Demmer, Ryan

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

Objective: To test the effect of physical activity on the gut microbiome and circulating short chain fatty acids among sedentary overweight/obese adults with prediabetes. We hypothesized that randomization to increased physical activity would result in gut microbiome changes. Methods: \We randomized 77 adults with prediabetes and a sedentary lifestyle into one of two groups: 1) Intervention Group: Invited to engage in home-based moderate intensity walking 3x/week for 30 minutes/session in weeks 1-4 and for 45 minutes/session during weeks 5-8 of the 8-week intervention; or 2) Control Group: Maintained habitual physical activity levels. We performed metagenomic sequencing from stool collected at baseline, week 4, and week 8, with short-chain fatty acids (SCFA) measured from serum collected at baseline and week 8. Taxonomic and functional profiling were performed on the metagenomic reads; alpha diversity metrics were subsequently derived. Linear regression assessed the difference in change between the intervention and control groups for alpha-diversity and SCFA levels. Results: We screened 1,533 participants for eligibility and consented 132. Of these, 87 entered the run-in phase and 77 were randomized. Participants were 51.4±8.9 years old, 87.7% female, and 74% non-Hispanic White. Mean fasting glucose was 103.3±13.2 while mean BMI was 34.4±5.7. In comparison to the control group, the intervention group experienced decreased alpha diversity as characterized by Shannon, Richness, and Faith’s diversity indices by week 8 of the intervention (P<0.05). SCFA levels trended towards improvement in the intervention group, but the results were not statistically significant. Functional analysis of KEGG ontologies revealed themes consistent with a microbiome with enhanced metabolic activity and host-relevant metabolic signaling (Figure). Conclusions: Randomization to a walking intervention resulted in modest gut microbiome changes among adults with overweight/obesity and prediabetes.

Introduction: Heart failure (HF) with preserved ejection fraction (HFpEF) is now the predominant HF subtype, largely driven by the syndemic of physical inactivity and overweight/obesity in an aging population. Deranged skeletal muscle energetics and regional ectopic adipose depots are key cardiometabolic pathways in the pathogenesis of HFpEF, both of which may be favorably modified by 1-2 hours/week of resistance exercise (RE). However, its association with HFpEF risk has not been thoroughly examined. We investigated the association between midlife RE behaviors and incident HFpEF in the Atherosclerosis Risk in Communities (ARIC) study. Hypothesis: Participation in RE at midlife is inversely associated with the risk of incident HFpEF. Methods: Our exposure (RE)—including weightlifting and bodyweight resistance exercises—was assessed using the validated Baecke questionnaire and reported weekly RE duration was averaged across Visits 1 and 3 (1987-1995). We dichotomized averaged RE as 0 hr/wk (‘No RE’, reference) and >0 hr/wk (‘Any RE’). Our outcome (incident HFpEF) was identified through committee-adjudicated HF hospitalizations (January 1, 2005 to December 31, 2023) using medical chart abstraction. Participants with prevalent HF, death, or loss to follow-up before January 1, 2005 were excluded. We constructed Cox regression models to evaluate the association between midlife RE and incident HFpEF. Model 1 adjusted for age, sex, race, field center, education, smoking status, alcohol consumption, and non-RE physical activity. Given that adiposity may lie on the causal pathway, waist-height ratio (WHtR; both measured in cm) was added in Model 2. Results: 10,751 Black and White participants (803 incident HFpEF cases) were analyzed over a median follow-up time of 14.4 years (mean±SD Visit 1 age, 53.3±5.6 years; average Visit 1 and 3 WHtR, 0.58±0.08; 24.7% Black; 57.4% female). 1,217 participants (11.3%) reported engaging in RE at Visits 1 and/or 3, with a median duration of 0.84 hr/wk (IQR, 0.50-1.61). Compared to No RE, the fully adjusted hazard ratio (HR) for Model 1 for Any RE was: 0.78 (95% CI, 0.61-1.00, P = 0.05). The association was attenuated after adjustment for WHtR: HR = 0.84 (0.65-1.07, P = 0.16). Conclusion: Participation in RE at midlife is associated with a 22% lower risk of incident HFpEF. To inform public health and clinical guidelines, further studies are needed to clarify the role of RE in HFpEF prevention.