Pikel, Karly

Abstract Background and aims Dementia represents a growing global health burden, with vascular dementia and Alzheimer's disease accounting for most cases through cumulative cerebrovascular damage. While periodontal disease (PD) is associated with cognitive decline, dental caries represents a distinct oral infection pathway characterized by bacterial invasion and infection, potentially contributing to vascular brain injury through microbial translocation, endothelial dysfunction, systemic inflammation, and cerebral microvascular damage. The relationship between dental caries and incident dementia within a vascular framework remains understudied. Methods We analyzed 6,542 participants from the Atherosclerosis Risk in Communities (ARIC) Study who received dental examinations at Visit 4 (1996–1998) and followed for incident dementia through 2023 using standardized surveillance (Figure-1). Cox proportional hazards models with competing risk accounted for death. Multivariable models adjusted for demographic factors, cardiovascular risk factors, BMI, physical activity, education, income, insurance status, APOE4 genotype, PD, and regular dental care. Results Mean age was 62.4 years; 54% female, 82% White, and 18% Black. Dental caries was present in 20%. Over median 25-year follow-up, individuals with dental caries demonstrated significantly higher cumulative dementia incidence (Gray’s test p<0.0001). After full adjustment, dental caries remained independently associated with increased dementia risk (adjusted HR 1.20, 95% CI 1.02–1.42), independent of PD and APOE4 status (Figure-2). Conclusions Dental caries was independently associated with increased incident dementia risk. These findings support a potential role for caries-related oral infection in vascular brain injury pathways relevant to vascular dementia and stroke-related cognitive impairment. Oral infection prevention may represent a modifiable target within cerebrovascular disease prevention strategies. Conflict of interest Alana E. Barton, Souvik Sen, Kevin Moss, James Selph, Ryan Demmer, Pamela L. Lutsey, Priya Palta, Kamakshi Lakshminarayan, Karly Pikel, Wayne Rosamond: nothing to disclose Figure 1 - belongs to Conclusions Figure 2 - belongs to Conclusions

Abstract Background and aims Systemic inflammation has been implicated in cognitive decline and dementia pathogenesis. Interleukin-6 (IL-6), a pro-inflammatory cytokine associated with cardiovascular disease, may play a role in cerebrovascular and neurodegenerative processes. We examined the relationship between IL-6 levels and incident dementia risk using the Atherosclerosis Risk In Communities (ARIC) study. Methods ARIC study participants at Visit 4 (1996-1998) had IL-6 measurements and were followed for incident dementia over 25 years. IL-6 levels were dichotomized at the median value of 1.5 pg/mL. Incident dementia cases were identified through standardized surveillance. Cox proportional hazards regression calculated hazard ratios (HR) with 95% confidence intervals (CI), adjusting for age, race, gender, hypertension, diabetes, obesity, physical activity, smoking, alcohol use, education, income, insurance status, and ApoE-ε4 allele status. Results Participants (n=5,662; mean age 62.4±5.6 years, 55% female, 83% White, 17% Black) were followed for a median of 25 years. Those with IL-6 >1.5 pg/mL demonstrated significantly increased dementia risk versus IL-6 ≤1.5 pg/mL. The crude HR was 1.23 (95% CI 1.11-1.37). After adjustment, the association remained significant with HR 1.13 (95% CI 1.01-1.27). Kaplan-Meier survival curves showed progressive divergence between groups, with lower dementia-free survival in the higher IL-6 group, log-rank p<0.001. Conclusions Elevated mid-life IL-6 levels (>1.5 pg/mL) independently predict increased long-term dementia risk over 25 years, even after adjusting for cardiovascular and sociodemographic confounders. These findings support systemic inflammation's role in dementia pathogenesis and highlight IL-6 as a potential biomarker for dementia risk. Conflict of interest Karly Pikel, Natasha Carmichael, Alana E. Barton, Kevin Moss, Christine Downey, Ryan T. Demmer, Pamela L. Lutsey, Souvik Sen: Nothing to disclose Figure 1 - belongs to Conclusions

Background: Periodontitis is a potential modifiable factor influencing dementia risk. We examined whether improving periodontal health via regular flossing is associated with lower dementia risk. Methods: A total of 9,766 Atherosclerosis Risk in Communities (ARIC) study participants with teeth were followed from visit 4 (1996-1998) through 2021. Cox proportional hazards regression was used to estimate associations between regular dental flossing (≥1/week) and incident dementia. Covariates included age, race, gender, hypertension, diabetes, alcohol use, smoking status, obesity, physical activity, education level, income, insurance status, brushing frequency, regular dental care use and apolipoprotein E4 (APOE4) allele status . Cumulative incidence functions were estimated using death as a competing event. Results: Participants had mean age 62.6 years (SD = 5.6), 56% female, 79% white, 21% black, 63% reported regular flossing and 29.2% participants carry at least one APOE4 allele. The cumulative incidence of dementia was 52.6 % overall over 25 years. Regular flossing was independently and significantly associated with a lower hazard of developing dementia (HR = 0.90, 95% CI: 0.82–0.98, p = 0.02) after adjustment for all the covariates. In contrast, tooth brushing frequency (p=0.55) and regular dental care visit (p=0.22) were not significantly associated with dementia risk. By 25 years of follow-up, the cumulative incidence of dementia was 50% among flossers compared with 57% among non-flossers (Gray’s test p<0.0001, Figure). This translated to an Absolute Risk Reduction of 7%, Relative Risk Reduction of 12%, Number Needed to Floss 14. Conclusion: Flossing, but not tooth brushing or regular dental care, is independently associated with a reduced hazard of incident dementia. Dental flossing may be an additional strategy to reduce dementia risk. For every 14 individuals who floss ≥1/week, one fewer person will develop dementia.