Abstract WP56: Dental Flossing associated with reduced White Matter Hyperintensity and Intracranial Atherosclerosis

Introduction: Prior studies have shown the association between oral infection, white matter hyperintensity (WMH), a marker of cerebral small vessel disease (CSVD), and asymptomatic intracranial atherosclerosis (ICAS). However, the impact of preventative oral behavior such as dental flossing is unknown. The relationship between flossing CSVD,&ICAS was tested using the Atherosclerosis Risk in Communities (ARIC) cohort study.

Methods: 3T MRI and MRA were performed in visit 5. CSVD was assessed using the log of WMH volume. WMH volume was derived from a semiautomated segmentation of FLAIR images, 3D time-of-flight MR angiogram and 3D high-isotropic resolution black blood MRI. ICAS was graded according to the criteria established by the Warfarin-Aspirin Symptomatic Intracranial Disease trial. In this study, we evaluated the relationship between flossing and ICAS, defined as ≥50% stenosis. Flossing was assessed by a medical history questionnaire performed in visit 4. Student t-tests were performed to test continuous variables, and X² test was used to compare categorical variables. Analysis of covariance (ANCOVA) was used for multivariate testing of continuous variables and multivariable logistic regression analyses for categorical variables.

Results: Among subjects who underwent vascular imaging, 1033 (90%) had <50% ICAS and 112 (10%) had ≥50% ICAS. Dental flossing was significantly associated with lower rates of ICAS≥50% (Crude OR 0.59 95% CI 0.39-0.90). The association remained significant after adjustment for age, race, gender, hypertension, diabetes, smoking status, education level and regular dental care use (Adjusted OR 0.61 95% CI 0.38-0.97). The log WMH volume was higher (9.5±0.85 vs. 9.3±0.89), the difference being statistically significant (p=0.003). The difference remained significant after adjustment for age and SBP (p=0.002).

Conclusion: We report a significant association between flossing, reduced WMH volume and ≥50% ICAS. This may be one of the first reported associations between dental flossing, and reduced WMH volume (a CSVD indicator) and moderately severe ICAS. These results emphasize the importance of dental flossing in reducing the rates of CSVD and moderately severe ICAS, both known risk factors for ischemic stroke.