Midlife cardiovascular risk factors and risk of dementia in late life

The association between serum cholesterol levels and mild-to-moderate cognitive impairment in the Suita Study and evidence from other epidemiological studies

BACKGROUND

Serum cholesterols are well-documented markers of cardiovascular diseases; however, their association with cognitive well-being is uncertain. This study investigated the association between serum cholesterol levels and mild-to-moderate cognitive impairment.

METHODS

Epidemiological evidence on the role of total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), non-HDL-C, and low-density lipoprotein cholesterol (LDL-C) in cognitive impairment was highlighted. Then, data from 6216 Japanese individuals, aged ≥50 years, from the Suita Study were analyzed. Mini-Mental State Examination (MMSE) scores <27 and < 24 were used to define cognitive impairment. Logistic regression was used to calculate the odds ratios (ORs) and 95 % confidence intervals (95 % CIs) for cognitive impairment.

RESULTS

Epidemiological studies investigating the association between serum cholesterol and cognitive impairment have shown conflicting findings: elevated risk with certain lipid components in some studies and no association in others. In the Suita Study, HDL-C < 40 mg/dL was associated with cognitive impairment: ORs (95 % CIs) = 1.36 (1.08, 1.72) for MMSE <27 and 1.61 (1.00, 2.60) for MMSE <24. Non-HDL-C ≥ 200 mg/dL was also associated with cognitive impairment: ORs (95 % CIs) = 1.53 (1.02, 2.31) for MMSE <27 and 1.80 (1.16, 2.79) for MMSE <24. No such associations were detected with TC.

CONCLUSION

While epidemiological evidence remains inconsistent, the Suita Study showed that decreased HDL-C and increased non-HDL-C, but not increased TC, were associated with mild-to-moderate cognitive impairment. Management of serum cholesterol levels should be considered to prevent cognitive impairment.

Hippocampal atrophy and white matter lesions characteristics can predict evolution to dementia in patients with vascular mild cognitive impairment

BACKGROUND

Vascular mild cognitive impairment (VMCI) is a transitional condition that may evolve into Vascular Dementia(VaD). Hippocampal volume (HV) is suggested as an early marker for VaD, the role of white matter lesions (WMLs) in neurodegeneration remains debated.

OBJECTIVES

Evaluate HV and WMLs as predictive markers of VaD in VMCI patients by assessing: (i)baseline differences in HV and WMLs between converters to VaD and non-converters, (ii) predictive power of HV and WMLs for VaD, (iii) associations between HV, WMLs, and cognitive decline, (iv)the role of WMLs on HV.

METHODS

This longitudinal multicenter study included 110 VMCI subjects (mean age:74.33 ± 6.63 years, 60males/50females) from the VMCI-Tuscany Study database. Subjects underwent brain MRI and cognitive testing, with 2-year follow-up data on VaD progression. HV and WMLs were semi-automatically segmented and measured. ANCOVA assessed group differences, while linear and logistic regression models evaluated predictive power.

RESULTS

After 2 years, 32/110 VMCI patients progressed to VaD. Converting patients had lower HV(p = 0.015) and higher lesion volumes in the posterior thalamic radiation (p = 0.046), splenium of the corpus callosum (p = 0.016), cingulate gyrus (p = 0.041), and cingulum hippocampus(p = 0.038). HV alone did not fully explain progression (p = 0.059), but combined with WMLs volume, the model was significant (p = 0.035). The best prediction model (p = 0.001) included total HV (p = 0.004) and total WMLs volume of the posterior thalamic radiation (p = 0.005) and cingulate gyrus (p = 0.005), achieving 80% precision, 81% specificity, and 74% sensitivity. Lower HV were linked to poorer performance on the Rey Auditory-Verbal Learning Test delayed recall (RAVLT) and Mini Mental State Examination (MMSE).

CONCLUSIONS

HV and WMLs are significant predictors of progression from VMCI to VaD. Lower HV correlate with worse cognitive performance on RAVLT and MMSE tests.

HMGCR Inhibitor Restores Mitochondrial Dynamics by Regulating Signaling Cascades in a Rodent Alzheimer's Disease Model

Atorvastatin an HMGCR inhibitor may play a role in enhancing spatial and long-term memory and combating anxious behavior deficits induced by Aβ1-42. Behavioral deficit studies, immunoblotting for the antioxidant/apoptotic protein expression, flow cytometry (FACS) for mitochondrial ROS, membrane potential (▲ψm), and histopathological alterations were performed against Aβ1-42 toxicity. Aβ1-42 was infused directly into the brain through i.c.v for the establishment of the AD model. Atorvastatin (ATOR) was administered orally and was used to treat AD in adult male Wistar rats aged between 200 and 250 g. We confirmed that ATOR administration significantly attenuates the Aβ1-42-induced cognitive decline targeted mitochondrial-mediated age-dependent disease progression. Nrf2 stabilizes to interact SOD2 antioxidant enzyme, allowing transcriptional activity by the steep increase in ▲ψm and a reduction in ROS by activating mitochondrial superoxide scavenger and Nrf2-dependent pathway. These findings confirmed that ATOR has the potential efficacy to modulate the interference in cognitive decline induced by Aβ1-42.

Heterogeneity in the effect of type 2 diabetes on dementia incidence in a diverse cohort of Asian American and non-Latino White older adults

Dementia incidence is lower among Asian Americans than among Whites, despite higher prevalence of type 2 diabetes, a well-known dementia risk factor. Determinants of dementia, including type 2 diabetes, have rarely been studied in Asian Americans. We followed 4846 Chinese, 4129 Filipino, 2784 Japanese, 820 South Asian, and 123 360 non-Latino White members of a California-based integrated health-care delivery system from 2002 to 2020. We estimated dementia incidence rates by race/ethnicity and type 2 diabetes status, and we fitted Cox proportional hazards and Aalen additive hazards models for the effect of type 2 diabetes (assessed 5 years before baseline) on age of dementia diagnosis, controlling for sex/gender, educational attainment, nativity, height, race/ethnicity, and a race/ethnicity × diabetes interaction. Type 2 diabetes was associated with higher dementia incidence in Whites (hazard ratio [HR] = 1.46; 95% CI, 1.40-1.52). Compared with Whites, the estimated effect of diabetes was larger in South Asians (HR = 2.26; 95% CI, 1.48-3.44), slightly smaller in Chinese (HR = 1.32; 95% CI, 1.08-1.62) and Filipino (HR = 1.31; 95% CI, 1.08-1.60) individuals, and similar in Japanese individuals (HR = 1.44; 95% CI, 1.15-1.81). Heterogeneity in this association across Asian subgroups may be related to type 2 diabetes severity. Understanding this heterogeneity may inform prevention strategies to prevent dementia for all racial and ethnic groups.

The association of pre-cancer diagnosis cardiovascular risk factors with memory aging after a cancer diagnosis, overall and by race/ethnicity

PURPOSE

Cardiovascular risk factors (CVRFs) are associated with increased risk for cognitive impairment and decline in the general population, but less is known about how CVRFs might influence cognitive aging among older cancer survivors. We aimed to determine how CVRFs prior to a cancer diagnosis affect post-cancer diagnosis memory aging, compared to cancer-free adults, and by race/ethnicity.

METHODS

Incident cancer diagnoses and memory (immediate and delayed recall) were assessed biennially in the US Health and Retirement Study (N = 5,736, 1998-2018). CVRFs measured at the wave prior to a cancer diagnosis included self-reported cigarette smoking, obesity, diabetes, heart disease, hypertension, and stroke. Multivariable-adjusted linear mixed-effects models evaluated the rate of change in standardized memory score (SD/decade) post-cancer diagnosis for those with no, medium, and high CVRFs, compared to matched cancer-free adults, overall and stratified by sex and race/ethnicity.

RESULTS

Higher number of CVRFs was associated with worse baseline memory for both men and women, regardless of cancer status. Cancer survivors with medium CVRFs had slightly slower rates of memory decline over time relative to cancer-free participants (0.04 SD units/decade [95% CI: 0.001, 0.08]). Non-Hispanic Black (NHB) and Hispanic cancer-free participants and cancer survivors had worse baseline memory than their Non-Hispanic White (NHW) counterparts.

CONCLUSIONS

CVRFs were associated with worse baseline memory function, but not decline, for cancer-free adults and cancer survivors. Racial disparities were largely similar between cancer survivors and cancer-free adults.

IMPLICATIONS FOR CANCER SURVIVORS

These findings may inform hypotheses about pre-diagnosis multimorbidity and cognitive aging of cancer survivors from diverse groups.

Association between metabolic syndrome and white matter integrity in young and mid-age post-9/11 adult Veterans

Metabolic syndrome has been associated with reduced brain white matter integrity in older individuals. However, less is known about how metabolic syndrome might impact white matter integrity in younger populations. This study examined metabolic syndrome-related global and regional white matter integrity differences in a sample of 537 post-9/11 Veterans. Metabolic syndrome was defined as ≥3 factors of: increased waist circumference, hypertriglyceridemia, low high-density lipoprotein cholesterol, hypertension, and high fasting glucose. T1 and diffusion weighted 3 T MRI scans were processed using the FreeSurfer image analysis suite and FSL Diffusion Toolbox. Atlas-based regions of interest were determined from a combination of the Johns Hopkins University atlas and a Tract-Based Spatial Statistics-based FreeSurfer WMPARC white matter skeleton atlas. Analyses revealed individuals with metabolic syndrome (n = 132) had significantly lower global fractional anisotropy than those without metabolic syndrome (n = 405), and lower high-density lipoprotein cholesterol levels was the only metabolic syndrome factor significantly related to lower global fractional anisotropy levels. Lobe-specific analyses revealed individuals with metabolic syndrome had decreased fractional anisotropy in frontal white matter regions compared with those without metabolic syndrome. These findings indicate metabolic syndrome is prevalent in this sample of younger Veterans and is related to reduced frontal white matter integrity. Early intervention for metabolic syndrome may help alleviate adverse metabolic syndrome-related brain and cognitive effects with age.

Soluble epoxide hydrolase inhibition reverses cognitive dysfunction in a mouse model of metabolic syndrome by modulating inflammation

Midlife metabolic syndrome (MetS) is associated with cognitive impairment in late life. The mechanism of delayed MetS-related cognitive dysfunction (MetSCD) is not clear, but it has been linked to systemic inflammation and chronic cerebral microangiopathy. Currently there is no treatment for late life MetSCD other than early risk factor modification. We investigated the effect of soluble epoxide hydrolase (sEH) inhibitor 4-[[trans-4-[[(tricyclo[3.3.1.13,7]dec-1-ylamino)carbonyl]amino]cyclohexyl]oxy]-benzoic acid (t-AUCB) on cognitive performance, cerebral blood flow (CBF), and central and peripheral inflammation in the high-fat diet (HFD) model of MetS in mice. At 6 weeks of age, male mice were randomly assigned to receive either HFD or standard chow (STD) for 6 months. Mice received either t-AUCB or vehicle for 4 weeks. Cognitive performance was evaluated, followed by CBF measurement using magnetic resonance imaging (MRI). At the end of the study, blood was collected for measurement of eicosanoids and inflammatory cytokines. The brains were then analyzed by immunohistochemistry for glial activation markers. The HFD caused a significant impairment in novel object recognition. Treatment with t-AUCB increased plasma levels of 14,15-EET, prevented this cognitive impairment and modified hippocampal glial activation and plasma cytokine levels, without affecting CBF in mice on HFD. In conclusion, sEH inhibition for four weeks prevents cognitive deficits in mice on chronic HFD by modulating inflammatory processes without affecting CBF.

Modifiable and Non-Modifiable Risk Factors for Dementia Among Non-Hispanic White and Black Populations Aged 50-64 in the United States, 2006-2016

BACKGROUND AND OBJECTIVES

Non-Hispanic Black populations (NHB) have a significantly higher prevalence of dementia than non-Hispanic Whites in the U.S., and the underlying risk factors may play a role in this racial disparity. We aimed to calculate risk scores for dementia among non-Hispanic White (NHW) and non-Hispanic Black populations aged 50-64 years over a period of 10 years, and to estimate potential differences of scores between NHW and NHB.

RESEARCH DESIGN AND METHODS

The Health and Retirement Study from 2006 to 2016 was used to calculate the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) risk score, a validated score for predicting dementia risk. Weighted average CAIDE score, as well as CAIDE score for modifiable factors hypertension, obese, hypercholesterolemia, physical inactivity), and non-modifiable factors (age, sex, education) were calculated for adults aged 50-64 years with normal cognition for 2006-2008, 2010-2012, 2014-2016. The associations of race with CAIDE score and elevated CAIDE score were examined.

RESULTS

A total of 10,871 participants were included in the analysis. The CAIDE score showed declining trends for NHB from 2006 to 2016, while NHB consistently had a higher total CAIDE score and CAIDE score for modifiable factors from 2006 to 2016, but not for non-modifiable factors.

DISCUSSION AND IMPLICATIONS

NHB had a higher level of dementia risk factors than NHW among adults aged 50-64 years in the U.S. from 2006 to 2016, and the difference is attributable to modifiable risk factors, which holds promise for risk reduction of dementia.

Exploring research hotspots and emerging trends in neuroimaging of vascular cognitive impairment: a bibliometric and visualized analysis

Background

Vascular cognitive impairment (VCI) manifests in memory impairment, mental slowness, executive dysfunction, behavioral changes, and visuospatial abnormalities, significantly compromising the quality of daily life for patients and causing inconvenience to caregivers. Neuroimaging serves as a crucial approach to evaluating the extent, location, and type of vascular lesions in patients suspected of VCI. Nevertheless, there is still a lack of comprehensive bibliometric analysis to discern the research status and emerging trends concerning VCI neuroimaging.

Objective

This study endeavors to explore the collaboration relationships of authors, countries, and institutions, as well as the research hotspots and frontiers of VCI neuroimaging by conducting a bibliometric analysis.

Methods

We performed a comprehensive retrieval within the Core Collection of Web of Science, spanning from 2000 to 2023. After screening the included literature, CiteSpace and VOSviewer were utilized for a visualized analysis aimed at identifying the most prolific author, institution, and journal, as well as extracting valuable information from the analysis of references.

Results

A total of 1,024 publications were included in this study, comprising 919 articles and 105 reviews. Through the analysis of keywords and references, the research hotspots involve the relationship between neuroimaging of cerebral small vessel disease (CSVD) and VCI, the diagnosis of VCI, and neuroimaging methods pertinent to VCI. Moreover, potential future research directions encompass CSVD, functional and structural connectivity, neuroimaging biomarkers, and lacunar stroke.

Conclusion

The research in VCI neuroimaging is constantly developing, and we hope to provide insights and references for future studies by delving into the research hotspots and frontiers within this field.

Assessment of disparities in timely diagnosis and comprehensive workup of cognitive impairment between English and Spanish speakers

BACKGROUND

Previous studies have examined disparities in dementia care that affect the U.S. Hispanic/Latino population, including clinician bias, lack of cultural responsiveness, and less access to health care. However, there is limited research that specifically investigates the impact of language barriers to health disparities in dementia diagnosis.

METHODS

In this retrospective cross-sectional study, 12,080 English- or Spanish- speaking patients who received an initial diagnosis of mild cognitive impairment (MCI) or dementia between July 2017 and June 2019 were identified in the Yale New Haven Health (YNHH) electronic medical record. To evaluate the timeliness of diagnosis, an initial diagnosis of MCI was classified as "timely", while an initial diagnosis of dementia was considered "delayed." Comprehensiveness of diagnosis was assessed by measuring the presence of laboratory studies, neuroimaging, specialist evaluation, and advanced diagnostics six months before or after diagnosis. Binomial logistic regressions were calculated with and without adjustment for age, legal sex, ethnicity, neighborhood disadvantage, and medical comorbidities.

RESULTS

Spanish speakers were less likely to receive a timely diagnosis when compared with English speakers both before (unadjusted OR, 0.65; 95% CI, 0.53-0.80, p <0.0001) and after adjusting for covariates (adjusted OR, 0.55; 95% CI, 0.40-0.75, p = 0.0001). Diagnostic services were provided equally between groups, except for referrals to geriatrics, which were more frequent among Spanish-speaking patients. A subgroup analysis revealed that Spanish-speaking Hispanic/Latino patients were less likely to receive a timely diagnosis compared to English-speaking Hispanic/Latino patients (adjusted OR, 0.53; 95% CI, 0.38-0.73, p = 0.0001).

CONCLUSIONS

Non-English language preference is likely to be a contributing factor to timely diagnosis of cognitive impairment. In this study, Spanish language preference rather than Hispanic/Latino ethnicity was a significant predictor of a less timely diagnosis of cognitive impairment. Policy changes are needed to reduce barriers in cognitive disorders care for Spanish-speaking patients.

Association between Age at Diagnosis of Hyperlipidemia and Subsequent Risk of Dementia

OBJECTIVES

The relationship between age at diagnosis of hyperlipidemia and dementia remains unclear. We examined whether younger age at diagnosis of hyperlipidemia is associated with higher risk of subsequent dementia.

DESIGN

A longitudinal population-based study with a median follow-up of 12.8 years.

SETTING AND PARTICIPANTS

We analyzed data on a sample of 489,642 participants in the United Kingdom.

METHODS

This study was based on the UK Biobank. Information on hyperlipidemia and dementia diagnoses was collected at baseline (2006-2010) and follow-up [median = 12.8 years, interquartile range (IQR): 12.1-13.6 years]. Propensity score matching method and Cox proportional hazards models were used to assess the association between age at diagnosis of hyperlipidemia and dementia.

RESULTS

Among 489,642 participants (mean age: 56.9 ± 8.1 years; female: 54.7%), 114,112 (23.3%) were diagnosed with hyperlipidemia. Younger age at diagnosis of hyperlipidemia (per 10-year decrease) was significantly associated with higher risks of all-cause dementia [hazard ratio (HR), 1.12; 95% CI, 1.07-1.18; P < .001], Alzheimer's disease (AD) (HR, 1.22; 95% CI, 1.14-1.31; P < .001), and vascular dementia (VD) (HR, 1.16; 95% CI, 1.05-1.27; P < .001). After propensity score matching, patients with hyperlipidemia diagnosed before 50 years had the highest HR for all-cause dementia (HR, 1.46; 95% CI, 1.15-1.86; P = .002), followed by patients diagnosed between 50 and 69 years (HR, 1.21; 95% CI, 1.12-1.31; P < .001) and then patients diagnosed aged 70 years and older (HR, 0.94; 95% CI, 0.84-1.06; P = .302). Similar results were observed for AD and VD.

CONCLUSIONS AND IMPLICATIONS

A dose-response relationship between age at hyperlipidemia diagnosis and risk of dementia was found in the longitudinal cohort study, with younger age at diagnosis of hyperlipidemia being associated with higher subsequent risk.

Midlife Residential Greenness and Late-Life Cognitive Decline among Nurses' Health Study Participants

BACKGROUND

Midlife residential exposure to greenspace may slow cognitive decline by increasing opportunities for physical activity and social connection, restoring attention, or reducing stress or adverse environmental exposures. However, prospective studies on the association between greenness and cognitive decline are sparse.

OBJECTIVE

We investigated the prospective association between greenness at midlife and cognitive decline later in life. We explored effect measure modification by apolipoprotein E (APOE)-ɛ4 carrier status, neighborhood socioeconomic status (NSES), and rural/urban regions.

METHODS

The Nurses' Health Study (N = 121,700 ) started in 1976 with married female nurses, 30-55 years of age, located across 11 US states. We examined 16,962 nurses who were enrolled in a substudy starting in 1995-2001 (mean age = 74 y ) through 2008. We assessed average summer residential greenness in a 270 -m buffer using Landsat Normalized Difference Vegetation Index data from 1986-1994. Starting in 1995-2001, participants underwent up to four repeated measures of five cognitive tests. A global composite score was calculated as the average of all z -scores for each task to evaluate overall cognition. We used linear mixed models to evaluate the association of average greenness exposure at midlife with cognitive decline in later life, adjusted for age, education, NSES, and depression.

RESULTS

In adjusted models, higher midlife greenness exposure [per interquartile range (IQR): 0.18] was associated with a 0.004-unit (95% CI: 0.001, 0.006) slower annual rate of cognitive decline. For comparison, we found that 1 year of age is related to a - 0.006 mean annual difference for global cognition in the full sample; thus, higher midlife greenness appeared equivalent to slowing cognitive decline by ∼ 8 months. In analysis exploring gene-environment interactions, we found that among APOE-ɛ4 carriers, an IQR increase in greenness was associated with a rate of decline that was slower by 0.01 units of global composite score (95% CI: 0.0004, 0.02). This association was attenuated among APOE-ɛ4 noncarriers. We did not observe associations between greenness and baseline or annual rate of cognitive decline of verbal memory.

DISCUSSION

Higher midlife greenness exposure is associated with slower cognitive decline later in life. Future research is necessary to confirm these findings. https://doi.org/10.1289/EHP13588.

Influence of Bilberry Extract on Neuronal Cell Toxicity

Increased intake of dietary antioxidants such as anthocyanins, which are enriched in colourful fruits, is a promising alternative to reduce the risk of degenerative diseases such as Alzheimer's Disease (AD). Since Amyloid β (Aβ) is one of the key components contributing to AD pathology, probably by reactive oxygen species (ROS) induction, this study investigated the preventive effect of anthocyanin-rich bilberry extract (BE) and its anthocyanin fraction (ACN) on ROS generation and cell toxicity. The results showed a significant and concentration-dependent decrease in neuroblastoma cell (SH-SY5Y) viability by BE or ACN, whereas no cell toxicity was observed in HeLa cells. Incubation with BE and ACN for 24 h diminished the generation of induced ROS levels in SH-SY5Y and HeLa cells. In addition, low concentrations of BE (1-5 µg/mL) showed protective effects against Aβ-induced cytotoxicity in SH-SY5Y cells. In conclusion, our results suggest antioxidant and protective effects of BE and ACN, which could potentially be used to delay the course of neurodegenerative diseases such as AD. Further studies are needed to clarify the high potential of anthocyanins and their in vivo metabolites on neuronal function.

Hypertension and Mild Cognitive Impairment: State-of-the-Art Review

BACKGROUND

Mid-life hypertension is associated with cognitive decline and dementia in later life. Reducing high blood pressure (BP) with antihypertensive agents is a well-researched strategy to prevent dementia and mild cognitive impairment (MCI). However, there is still limited direct evidence to support the approach, and particularly for the treatment of the very old and those with existing MCI.

METHODS

This review presents an overview of the current evidence for the relationship between MCI and hypertension, and of the potential pathophysiological mechanisms related to cognitive decline and incidence dementia in relation to aging.

RESULTS

Although observational data are near consistent in showing an association between mid-life hypertension and MCI and/or dementia, the evidence in relation to hypertension in younger adults and the very old (age >80 years) is much more limited. Most of the commonly available antihypertensive agents appear to provide beneficial effects in reducing the risk dementia, but there is limited evidence to support such treatment in those with existing MCI.

CONCLUSIONS

Further studies are needed to determine the optimal levels of BP control across different age groups, especially in adults with MCI, and which class(es) of antihypertensive agents and duration of treatment best preserve cognitive function in those at risk of, or with established, MCI.

Differential Effects of Aging on Regional Corpus Callosum Microstructure and the Modifying Influence of Pulse Pressure

The corpus callosum is composed of several subregions, distinct in cellular and functional organization. This organization scheme may render these subregions differentially vulnerable to the aging process. Callosal integrity may be further compromised by cardiovascular risk factors, which negatively influence white matter health. Here, we test for heterochronicity of aging, hypothesizing an anteroposterior gradient of vulnerability to aging that may be altered by the effects of cardiovascular health. In 174 healthy adults across the adult lifespan (mean age = 53.56 ± 18.90; range, 20-94 years old, 58.62% women), pulse pressure (calculated as participant's systolic minus diastolic blood pressure) was assessed to determine cardiovascular risk. A deterministic tractography approach via diffusion-weighted imaging was utilized to extract fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD) from each of five callosal subregions, serving as estimates of microstructural health. General linear models tested the effects of age, hypertension, and pulse pressure on these cross-sectional metrics. We observed no significant effect of hypertensive diagnosis on callosal microstructure. We found a significant main effect of age and an age-pulse pressure interaction whereby older age and elevated pulse pressure were associated with poorer FA, AD, and RD. Age effects revealed nonlinear components and occurred along an anteroposterior gradient of severity in the callosum. This gradient disappeared when pulse pressure was considered. These results indicate that age-related deterioration across the callosum is regionally variable and that pulse pressure, a proxy of arterial stiffness, exacerbates this aging pattern in a large lifespan cohort.

Effects of risk factors on the development and mortality of early- and late-onset dementia: an 11-year longitudinal nationwide population-based cohort study in South Korea

BACKGROUND

Early-onset dementia (EOD, onset age < 65) and late-onset dementia (LOD, onset age ≥ 65) exhibit distinct features. Understanding the risk factors for dementia development and mortality in EOD and LOD respectively is crucial for personalized care. While risk factors are known for LOD development and mortality, their impact on EOD remains unclear. We aimed to investigate how hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation, and osteoporosis influence the development and mortality of EOD and LOD, respectively.

METHODS

Using the Korean National Health Insurance Service (NHIS) database, we collected 546,709 dementia-free individuals and followed up for 11 years. In the two study groups, the Younger group (< 65 years old) and the Older group (≥ 65 years old), we applied Cox proportional hazard models to assess risk factors for development of EOD and LOD, respectively. Then, we assessed risk factors for mortality among EOD and LOD.

RESULTS

Diabetes mellitus and osteoporosis increased the risk of EOD and LOD development. Hypertension increased the risk of EOD, while atrial fibrillation increased the risk of LOD. Conversely, hyperlipidemia exhibited a protective effect against LOD development. Additionally, diabetes mellitus increased mortality in EOD and LOD. Hypertension and atrial fibrillation increased mortality in LOD, while hyperlipidemia decreased mortality in EOD and LOD.

CONCLUSIONS

Risk factors influencing dementia development and mortality differed in EOD and LOD. Targeted public health interventions addressing age-related risk factors may reduce dementia incidence and mortality.

Chronic kidney disease and cognitive performance: NHANES 2011-2014

PURPOSE

Previous studies suggest an association between chronic kidney disease (CKD) and cognitive impairment. The purpose of this study was to explore the association between the diverse stages of CKD and the cognitive performance of elderly American adults.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 were used. Multivariate adjusted logistic regression, subgroup analysis, and the restricted cubic spline model were used to assess the associations of CKD stage and estimated glomerular filtration rate (eGFR) with cognitive performance. The measures used to evaluate cognitive function included the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) test, the Animal Fluency test, and the Digit Symbol Substitution test (DSST).

RESULTS

This study included 2234 participants aged ≥ 60 years. According to the fully adjusted model, stages 3-5 CKD were significantly associated with the CERAD test score (OR = 0.70, 95% CI [0.51, 0.97], p = 0.033), the Animal Fluency test score (OR = 0.64, 95% CI [0.48, 0.85], p = 0.005), and the DSST score (OR = 0.60, 95% CI [0.41, 0.88], p = 0.013). In addition, the incidence of poor cognitive function increased with decreasing eGFR, especially for individuals with low and moderate eGFRs. Both the DSST score (p nonlinearity < 0.0001) and the Animal Fluency test score (p nonlinearity = 0.0001) had nonlinear dose-response relationships with the eGFR. However, a linear relationship was shown between the eGFR and CERAD test score (p nonlinearity = 0.073).

CONCLUSIONS

CKD, especially stages3-5 CKD, was significantly associated with poor cognitive performance in terms of executive function, learning, processing speed, concentration, and working memory ability. All adults with CKD should be screened for cognitive impairment.

Large Neutral Amino Acids Moderate the Effects of Metabolic Syndrome on Cognitive Performance in Middle-Aged Adults

INTRODUCTION

Two large neutral amino acids (LNAA), tryptophan and tyrosine, are precursors to cerebral neurotransmitters and are involved in cognitive function. Higher levels of LNAA in young adults are associated with improved cognition, although these associations appear to reverse over time. Given that exposure to metabolic syndrome (MetS) may induce premature cognitive aging, the current project aims to fill the gap in the literature by examining the effect of LNAA on cognitive performance in midlife adults with metabolic risks.

METHODS

Eighty-eight adults, ages 40-61 years, participated in this cross-sectional study. LNAA metabolites were quantified, MetS components were measured using high-performance liquid chromatography, and MetS components were assessed in the laboratory. Composite verbal memory and executive functioning scores were computed using principal component analysis. We used linear regression models to test the interaction between LNAA and MetS while covarying for sex, age, and education.

RESULTS

The kynurenine/tryptophan ratio moderated the relation between MetS and verbal memory, even after adjusting for relevant covariates. Tyrosine metabolites were not significant moderators of the association between MetS and executive functioning.

CONCLUSION

Our findings suggest that the detected weaker memory performance in adults with a high number of MetS components may be related to relative tryptophan depletion and possible decreases in serotonin production. Further investigation is warranted to examine the potential role of LNAA in associations between cognitive performance and metabolic risks over time.

Associations of Polycystic Ovary Syndrome With Indicators of Brain Health at Midlife in the CARDIA Cohort

BACKGROUND AND OBJECTIVES

Polycystic ovary syndrome (PCOS) is a common reproductive disorder associated with an adverse cardiometabolic profile early in life. Increasing evidence links cardiovascular risk factors, such as diabetes and hypertension, to accelerated cognitive aging. However, less is known about PCOS and its relationship to brain health, particularly at midlife. Our goal was to investigate possible associations between PCOS and midlife cognitive function and brain MRI findings in an ongoing prospective study.

METHODS

We used data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a geographically diverse prospective cohort study of individuals who were 18-30 years at baseline (1985-1986) and followed for 30 years. We identified women with PCOS from an ancillary study (CARDIA Women's study (CWS); n = 1,163) as those with elevated androgen levels and/or hirsutism in conjunction with symptoms of oligomenorrhea. At year 30, participants completed cognitive testing, including the Montreal Cognitive Assessment, Rey Auditory Verbal Learning Test (RAVLT) (verbal learning and memory), Digit Symbol Substitution Test (processing speed and executive function), Stroop test (attention and cognitive control), and category and letter fluency tests (semantics and attention). A subset completed brain MRI to assess brain structure and white matter integrity. Multivariable linear regression models estimated the association between PCOS and outcomes, adjusting for age, race, education, and study center.

RESULTS

Of the 1163 women in CWS, 907 completed cognitive testing, and of these, 66 (7.1%) met criteria for PCOS (age 54.7 years). Women with and without PCOS were similar for age, BMI, smoking/drinking status, and income. At year 30, participants with PCOS performed lower (mean z score; 95% CI) on Stroop (-0.323 (-0.69 to -7.37); p = 0.008), RAVLT (-0.254 (-0.473 to -0.034); p = 0.002), and category fluency (-0.267 (-0.480 to -0.040); p = 0.02) tests. Of the 291 participants with MRI, 25 (8.5%) met PCOS criteria and demonstrated lower total white matter fractional anisotropy, a measure of white matter integrity (coefficient (95% CI) -0.013 (-0.021 to -0.005); p = 0.002), though not abnormal white matter.

DISCUSSION

Our results suggest that women with PCOS have lower cognitive performance and lower white matter integrity at midlife. Additional research is needed to confirm these findings and to determine potential mechanistic pathways including potential modifiable factors.

Comorbid Conditions Are Associated With Cognitive Impairment in Native Hawaiians and Pacific Islanders

We examined the association between comorbid conditions and mild cognitive impairment (MCI) in Native Hawaiians and Pacific Islanders (NHPI) (n = 54). Cross-sectional, self-reported questionnaires were utilized to collect demographic, comorbid conditions, and MCI (via the AD8 index) data. Separate logistic regression models were conducted to investigate the relationship between comorbid conditions and MCI, adjusting for other covariates. We found significantly increased odds of MCI in those reporting high blood pressure (OR = 5.27; 95% CI: [1.36, 20.46]; p = 0.016), high cholesterol (OR = 7.30; 95% CI: [1.90, 28.14], p = 0.004), and prediabetes or borderline diabetes (OR = 4.53; 95% CI: [1.27, 16.16], p = 0.02) compared with those not reporting these respective conditions. These data show that hypertension, hypercholesterolemia, and prediabetes are associated with MCI in the NHPI community, suggesting that preventive strategies to reduce chronic conditions may also potentially slow cognitive decline in underrepresented/understudied NHPI.

Individual and dual trajectories of insomnia symptoms and body mass index before and after retirement and their associations with changes in subjective cognitive functioning

BACKGROUND

We examined individual and dual trajectories of insomnia symptoms and body mass index (BMI) before and after retirement, and their associations with changes in subjective cognitive functioning after retirement.

METHODS

We used the Helsinki Health Study's (n = 2360, 79% women, aged 40-60 at baseline, Finland) repeated surveys to identify the developmental patterns of insomnia symptoms and BMI (2000-2017) and changes in subjective cognitive functioning (2017-2022). We analysed the data using latent group-based dual trajectory modelling and logistic regression analysis.

RESULTS

Three latent groups were identified for insomnia symptoms (stable low, decreasing and increasing symptoms) and BMI (stable healthy weight, stable overweight and stable obesity). Insomnia symptoms were associated with declining subjective cognitive functioning and largely explained the effects in the dual models.

CONCLUSION

The association between dual trajectories of insomnia symptoms and BMI with subjective cognitive decline is dominated by insomnia symptoms.

Lifestyle and factors of vascular and metabolic health and inflammation are associated with sensorineural-neurocognitive aging in older adults

This study's aim was to identify risk factors associated with sensorineural and neurocognitive function (brain aging) in older adults. In N = 1,478 Epidemiology of Hearing Loss Study participants (aged 64-100 years, 59% women), we conducted sensorineural and cognitive tests, which were combined into a summary measure using Principal Component Analysis (PCA). Participants with a PCA score <-1 standard deviation (SD) were considered to have brain aging. Incident brain aging was defined as PCA score <-1 SD at 5-year follow-up among participants who had a PCA score ≥-1 SD at baseline. Logistic regression and Poisson models were used to estimate associations between baseline risk factors of lifestyle, vascular and metabolic health, and inflammation and prevalent or incident brain aging, respectively. In an age-sex adjusted multivariable model, not consuming alcohol (odds ratio(OR) = 1.77, 95% confidence Interval (CI) = 1.18,2.66), higher interleukin-6 levels (OR = 1.30, 95% CI = 1.03,1.64), and depressive symptoms (OR = 2.44, 95% CI = 1.63,3.67) were associated with a higher odds of having brain aging, while higher education had protective effects (OR = 0.55, 95% CI = 0.33,0.94). A history of stroke, arterial stiffness, and obesity were associated with an increased risk of developing brain aging during the five years of follow-up. Lifestyle, vascular, metabolic and inflammatory factors were associated with brain aging in older adults, which adds to the evidence of shared pathways for sensorineural and neurocognitive declines in aging. Targeting these shared central processing etiological factors with interventions may lead to retention of better neurological function, benefiting multiple systems, i.e., hearing, smell, and cognition, ultimately helping older adults retain independence and higher quality of life longer.

Association of Statin Use with Dementia Risk Among Older Adults in Japan: A Nested Case-Control Study Using the LIFE Study

Background

Previous studies have shown a possible association between statin use and a decreased risk of dementia, but the association has not been sufficiently established, especially in the super-aging society of Japan.

Objective

This study aimed to determine the association between statin use and the risk of dementia among Japanese participants aged> =65 years old.

Methods

Data from the Longevity Improvement and Fair Evidence (LIFE) Study were utilized, including medical and long-term care (LTC) claim data from 17 municipalities between April 2014 and December 2020. A nested case-control study was conducted with one case matched to five controls based on age, sex, municipality, and year of cohort entry. We used a conditional logistic regression model to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results

This study included 57,302 cases and 283,525 controls, with 59.7% of the participants being woman. After adjusting for potential confounders, statin use was associated with a lower risk of dementia (OR, 0.70; 95% CI: 0.68-0.73) and Alzheimer's disease (OR: 0.66; 95% CI: 0.63-0.69). Compared with non-users, the ORs of dementia were as follows: 1.42 (1.34-1.50) for 1-30 total standardized daily dose (TSDD), 0.91 (0.85-0.98) for 31-90 TSDD, 0.63 (0.58-0.69) for 91-180 TSDD, and 0.33 (0.31-0.36) for >180 TSDD in dose-analysis.

Conclusions

Statin use is associated with a reduced risk of dementia and Alzheimer's disease among older Japanese adults. A low cumulative statin dose is associated with an increased risk of dementia, whereas a high cumulative statin dose is a protective factor against dementia.

Optimizing the Implementation of a Lifestyle Dementia Prevention Intervention for Older Patients in an Academic Healthcare System

Background

Interventions that promote healthy lifestyles are critical for the prevention of Alzheimer's disease and Alzheimer's disease related dementias (AD/ADRD). However, knowledge of the best practices for implementing AD/ADRD prevention in healthcare settings remains limited.

Objective

We aimed to qualitatively identify barriers and facilitators to implementing a clinical trial of a novel lifestyle intervention (My Healthy Brain) in our medical center for older patients with subjective cognitive decline who are at-risk for AD/ADRD.

Methods

We conducted focus groups with 26 healthcare professionals (e.g., physicians, psychology, nursing) from 5 clinics that treat older patients (e.g., memory care, psychiatry). Our qualitative analysis integrated two implementation frameworks to systematically capture barriers and facilitators to AD/ADRD prevention (Consolidated Framework for Implementation Science Research) that impact implementation outcomes of acceptability, appropriateness, and feasibility (Proctor's framework).

Results

We found widespread support for an RCT of My Healthy Brain and AD/ADRD prevention. Participants identified barriers related to patients (stigma, technological skills), providers (dismissiveness of "worried well," doubting capacity for behavior change), clinics (limited time and resources), and the larger healthcare system (underemphasis on prevention). Implementation strategies guided by Expert Recommendations for Implementing Change (ERIC) included: developing tailored materials, training staff, obtaining buy-in from leadership, addressing stigmatized language and practices, identifying "champions," and integrating with workflows and resources.

Conclusions

The results will inform our recruitment, enrollment, and retention procedures to implement the first randomized clinical trial of My Healthy Brain. Our study provides a blueprint for addressing multi-level barriers to the implementation of AD/ADRD prevention for older patients in medical settings.

Capillary dysfunction in healthy elderly APOE ε4 carriers with raised brain Aβ deposition

INTRODUCTION

Capillary dysfunction, characterized by disturbances in capillary blood flow distribution, might be an overlooked factor in the development of Alzheimer's disease (AD). This study investigated microvascular blood flow in preclinical and prodromal AD individuals.

METHODS

Using dynamic susceptibility contrast magnetic resonance imaging and positron emission tomography, we examined alterations in microvascular circulation and levels of Aβ deposition in two independent cohorts of APOE ε4 carriers.

RESULTS

Capillary dysfunction was elevated in both prodromal and preclinical AD individuals compared to age-matched controls. Additionally, the prodromal group exhibited higher levels of capillary dysfunction compared to the preclinical group.

DISCUSSION

These findings suggest that capillary dysfunction can be detected at the preclinical stage of AD and indicates a worsening of capillary dysfunction throughout the AD continuum. Understanding the interaction between capillary dysfunction and Aβ could provide insights into the relationship between cardiovascular risk factors and the development of AD.

HIGHLIGHTS

Alzheimer's disease (AD) is associated with disturbances in microvascular circulation. Capillary dysfunction can be detected in preclinical AD. As cognitive symptoms progress in prodromal AD, capillary dysfunction worsens. Capillary dysfunction may impede the clearance of beta-amyloid (Aβ). Capillary dysfunction might contribute to the development of AD.

[Cognitive impairment in cerebrovascular diseases]

Cognitive impairment, which is highly prevalent, especially among older people, leads to a decrease in the quality of life of patients, impairment of daily activities, and an increased risk of dementia and mortality. Currently, much attention is paid to mild cognitive impairment. The article discusses diagnostic criteria and possible clinical variants of this syndrome. Given the high rate of progression of mild cognitive impairment to dementia, it is necessary to identify risk groups and carry out therapeutic preventive measures. Correction of potentially modifiable risk factors is considered as a promising direction of therapy. Sufficient physical and mental activity, proper diet, normalization of sleep, visual acuity and hearing are necessary. Preventing stroke and controlling vascular risk factors may reduce the risk of mild cognitive impairment progressing to dementia.

The Relation Between Arterial Hypertension and Cognitive Impairment: A Literature Review

The global increase in dementia cases, driven by improved life expectancy and reduced elderly mortality rates, presents a significant public health challenge. Dementia, characterized by a gradual and irreversible decline in cognitive abilities, affects individuals aged 65 and older, disrupting lives and straining healthcare systems. Hypertension significantly influences dementia development. Research consistently links midlife hypertension to cognitive decline, mild cognitive impairment (MCI), and dementia, but findings in older adults vary. While some studies suggest that late-life hypertension accelerates cognitive decline and dementia risk, others propose a protective effect. The impact of hypertension on cognition varies across age groups, spanning from childhood to late life. High blood pressure during midlife and earlier life stages consistently predicts poorer cognitive outcomes. Executive function, attention, and motor speed are the cognitive domains most affected by hypertension, particularly in subcortical diseases. Memory impairments in hypertension-related dementias are complex, often overlapping with other causes. Understanding the inconsistent findings in older adults regarding hypertension, cognitive decline, and dementia risk requires comprehensive exploration of methodological and biological factors. Addressing hypertension and its management may hold the key to reducing the risk of cognitive decline and dementia, especially in midlife and earlier life stages.

Association between cerebrovascular disease and perioperative neurocognitive disorders: a retrospective cohort study

BACKGROUND

Previous studies have shown that patients with cerebrovascular disease (CVD) have a significantly increased risk of cognitive decline or dementia; however, the association between preoperative CVD and perioperative neurocognitive disorders (PNDs) remains unclear. This study aimed to explore the correlation between preoperative CVD and PNDs, as well as combine logistic regression and receiver operating characteristic (ROC) curves to construct a clinical prediction PND model.

MATERIALS AND METHODS

This retrospective cohort study evaluated 13 899 surgical patients of a large-scale comprehensive hospital between January 2021 and January 2022 to explore the association between preoperative CVD and PNDs, with follow-up to monitor postoperative survival until 28 February 2023, unless the patient died. The study participants comprised all inpatients from the Bone and Joint Surgery, Spine Surgery, Urology, Hepatobiliary Surgery, Gastrointestinal Surgery, and Thoracic Surgery departments. Patients were classified into two groups: the CVD group with a confirmed diagnosis and the noncerebrovascular disease group. The incidence of PNDs was measured, and potential associations between patient demographic information, preoperative comorbidities, and CVD, as well as the correlation between preoperative CVD and PNDs, were investigated by multivariate logistic regression analysis. Next, the authors constructed a clinical prediction PND model by drawing the ROC curve. The postoperative survival of all patients was tracked, and a survival curve was constructed and incorporated into the Cox proportional hazard regression model to analyze the relationship between preoperative CVD and the overall postoperative survival rate.

RESULTS

Of the included 13 899 patients, propensity score matching yielded 1006 patient pairs. Multivariate logistic regression analysis revealed that CVD was an independent risk factor for PNDs [odds ratio: 10.193; 95% CI: 7.454-13.938; P <0.001]. Subsequently, the authors developed a clinical prediction model for PNDs by multivariate logistic regression analysis. The area under the ROC curve was 0.798 (95% CI: 0.765-0.830). The survival of 11 702 patients was followed up. Multivariate Cox hazard ratio regression analysis revealed that CVD affected the overall postoperative survival rate (hazard ratio, 1.398; 95% CI: 1.112-1.758; P <0.001).

CONCLUSION

CVD was an independent risk factor for PNDs and affected the overall postoperative survival rate of surgical patients with preoperative CVD.

Midlife sensory and motor functions improve long-term predictions of cognitive decline and incidence of cognitive impairment

INTRODUCTION

We aimed to assess whether midlife sensory and motor functions improve risk prediction of 10-year cognitive decline and impairment when added to risk prediction models using the Cardiovascular Risk Factors, Aging, and Incidence of Dementia Score (CAIDE) and Framingham Risk Score (FRS).

METHODS

Longitudinal data of N = 1529 (mean age 49 years; 54% women) Beaver Dam Offspring Study (BOSS) participants from baseline, 5 and 10-year follow-up were included. We tested whether including baseline sensory (hearing, vision, olfactory) impairment and motor function improves CAIDE or FRS risk predictions of 10-year cognitive decline or cognitive impairment incidence using logistic regressions.

RESULTS

Adding sensory and motor measures to CAIDE-only and FRS-only models significantly improved areas under the curve for cognitive decline and impairment models.

DISCUSSION

Including midlife sensory and motor function improved risk predictions of long-term cognitive decline and impairment in middle-aged to older adults. Sensory and motor assessments could contribute to cost-effective and non-invasive screening tools that identify high-risk individuals earlier to target intervention and prevention strategies.

Highlights

Sensory and motor measures improve risk prediction models of cognitive decline.Sensory and motor measures improve risk prediction models of cognitive impairment.Prediction improvements were strongest in midlife (adults < 55 years of age).Sensory and motor changes may help identify high-risk individuals early.

Midlife sensory and motor functions improve prediction of blood-based measures of neurodegeneration and Alzheimer's disease in late middle-age

INTRODUCTION

We assessed whether midlife sensory and motor functions added to prediction models using the Cardiovascular Risk Factors, Aging, and Incidence of Dementia Score (CAIDE) and Framingham Risk Score (FRS) improve risk predictions of 10-year changes in biomarkers of neurodegeneration and Alzheimer's disease.

METHODS

Longitudinal data of N = 1529 (mean age 49years) Beaver Dam Offspring Study participants from baseline, 5-year, and 10-year follow-up were included. We tested whether including baseline sensory (hearing, vision, olfactory) impairment and motor function measures improves CAIDE or FRS risk predictions of 10-year incidence of biomarker positivity of serum-based neurofilament light chain (NfL) and amyloid beta (Aβ)42/Aβ40 using logistic regression.

RESULTS

Adding sensory and motor measures to CAIDE-only and FRS-only models significantly improved NfL and Aβ42/Aβ40 positivity predictions in adults above the age of 55.

DISCUSSION

Including midlife sensory and motor function improved long-term biomarker positivity predictions. Non-invasive sensory and motor assessments could contribute to cost-effective screening tools that identify individuals at risk for neurodegeneration early to target interventions and preventions.

Highlights

Sensory and motor measures improve risk prediction models of neurodegenerative biomarkersSensory and motor measures improve risk prediction models of AD biomarkersPrediction improvements were strongest in late midlife (adults >55 years of age)Sensory and motor assessments may help identify high-risk individuals early.

Sex-specific blood biomarkers linked to memory changes in middle-aged adults: The Framingham Heart Study

The relationship between sex-specific blood biomarkers and memory changes in middle-aged adults remains unclear. We aimed to investigate this relationship using the data from the Framingham Heart Study (FHS). We conducted association analysis, partial correlation analysis, and causal dose-response curves using blood biomarkers and other data from 793 middle-aged participants (≤ 60 years) from the FHS Offspring Cohort. The results revealed associations of adiponectin and fasting blood glucose with midlife memory change, along with a U-shaped relationship of high-density lipoprotein cholesterol with memory change. No significant associations were found for the other blood biomarkers (e.g., amyloid beta protein 42) with memory change. To our knowledge, this is the first sex-specific network analysis of blood biomarkers related to midlife memory change in a prospective cohort study. Our findings highlight the importance of targeting cardiometabolic risks and the need to validate midlife-specific biomarkers that can accelerate the development of primary preventive strategies.

Association of cardiovascular disease management drugs with Lewy body dementia: a case-control study

Lewy body dementia is the second most common neurodegenerative dementia after Alzheimer's disease. Disease-modifying therapies for this disabling neuropsychiatric condition are critically needed. To identify drugs associated with the risk of developing Lewy body dementia, we performed a population-based case-control study of 148 170 US Medicare participants diagnosed with Lewy body dementia between 1 January 2008 and 31 December 2014 and of 1 253 043 frequency-matched controls. We estimated odds ratios and 95% confidence intervals for the association of Lewy body dementia risk with 1017 prescription drugs overall and separately for the three major racial groups (Black, Hispanic and White Americans). We identified significantly reduced Lewy body dementia risk associated with drugs used to treat cardiovascular diseases (anti-hypertensives: odds ratio = 0.72, 95% confidence interval = 0.70-0.74, P-value = 0; cholesterol-lowering agents: odds ratio = 0.85, 95% confidence interval = 0.83-0.87, P-value = 0; anti-diabetics: odds ratio = 0.83, 95% confidence interval = 0.62-0.72, P-value = 0). Notably, anti-diabetic medications were associated with a larger risk reduction among Black Lewy body dementia patients compared with other racial groups (Black: odds ratio = 0.67, 95% confidence interval = 0.62-0.72, P-value = 0; Hispanic: odds ratio = 0.86, 95% = 0.80-0.92, P-value = 5.16 × 10-5; White: odds ratio = 0.85, 95% confidence interval = 0.82-0.88, P-value = 0). To independently confirm the epidemiological findings, we looked for evidence of genetic overlap between Lewy body dementia and cardiovascular traits using whole-genome sequence data generated for 2591 Lewy body dementia patients and 4027 controls. Bivariate mixed modelling identified shared genetic risk between Lewy body dementia and low-density lipoprotein cholesterol levels, Type 2 diabetes and hypertension. By combining epidemiological and genomic data, we demonstrated that drugs treating cardiovascular diseases are associated with reduced Lewy body dementia risk, and these associations varied across racial groups. Future randomized clinical trials need to confirm our findings, but our data suggest that assiduous management of cardiovascular diseases may be beneficial in this understudied form of dementia.

Innate Sleep Apnea in Spontaneously Hypertensive Rats Is Associated With Microvascular Rarefaction and Neuronal Loss in the preBötzinger Complex

BACKGROUND

Sleep apnea (SA) is a major threat to physical health and carries a significant economic burden. These impacts are worsened by its interaction with, and induction of, its comorbidities. SA holds a bidirectional relationship with hypertension, which drives atherosclerosis/arteriolosclerosis, ultimately culminating in vascular dementia.

METHODS

To enable a better understanding of these sequelae of events, we investigated innate SA and its effects on cognition in adult-aged spontaneously hypertensive rats, which have a range of cardiovascular disorders: plethysmography and electroencephalographic/electromyographic recordings were used to assess sleep-wake state, breathing parameters, and sleep-disordered breathing; immunocytochemistry was used to assess vascular and neural health; the forced alteration Y maze and Barnes maze were used to assess short- and long-term memories, respectively; and an anesthetized preparation was used to assess baroreflex sensitivity.

RESULTS

Spontaneously hypertensive rats displayed a higher degree of sleep-disordered breathing, which emanates from poor vascular health leading to a loss of preBötzinger Complex neurons. These rats also display small vessel white matter disease, a form of vascular dementia, which may be exacerbated by the SA-induced neuroinflammation in the hippocampus to worsen the related deficits in both long- and short-term memories.

CONCLUSIONS

Therefore, we postulate that hypertension induces SA through vascular damage in the respiratory column, culminating in neuronal loss in the inspiratory oscillator. This induction of SA, which, in turn, will independently exacerbate hypertension and neural inflammation, increases the rate of vascular dementia.

Diabetes status and cognitive function in middle-aged and older adults in the Canadian longitudinal study on aging

Objectives

Diabetes is recognized as a significant risk factor for cognitive impairment. However, this association has not been thoroughly examined using large-scale population-based datasets in the Canadian context. The objective of this study was to investigate the potential association between cognitive function and diabetes in a large population-based sample of middle-aged and older Canadians.

Methods

We utilized baseline data from the Canadian Longitudinal Study on Aging (N=30,097) to test our hypotheses, using five indicators of cognitive function (animal fluency, Stroop interference, reaction time, immediate and delayed memory recall). We conducted multivariate multivariable linear regression and subsequently performed tests for moderation analysis with lifestyle factors and health status.

Results

The analysis revealed that type 2 diabetes (T2DM) was associated with lower performance on most cognitive tasks, including those assessing executive function (b=0.60, 95% CI 0.31 to 0.90), reaction time (b=16.94, 95% CI 9.18 to 24.70), immediate memory recall (b=-0.10, 95% CI -0.18 to -0.02), and delayed memory recall (b=-0.12, 95% CI -0.21 to -0.02). However, no significant association was observed between other types of diabetes and cognitive performance. Moderation effects were largely null for T2DM, with the exception of alcohol intake for reaction time, and physical activity for animal fluency.

Conclusions

The study showed that individuals with T2DM exhibit poor performance on tasks that assess executive function, reaction time, and memory. Therefore, optimizing cognitive health among individuals with T2DM should be a priority in primary care. Additionally, further studies should examine this association using longitudinal data.

Low- and High-Density Lipoprotein Cholesterol and Dementia Risk Over 17 Years of Follow-up Among Members of a Large Health Care Plan

BACKGROUND AND OBJECTIVES

The associations of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) with dementia risk in later life may be complex, and few studies have sufficient data to model nonlinearities or adequately adjust for statin use. We evaluated the observational associations of HDL-C and LDL-C with incident dementia in a large and well-characterized cohort with linked survey and electronic health record (EHR) data.

METHODS

Kaiser Permanente Northern California health plan members aged 55 years and older who completed a health behavior survey between 2002 and 2007, had no history of dementia before the survey, and had laboratory measurements of cholesterol within 2 years after survey completion were followed up through December 2020 for incident dementia (Alzheimer disease-related dementia [ADRD]; Alzheimer disease, vascular dementia, and/or nonspecific dementia) based on ICD-9 or ICD-10 codes in EHRs. We used Cox models for incident dementia with follow-up time beginning 2 years postsurvey (after cholesterol measurement) and censoring at end of membership, death, or end of study period. We evaluated nonlinearities using B-splines, adjusted for demographic, clinical, and survey confounders, and tested for effect modification by baseline age or prior statin use.

RESULTS

A total of 184,367 participants [mean age at survey = 69.5 years, mean HDL-C = 53.7 mg/dL (SD = 15.0), mean LDL-C = 108 mg/dL (SD = 30.6)] were included. Higher and lower HDL-C values were associated with elevated ADRD risk compared with the middle quantile: HDL-C in the lowest quintile was associated with an HR of 1.07 (95% CI 1.03-1.11), and HDL-C in the highest quintile was associated with an HR of 1.15 (95% CI 1.11-1.20). LDL-C was not associated with dementia risk overall, but statin use qualitatively modified the association. Higher LDL-C was associated with a slightly greater risk of ADRD for statin users (53% of the sample, HR per 10 mg/dL increase = 1.01, 95% CI 1.01-1.02) and a lower risk for nonusers (HR per 10 mg/dL increase = 0.98; 95% CI 0.97-0.99). There was evidence for effect modification by age with linear HDL-C (p = 0.003) but not LDL-C (p = 0.59).

DISCUSSION

Both low and high levels of HDL-C were associated with elevated dementia risk. The association between LDL-C and dementia risk was modest.

Is the association between blood pressure and cognition in the oldest-old modified by physical, vascular or brain pathology markers? The EMIF-AD 90 + Study

BACKGROUND

Prior studies suggest a changing association between blood pressure (BP) and cognition with aging, however work in the oldest-old has yielded ambiguous results. Potentially, these mixed results can be explained by modifying factors. The aim of this study was to establish whether physical, vascular or brain pathology markers that describe a state of increased vulnerability, affect the association between BP and cognition in the oldest-old. Results may influence clinicians' decisions regarding the use of antihypertensives in this age group.

METHODS

We included 122 individuals (84 without cognitive impairment and 38 with cognitive impairment) from the EMIF-AD 90 + Study (mean age 92.4 years). First, we tested cross-sectional associations of systolic and diastolic BP with a cognitive composite score. Second, we tested whether these associations were modified by physical markers (waist circumference, muscle mass, gait speed and handgrip strength), vascular markers (history of cardiac disease, carotid intima media thickness as a proxy for atherosclerosis and carotid distensibility coefficient as a proxy for arterial stiffness) or brain pathology markers (white matter hyperintensities and cortical thickness).

RESULTS

In the total sample, there was no association between BP and cognition, however, waist circumference modified this association (p-value for interaction with systolic BP: 0.03, with diastolic BP: 0.01). In individuals with a high waist circumference, higher systolic and diastolic BP tended to be associated with worse cognition, while in individuals with a low waist circumference, higher systolic BP was associated with better cognition. The others physical, vascular and brain pathology markers did not modify the association between BP and cognition.

CONCLUSIONS

When examining various markers for physical, vascular and brain vulnerability, only waist circumference affected the association between BP and cognition. This warrants further research to evaluate whether waist circumference may be a marker in clinical practice influencing the use of antihypertensives in the oldest-old.

Examining the heterogeneity by employment status in dynamics between BMI and cognition: a longitudinal cohort study of the Korean aging population

PURPOSE

This study investigated the potential heterogeneity by employment status in the relationship between body mass index (BMI) trajectory and cognitive function among an aging population.

METHODS

We analyzed 2010-2018 cohort data from the Korean Longitudinal Study of Aging involving 4889 individuals aged over 45. We used statistical techniques of quadratic terms, interaction terms, time-invariant unobserved fixed effects, and time-lag effects to estimate the dynamic and interactive relationships among study variables.

RESULTS

The effect of BMI on cognitive function was heterogeneous based on employment status. For the nonemployed group, the impact of BMI on cognitive function showed an inverted U-shape with a turning point (BMI 25); a higher BMI (up to 25) was associated with higher cognitive function, but further increases beyond this threshold led to decreased cognitive function. For the employed group, however, the impact of BMI on cognitive function was nonsignificant. The nonlinear effect of BMI on cognitive function for the nonemployed group was robust across various subgroups and specifications.

CONCLUSIONS

The findings highlight the risk of obesity (BMI ≥ 25) on cognitive decline, particularly among nonemployed individuals. This illuminates the critical role of labor activity in regulating the impact of BMI on cognitive function among an aging population.

Alzheimer's Disease in Diabetic Patients: A Lipidomic Prospect

Diabetes Mellitus (DM) and Alzheimer's disease (AD) have been two of the most common chronic diseases affecting people worldwide. Type 2 DM (T2DM) is a metabolic disease depicted by insulin resistance, dyslipidemia, and chronic hyperglycemia while AD is a neurodegenerative disease marked by Amyloid β (Aβ) accumulation, neurofibrillary tangles aggregation, and tau phosphorylation. Various clinical, epidemiological, and lipidomics studies have linked those diseases claiming shared pathological pathways raising the assumption that diabetic patients are at an increased risk of developing AD later in their lives. Insulin resistance is the tipping point beyond where advanced glycation end (AGE) products and free radicals are produced leading to oxidative stress and lipid peroxidation. Additionally, different types of lipids are playing a crucial role in the development and the relationship between those diseases. Lipidomics, an analysis of lipid structure, formation, and interactions, evidently exhibits these lipid changes and their direct and indirect effect on Aβ synthesis, insulin resistance, oxidative stress, and neuroinflammation. In this review, we have discussed the pathophysiology of T2DM and AD, the interconnecting pathological pathways they share, and the lipidomics where different lipids such as cholesterol, phospholipids, sphingolipids, and sulfolipids contribute to the underlying features of both diseases. Understanding their role can be beneficial for diagnostic purposes or introducing new drugs to counter AD.

Have We Been Underestimating Modifiable Dementia Risk? An Alternative Approach for Calculating the Combined Population Attributable Fraction for Modifiable Dementia Risk Factors

Estimating the fraction of dementia cases in a population attributable to a risk factor or combination of risk factors (the population attributable fraction (PAF)) informs the design and choice of dementia risk-reduction activities. It is directly relevant to dementia prevention policy and practice. Current methods employed widely in the dementia literature to combine PAFs for multiple dementia risk factors assume a multiplicative relationship between factors and rely on subjective criteria to develop weightings for risk factors. In this paper we present an alternative approach to calculating the PAF based on sums of individual risk. It incorporates individual risk factor interrelationships and enables a range of assumptions about the way in which multiple risk factors will combine to affect dementia risk. Applying this method to global data demonstrates that the previous estimate of 40% is potentially too conservative an estimate of modifiable dementia risk and would necessitate subadditive interaction between risk factors. We calculate a plausible conservative estimate of 55.7% (95% confidence interval: 55.2, 56.1) based on additive risk factor interaction.

Amyloid and tau pathology are associated with cerebral blood flow in a mixed sample of nondemented older adults with and without vascular risk factors for Alzheimer's disease

Identification of biomarkers for the early stages of Alzheimer's disease (AD) is an imperative step in developing effective treatments. Cerebral blood flow (CBF) is a potential early biomarker for AD; generally, older adults with AD have decreased CBF compared to normally aging peers. CBF deviates as the disease process and symptoms progress. However, further characterization of the relationships between CBF and AD risk factors and pathologies is still needed. We assessed the relationships between CBF quantified by arterial spin-labeled magnetic resonance imaging, hypertension, APOEε4, and tau and amyloid positron emission tomography in 77 older adults: cognitively normal, subjective cognitive decline, and mild cognitive impairment. Tau and amyloid aggregation were related to altered CBF, and some of these relationships were dependent on hypertension or APOEε4 status. Our findings suggest a complex relationship between risk factors, AD pathologies, and CBF that warrants future studies of CBF as a potential early biomarker for AD.

Association between Dietary Patterns and Cognitive Function among Qatari Adults: A Cross-Sectional Analysis of the Qatar Biobank Study

This study aimed to assess the association between dietary patterns and cognitive function among Qatari adults. In a cross-sectional analysis, data on 1000 Qatari adults attending the Qatar Biobank Study (QBB) aged ≥18 years were obtained. Using factor analysis, dietary patterns were constructed based on habitual dietary intake assessed by food frequency questionnaires (FFQs). The mean reaction time (MRT) derived from self-administered touch screen tests was used as an indicator of cognitive function. The association between dietary patterns and MRT was investigated using linear regression. The mean age of the participants was 35.8 (SD 10.3) years, and the mean MRT was 715.3 (SD 204.1) milliseconds. Three dietary patterns were identified. The "traditional" dietary pattern, characterized by high intakes of white rice, mixed dishes and soups/starters possibly high in saturated fat and sodium, was positively associated with MRT. In the multivariable model, comparing the highest to lowest quartiles of the traditional pattern, the regression coefficient for MRT was 50.0 (95% CI 16.9, 83.1; p for trend 0.001). There was an effect modification of diabetes and age on the association between the "modern" dietary pattern and MRT. The "convenient" dietary pattern was not associated with cognition. In conclusion, the traditional rice-based dietary pattern may be associated with poor cognitive function.

The quantity and quality of cardiovascular fat at mid-life and future cognitive performance among women: The SWAN cardiovascular fat ancillary study

INTRODUCTION

Cardiovascular fat is a novel risk factor that may link to dementia. Fat volume and radiodensity are measurements of fat quantity and quality, respectively. Importantly, high fat radiodensity could indicate healthy or adverse metabolic processes.

METHODS

The associations of cardiovascular fat (including epicardial, paracardial, and thoracic perivascular adipose tissue [PVAT]) quantity and quality assessed at mean age of 51 with subsequent cognitive performance measured repeatedly over 16 years of follow-up were examined using mixed models among 531 women.

RESULTS

Higher thoracic PVAT volume was associated with a higher future episodic memory (β[standard error (SE)] = 0.08 [0.04], P = 0.033), while higher thoracic PVAT radiodensity with lower future episodic (β[SE] = -0.06 [0.03], P = 0.045) and working (β[SE] = -0.24 [0.08], P = 0.003) memories. The latter association is prominent at higher volume of thoracic PVAT.

DISCUSSION

Mid-life thoracic PVAT may have a distinct contribution to future cognition possibly due to its distinct adipose tissue type (brown fat) and anatomical proximity to the brain circulation.

HIGHLIGHTS

Higher mid-life thoracic perivascular adipose tissue (thoracic PVAT) volume is related to a better future episodic memory in women. Higher mid-life thoracic PVAT radiodensity is related to worse future working and episodic memories. Negative association of high thoracic PVAT radiodensity with working memory is prominent at higher thoracic PVAT volume. Mid-life thoracic PVAT is linked to future memory loss, an early sign of Alzheimer's disease. Mid-life women's epicardial and paracardial fat are not related to future cognition.

Role of fruit and vegetables in sustaining healthy cognitive function: evidence and issues

Modifiable lifestyle factors, such as improved nutrition, are crucial in maintaining cognitive health in older age. Fruit and vegetables represent healthy and sustainable sources of nutrients with the potential to prevent age-related cognitive decline. The aim of this review is to synthesise the available evidence, from epidemiological and randomised controlled trials (RCT), regarding the role of fruit and vegetables in sustaining healthy cognitive function. Epidemiological studies of combined fruit and vegetable intake suggest that increased consumption may sustain cognition in later life. The evidence appears to be stronger for an association between vegetables and cognition, particularly for green leafy and cruciferous vegetables. Specific benefits shown for berries, citrus fruits, avocado and nuts suggest fruit is worthy of further investigation in relation to cognition. Data from RCT indicate benefits to differing aspects of cognition following citrus and berry fruits, cocoa and peanuts, but the data are limited and there are a lack of studies exploring effects of vegetables. There is growing evidence for an association between fruit and vegetable intake and cognitive function, but this is not always consistent and the data from RCT are limited. Issues in previous research are highlighted, such as strict exclusion criteria, absence of baseline nutritional status data and lack of consideration of individual differences, which may explain the weaker findings from RCT. Inclusion of those most at risk for cognitive decline is recommended in future nutrition and cognition research.

Associations among multidomain lifestyles, chronic diseases, and dementia in older adults: a cross-sectional analysis of a cohort study

Background

Unhealthy lifestyles and chronic diseases are commonly seen and treatable factors in older adults and are both associated with dementia. However, the synergistic effect of the interaction of lifestyles and chronic diseases on dementia is unknown.

Methods

We determined independent associations of multidomain lifestyles and chronic diseases (cerebrovascular disease, diabetes, and hypertension) with dementia and examined their synergistic impact on dementia among older adults. The data were drawn from the Hubei Memory and Aging Cohort Study. We created a summary score of six factors for multidomain lifestyles. Dementia was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders IV. Logistic regression and multiple correspondence analyses were used to explore the relationships among multidomain lifestyles, chronic diseases, and dementia. A sensitivity analysis was performed to minimize the interference of reverse causality and potential confounders.

Results

Independent associations with dementia were found in unhealthy (OR = 1.90, 95% CI: 1.38-2.61) and intermediate healthy lifestyles (OR, 3.29, 2.32-4.68), hypertension (OR, 1.21, 1.01-1.46), diabetes (OR, 1.30, 1.04-1.63), and cerebrovascular disease (OR, 1.39, 1.12-1.72). Interactions of diabetes (p = 0.004), hypertension (p = 0.004), and lifestyles were significant, suggesting a combined impact on dementia. Sensitivity analysis supported the strong association among multidomain lifestyles, chronic diseases, and dementia prevalence.

Conclusion

An unhealthy lifestyle was associated with a higher prevalence of dementia, regardless of whether the participants had chronic diseases; however, this association was stronger in individuals with chronic diseases. Multidomain lifestyles and chronic diseases may have an enhanced impact on dementia.

Cardiovascular and metabolic health is associated with functional brain connectivity in middle-aged and older adults: Results from the Human Connectome Project-Aging study

Several cardiovascular and metabolic indicators, such as cholesterol and blood pressure have been associated with altered neural and cognitive health as well as increased risk of dementia and Alzheimer's disease in later life. In this cross-sectional study, we examined how an aggregate index of cardiovascular and metabolic risk factor measures was associated with correlation-based estimates of resting-state functional connectivity (FC) across a broad adult age-span (36-90+ years) from 930 volunteers in the Human Connectome Project Aging (HCP-A). Increased (i.e., worse) aggregate cardiometabolic scores were associated with reduced FC globally, with especially strong effects in insular, medial frontal, medial parietal, and superior temporal regions. Additionally, at the network-level, FC between core brain networks, such as default-mode and cingulo-opercular, as well as dorsal attention networks, showed strong effects of cardiometabolic risk. These findings highlight the lifespan impact of cardiovascular and metabolic health on whole-brain functional integrity and how these conditions may disrupt higher-order network integrity.

CETP inhibitor evacetrapib enters mouse brain tissue

High levels of plasma cholesterol, especially high levels of low-density lipoprotein cholesterol (LDL-C), have been associated with an increased risk of Alzheimer's disease. The cholesteryl ester transfer protein (CETP) in plasma distributes cholesteryl esters between lipoproteins and increases LDL-C in plasma. Epidemiologically, decreased CETP activity has been associated with sustained cognitive performance during aging, longevity, and a lower risk of Alzheimer's disease. Thus, pharmacological CETP inhibitors could be repurposed for the treatment of Alzheimer's disease as they are safe and effective at lowering CETP activity and LDL-C. Although CETP is mostly expressed by the liver and secreted into the bloodstream, it is also expressed by astrocytes in the brain. Therefore, it is important to determine whether CETP inhibitors can enter the brain. Here, we describe the pharmacokinetic parameters of the CETP inhibitor evacetrapib in the plasma, liver, and brain tissues of CETP transgenic mice. We show that evacetrapib crosses the blood-brain barrier and is detectable in brain tissue 0.5 h after a 40 mg/kg i.v. injection in a non-linear function. We conclude that evacetrapib may prove to be a good candidate to treat CETP-mediated cholesterol dysregulation in Alzheimer's disease.

Pathogenesis of miR-155 on nonmodifiable and modifiable risk factors in Alzheimer's disease

Alzheimer's disease (AD) is a common age-related neurodegenerative disease in the central nervous system and is the primary cause of dementia. It is clinically characterized by the memory impairment, aphasia, apraxia, agnosia, visuospatial and executive dysfunction, behavioral changes, and so on. Incidence of this disease was bound up with age, genetic factors, cardiovascular and cerebrovascular dysfunction, and other basic diseases, but the exact etiology has not been clarified. MicroRNAs (miRNAs) are small endogenous non-coding RNAs that were involved in the regulation of post-transcriptional gene expression. miRNAs have been extensively studied as noninvasive potential biomarkers for disease due to their relative stability in bodily fluids. In addition, they play a significant role in the physiological and pathological processes of various neurological disorders, including stroke, AD, and Parkinson's disease. MiR-155, as an important pro-inflammatory mediator of neuroinflammation, was reported to participate in the progression of β-amyloid peptide and tau via regulating immunity and inflammation. In this review, we put emphasis on the effects of miR-155 on AD and explore the underlying biological mechanisms which could provide a novel approach for diagnosis and treatment of AD.

Examination of potentially modifiable dementia risk factors across the adult life course: The Framingham Heart Study

INTRODUCTION

We examined for associations between potentially modifiable risk factors across the adult life course and incident dementia.

METHODS

Participants from the Framingham Heart Study were included (n = 4015). Potential modifiable risk factors included education, alcohol intake, smoking, body mass index (BMI), physical activity, social network, diabetes, and hypertension. Cox models were used to examine associations between each factor and incident dementia, stratified by early adult life (33-44 years), midlife (45-65 years), and late life (66-80 years).

RESULTS

Increased dementia risk was associated with diabetes (hazard ratio [HR] = 1.62; 95% confidence interval [CI] = 1.07-2.46) and physical inactivity (HR = 1.57; 95% CI = 1.12-2.20) in midlife, and with obesity (HR = 1.76; 95% CI = 1.08-2.87) in late life. Having multiple potential modifiable risk factors in midlife and late life was associated with greater risk.

DISCUSSION

Potentially modifiable risk factors individually have limited impact on dementia risk in this population across the adult life course, although in combination they may have a synergistic effect.

HIGHLIGHTS

Diabetes and physical inactivity in midlife is associated with increased dementia risk. Obesity in late life is associated with increased dementia risk. Having more potentially modifiable risk factors in midlife and late life is associated with greater dementia risk.