Dental Flossing May Lower the Risk for Incident Ischemic Stroke, Cardioembolic Stroke Subtype, and Atrial...

Prior studies have demonstrated an association between oral infection and both incident stroke and atrial fibrillation (AF), a major cause of cardioembolic stroke. However, the impact of preventive oral behaviors such as dental flossing on incident stroke and AF remains unclear. We evaluated the relationship between flossing, incident stroke subtypes, and AF from the ARIC study (Atherosclerosis Risk in Communities).

We conducted a prospective cohort study using data from the ARIC study. Flossing was assessed via a structured questionnaire at visit 4 (1996-1998). Participants were censored at the first stroke, death, or loss-to-follow-up through December 31, 2021. Incident ischemic stroke and subtypes were evaluated using Cox proportional hazards models, adjusting for cardiovascular risk factors, education, regular brushing, dental care utilization, periodontal disease, and dental caries.

Among 6200 dentate participants without prior stroke, 65% (n=4049) reported regular flossing. Flossers had significantly lower prevalence of vascular risk factors, periodontal disease, and dental caries at baseline. Flossers had lower IL (interleukin)-6 levels in crude analysis, but this difference was explained by confounding from age, body mass index, and smoking. CRP (C-reactive protein) levels did not differ between groups. During a median 23.7 years follow-up, 434 ischemic strokes occurred, including 146 thrombotic, 102 cardioembolic, 95 lacunar, and 91 other ischemic subtypes. Nonflossers had higher rates of both ischemic stroke (8.7% versus 6.1%) and nonstroke mortality (40.8% versus 34.5%). Flossing was associated with lower risk of ischemic stroke (adjusted hazard ratio, 0.77 [95% CI, 0.64-0.96]), cardioembolic stroke (adjusted hazard ratio, 0.60 [95% CI, 0.38-0.94]), and AF (adjusted hazard ratio, 0.88 [95% CI, 0.77-0.99]) with dose-response relationship (P trend=0.001) 6.6% of the effect mediated by lower AF incidence. Results remained robust in competing risk analysis (adjusted hazard ratio, 0.79 [95% CI, 0.63-0.98]) with an E value of 1.87.

Regular flossing was associated with a lower risk of ischemic stroke, primarily driven by reductions in cardioembolic stroke and AF, independent of other oral health behaviors.

URL: https://www.clinicaltrials.gov; Unique identifier: NCT00005131.