Abstract Body: Introduction: Prior studies have shown the association between oral infection, incident stroke and atrial fibrillation (AF) a cause of cardioembolic stroke. However, the impact of preventative oral behavior such as dental flossing on stroke, cardioembolic stroke and AF are unknown. The relationship between flossing incident stroke, stroke subtypes and AF was tested in the Atherosclerosis Risk in Communities (ARIC) cohort study.

Methods: In the ARIC study, home use of flossing was assessed through a structured questionnaire in visit 4 along with assessment of covariates including age, gender, race-center, hypertension, diabetes, hyperlipidemia, smoking, body mass index, education-level, regular brushing and regular dental care utilization . Outcomes were compared across index subtypes (infarction: thrombotic, cardioembolic, and lacunar strokes) using Kaplan-Meier analysis and Cox proportional hazards regression, adjusting hazards ratio (HR) for all the above covariates along with 95% confidence interval (CI).

Results: In the ARIC study, 6278 dentate participants, without a prior history of stroke and 6108 without prior AF were followed for incident ischemic stroke, stroke subtypes and AF over a 25-year period. Of them 65% (N=4092 in stroke-free cohort and 4050 in AF-free cohort) reported flossing. During the follow-up period,434 were identified as having strokes, of whom 147 thrombotic, 97 cardioembolic and 95 lacunar subtypes. A total of 1291 (20%) participants were noted to have incident AF. The individuals reporting dental flossing had a lower rate of incident ischemic stroke, cardioembolic stroke and AF (Kaplan-Meier curves below). Dental flossing was significantly associated with a lower risk of ischemic stroke (adjusted HR, 0.78; 95% CI, 0.63-0.96), cardioembolic stroke subtype (adjusted HR, 0.56; 95 CI, 0.36-0.87) and AF ( adjusted HR, 0.88; 95% CI, 0.78-1.00), but not thrombotic (adjusted HR, 0.91; 95% CI, 0.63-1.32) or lacunar stroke (adjusted HR 1.09; 95% CI 0.68-1.76).

Conclusion: Those reporting dental flossing have a lower risk for incident ischemic stroke, driven by cardioembolic stroke subtype and AF. The associated lower risks are independent of oral care/behavior measures such as regular brushing and regular dental care utilization, suggesting it may be a key behavior modification to emphasize in stroke risk reduction.