Demmer, Ryan T.

ABSTRACT Aim To systematically review and meta‐analyze cohort studies evaluating associations of gingival inflammation, periodontitis, and tooth loss with cognitive decline and incident mild cognitive impairment or dementia. Methods PROSPERO‐registered searches of MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library identified cohort studies from inception through October 10, 2025, with a PubMed update on June 24, 2026. Random‐effects meta‐analyses pooled adjusted hazard ratios (HRs) for dementia/MCI; cognitive function outcomes were summarized qualitatively. Risk of bias (RoB) was assessed using the Newcastle–Ottawa Scale. Results Fifty‐nine studies met inclusion criteria; 28 contributed to dementia/MCI meta‐analyses. Severe periodontitis (HR: 1.16; 95% CI: 1.06–1.27; I 2 = 0%; Q ‐test p = 0.49), periodontitis of unspecified severity (HR: 1.45; 95% CI: 1.21–1.73; I 2 = 98%; Q ‐test p < 0.001), edentulism (HR: 1.26; 95% CI: 1.19–1.33), and low tooth count (HR: 1.27; 95% CI: 1.14–1.42; I 2 = 94%; Q ‐test p < 0.001) were associated with elevated dementia/MCI risk. RoB was low in 31 studies (53%), moderate in 25 (42%), and high in 3 (5%); inadequate confounder adjustment was common. Meta‐regression showed stronger estimates for ICD‐code periodontitis definitions (fold change (FC) = 1.44 95% CI: 1.04–2.01), older cohorts (FC per year = 1.02 95% CI: 1.00, 1.05), and weaker estimates with lower RoB (FC per NOS star = 0.81 95% CI: 0.73–0.92). Follow‐up duration, cohort age, and RoB were not associated with tooth‐count estimates. Conclusion Periodontitis and tooth loss are associated with modestly higher dementia/MCI risk and poorer cognitive function, but heterogeneity, residual confounding, and bias temper causal interpretation. Longitudinal studies with rigorous baseline cognition assessment and intervention studies are needed.

Abstract Background and Aims Exercise stress echocardiography is recommended as an alternative to invasive testing for diagnosing heart failure with preserved ejection fraction (HFpEF), but an evidence-based operational framework guiding its application is lacking. Methods Patients with chronic unexplained dyspnoea underwent invasive haemodynamic exercise testing with simultaneous echocardiography to test the hypotheses that (i) the current diagnostic algorithms (H2FPEF, HFA-PEFF, and HFpEF-ABA scores) could be enhanced when combined with exercise echocardiography; and (ii) incorporating resting left atrial (LA) compliance (LA reservoir strain divided by E/e′) could further improve diagnostic triage, using separate cut points optimizing sensitivity and specificity. Findings were then validated in an international multicentre cohort. Results Of 482 patients, HFpEF was present in 386 and non-cardiac dyspnoea in 96. Sensitivity to detect HFpEF was only 55%–60% and accuracy 61%–67% using individual diagnostic scores with currently recommended exercise echocardiography. Addition of abnormal resting LA compliance to exercise echocardiography increased sensitivity to 84%–85% but increased the false-positive rate to 31%–43%. Applying separate cut points that optimize specificity and sensitivity (either exercise E/e′ ≥ 13.8 or resting LA compliance ≤1.6% to rule-in HFpEF; both exercise E/e′ &lt; 7.2 and resting LA compliance &gt;4.4% to rule-out HFpEF, remaining patients indeterminate who require invasive testing) improved sensitivity to 95%–99% among definitively classified patients and reduced the number of patients that require invasive exercise testing from ∼60% to ∼30%. Findings were replicated in a multicentre, international validation cohort of patients undergoing rest–exercise echocardiography and invasive exercise testing. Conclusions Currently used non-invasive approaches to HFpEF diagnosis have inadequate sensitivity, indicating that exercise echocardiography cannot supplant invasive testing. Addition of LA strain imaging with optimized rule-in or rule-out values improves diagnostic triage by expanding non-invasive rule-in/rule-out classifications while identifying patients who still require invasive testing in the evaluation of HFpEF.

Background We examined the relationship between infection‐related hospitalization (IRH) and heart failure (HF) in a large clinical health system and assessed whether IRH improved prediction beyond HF risk equations. Methods We studied 80 880 adults (14 150 with IRH and 66 730 age‐ and sex‐matched comparators) aged ≥18 years without HF in the Rochester Epidemiology Project from 1/1/2005–12/31/2019. IRH was identified using International Classification of Diseases ( ICD ) codes. HF incidence was defined as ≥1 HF‐related ICD code. Multivariable Cox models assessed the association between IRH and incident HF. Among 29 219 adults aged 30 to 79 years without baseline cardiovascular disease in the Rochester Epidemiology Project, Harrell's concordance statistic assessed whether IRH improved discrimination of the Predicting Risk of Cardiovascular Disease EVENTs–Heart Failure (PREVENT‐HF) equations. Results Participants were 53.3% women, 85.6% White individuals, and 95.1% non‐Hispanic individuals, with a mean age of 56.0±20.0 years. Median follow‐up time was 6.2 years. Among the IRH group, 2729 developed incident HF (2.75/100 person‐years) versus 4854 (1.00/100 person‐years) in the comparator. The multivariable adjusted hazard ratio for incident HF among participants with versus without an IRH was 1.85 (95% CI, 1.76, 1.94). In a separate cohort, incorporating IRH into PREVENT‐HF increased the concordance statistic from 0.776 to 0.779 (change, 0.003 [95% CI, 0.001–0.004]). The PREVENT‐HF risk score underestimated the 10‐year risk of HF by up to 9% among participants with an IRH. Conclusions IRH was associated with incident HF but provided negligible change to 10‐year HF risk discrimination. However, among individuals with an IRH, incorporating this information meaningfully improved 10‐year HF risk prediction. Severe infections may serve as a risk‐enhancing factor warranting enhanced preventive measures, particularly in populations where IRH is more common.

Abstract Rationale The impacts of COVID-19 vaccination and SAR-CoV-2 infection on brain tissues and structures remain controversial. This study examines whether COVID-19-related exposures are associated with measurable changes in structural magnetic resonance imaging (MRI) using data from the US general population-based Collaborative Cohort of Cohorts for COVID-19 Research (C4R) Study. Methods The C4R study is an observational meta-cohort study of 14 NIH-funded population-based cohorts, with directly measured data on COVID-19-related exposures, including vaccination and infection. For this analysis, we included participants with C4R data and paired brain MRI scans from both before and after the onset of the COVID-19 pandemic (defined as March 1, 2020) from two cohorts: the Atherosclerosis Risk in Communities study (ARIC) and Framingham Heart Study (FHS). MRI features examined as outcomes were white matter volume (WMV), gray matter volume (GMV), total brain volume (BV), hippocampal volume (HV), and white matter hyperintensity volume (WMH), a marker of microvascular disease. Exposures included SARS-CoV-2 infections identified via questionnaires, serosurveys, and medical record reviews from 2020-2025. Infections resulting in hospitalization were classified as severe. Time-to-recovery, symptoms of long COVID, and vaccination status were self-reported by questionnaire. Analysis of covariance (ANCOVA) estimated associations between COVID-19-related exposures and pandemic MRI-measured outcomes, with adjustment for: the corresponding pre-pandemic MRI measure, the time between the two MRI scans, age, sex, systolic blood pressure, diabetes, and cardiovascular disease. Results Of 270 participants with available data, mean (SD) age was 80.6 years (10.6); 43.0% were male; and the mean (SD) interval between paired MRI scans was 4.2 (2.0) years. Most (90%) were vaccinated (of whom 6.7% vaccinated before infection) and 7.9% reported SARS-CoV-2 infection (of which 13.6% were severe infections) prior to their pandemic MRI (conducted March 2020 - June 2022). In fully adjusted models, there was no statistically significant association for change in WMV, GMV, BV, HV, or WMH with SAR-CoV2 infection status, infection severity, vaccination status, or vaccination timing (Table, P &gt; 0.05 for all comparisons). Self-reported symptoms of long COVID and vaccine manufacturer were also not associated with MRI outcomes. Conclusions Based on repeated (pre-pandemic and pandemic era) structural MRI scans, we found no evidence that SARS-CoV-2 infection or COVID-19 vaccination were associated with changes in brain structure or brain microvascular disease. These findings are consistent with prior data supporting COVID-19 vaccine safety and suggest resilience of brain structures following SARS-CoV-2 exposures. Nonetheless, further research is warranted using more sensitive measures and assessing longer term effects. This abstract is funded by: OT2HL156812

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&lt;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 &gt;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&lt;0.001. Conclusions Elevated mid-life IL-6 levels (&gt;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.

OBJECTIVE To test the effect of physical activity on the gut microbiome and circulating short-chain fatty acids (SCFAs) among sedentary adults with prediabetes and overweight or obesity. RESEARCH DESIGN AND METHODS In a pilot and feasibility trial, we randomized 77 adults with prediabetes and a sedentary lifestyle into one of two groups: 1) intervention: invited to engage in home-based moderate-intensity walking 3×/week for 30 min/session in weeks 1–4 and for 45 min/session during weeks 5–8 of the 8-week intervention; or 2) control: maintained habitual physical activity levels. We performed metagenomic sequencing from stool collected at baseline, week 4, and week 8, with SCFAs measured from serum collected at baseline and week 8. Taxonomic and functional profiling was performed on the metagenomic reads; α-diversity metrics were subsequently derived. Linear regression assessed the difference in change between the intervention and control groups for α-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 mean (SD) 51.4 (8.9) years old, 87.7% female, and 74% non-Hispanic White. Mean fasting glucose was 103.3 (13.2) mg/dL, while mean BMI was 34.4 (5.7) kg/m2. Compared with the control group, the intervention group experienced decreased α-diversity as characterized by Shannon, Richness, and Faith diversity indices by intervention week 8 (P &lt; 0.05). Changes in SCFA levels were not statistically significant different in intervention versus control. CONCLUSIONS Randomization to a walking intervention resulted in modest gut microbiome changes among adults with overweight or obesity and prediabetes.