Barton, Alana

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