CAIDE Score, Alzheimer's Disease Pathology, and Cognition in Cognitively Normal Adults: The CABLE Study.

Background: Cardiovascular Risk Factors, Ageing and Dementia (CAIDE) risk score serves as a credible predictor of an individual's risk of dementia. However, studies on the link of the CAIDE score to Alzheimer's disease (AD) pathology are scarce. Objective: To explore the links of CAIDE score to cerebrospinal fluid (CSF) biomarkers of AD as well as to cognitive performance. Methods: In the Chinese Alzheimer's Biomarker and LifestylE (CABLE) study, we recruited 600 cognitively normal participants. Correlations between the CAIDE score and CSF biomarkers of AD as well as cognitive performance were probed through multiple linear regression models. Whether the correlation between CAIDE score and cognitive performance was mediated by AD pathology was researched by means of mediation analyses. Results: Linear regression analyses illustrated that CAIDE score was positively associated with tau-related biomarkers, including pTau (p <  0.001), tTau (p <  0.001), as well as tTau/Aß42 (p = 0.008), while it was in negative association with cognitive scores, consisting of MMSE score (p <  0.001) as well as MoCA score (p <  0.001). The correlation from CAIDE score to cognitive scores was in part mediated by tau pathology, with a mediation rate varying from 3.2% to 13.2% . Conclusions: A higher CAIDE score, as demonstrated in our study, was linked to more severe tau pathology and poorer cognitive performance, and tau pathology mediated the link of CAIDE score to cognitive performance. Increased dementia risk will lead to cognitive decline through aggravating neurodegeneration.

Associations of sleep disorders with serum neurofilament light chain levels in Parkinson's disease.

BACKGROUND: Sleep disorders are a prevalent non-motor symptom of Parkinson's disease (PD), although reliable biological markers are presently lacking. OBJECTIVES: To explore the associations between sleep disorders and serum neurofilament light chain (NfL) levels in individuals with prodromal and early PD. METHODS: The study contained 1113 participants, including 585 early PD individuals, 353 prodromal PD individuals, and 175 healthy controls (HCs). The correlations between sleep disorders (including rapid eye movement sleep behavior disorder (RBD) and excessive daytime sleepiness (EDS)) and serum NfL levels were researched using multiple linear regression models and linear mixed-effects models. We further investigated the correlations between the rates of changes in daytime sleepiness and serum NfL levels using multiple linear regression models. RESULTS: In baseline analysis, early and prodromal PD individuals who manifested specific behaviors of RBD showed significantly higher levels of serum NfL. Specifically, early PD individuals who experienced nocturnal dream behaviors (ß = 0.033; P = 0.042) and movements of arms or legs during sleep (ß = 0.027; P = 0.049) showed significantly higher serum NfL levels. For prodromal PD individuals, serum NfL levels were significantly higher in individuals suffering from disturbed sleep (ß = 0.038; P = 0.026). Our longitudinal findings support these baseline associations. Serum NfL levels showed an upward trend in early PD individuals who had a higher total RBDSQ score (ß = 0.002; P = 0.011) or who were considered as probable RBD (ß = 0.012; P = 0.009) or who exhibited behaviors on several sub-items of the RBDSQ. In addition, early PD individuals who had a high total ESS score (ß = 0.001; P = 0.012) or who were regarded to have EDS (ß = 0.013; P = 0.007) or who exhibited daytime sleepiness in several conditions had a trend toward higher serum NfL levels. CONCLUSION: Sleep disorders correlate with higher serum NfL, suggesting a link to PD neuronal damage. Early identification of sleep disorders and NfL monitoring are pivotal in detecting at-risk PD patients promptly, allowing for timely intervention. Regular monitoring of NfL levels holds promise for tracking both sleep disorders and disease progression, potentially emerging as a biomarker for evaluating treatment outcomes.

Echocardiographic measures of the left heart and cerebrospinal fluid biomarkers of Alzheimer's disease pathology in cognitively intact adults: The CABLE study.

INTRODUCTION: This study delineated the interrelationships between subclinical alterations in the left heart, cerebrospinal fluid (CSF), Alzheimer's disease (AD) biomarkers, and cognition. METHODS: Multiple linear regressions were conducted in 1244 cognitively normal participants (mean age = 65.5; 43% female) who underwent echocardiography (left atrial [LA] and left ventricular [LV] morphologic or functional parameters) and CSF AD biomarkers measurements. Mediating effects of AD pathologies were examined. Differences in cardiac parameters across ATN categories were tested using analysis of variance (ANOVA) and logistic regressions. RESULTS: LA or LV enlargement (characterized by increased diameters and volumes) and LV hypertrophy (increased interventricular septal or posterior wall thickness and ventricular mass) were associated with higher CSF phosphorylated (p)-tau and total (t)-tau levels, and poorer cognition. Tau pathologies mediated the heart-cognition relationships. Cardiac parameters were higher in stage 2 and suspected non-Alzheimer's pathology groups than controls. DISCUSSION: These findings suggested close associations of subclinical cardiac changes with tau pathologies and cognition. HIGHLIGHTS: Various subclinical alterations in the left heart related to poorer cognition. Subclinical cardiac changes related to tau pathologies in cognitively normal adults. Tau pathologies mediated the heart-cognition relationships. Subclinical cardiac changes related to the AD continuum, especially to stage 2. The accumulation of cardiac alterations magnified their damage to the brain.

Total Tau Protein Mediates the Association of Ischemic Cerebrovascular Disease with Cognitive Decline.

Background: Patients with transient ischemic attack (TIA) or ischemic stroke demonstrate an increased risk of cognitive dysfunction. Accumulating evidence indicates that ischemic cerebrovascular disease (ICVD) may interact with the amyloid/tau/neurodegeneration (AT[N]) biomarkers to promote dementia. However, the precise pathological mechanisms remain to be fully characterized. Objective: To elucidate the interrelationships among ICVD, ATN biomarkers in cerebrospinal fluid (CSF), and cognition. Methods: A total of 2524 participants were recruited from the CABLE study. ICVD referred to TIA/ischemic stroke. Cognitive performance was assessed by China Modified Mini-Mental State Examination (CM-MMSE) and Montreal Cognitive Assessment-b (MoCA-b). Multivariate linear regression analyses were performed to evaluate the associations of ICVD with CSF ATN biomarkers and cognition. Causal mediation analyses were used to identify whether the association was mediated by ATN biomarkers. Results: ICVD was associated with higher total-tau (t-tau) (p = 2.828×10-2) and poorer cognition (CM-MMSE: p = 1.539×10-5, MoCA-b: p = 4.552×10-6). Additionally, no discernible correlation surfaced between ICVD and amyloid-ß (Aß) 42 (p = 6.910×10-1) or phosphorylated tau (p-tau) (p = 4.324×10-1). The influence of ICVD on cognitive function was partially mediated by CSF t-tau (CM-MMSE: proportion: 2.74%, MoCA-b: proportion: 2.51%). Subgroup analyses revealed the influences of t-tau were especially evident in male (CM-MMSE: proportion: 5.45%, MoCA-b: proportion: 5.38%) and mid-life group (CM-MMSE: proportion: 9.83%, MoCA-b: proportion: 5.31%). Conclusions: These results delineated t-tau as a potential mediator for the influence of ICVD on cognition. Targeting brain ischemia and alleviating neuronal injury induced by ischemia may be a promising approach for preventing cognitive decline.

Associations of Frailty with Neuropsychiatric Symptoms of Alzheimer's Disease: A Longitudinal Study.

Background: Frailty is a vulnerability state increasing the risk of many adverse health outcomes, but little is known about the effects of frailty on neuropsychiatric health. Objective: To explore the associations between frailty and the risk of neuropsychiatric symptoms (NPSs) in Alzheimer's disease (AD), especially in its different clinical stages. Methods: We included 2,155 individuals assessed using modified frailty index-11 (mFI-11), Neuropsychiatric Inventory (NPI) and Neuropsychiatric Inventory Questionnaire (NPI-Q) in the Alzheimer's Disease Neuroimaging Initiative (ADNI). The relationships between frailty and NPSs were explored with logistic regression models and Cox proportional hazard regression models. Causal mediation analyses were conducted to explore the mediation factors between frailty and NPSs. Results: Among mild cognitive impairment (MCI) participants, frailty was cross-sectionally associated with an increased risk of apathy, and longitudinally associated with increased risk of depression and apathy. Among AD participants, frailty was cross-sectionally associated with increased risk of depression and anxiety, and longitudinally associated with an increased risk of apathy. Among participants with cognitive progression, frailty was associated with increased risk of depression and apathy. In MCI participants, the influence of frailty on NPSs was partially mediated by hippocampus volume, whole brain volume, and monocytes, with mediating proportions ranging from 8.40% to 9.29%. Conclusions: Frailty was associated with NPSs such as depression, anxiety, and apathy among MCI, AD, and cognitive progression participants. Atrophy of the hippocampus and whole brain, as well as peripheral immunity may be involved in the potential mechanisms underlying the above associations.

Amyloid pathology mediates the associations between plasma fibrinogen and cognition in non-demented adults.

Though previous studies revealed the potential associations of elevated levels of plasma fibrinogen with dementia, there is still limited understanding regarding the influence of Alzheimer's disease (AD) biomarkers on these associations. We sought to investigate the interrelationships among fibrinogen, cerebrospinal fluid (CSF) AD biomarkers, and cognition in non-demented adults. We included 1996 non-demented adults from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) study and 337 from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. The associations of fibrinogen with AD biomarkers and cognition were explored using multiple linear regression models. The mediation analyses with 10 000 bootstrapped iterations were conducted to explore the mediating effects of AD biomarkers on cognition. In addition, interaction analyses and subgroup analyses were conducted to assess the influence of covariates on the relationships between fibrinogen and AD biomarkers. Participants exhibiting low Aß42 were designated as A+, while those demonstrating high phosphorylated tau (P-tau) and total tau (Tau) were labeled as T+ and N+, respectively. Individuals with normal measures of Aß42 and P-tau were categorized as the A-T- group, and those with abnormal levels of both Aß42 and P-tau were grouped under A+T+. Fibrinogen was higher in the A+ subgroup compared to that in the A- subgroup (p = 0.026). Fibrinogen was higher in the A+T+ subgroup compared to that in the A-T- subgroup (p = 0.011). Higher fibrinogen was associated with worse cognition and Aß pathology (all p < 0.05). Additionally, the associations between fibrinogen and cognition were partially mediated by Aß pathology (mediation proportion range 8%-28%). Interaction analyses and subgroup analyses showed that age and ApoE ε4 affect the relationships between fibrinogen and Aß pathology. Fibrinogen was associated with both cognition and Aß pathology. Aß pathology may be a critical mediator for impacts of fibrinogen on cognition.

ANU-ADRI scores, tau pathology, and cognition in non-demented adults: the CABLE study.

BACKGROUND: It has been reported that the risk of Alzheimer's disease (AD) could be predicted by the Australian National University Alzheimer Disease Risk Index (ANU-ADRI) scores. However, among non-demented Chinese adults, the correlations of ANU-ADRI scores with cerebrospinal fluid (CSF) core biomarkers and cognition remain unclear. METHODS: Individuals from the Chinese Alzheimer's Biomarker and LifestyLE (CABLE) study were grouped into three groups (low/intermediate/high risk groups) based on their ANU-ADRI scores. The multiple linear regression models were conducted to investigate the correlations of ANU-ADRI scores with several biomarkers of AD pathology. Mediation model and structural equation model (SEM) were conducted to investigate the mediators of the correlation between ANU-ADRI scores and cognition. RESULTS: A total of 1078 non-demented elders were included in our study, with a mean age of 62.58 (standard deviation [SD] 10.06) years as well as a female proportion of 44.16% (n = 476). ANU-ADRI scores were found to be significantly related with MMSE (ß = -0.264, P < 0.001) and MoCA (ß = -0.393, P < 0.001), as well as CSF t-tau (ß = 0.236, P < 0.001), p-tau (ß = 0.183, P < 0.001), and t-tau/Aß42 (ß = 0.094, P = 0.005). Mediation analyses indicated that the relationships of ANU-ADRI scores with cognitive scores were mediated by CSF t-tau or p-tau (mediating proportions ranging from 4.45% to 10.50%). SEM did not reveal that ANU-ADRI scores affected cognition by tau-related pathology and level of CSF soluble triggering receptor expressed on myeloid cells 2 (sTREM2). CONCLUSION: ANU-ADRI scores were associated with cognition and tau pathology. We also revealed a potential pathological mechanism underlying the impact of ANU-ADRI scores on cognition.

Predicting the reversion from mild cognitive impairment to normal cognition based on magnetic resonance imaging, clinical, and neuropsychological examinations.

BACKGROUND: Reversion from mild cognitive impairment (MCI) to normal cognition (NC) is not uncommon and indicates a better cognitive trajectory. This study aims to identify predictors of MCI reversion and develop a predicting model. METHOD: A total of 391 MCI subjects (mean age = 74.3 years, female = 61 %) who had baseline data of magnetic resonance imaging, clinical, and neuropsychological measurements were followed for two years. Multivariate logistic analyses were used to identify the predictors of MCI reversion after adjusting for age and sex. A stepwise backward logistic regression model was used to construct a predictive nomogram for MCI reversion. The nomogram was validated by internal bootstrapping and in an independent cohort. RESULT: In the training cohort, the 2-year reversion rate was 19.95 %. Predictors associated with reversion to NC were higher education level (p = 0.004), absence of APOE4 allele (p = 0.001), larger brain volume (p < 0.005), better neuropsychological measurements performance (p < 0.001), higher glomerular filtration rate (p = 0.035), and lower mean arterial pressure (p = 0.060). The nomogram incorporating five predictors (education, hippocampus volume, the Alzheimer's Disease Assessment Scale-Cognitive score, the Rey Auditory Verbal Learning Test-immediate score, and mean arterial pressure) achieved good C-indexes of 0.892 (95 % confidence interval [CI], 0.859-0.926) and 0.806 (95 % CI, 0.709-0.902) for the training and validation cohort. LIMITATION: Observational duration is relatively short; The predicting model warrant further validation in larger samples. CONCLUSION: This prediction model could facilitate risk stratification and early management for the MCI population.

Association of peripheral immunity and cerebral small vessel disease in older adults without dementia: A longitudinal study.

This study explored the associations between peripheral immunity with cerebral small vessel diseases. Older adults without dementia from the Alzheimer's Disease Neuroimaging Initiative were investigated. Peripheral blood was obtained, and magnetic resonance imaging was performed to measure cerebral microbleeds (CMB), lacunar infarctions (LI), and white matter hyperintensities (WMH). Multivariable-adjusted regression models, linear mixed-effects models, and the Spearman correlations were used to evaluate the associations. At baseline, individuals with greater neutrophils (odds ratio [OR] =1.10, 95% confidence interval [CI] 1.00-1.20, p=0.042) and monocytes (OR=1.12, 95% CI 1.02-1.22, p=0.016) had higher WMH volume. On the contrary, a higher lymphocyte-to-monocyte ratio (LMR) was related to lower WMH volume (OR=0.91, 95% CI 0.82-1.00, p=0.041). Longitudinally, higher neutrophils (ρ=0.084, p=0.049) and NLR (ρ=0.111, p=0.009) predicted accelerated progression of WMH volume, while a greater LMR (ρ=-0.101, p=0.018) was linked to slower growth of WMH volume. Nevertheless, associations between peripheral immunity with CMB or LI were not observed at baseline and follow-up. Our study found that peripheral immune indexes could serve as convenient noninvasive biomarkers of WMH.

Associations between cardiometabolic multimorbidity and cerebrospinal fluid biomarkers of Alzheimer's disease pathology in cognitively intact adults: the CABLE study.

BACKGROUND: Cardiometabolic multimorbidity is associated with an increased risk of dementia, but the pathogenic mechanisms linking them remain largely undefined. We aimed to assess the associations of cardiometabolic multimorbidity with cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) pathology to enhance our understanding of the underlying mechanisms linking cardiometabolic multimorbidity and AD. METHODS: This study included 1464 cognitively intact participants from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) database. Cardiometabolic diseases (CMD) are a group of interrelated disorders such as hypertension, diabetes, heart diseases (HD), and stroke. Based on the CMD status, participants were categorized as CMD-free, single CMD, or CMD multimorbidity. CMD multimorbidity is defined as the coexistence of two or more CMDs. The associations of cardiometabolic multimorbidity and CSF biomarkers were examined using multivariable linear regression models with demographic characteristics, the APOE ε4 allele, and lifestyle factors as covariates. Subgroup analyses stratified by age, sex, and APOE ε4 status were also performed. RESULTS: A total of 1464 individuals (mean age, 61.80 years; age range, 40-89 years) were included. The markers of phosphorylated tau-related processes (CSF P-tau181: ß = 0.165, P = 0.037) and neuronal injury (CSF T-tau: ß = 0.065, P = 0.033) were significantly increased in subjects with CMD multimorbidity (versus CMD-free), but not in those with single CMD. The association between CMD multimorbidity with CSF T-tau levels remained significant after controlling for Aß42 levels. Additionally, significantly elevated tau-related biomarkers were observed in patients with specific CMD combinations (i.e., hypertension and diabetes, hypertension and HD), especially in long disease courses. CONCLUSIONS: The presence of cardiometabolic multimorbidity was associated with tau phosphorylation and neuronal injury in cognitively normal populations. CMD multimorbidity might be a potential independent target to alleviate tau-related pathologies that can cause cognitive impairment.

Associations of Growth-Associated Protein 43 with Cerebral Microbleeds: A Longitudinal Study.

Background: Cerebral microbleeds (CMB) play an important role in neurodegenerative pathology. Objective: The present study aims to test whether cerebrospinal fluid (CSF) growth-associated protein 43 (GAP-43) level is linked to CMBs in elderly people. Methods: A total of 750 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) who had measurements of GAP-43 and CMBs were included in the study. According to the presence and extent of CMBs, participants were stratified into different groups. Regression analyses were used to assess cross-sectional and longitudinal associations between GAP-43 and CMBs. Results: Participants with CMB were slightly older and had higher concentrations of CSF GAP43. In multivariable adjusted analyses for age, gender, APOEɛ4 status, and cognitive diagnoses, higher CSF GAP-43 concentrations were modestly associated with CMB presence (OR = 1.169, 95% CI = 1.001-1.365) and number (ß= 0.020, SE = 0.009, p = 0.027). Similarly, higher CSF GAP43 concentrations were accrual of CMB lesions, associated with higher CMB progression (OR = 1.231, 95% CI = 1.044-1.448) and number (ß= 0.017, SE = 0.005, p = 0.001) in the follow up scan. In stratified analyses, slightly stronger associations were noted in male participants, those 65 years and older, carriers of APOEɛ4 alleles, and with more advanced cognitive disorders. Conclusions: CSF GAP-43 was cross-sectionally associated with the presence and extent of CMBs. GAP-43 might be used as a biomarker to track the dynamic changes of CMBs in elderly persons.

Association of grip strength and walking pace with the risk of incident Parkinson's disease: a prospective cohort study of 422,531 participants.

BACKGROUND: Muscle weakness is a prominent feature of Parkinson's disease, but whether the occurrence of this deficit in healthy adults is associated with subsequent PD diagnosis remains unclear. OBJECTIVE: This study sought to examine the relationship between muscle strength, represented by grip strength and walking pace, and the risk of incident PD. METHODS: A total of 422,531 participants from the UK biobank were included in this study. Longitudinal associations of grip strength and walking pace with the risk of incident PD were investigated by Cox proportional hazard models adjusting for several well-established risk factors. Subgroup and sensitivity analyses were also conducted for further validation. RESULTS: After a median follow-up of 9.23 years, 2,118 (0.5%) individuals developed incident PD. For per 5 kg increment of absolute grip strength, there was a significant 10.2% reduction in the risk of incident PD (HR = 0.898, 95% CI [0.872-0.924], P < 0.001). Similarly, per 0.05 kg/kg increment of relative grip strength was related to a 9.2% reduced risk of incident PD (HR = 0.908, 95% CI [0.887-0.929], P < 0.001). Notably, the associations remained consistent when grip strength was calculated as quintiles. Moreover, participants with a slower walking pace demonstrated an elevated risk of incident PD (HR = 1.231, 95%CI [1.075-1.409], P = 0.003). Subgroup and sensitivity analyses further validated the robustness of the observed associations. CONCLUSION: Our findings showed a negative association of grip strength and walking pace with the risk of incident PD independent of important confounding factors. These results hold potential implications for the early screening of people at high-risk of PD.

Associations between antipsychotics exposure and dementia risk: A prospective cohort study of 415,100 participants.

BACKGROUND: Antipsychotics (APs) are among the most widely prescribed medications, and have been shown to cause cognitive decline. But previous studies on their effects on dementia risk are controversial and scarce. We aimed to examine the relationships of APs exposure with the risk of dementia. METHODS: Data were obtained from a prospective cohort of 415,100 UK Biobank (UKB) participants. We investigated the effects of APs exposure and their various classes on dementia risk by using multivariable Cox proportional hazard models and further the dose-response effects of oral APs. RESULTS: After a mean follow-up of 8.64 years, 5235 (1.3 %) participants developed all-cause dementia (ACD), among whom 2313 (0.6 %) developed Alzheimer's disease (AD), and 1213 (0.3 %) developed vascular dementia (VaD). Exposure to any APs conferred increased risks of ACD (HR: 1.33, 95 % CI = 1.17-1.51, P < 0.001) and VaD (HR: 1.90, 95 % CI = 1.51-2.40, P < 0.001), but not AD (HR: 1.22, 95 % CI = 1.00-1.48, P = 0.051). Cumulative dose-response relationships of oral APs with the risks of ACD and VaD were observed (P for trend, P < 0.05). LIMITATIONS: Our study is observational and does not show evidence of causality. Since there are relatively few cases of dementia in the UKB, APs exposure may be higher than estimated in our study. CONCLUSIONS: APs exposure increased the risk of developing dementia. Dose-response relationships were found between oral APs and dementia risk. Efforts to raise awareness of doctors and patients about this potential drug-related risk are critical to reducing APs use.

Associations of cerebrospinal fluid complement proteins with Alzheimer's pathology, cognition, and brain structure in non-dementia elderly.

BACKGROUND: Cerebrospinal fluid (CSF) complement activation is a key part of neuroinflammation that occurs in the early stages of Alzheimer's disease (AD). However, the associations of CSF complement proteins with AD pathology, cognition, and structural neuroimaging biomarkers for AD have been rarely investigated. METHODS: A total of 210 participants (125 mild cognitive impairment [MCI] patients and 85 normal controls) were included from Alzheimer's Disease Neuroimaging Initiative (ADNI) database who measured AD pathology, cognition, and neuroimaging at baseline and every 12 months. The mixed-effect linear models were utilized to investigate longitudinal associations of CSF complement proteins with AD pathology, cognition, and neuroimaging in cognitively normal (CN) and mild cognitive impairment (MCI) subjects. Causal mediation analyses were conducted to explore the potential mediators between CSF complement proteins and cognitive changes. RESULTS: We found that the subjects with low CSF complement protein levels at baseline had worse outcomes in AD pathology, indicated by their lowest concentrations observed in A + and A + T + individuals. The reduced CSF complement proteins were associated with faster accumulation of tau among CN subjects and with cognitive decline and greater brain atrophy of specific regions among MCI subjects. Furthermore, mediation analyses showed that the effects of CSF complement proteins on cognitive performance were partially mediated by regional brain structures (mediation proportions range from 19.78 to 94.92%; p < 0.05). CONCLUSIONS: This study demonstrated that CSF complement proteins were involved in the early progression of AD. Our results indicated that regional brain atrophy might be a plausible way to connect CSF complement protein levels and cognition.

Genetic susceptibility modifies the association of long-term air pollution exposure on Parkinson's disease.

Inconsistent findings exist regarding the potential association between polluted air and Parkinson's disease (PD), with unclear insights into the role of inherited sensitivity. This study sought to explore the potential link between various air pollutants and PD risk, investigating whether genetic susceptibility modulates these associations. The population-based study involved 312,009 initially PD-free participants with complete genotyping data. Annual mean concentrations of PM2.5, PM10, NO2, and NOx were estimated, and a polygenic risk score (PRS) was computed to assess individual genetic risks for PD. Cox proportional risk models were employed to calculate hazard ratios (HR) and 95% confidence intervals (CI) for the associations between ambient air pollutants, genetic risk, and incident PD. Over a median 12.07-year follow-up, 2356 PD cases (0.76%) were observed. Compared to the lowest quartile of air pollution, the highest quartiles of NO2 and PM10 pollution showed HRs and 95% CIs of 1.247 (1.089-1.427) and 1.201 (1.052-1.373) for PD incidence, respectively. Each 10 µg/m3 increase in NO2 and PM10 yielded elevated HRs and 95% CIs for PD of 1.089 (1.026-1.155) and 1.363 (1.043-1.782), respectively. Individuals with significant genetic and PM10 exposure risks had the highest PD development risk (HR: 2.748, 95% CI: 2.145-3.520). Similarly, those with substantial genetic and NO2 exposure risks were over twice as likely to develop PD compared to minimal-risk counterparts (HR: 2.414, 95% CI: 1.912-3.048). Findings suggest that exposure to air contaminants heightens PD risk, particularly in individuals genetically predisposed to high susceptibility.

Associations between multimorbidity burden and Alzheimer's pathology in older adults without dementia: the CABLE study.

Studies have shown that multimorbidity may be associated with the Alzheimer's disease (AD) stages, but it has not been fully characterized in patients without dementia. A total of 1402 Han Chinese older adults without dementia from Chinese Alzheimer's Biomarker and LifestylE (CABLE) study were included and grouped according to their multimorbidity patterns, defined by the number of chronic disorders and cluster analysis. Multivariable linear regression models were used to detect the associations with AD-related cerebrospinal fluid (CSF) biomarkers. Multimorbidity and severe multimorbidity (≥4 chronic conditions) were significantly associated with CSF amyloid and tau levels (pFDR < 0.05). Metabolic patterns were significantly associated with higher levels of CSF Aß40 (ß = 0.159, pFDR = 0.036) and tau (P-tau: ß = 0.132, pFDR = 0.035; T-tau: ß = 0.126, pFDR = 0.035). The above associations were only significant in the cognitively normal (CN) group. Multimorbidity was associated with brain AD pathology before any symptomatic evidence of cognitive impairment. Identifying such high-risk groups might allow tailored interventions for AD prevention.

Genetic architectures of cerebral ventricles and their overlap with neuropsychiatric traits.

The cerebral ventricles are recognized as windows into brain development and disease, yet their genetic architectures, underlying neural mechanisms and utility in maintaining brain health remain elusive. Here we aggregated genetic and neuroimaging data from 61,974 participants (age range, 9 to 98 years) in five cohorts to elucidate the genetic basis of ventricular morphology and examined their overlap with neuropsychiatric traits. Genome-wide association analysis in a discovery sample of 31,880 individuals identified 62 unique loci and 785 candidate genes associated with ventricular morphology. We replicated over 80% of loci in a well-matched cohort of lateral ventricular volume. Gene set analysis revealed enrichment of ventricular-trait-associated genes in biological processes and disease pathogenesis during both early brain development and degeneration. We explored the age-dependent genetic associations in cohorts of different age groups to investigate the possible roles of ventricular-trait-associated loci in neurodevelopmental and neurodegenerative processes. We describe the genetic overlap between ventricular and neuropsychiatric traits through comprehensive integrative approaches under correlative and causal assumptions. We propose the volume of the inferior lateral ventricles as a heritable endophenotype to predict the risk of Alzheimer's disease, which might be a consequence of prodromal Alzheimer's disease. Our study provides an advance in understanding the genetics of the cerebral ventricles and demonstrates the potential utility of ventricular measurements in tracking brain disorders and maintaining brain health across the lifespan.

Associations between liver function and cerebrospinal fluid biomarkers of Alzheimer's disease pathology in non-demented adults: The CABLE study.

Liver function has been suggested as a possible factor in the progression of Alzheimer's disease (AD) development. However, the association between liver function and cerebrospinal fluid (CSF) levels of AD biomarkers remains unclear. In this study, we analyzed the data from 1687 adults without dementia from the Chinese Alzheimer's Biomarker and LifestylE study to investigate differences in liver function between pathological and clinical AD groups, as defined by the 2018 National Institute on Aging-Alzheimer's Association Research Framework. We also examined the linear relationship between liver function, CSF AD biomarkers, and cognition using linear regression models. Furthermore, mediation analyses were applied to explore the potential mediation effects of AD pathological biomarkers on cognition. Our findings indicated that, with AD pathological and clinical progression, the concentrations of total protein (TP), globulin (GLO), and aspartate aminotransferase/alanine transaminase (ALT) increased, while albumin/globulin (A/G), adenosine deaminase, alpha-L-fucosidase, albumin, prealbumin, ALT, and glutamate dehydrogenase (GLDH) concentrations decreased. Furthermore, we also identified significant relationships between TP (ß = -0.115, pFDR < 0.001), GLO (ß = -0.184, pFDR < 0.001), and A/G (ß = 0.182, pFDR < 0.001) and CSF ß-amyloid1-42 (Aß1-42 ) (and its related CSF AD biomarkers). Moreover, after 10 000 bootstrapped iterations, we identified a potential mechanism by which TP and GLDH may affect cognition by mediating CSF AD biomarkers, with mediation effect sizes ranging from 3.91% to 16.44%. Overall, our results suggested that abnormal liver function might be involved in the clinical and pathological progression of AD. Amyloid and tau pathologies also might partially mediate the relationship between liver function and cognition. Future research is needed to fully understand the underlying mechanisms and causality to develop an approach to AD prevention and treatment approach.

Disease trajectories in older adults with non-AD pathologic change and comparison with Alzheimer's disease pathophysiology: A longitudinal study.

Based on the 'AT(N)' system, individuals with normal amyloid biomarkers but abnormal tauopathy or neurodegeneration biomarkers are classified as non-Alzheimer's disease (AD) pathologic change. This study aimed to assess the long-term clinical and cognitive trajectories of individuals with non-AD pathologic change among older adults without dementia, comparing them to those with normal AD biomarkers and AD pathophysiology. Analyzing Alzheimer's Disease Neuroimaging Initiative data, we evaluated clinical outcomes and conversion risk longitudinally using mixed effects models and multivariate Cox proportional hazard models. We found that compared to individuals with A-T-N-, those with abnormal tauopathy or neurodegeneration biomarkers (A-T + N-, A-T-N + , and A-T + N + ) had a faster rate of cognitive decline and disease progression. Individuals with A-T + N + had a faster rate of decline than those with A-T + N-. Additionally, in individuals with the same baseline tauopathy and neurodegeneration biomarker status, the presence of baseline amyloid could accelerate cognitive decline and clinical progression. These findings provide a foundation for future studies on non-AD pathologic change and its comparison with AD pathophysiology.

Associations of liver dysfunction with incident dementia, cognition, and brain structure: A prospective cohort study of 431 699 adults.

The relationship between liver dysfunction and dementia has been researched extensively but remains poorly understood. In this study, we investigate the longitudinal and cross-sectional associations between liver function and liver diseases and risk of incident dementia, impaired cognition, and brain structure abnormalities using Cox proportion hazard model and linear regression model. 431 699 participants with a mean of 8.65 (standard deviation [SD] 2.61) years of follow-up were included from the UK Biobank; 5542 all-cause dementia (ACD), 2427 Alzheimer's disease (AD), and 1282 vascular dementia (VaD) cases were documented. We observed that per SD decreases in alanine transaminase (ALT; hazard ratio [HR], 0.917; PFDR <0.001) and per SD increases in aspartate aminotransferase (AST; HR, 1.048; PFDR = 0.010), AST to ALT ratio (HR, 1.195; PFDR <0.001), gamma-glutamyl transpeptidase (GGT; HR, 1.066; PFDR <0.001), alcoholic liver disease (ALD; HR, 2.872; PFDR <0.001), and fibrosis and cirrhosis of liver (HR, 2.285; PFDR = 0.002), being significantly associated with a higher risk of incident ACD. Restricted cubic spline models identified a strong U-shaped association between Alb and AST and incident ACD (Pnonlinear <0.05). Worse cognition was positively correlated with AST, AST to ALT ratio, direct bilirubin (DBil), and GGT; negatively correlated with ALT, Alb, and total bilirubin (TBil); and ALD and fibrosis and cirrhosis of liver (PFDR <0.05). Moreover, changes in ALT, GGT, AST to ALT ratio, and ALD were significantly associated with altered cortical and subcortical regions, including hippocampus, amygdala, thalamus, pallidum, and fusiform (PFDR <0.05). In sensitivity analysis, metabolic dysfunction-associated steatotic liver disease (MASLD) was associated with the risk of ACD and brain subcortical changes. Our findings provide substantial evidence that liver dysfunction may be an important factor for incident dementia. Early intervention in the unhealthy liver may help prevent cognitive impairment and dementia incidence.