Search

Majority of dementia research is conducted in non-Hispanic White participants despite a greater prevalence of dementia in other racial groups. To obtain a better understanding of biomarker presentation of Alzheimer's disease (AD) in the non-Hispanic White population, this study exclusively examined AD biomarker abnormalities in 85 Black and/or African American participants within the Alzheimer's Disease Neuroimaging Initiative (ADNI). Participants were classified by the ADNI into 3 clinical groups: cognitively normal, mild cognitive impairment, or dementia. Data examined included demographics, apolipoprotein E (APOE) ε4, cerebrospinal fluid (CSF) Aβ1-42, CSF total tau (t-tau), CSF phosphorylated tau (p-tau), 3T magnetic resonance imaging (MRI), and measures of cognition and function. Analyses of variance and covariance showed lower cortical thickness in 5 of 7 selected MRI regions, lower hippocampal volume, greater volume of white matter hyperintensities, lower measures of cognition and function, lower measures of CSF Aβ1-42, and greater measures of CSF t-tau and p-tau between clinical groups. Our findings confirmed greater AD biomarker abnormalities between clinical groups in this sample.

BackgroundIt remains unclear whether persistent loneliness is related to brain structures that are associated with cognitive decline and development of Alzheimer's disease (AD). This study aimed to investigate the relationships between different loneliness types, cognitive functioning, and regional brain volumes.MethodsLoneliness was measured longitudinally, using the item from the Center for Epidemiologic Studies Depression Scale in the Framingham Heart Study, Generation 3, with participants' average age of 46·3 ± 8·6 years. Robust regression models tested the association between different loneliness types with longitudinal neuropsychological performance (n = 2,609) and regional magnetic resonance imaging brain data (n = 1,829) (2002-2019). Results were stratified for sex, depression, and Apolipoprotein E4 (ApoE4).FindingsPersistent loneliness, but not transient loneliness, was strongly associated with cognitive decline, especially memory and executive function. Persistent loneliness was negatively associated with temporal lobe volume (β = -0.18, 95%CI [-0.32, -0.04], P = 0·01). Among women, persistent loneliness was associated with smaller frontal lobe (β = -0.19, 95%CI [-0.38, -0.01], P = 0·04), temporal lobe (β = -0.20, 95%CI [-0.37, -0.03], P = 0·02), and hippocampus volumes (β = -0.23, 95%CI [-0.40, -0.06], P = 0·007), and larger lateral ventricle volume (β = 0.15, 95%CI [0.02, 0.28], P = 0·03). The higher cumulative loneliness scores across three exams, the smaller parietal, temporal, and hippocampus volumes and larger lateral ventricle were evident, especially in the presence of ApoE4.InterpretationPersistent loneliness in midlife was associated with atrophy in brain regions responsible for memory and executive dysfunction. Interventions to reduce the chronicity of loneliness may mitigate the risk of age-related cognitive decline and AD.FundingUS National Institute on Aging.

Objective: Sex differences in the association between cardiovascular risk factors and the incident all‐cause dementia and the subtype Alzheimer's disease (AD) risk are unclear. Methods: Framingham Heart Study (FHS) participants (n = 4,171, 54% women, aged 55 to 69 years) were included at baseline and followed up to 40 years. The Framingham Stroke Risk Profile (FSRP) was dichotomized into 2 levels (cutoff: 75th percentile of the FSRP z‐scores). Cause‐specific hazard models, with death as a competing event, and restricted mean survival time (RMST) model were used to analyze the association between FSRP levels and incident all‐cause dementia and AD. Interactions between FSRP and sex were estimated, followed by a sex‐stratified analysis to examine the sex modification effect. Results: High FSRP was significantly associated with all‐cause dementia (hazard ratio [HR] = 1.25, robust 95% confidence interval [CI] = 1.21 to 1.29, p < 0.001) and AD (HR = 1.58, robust 95% CI = 1.57 to 1.59, p < 0.001) in cause‐specific hazard models. High FSRP was significantly associated with incident dementia (HR = 2.81, robust 95% CI = 2.75 to 2.87, p < 0.001) and AD (HR = 2.96, robust 95% CI = 2.36 to 3.71, p < 0.001) in women, but not in men. Results were consistent in the RMST models. Current diabetes and high systolic blood pressure as FSRP components were significantly associated with dementia and AD in women but not in men. Interpretation: High FSRP in mid‐ to early late life is a critical risk factor for all‐cause dementia and AD, particularly in women. Sex‐specific interventions and further research to elucidate underlying mechanisms are warranted. ANN NEUROL 2024;96:1124–1134 [ABSTRACT FROM AUTHOR]

INTRODUCTION: Brain magnetic resonance imaging (MRI) and inflammatory biomarkers are crucial for investigating preclinical neurocognitive disorders. Current investigations focus on a few inflammatory markers. The study aims to investigate the associations between inflammatory biomarkers and MRI measures and to examine sex differences among the associations in the Framingham Heart Study. METHODS: Dementia and stroke‐free participants underwent OLINK Proteomics profiling and MRI measurements within 5 years. Pairwise cross‐sectional analysis assessed 68 biomarkers with 13 brain MRI volumes, adjusting for covariates and familial correlations. RESULTS: Elevated CDCP1, IL6, OPG, and 4E.BP1 were related to smaller total cerebral brain volume (TCBV), whereas higher HGF, IL8, and MMP10 were associated with smaller TCBV, total and frontal white matter volumes. Higher SCF and TWEAK were associated with larger TCBV. In sex‐stratified analyses, associations were observed exclusively among males. DISCUSSION: We report several associations between inflammatory biomarkers and brain volumes, highlighting different associations within sex subgroups. Highlights: Higher CDCP1, IL6, OPG, and 4E.BP1 levels were associated with smaller TCBV.Higher levels of HGF, IL8 and MMP10 were associated with smaller TCBV, CWV and FWV.Higher levels of SCF and TWEAK, were associated with larger TCBV.Significance diminished in models adjusting for CVD risk factors.Associations were observed exclusively in males. [ABSTRACT FROM AUTHOR]

This cohort study investigates the risk of mild cognitive impairment, Alzheimer disease, and all-cause dementia associated with subjective cognitive decline using the subjective cognitive decline–plus criteria among cognitively normal adults in the community. Key Points: Question: Among cognitively normal adults in the community, what is the risk from subjective cognitive decline (SCD), using SCD-plus (SCD+) criteria and assessed longitudinally, associated with mild cognitive impairment (MCI), Alzheimer disease (AD), and all-cause dementia? Findings: In this cohort study using longitudinal data from the Framingham Heart Study including 3585 participants, SCD+ was significantly associated with survival time to MCI, AD, and all-cause dementia. Associations were independent of APOE status and an AD polygenic risk score. Meaning: In a community setting, SCD+ was associated with an increased risk of future MCI, AD, and all-cause dementia with similar hazards estimated in clinic-based settings. Importance: Subjective cognitive decline (SCD) is recognized to be in the Alzheimer disease (AD) cognitive continuum. The SCD Initiative International Working Group recently proposed SCD-plus (SCD+) features that increase risk for future objective cognitive decline but that have not been assessed in a large community-based setting. Objective: To assess SCD risk for mild cognitive impairment (MCI), AD, and all-cause dementia, using SCD+ criteria among cognitively normal adults. Design, Setting, and Participants: The Framingham Heart Study, a community-based prospective cohort study, assessed SCD between 2005 and 2019, with up to 12 years of follow-up. Participants 60 years and older with normal cognition at analytic baseline were included. Cox proportional hazards (CPH) models were adjusted for baseline age, sex, education, APOE ε4 status, and tertiles of AD polygenic risk score (PRS), excluding the APOE region. Data were analyzed from May 2021 to November 2023. Exposure: SCD was assessed longitudinally using a single question and considered present if endorsed at the last cognitively normal visit. It was treated as a time-varying variable, beginning at the first of consecutive, cognitively normal visits, including the last, at which it was endorsed. Main Outcomes and Measures: Consensus-diagnosed MCI, AD, and all-cause dementia. Results: This study included 3585 participants (mean [SD] baseline age, 68.0 [7.7] years; 1975 female [55.1%]). A total of 1596 participants (44.5%) had SCD, and 770 (21.5%) were carriers of APOE ε4. APOE ε4 and tertiles of AD PRS status did not significantly differ between the SCD and non-SCD groups. MCI, AD, and all-cause dementia were diagnosed in 236 participants (6.6%), 73 participants (2.0%), and 89 participants (2.5%), respectively, during follow-up. On average, SCD preceded MCI by 4.4 years, AD by 6.8 years, and all-cause dementia by 6.9 years. SCD was significantly associated with survival time to MCI (hazard ratio [HR], 1.57; 95% CI, 1.22-2.03; P <.001), AD (HR, 2.98; 95% CI, 1.89-4.70; P <.001), and all-cause dementia (HR, 2.14; 95% CI, 1.44-3.18; P <.001). After adjustment for APOE and AD PRS, the hazards of SCD were largely unchanged. Conclusions and Relevance: Results of this cohort study suggest that in a community setting, SCD reflecting SCD+ features was associated with an increased risk of future MCI, AD, and all-cause dementia with similar hazards estimated in clinic-based settings. SCD may be an independent risk factor for AD and other dementias beyond the risk incurred by APOE ε4 and AD PRS. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Type 2 diabetes and glucose metabolism have previously been linked to Alzheimer disease (AD). Yet, findings on the relation of glucose metabolism with amyloid-β and tau pathology later in life remain unclear. RESEARCH DESIGN AND METHODS: We included 288 participants (mean age 43.1 years, SD 10.7, range 20–70 years) without dementia, from the Framingham Heart Study, who had available measures of glucose metabolism (i.e., one-time fasting plasma glucose and insulin) and positron emission tomography (PET) measures of amyloid-β and/or tau 14 years later. We performed linear regression analyses to test associations of plasma glucose (continuously and categorically; elevated defined as >100 mg/dL), plasma insulin, homeostatic model assessment for insulin resistance (HOMA-IR) with amyloid-β or tau load on PET. When significant, we explored whether age, sex, and APOE ε4 allele carriership (AD genetic risk) modified these associations. RESULTS: Our findings indicated that elevated plasma glucose was associated with greater tau load 14 years later (B [95% CI] = 0.03 [0.01–0.05], P = 0.024 after false discovery rate [FDR] correction) but not amyloid-β. APOE ε4 carriership modified this association (B [95% CI] = −0.08 [−0.12 to −0.03], P = 0.001), indicating that the association was only present in APOE ε4 noncarriers (n = 225). Plasma insulin and HOMA-IR were not associated with amyloid-β or tau load 14 years later after FDR correction. CONCLUSIONS: Our findings suggest that glucose metabolism is associated with increased future tau but not amyloid-β load. This provides relevant knowledge for prevention strategies and prognostics to improve health care. [ABSTRACT FROM AUTHOR]

Background: Although cerebrospinal fluid (CSF) amyloid-β42 peptide (Aβ42) and phosphorylated tau (p-tau) and blood p-tau are valuable for differential diagnosis of Alzheimer's disease (AD) from cognitively normal (CN) there is a lack of validated biomarkers for mild cognitive impairment (MCI). Objective: This study sought to determine how plasma and CSF protein markers compared in the characterization of MCI and AD status. Methods: This cohort study included Alzheimer's Disease Neuroimaging Initiative (ADNI) participants who had baseline levels of 75 proteins measured commonly in plasma and CSF (257 total, 46 CN, 143 MCI, and 68 AD). Logistic regression, least absolute shrinkage and selection operator (LASSO) and Random Forest (RF) methods were used to identify the protein candidates for the disease classification. Results: We observed that six plasma proteins panel (APOE, AMBP, C3, IL16, IGFBP2, APOD) outperformed the seven CSF proteins panel (VEGFA, HGF, PRL, FABP3, FGF4, CD40, RETN) as well as AD markers (CSF p-tau and Aβ42) to distinguish the MCI from AD [area under the curve (AUC) = 0.75 (plasma proteins), AUC = 0.60 (CSF proteins) and AUC = 0.56 (CSF p-tau and Aβ42)]. Also, these six plasma proteins performed better than the CSF proteins and were in line with CSF p-tau and Aβ42 in differentiating CN versus MCI subjects [AUC = 0.89 (plasma proteins), AUC = 0.85 (CSF proteins) and AUC = 0.89 (CSF p-tau and Aβ42)]. These results were adjusted for age, sex, education, and APOEϵ4 genotype. Conclusions: This study suggests that the combination of 6 plasma proteins can serve as an effective marker for differentiating MCI from AD and CN. [ABSTRACT FROM AUTHOR]

Background: Cerebral microbleeds (CMB) increase the risk for Alzheimer disease. Current neuroimaging methods that are used to detect CMB are costly and not always accessible. Objective: This study aimed to explore whether the digital clock-drawing test (DCT) may provide a behavioral indicator of CMB. Methods: In this study, we analyzed data from participants in the Framingham Heart Study offspring cohort who underwent both brain magnetic resonance imaging scans (Siemens 1.5T, Siemens Healthcare Private Limited; T2*-GRE weighted sequences) for CMB diagnosis and the DCT as a predictor. Additionally, paper-based clock-drawing tests were also collected during the DCT. Individuals with a history of dementia or stroke were excluded. Robust multivariable linear regression models were used to examine the association between DCT facet scores with CMB prevalence, adjusting for relevant covariates. Receiver operating characteristic (ROC) curve analyses were used to evaluate DCT facet scores as predictors of CMB prevalence. Sensitivity analyses were conducted by further including participants with stroke and dementia. Results: The study sample consisted of 1020 (n=585, 57.35% female) individuals aged 45 years and older (mean 72, SD 7.9 years). Among them, 64 (6.27%) participants exhibited CMB, comprising 46 with lobar-only, 11 with deep-only, and 7 with mixed (lobar+deep) CMB. Individuals with CMB tended to be older and had a higher prevalence of mild cognitive impairment and higher white matter hyperintensities compared to those without CMB (P <.05). While CMB were not associated with the paper-based clock-drawing test, participants with CMB had a lower overall DCT score (CMB: mean 68, SD 23 vs non-CMB: mean 76, SD 20; P =.009) in the univariate comparison. In the robust multiple regression model adjusted for covariates, deep CMB were significantly associated with lower scores on the drawing efficiency (β=–0.65, 95% CI –1.15 to –0.15; P =.01) and simple motor (β=–0.86, 95% CI –1.43 to –0.30; P =.003) domains of the command DCT. In the ROC curve analysis, DCT facets discriminated between no CMB and the CMB subtypes. The area under the ROC curve was 0.76 (95% CI 0.69-0.83) for lobar CMB, 0.88 (95% CI 0.78-0.98) for deep CMB, and 0.98 (95% CI 0.96-1.00) for mixed CMB, where the area under the ROC curve value nearing 1 indicated an accurate model. Conclusions: The study indicates a significant association between CMB, especially deep and mixed types, and reduced performance in drawing efficiency and motor skills as assessed by the DCT. This highlights the potential of the DCT for early detection of CMB and their subtypes, providing a reliable alternative for cognitive assessment and making it a valuable tool for primary care screening before neuroimaging referral. [ABSTRACT FROM AUTHOR]

Background: Subjective cognitive decline (SCD) is recognized to be in the Alzheimer's disease (AD) cognitive continuum. An international working group known as the SCD‐initiative recently proposed "SCD plus" features, including report of memory problems, recent SCD relative to conversion, SCD over age 60, and consistent SCD over time, that increase the risk for future objective cognitive decline. These have not been fully assessed in a large community‐based setting. Method: Participants from all cohorts of the Framingham Heart Study who were ≥ 60 years with normal cognition at analytic baseline were included. SCD was assessed longitudinally using a single question. We treated SCD as a time‐varying variable and considered SCD to be present if it was endorsed at the last cognitively normal visit. If SCD was endorsed during two or more consecutive visits, including the last valid visit, it was considered to begin at the first of the consecutive visits. Outcomes included consensus‐diagnosed mild cognitive impairment (MCI), AD, and all‐cause dementia. Survival analyses were performed on time‐to‐event data obtained between 2005 and 2019 with up to 12 years of follow‐up. Models were adjusted for baseline age, sex, education, APOE ε4 status, and tertiles of AD polygenic risk score (PRS) excluding the APOE region. Result: 3,735 participants (mean baseline age: 68.0 years, women: 55.1%, non‐Hispanic Whites: 91.6%, SCD: 44.5%, APOEε4 carriers: 21.5%) were included. On average, SCD preceded MCI by 4.4 years, AD by 6.8 years, and all‐cause dementia by 6.9 years. APOEε4 and tertiles of AD PRS status did not significantly differ between SCD and non‐SCD groups. SCD was significantly associated with survival time to MCI (HR = 1.57; 95% CI = 1.22−2.03; P = 4.79×10−4), AD (HR = 2.98; 95% CI = 1.89−4.70; P = 2.80×10−6), and all‐cause dementia (HR = 2.14; 95% CI = 1.44−3.18; P = 1.82×10−4). After adjustment for APOE and AD PRS, the effects of SCD were largely unchanged. Conclusion: In a community setting, SCD reflecting "SCD plus" features increased the risk of future MCI, AD, and all‐cause dementia with about the same HR estimated in clinic‐based settings. SCD may be an independent clinically expressed risk factor for preclinical AD and other dementias beyond the risk incurred by APOEε4 and AD PRS. [ABSTRACT FROM AUTHOR]

Inflammatory protein biomarkers induced by immune responses have been associated with cognitive decline and the pathogenesis of Alzheimer's disease (AD). Here, we investigate associations between a panel of inflammatory biomarkers and cognitive function and incident dementia outcomes in the well‐characterized Framingham Heart Study Offspring cohort. Participants aged ≥40 years and dementia‐free at Exam 7 who had a stored plasma sample were selected for profiling using the OLINK proteomics inflammation panel. Cross‐sectional associations of the biomarkers with cognitive domain scores (N = 708, 53% female, 22% apolipoprotein E (APOE) ε4 carriers, 15% APOE ε2 carriers, mean age 61) and incident all‐cause and AD dementia during up to 20 years of follow‐up were tested. APOE genotype‐stratified analyses were performed to explore effect modification. Higher levels of 12 and 3 proteins were associated with worse executive function and language domain factor scores, respectively. Several proteins were associated with more than one cognitive domain, including IL10, LIF‐R, TWEAK, CCL19, IL‐17C, MCP‐4, and TGF‐alpha. Stratified analyses suggested differential effects between APOE ε2 and ε4 carriers: most ε4 carrier associations were with executive function and memory domains, whereas most ε2 associations were with the visuospatial domain. Higher levels of TNFB and CDCP1 were associated with higher risks of incident all‐cause and AD dementia. Our study found that TWEAK concentration was associated both with cognitive function and risks for AD dementia. The association of these inflammatory biomarkers with cognitive function and incident dementia may contribute to the discovery of therapeutic interventions for the prevention and treatment of cognitive decline. [ABSTRACT FROM AUTHOR]

Background: Previously, we found that elevated blood C‐reactive protein (CRP) increased the impact of the apolipoprotein ε4 allele (APOE ε4) on the risk of Alzheimer's disease (AD).1 In this study, we hypothesized that interactions between CRP and other AD‐associated genes also increase AD risk. Method: SNPs in 10 AD risk loci, which also encode proteins related to inflammation, were used to test interaction with CRP on AD risk using additive model or dominant model with Cox proportional hazards regression and survival analysis. Result: There were 279,176 UKBB white participants with average age (mean±SD) 60.1 ± 5.5 years including 53.9% females and 803 (0.3%) incident AD cases among 8.3 ± 0.9 years follow‐up on average. We found that for higher concentrations of serum CRP, the AD risk increased for SNP genotypes in 3 AD associated genes (SPI1, CD33 and CLU). Using Cox proportional hazards model in stratified genotype analysis, the hazard ratios (HR) for the association between higher CRP level (≥ 10 vs < 10 mg/L) and the risk of incident AD were 1.94 (95% CI: 1.33‐2.84, p<0.001) among SPI1 rs1057233‐AA genotype, 1.75 (95% CI: 1.20‐2.55, p = 0.004) for CD33 rs3865444‐CC genotype, and 1.76 (95% CI: 1.25‐2.48, p = 0.001) for CLU rs9331896‐CC+CT genotype, respectively. All models adjusted for age at baseline, sex, years of education, APOE ε4 and population principal components. In contrast, these associations were not observed in the other genotypes of these genes. Similar results for SPI1 and CD33 genotypes impacted by elevated CRP levels were observed for MCI to AD conversion and CSF AD biomarkers including t‐Tau and p‐Tau in the ADNI cohort (p<0.01). Conclusion: Elevated blood CRP released in peripheral inflammation may be an important mediator in the association of genetic variants in SPI1, CD33 and CLU in addition to APOE ε4 for AD risk. Monitoring of CRP levels may be useful for more precise intervention and prevention of AD for these genotype carriers. 1. Tao Q, Ang TFA, DeCarli C, et al. Association of Chronic Low‐grade Inflammation With Risk of Alzheimer Disease in ApoE4 Carriers. JAMA Netw Open. Oct 5 2018;1(6):e183597. https://doi.org/10.1001/jamanetworkopen.2018.3597 [ABSTRACT FROM AUTHOR]

Introduction: C‐Reactive protein (CRP) and monocyte chemoattractant protein‐1 (MCP‐1) are both implicated in the peripheral proinflammatory cascade and blood‒brain barrier (BBB) disruption. Since the blood CRP level increases Alzheimer's disease (AD) risk depending on the apolipoprotein E (APOE) genotype, we hypothesized that the blood MCP‐1 level exerts different effects on the AD risk depending on the genotypes. Methods: Using multiple regression analyses, data from the Framingham Heart Study (n = 2884) and Alzheimer's Disease Neuroimaging Initiative study (n = 231) were analyzed. Results: An elevated blood MCP‐1 level was associated with AD risk in major histocompatibility complex, Class II, DR beta 1 (HLA‐DRB1) rs9271192‐AC/CC (hazard ratio [HR] = 3.07, 95% confidence interval [CI] = 1.50–6.28, p = 0.002) and in APOE ε4 carriers (HR = 3.22, 95% CI = 1.59–6.53, p = 0.001). In contrast, among HLA‐DRB1 rs9271192‐AA and APOE ε4 noncarriers, blood MCP‐1 levels were not associated with these phenotypes. Discussion: Since HLA‐DRB1 and APOE are expressed in the BBB, blood MCP‐1 released in the peripheral inflammatory cascade may function as a mediator of the effects of HLA‐DRB1 rs9271192‐AC/CC and APOE ε4 genotypes on AD pathogenesis in the brain via the BBB pathways. [ABSTRACT FROM AUTHOR]