stroke prevention beyond conventional vascular risk factor management. Promoting adjunctive oral hygiene practices could represent a simple, accessible, and population-based strategy for reducing ischemic stroke risk in middle-aged and older adults.