Smoking and increased Alzheimer's disease risk: a review of potential mechanisms

Sex differences in risk factors for Alzheimer dementia encephalopathy patients

Background

The objective is to identify risk factors that contribute to sex differences in Alzheimer dementia (AD) patients with encephalopathy (ADEN) and determine whether these factors are different between male and female ADEN patients. This is the first large-scale study comparing sex-specific ADEN risk profiles.

Methods

Our retrospective cohort study analyzed data collected from February 2016 to August 2020. It included a total of 128,769 AD patients, among whom 41,266 AD patients also presented with encephalopathy, compared to 87,503 AD patients that did not. The univariate analysis was used to determine differences in risk factors for male and female AD patients. Multivariate analysis predicted specific risk factors associated with male and female ADEN patients.

Result

In the adjusted analysis, males presented with hypertension (OR = 1.144, 95% CI, 1.094-1.197, p < 0.001), peripheral vascular disease (OR = 1.606, 95% CI, 1.485-1.737, p < 0.001), atrial fibrillation (OR = 1.555, 95% CI, 1.443-1.676, p < 0.001), hallucinations (OR = 1.406, 95% CI, 1.119-1.766, p = 0.003), and traumatic head injury (OR = 3.211, 95% CI, 2.346-4.395, p < 0.001). Females presented with osteoporosis (OR = 0.307, 95% CI, 0.278-0.340, p < 0.001), unspecified cancer (OR = 0.615, 95% CI, 0.512-0.740, p < 0.001), anxiety (OR = 0.609, 95% CI, 0.565-0.655, p < 0.001), urinary tract infections (UTI) (OR = 0.451, 95% CI, 0.423-0.481, p < 0.001), upper respiratory infections (URI) (OR = 0.531, 95% CI, 0.432-0.653, p < 0.001) and gastrointestinal ulceration (OR = 0.338, 95% CI, 0.269-0.424, p < 0.001).

Conclusion

Our analysis identified risk factors that contribute to sex differences in ADEN. This difference was fully mediated by peripheral vascular disease, atrial fibrillation, hallucinations, and traumatic head injury for males and unspecified cancer, anxiety, urinary tract infections, upper respiratory infections, and gastrointestinal ulceration for females. These findings provide valuable insights into the risk factors that can be managed to improve the care of male and female ADEN patients.

Global, regional, and national disease burden of tobacco-related Alzheimer's disease among individuals over the age of 55: a global burden of disease study

Background

Alzheimer's disease is a progressive neurodegenerative disorder characterized by an insidious onset. Numerous studies have identified a significant association between tobacco use and Alzheimer's disease. This study aims to explore the epidemiological patterns and trends concerning tobacco-related Alzheimer's disease at global, national and regional levels.

Methods

We analyzed data on mortality, age-standardized DALY rate (ASDR), and estimated annual percentage changes (EAPCs) sourced from the Global Burden of Disease data for 2021. The analysis was further stratified by country and region, socio-demographic index (SDI), gender, and age. A Bayesian Age-Period-Cohort (BAPC) model was employed to project the global burden in the future.

Results

In 2021, the total burden revealed a decline in the number of deaths and ASDR compared to 1990. The highest proportions of mortality and ASDR were observed in the age group over 95 years. The disease burden among men was significantly higher than of among women, approximately three times greater. Conversely, in Australia and North America, the burden of disease among women surpassed that of men. In most of the 21 regions worldwide, both mortality and ASDRs have decreased since 1990, and intra-regional mortality rates have declined as SDI has increased. It is anticipated that the burden will continue to gradually decrease from 2021 to 2040.

Conclusion

Although the global burden of tobacco-related Alzheimer's disease among the older adults declined from 1990 to 2021, significant disparities existed across regions, age groups, sex, and SDI.

Sestrin2 alleviates cognitive impairment via inhibiting hippocampus ferroptosis in cigarette smoke-induced chronic obstructive pulmonary disease

Cognitive dysfunction is an essential comorbidity that contributing to the whole disease process of the individual of chronic obstructive pulmonary disease (COPD), yet its specific mechanism remains controversial due to a lack of cellular and molecular evidence. Our clinical data revealed a significant reduction in total hippocampal volume in patients with COPD, with the CA1 subfield notably smaller and associated with lung function. Long-term CS exposure caused hippocampus impairment, leading to spatial and working memory impairments in COPD model mice. CS exposure triggered ferroptosis in vivo and in vitro. Bioinformatics analysis suggested that sestrin2 is a key ferroptosis-related gene involved in cognitive impairment. Sestrin2 protein levels were consistently increased in the hippocampus of COPD model mice and CSE treated HT22 cells. Sestrin2 knockdown exacerbated ferroptosis and enhanced the down-regulation of synaptophysin and PSD95, while sestrin2 overexpression inhibited these damaging processes in vitro. This neuroprotection of sestrin2 is dependent on its binding with heterogeneous nuclear ribonucleoprotein L (HNRNPL). Moreover, sestrin2 overexpression and DFO ameliorated hippocampal impairment and neurocognitive deficits by correcting CS-induced ferroptosis and synaptic proteins alterations in vivo. Overall, our study reveals that sestrin2 improves CS-induced adverse changes in hippocampal neurons and neurobehavior, providing new insights into the molecular mechanisms underlying COPD-related cognitive dysfunction.

Exploring morphological and microstructural signatures across the Alzheimer's spectrum and risk factors

Neural alterations, including myelin degeneration and inflammation-related iron burden, may accompany early Alzheimer's disease (AD) pathophysiology. This study aims to identify multi-modal signatures associated with MRI-derived atrophy and quantitative MRI (qMRI) measures of myelin and iron in a unique dataset of 158 participants across the AD spectrum, including those without cognitive impairment, at familial risk for AD, with mild cognitive impairment, and with AD dementia. Our results revealed a brain pattern with decreased cortical thickness, indicating increased neuronal death, and compromised hippocampal integrity due to reduced myelin content. This pattern was associated with lifestyle factors such as smoking, high blood pressure, high cholesterol, and anxiety, as well as older age, AD progression, and APOE-ɛ4 carrier status. These findings underscore the value of qMRI metrics as a non-invasive tool, offering sensitivity to lifestyle-related modifiable risk factors and medical history, even in preclinical stages of AD.

DNA methylation signature of a lifestyle-based resilience index for cognitive health

Cognitive resilience (CR) contributes to the variability in risk for developing and progressing in Alzheimer's disease (AD) among individuals. Beyond genetics, recent studies highlight the critical role of lifestyle factors in enhancing CR and delaying cognitive decline. DNA methylation (DNAm), an epigenetic mechanism influenced by both genetic and environmental factors, including CR-related lifestyle factors, offers a promising pathway for understanding the biology of CR. We studied DNAm changes associated with the Resilience Index (RI), a composite measure of lifestyle factors, using blood samples from the Healthy Brain Initiative (HBI) cohort. After corrections for multiple comparisons, our analysis identified 19 CpGs and 24 differentially methylated regions significantly associated with the RI, adjusting for covariates age, sex, APOE ε4, and immune cell composition. The RI-associated methylation changes are significantly enriched in pathways related to lipid metabolism, synaptic plasticity, and neuroinflammation, and highlight the connection between cardiovascular health and cognitive function. By identifying RI-associated DNAm, our study provided an alternative approach to discovering future targets and treatment strategies for AD, complementary to the traditional approach of identifying disease-associated variants directly. Furthermore, we developed a Methylation-based Resilience Score (MRS) that successfully predicted future cognitive decline in an external dataset from the Alzheimer's Disease Neuroimaging Initiative (ADNI), even after accounting for age, sex, APOE ε4, years of education, baseline diagnosis, and baseline MMSE score. Our findings are particularly relevant for a better understanding of epigenetic architecture underlying cognitive resilience. Importantly, the significant association between baseline MRS and future cognitive decline demonstrated that DNAm could be a predictive marker for AD, laying the foundation for future studies on personalized AD prevention.

Uncovering leading compounds for alzheimer's disease treatment: mendelian randomization and virtual screening insights into plasma protein modulation

Alzheimer's disease (AD) is a neurodegenerative disorder influenced by both genetic and environmental factors. Identifying therapeutic targets and interventions remains challenging. This study utilized Mendelian Randomization (MR) to investigate causal relationships between plasma proteins, lifestyle factors, and AD, along with virtual screening to identify potential drug compounds. A two-sample MR analysis assessed associations between plasma proteins, identified through genome-wide association studies (GWAS), and AD risk. Co-localization analysis (CA) confirmed the overlap between protein expression and AD susceptibility loci, and reverse MR ruled out reverse causality. A protein-protein interaction (PPI) network was constructed to explore therapeutic targets, followed by virtual screening to identify small-molecule inhibitors for selected proteins. The analysis found significant associations between eight plasma proteins and AD, with five proteins (GSTP1, BIN1, Siglec-3, SERPINF2, and GRN) showing strong evidence of involvement in AD pathogenesis. Virtual screening identified six compounds as potential inhibitors of GSTP1 and four compounds as potential inhibitors of BIN1. Furthermore, MR analysis of lifestyle factors, such as dietary behaviors and smoking cessation, indicated they may influence AD risk through their effects on specific proteins. These findings offer novel insights into the genetic mechanisms underlying AD and highlight the potential of combining MR with virtual screening to identify therapeutic targets. The study also suggests that lifestyle modifications could offer alternative prevention and treatment strategies for AD. Future research should focus on the experimental validation of the identified compounds and further explore the mechanisms linking lifestyle factors to AD.

Murine Non-Transgenic Models of Alzheimer's Disease Pathology: Focus on Risk Factors

Alzheimer's disease (AD) represents a significant challenge among neurodegenerative disorders, as effective treatments and therapies remain largely undeveloped. Despite extensive research efforts employing various methodologies and diverse genetic models focused on amyloid-β (Aβ) pathology, the research for effective therapeutic strategies remains inconclusive. The key pathological features of AD include Aβ senile plaques, neurofibrillary tangles (NFTs), and the activation of neuroinflammatory pathways. Presently, investigations into AD and assessing potential treatments predominantly utilize Aβ transgenic models. Conversely, non-transgenic models may provide valuable insights into the multifaceted pathological states associated with AD. Thus, these models may serve as practical complementary tools for evaluating therapeutic and intervention strategies, since the primary AD risk factors are most frequently modeled. This review aims to critically assess the existing literature on AD non-transgenic models induced by streptozotocin, scopolamine, aging, mechanical stress, metals, and dietary patterns to enhance their application in AD research.

Lifestyle factors and plasma biomarkers of Alzheimer's disease: A narrative review

Alzheimer's disease (AD) is a neurodegenerative disorder characterised by amyloid-β (Aβ), tau hyperphosphorylation and neurodegeneration. Blood-based biomarkers are emerging as a minimally invasive tool for disease detection and monitoring. This review depicts the relationships between modifiable lifestyle factors (nutrition, physical activity (PA), sleep, alcohol consumption, smoking, and social isolation) and plasma biomarkers of AD: Aβ42, Aβ40, Aβ42/40, phosphorylated tau, total tau, neurofilament light chain (NfL) and glial fibrillary acidic protein. Limited evidence suggests that better nutrition is associated with favourable AD plasma biomarker profiles and that PA is associated with less plasma NfL and Aβ, whilst poor sleep is associated with elevated plasma Aβ. However, lack of data and inconsistent findings highlight the need for further investigation to substantiate or refute these trends. Moreover, future research should include the analysis of lifestyle on plasma biomarkers according to gender, metabolic health and APOE status. Considering the growing emphasis on modifiable lifestyle factors for preventing and delaying dementia onset further investigation is justified.

Prevalence and Risk Factors of Poststroke Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Stroke is a common disease that poses a significant threat to human health. Approximately one-third of stroke patients experience poststroke cognitive impairment (PSCI), which severely impacts their quality of life and survival time. Although the prevalence and risk factors for PSCI have been widely reported, these results have not been synthesized.

OBJECTIVES

This systematic review was conducted to explore the prevalence and risk factors of PSCI.

METHODS

PubMed, EMBASE, Web of Science, and Cochrane Library were comprehensively searched for studies exploring the prevalence and risk factors of PSCI from inception to July 5, 2022.

RESULTS

A total of 49 articles were included for meta-analysis. It was found that the combined prevalence of PSCI was 39%-47%. Risk factors for PSCI include female gender, age, education level less than 7 years, atrial fibrillation, diabetes, smoking, drinking, hypertension, coronary artery disease, carotid artery plaque, admission NIHSS score ≥ 5, unemployment, and homocysteine.

CONCLUSIONS

This systematic review has revealed a combined prevalence of PSCI is ranging from 39% to 47% and identified several risk factors for PSCI. These findings indicate a high incidence of the condition and underscore the need for increased public awareness. Future investigations should prioritize the identification of PSCI risk factors, providing a theoretical basis for nursing professionals to effectively manage and treat PSCI patients.

Smoking-attributable neurological health loss: age-specific burden and health disparities

BACKGROUND

Smoking is a significant risk factor for neurological disorders, yet its global impact on these conditions remains underexplored.

METHODS

Using Global Burden of Diseases 2021 data, we analysed trends in age-standardised disability-adjusted life-years (DALYs) and deaths attributable to smoking from 1990 to 2021 for three neurological disorders: stroke, Alzheimer's disease and other dementias, and Multiple Sclerosis. Socioeconomic disparities were assessed using the lope index of inequality and the relative concentration index. Bayesian age-period-cohort models were employed to forecast smoking-attributable burden through 2050.

RESULTS

Between 1990 and 2021, annual smoking-attributable DALYs and death rates slightly declined by -1.93% and -1.92%, respectively, but absolute numbers continued to rise, from 26.10 million to 30.18 million DALYs and from 0.93 million to 1.15 million deaths. Older adults (aged 60 and above) experienced the greatest burden, contributing 58.15% of DALYs and 75.57% of deaths in 2021. Smoking-attributable stroke was increasingly concentrated in low sociodemographic index regions, whereas disparities in dementias and multiple sclerosis were more pronounced in socioeconomically advantaged regions, particularly for multiple sclerosis.

CONCLUSIONS

This study identified an age-specific burden and widening disparities for neurological disorders attributable to smoking, with older adults disproportionately experiencing an escalating impact. Targeted prevention and equitable healthcare access tailored for older adults are critical to mitigating smoking-attributable neurological health loss.

Identification of critical genes and drug repurposing targets in entorhinal cortex of Alzheimer's disease

Alzheimer's disease (AD) is a slow brain degeneration disorder in which the accumulation of beta-amyloid precursor plaque and an intracellular neurofibrillary tangle of hyper-phosphorylated tau proteins in the brain have been implicated in neurodegeneration. In this study, we identified the most important genes that are unique and sensitive in the entorhinal region of the brain to target AD effectively. At first, microarrays data are selected and constructed protein-protein interaction network (PPIN) and gene regulatory network (GRN) from differentially expressed genes (DEGs) using Cytoscape software. Then, networks analysis was performed to determine hubs, bottlenecks, clusters, and signaling pathways in AD. Finally, critical genes were selected as targets for repurposing drugs. Analyzing the constructed PPIN and GRN identified CD44, ELF1, HSP90AB1, NOC4L, BYSL, RRP7A, SLC17A6, and RUVBL2 as critical genes that are dysregulated in the entorhinal region of AD suffering patients. The functional enrichment analysis revealed that DEG nodes are involved in the synaptic vesicle cycle, glutamatergic synapse, PI3K-Akt signaling pathway, retrograde endocannabinoid signaling, endocrine and other factor-regulated calcium reabsorption, ribosome biogenesis in eukaryotes, and nicotine addiction. Gentamicin, isoproterenol, and tumor necrosis factor are repurposing new drugs that target CD44, which plays an important role in the development of AD. Following our model validation using the existing experimental data, our model based on previous experimental reports suggested critical molecules and candidate drugs involved in AD for further investigations in vitro and in vivo.

Smoke-free hospitality environments and cognitive health: A population-based study in the United States

Introduction

Cigarette smoking is among the largest risk factors for cognitive decline in later life. This study examines the associations between hospitality smoke-free coverage in the US and the prevalence of self-rated cognitive function decline and disparities therein.

Methods

I use the repeated cross-sectional Behavioral Risk Factor Surveillance data collected between 2017 and 2022 from a sample of Americans 45 years and older and estimate logistic regression models predicting self-rated cognitive function decline by calculated smoke-free hospitality coverage in restaurants and bars.

Results

Fully adjusted models indicate a marginally statistically significant 0.16 percentage point reduction [CI -0.35 to 0.02] in the probability of self-rated cognitive function decline for a 10 % increase in the smoke-free bar coverage. The effect is statistically significant and larger for women, a 0.29 [CI -0.50 to -0.01] percentage point decrease, and for non-smokers, a 0.35 [CI -0.56 to -0.15] percentage point decrease. I do not find a parallel effect of smoke-free restaurant laws and I find no effect of either law on self-rated cognitive function decline-related limitations in daily life for either hospitality law.

Conclusions

The findings suggest that smoke-free bar laws could play a role in preventing cognitive decline among older adults in the United States. Effective public health strategies against cognitive decline should include both targeted and broad-based policy measures.

Association of shared decision-making cessation model and adult smoking cessation rate: A prospective cohort study

INTRODUCTION

It remains unclear whether shared decision-making (SDM) can help smoking cessation. This study aims to determine whether the SDM model increases the 24-week point abstinence rate and medication adherence rate for adult smokers.

METHODS

This prospective cohort study, conducted between January 2019 and June 2021, enrolled 1268 adult smokers at the outpatient cessation clinic of a national medical center. SDM-integrated counseling was provided to those opting for the SDM cessation model, involving cessation educators and decision aids. Patients who declined the model received cessation medication. The self-reported 7-day point prevalence abstinence rate at week 24, medication adherence rate, and the proportion of participants agreeing to receive pharmacotherapy were measured.

RESULTS

Out of the 1268 participants, 1187 (93.6%) were included in the primary analysis. Of these, 610 (48%) opted for the SDM model. Participants in the SDM group used cessation medication more frequently (83.4% vs 71.9%, p<0.001) and exhibited higher medication adherence (39.1% vs 28.6%, p=0.04). Logistic regression analysis revealed that the SDM group did not demonstrate a significantly higher 7-day point abstinence rate at week 24 (OR=0.89; 95% CI: 0.68-1.15; p=0.37).

CONCLUSIONS

The SDM cessation model was positively associated with medication adherence and the proportion of participants using pharmacotherapies. However, the association of SDM with the 7-day point prevalence of abstinence at week 24 was not statistically significant. Longer follow-up studies are needed to understand the association of the SDM intervention with absolute abstinence.

Comparative Assessment of Acute Pulmonary Effects Induced by Heat-Not-Burn Tobacco Aerosol Inhalation in a Murine Model

Tobacco smoking remains a major global health concern, causing preventable deaths and economic strain. Although new tobacco products such as heat-not-burn (HnB) are safer alternatives to traditional cigarettes, research on their associated risks remains limited. This study aimed to investigate the effects of HnB smoke exposure on the lungs compared to those of traditional cigarettes and the combined use of HnB and cigarettes using experiments with a mouse model. We quantitatively analyzed changes in the levels of 92 blood plasma proteins using the proximity extension assay method and observed significant changes in their levels in mice exposed to different smoke conditions; specifically, the levels of certain proteins, including Ccl20, Cxcl1, and Pdgfb, increased in the HnB smoke-exposed group, suggesting activation of nicotine pathways. Comparative analysis with traditional cigarette smoke-exposed mice further highlighted similarities and differences in their protein expression profiles. This study contributes to an improved understanding of the biological mechanisms underlying the harmful effects of alternative nicotine delivery systems and identifies potential biomarkers associated with the harmful effects of HnB smoke exposure. However, the precise impact of nicotine on the immune system may be influenced by various factors, necessitating further research.

CD34+ Hematopoietic Stem Cell Counts in Alzheimer's Disease: A Meta-Analysis

PURPOSE

To assess the presence and quantity of CD34+ hematopoietic stem cells in patients with Alzheimer's disease (AD) through a meta-analysis.

METHODS

A systematic search of the databases identified the observational and interventional studies reporting baseline CD34+ cell counts in AD patients. The data on mean counts and the measures of variation were extracted. Standardized mean differences (SMDs) were calculated using common and random effects models to compare the CD34+ cell counts between the AD patients and controls. Heterogeneity among the studies was evaluated using tau2, tau, and I2 statistics. The risk of bias was assessed using the Newcastle-Ottawa Scale and the ROBINS-I tool.

PATIENTS

Five studies were included, comprising four observational studies and one open-label trial, with a total of 271 participants (139 AD patients and 132 controls).

RESULTS

The meta-analysis indicated an increase in CD34+ cell counts of the AD patients when compared to the controls. The common effects model showed a moderate SMD of 0.2964 (95% CI:0.0490-0.5437). However, the random effects model yielded a non-significant SMD of 0.2326 (95% CI: -0.4832-0.9484). Significant heterogeneity was observed among the studies (I2 = 87.1%, p < 0.0001).

CONCLUSION

AD patients may exhibit higher circulating CD34+ cell counts than the controls, but substantial heterogeneity and potential biases limit definitive conclusions.

The potential link between the development of Alzheimer's disease and osteoporosis

Alzheimer's disease (AD) and osteoporosis (OP) pose distinct but interconnected health challenges, both significantly impacting the aging population. AD, a neurodegenerative disorder characterized by memory impairment and cognitive decline, is primarily associated with the accumulation of abnormally folded amyloid beta (Aβ) peptides and neurofibrillary tangles in the brain. OP, a skeletal disorder marked by low bone mineral density, involves dysregulation of bone remodeling and is associated with an increased risk of fractures. Recent studies have revealed an intriguing link between AD and OP, highlighting shared pathological features indicative of common regulatory pathophysiological pathways. In this article, we elucidate the signaling mechanisms that regulate the pathology of AD and OP and offer insights into the intricate network of factors contributing to these conditions. We also examine the role of bone-derived factors in the progression of AD, underscoring the plausibility of bidirectional communication between the brain and the skeletal system. The presence of amyloid plaques in the brain of individuals with AD is akin to the accumulation of brain Aβ in vascular dementia, pointing towards the need for further investigation of shared molecular mechanisms. Moreover, we discuss the role of bone-derived microRNAs that may regulate the pathological progression of AD, providing a novel perspective on the role of skeletal factors in neurodegenerative diseases. The insights presented here should help researchers engaged in exploring innovative therapeutic approaches targeting both neurodegenerative and skeletal disorders in aging populations.

A Comprehensive Review on Preclinical Alzheimer's Disease Models: Evaluating their Clinical Relevance

Alzheimer's disease (AD) is a neurological disorder that increases with age and must be treated immediately by worldwide healthcare systems. Internal neurofibrillary tau tangles and extracellular amyloid accumulation have been widely recognized as the primary causes of Alzheimer's disease. These degenerative age-related ailments are expected to proliferate exponentially as life expectancy rises. Experimental models of AD are essential for acquiring a deep knowledge of its pathogenesis and determining the viability of novel therapy options. Although there isn't a model that encompasses all the characteristics of real AD, these models are nonetheless highly helpful for the research of various modifications associated with it, even though they are only partially indicative of the disease circumstances being studied. Better knowledge of the advantages and disadvantages of each of the different models, as well as the use of more than one model to evaluate potential medications, would increase the effectiveness of therapy translation from preclinical research to patients. We outline the pathogenic characteristics and limitations of the main experimental models of AD in this review, including transgenic mice, transgenic rats, primates and non-primate models along with in-vitro cell culture models in humans. Additionally, it highlights the possible future of experimental modeling of AD and includes the co-morbid models.

Metal mixtures exposure with risk of elevated serum neurofilament light chain concentrations in U.S. general adults, NHANES 2013-2014

BACKGROUND

A relatively well-established link was observed between metal mixtures exposure and neurodegenerative diseases. However, the relationship between metal mixtures exposure and serum neurofilament light chain (sNfL) concentrations, a valuable non-invasive biomarker of neurodegenerative diseases, in general adult populations remains understudied and unclear.

OBJECTIVE

This study seeks to elucidate the potential impact of metal mixtures exposure on sNfL concentrations in a representative sample of U.S. general adults.

METHODS

Twelve urinary metal levels, including barium (Ba), cadmium (Cd), cobalt (Co), cesium (Cs), molybdenum (Mo), lead (Pb), antimony (Sb), tin (Sn), strontium (Sr), thallium (Tl), tungsten (W) and uranium (U), were analyzed in U.S. general adults recruited from the 2013-2014 National Health and Nutrition Examination Survey using inductively coupled plasma mass spectrometry (ICP-MS) after a simple dilution step. Urine samples are diluted with 2 % concentrated nitric acid (1:9). We employed a two-pronged approach, combining weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models, to examine the association between the multiple-metals effect and sNfL concentrations. Survey-weighted multivariate linear regression was used to explore the correlation between single-metal effect and sNfL concentrations.

RESULTS

With the increasing quartiles of log-transformed sNfL (log-sNfL) concentrations, the fourth quartile had a higher proportion of smokers and hypertensive individuals (P < 0.001). Cd (69.6 %) and Pb (8.9 %) were the primary drivers of the association between metal mixtures exposure and sNfL concentrations. Analysis of WQS and BKMR models showed a positive association between metal mixtures exposure and sNfL concentrations, especially in older, and male participants.

CONCLUSION

In the U.S. general adult, a significant correlation between metal mixtures exposure and increased sNfL concentrations was observed, and urinary Cd levels play a pivotal role in this positive correlation. Notably, stronger risk associations were observed among elderly, males, smokers, and hypertensive individuals. The results could be significant for detecting and tracking the beginning of neurodegenerative diseases early, as well as helping to pinpoint individuals at high risk.

Tobacco cigarette smoking induces cerebrovascular dysfunction followed by oxidative neuronal injury with the onset of cognitive impairment

While chronic smoking triggers cardiovascular disease, controversy remains regarding its effects on the brain and cognition. We investigated the effects of long-term cigarette smoke (CS) exposure (CSE) on cerebrovascular function, neuronal injury, and cognition in a novel mouse exposure model. Longitudinal studies were performed in CS or air-exposed mice, 2 hours/day, for up to 60 weeks. Hypertension and carotid vascular endothelial dysfunction (VED) occurred by 16 weeks of CSE, followed by reduced carotid artery blood flow, with oxidative stress detected in the carotid artery, and subsequently in the brain of CS-exposed mice with generation of reactive oxygen species (ROS) and secondary protein and DNA oxidation, microglial activation and astrocytosis. Brain small vessels exhibited decreased levels of endothelial NO synthase (eNOS), enlarged perivascular spaces with blood brain barrier (BBB) leak and decreased levels of tight-junction proteins. In the brain, amyloid-β deposition and phosphorylated-tau were detected with increases out to 60 weeks, at which time mice exhibited impaired spatial learning and memory. Thus, long-term CSE initiates a cascade of ROS generation and oxidative damage, eNOS dysfunction with cerebral hypoperfusion, as well as cerebrovascular and BBB damage with intracerebral inflammation, and neuronal degeneration, followed by the onset of impaired cognition and memory.

Alzheimer's disease: a comprehensive review of epidemiology, risk factors, symptoms diagnosis, management, caregiving, advanced treatments and associated challenges

Background

Alzheimer's disease (AD) is a chronic, progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired reasoning. It is the leading cause of dementia in older adults, marked by the pathological accumulation of amyloid-beta plaques and neurofibrillary tangles. These pathological changes lead to widespread neuronal damage, significantly impacting daily functioning and quality of life.

Objective

This comprehensive review aims to explore various aspects of Alzheimer's disease, including its epidemiology, risk factors, clinical presentation, diagnostic advancements, management strategies, caregiving challenges, and emerging therapeutic interventions.

Methods

A systematic literature review was conducted across multiple electronic databases, including PubMed, MEDLINE, Cochrane Library, and Scopus, from their inception to May 2024. The search strategy incorporated a combination of keywords and Medical Subject Headings (MeSH) terms such as "Alzheimer's disease," "epidemiology," "risk factors," "symptoms," "diagnosis," "management," "caregiving," "treatment," and "novel therapies." Boolean operators (AND, OR) were used to refine the search, ensuring a comprehensive analysis of the existing literature on Alzheimer's disease.

Results

AD is significantly influenced by genetic predispositions, such as the apolipoprotein E (APOE) ε4 allele, along with modifiable environmental factors like diet, physical activity, and cognitive engagement. Diagnostic approaches have evolved with advances in neuroimaging techniques (MRI, PET), and biomarker analysis, allowing for earlier detection and intervention. The National Institute on Aging and the Alzheimer's Association have updated diagnostic criteria to include biomarker data, enhancing early diagnosis.

Conclusion

The management of AD includes pharmacological treatments, such as cholinesterase inhibitors and NMDA receptor antagonists, which provide symptomatic relief but do not slow disease progression. Emerging therapies, including amyloid-beta and tau-targeting treatments, gene therapy, and immunotherapy, offer potential for disease modification. The critical role of caregivers is underscored, as they face considerable emotional, physical, and financial burdens. Support programs, communication strategies, and educational interventions are essential for improving caregiving outcomes. While significant advancements have been made in understanding and managing AD, ongoing research is necessary to identify new therapeutic targets and enhance diagnostic and treatment strategies. A holistic approach, integrating clinical, genetic, and environmental factors, is essential for addressing the multifaceted challenges of Alzheimer's disease and improving outcomes for both patients and caregivers.

The blood metabolome of cognitive function and brain health in middle-aged adults - influences of genes, gut microbiome, and exposome

Increasing evidence suggests the involvement of metabolic alterations in neurological disorders, including Alzheimer's disease (AD), and highlights the significance of the peripheral metabolome, influenced by genetic factors and modifiable environmental exposures, for brain health. In this study, we examined 1,387 metabolites in plasma samples from 1,082 dementia-free middle-aged participants of the population-based Rotterdam Study. We assessed the relation of metabolites with general cognition (G-factor) and magnetic resonance imaging (MRI) markers using linear regression and estimated the variance of these metabolites explained by genes, gut microbiome, lifestyle factors, common clinical comorbidities, and medication using gradient boosting decision tree analysis. Twenty-one metabolites and one metabolite were significantly associated with total brain volume and total white matter lesions, respectively. Fourteen metabolites showed significant associations with G-factor, with ergothioneine exhibiting the largest effect (adjusted mean difference = 0.122, P = 4.65×10-7). Associations for nine of the 14 metabolites were replicated in an independent, older cohort. The metabolite signature of incident AD in the replication cohort resembled that of cognition in the discovery cohort, emphasizing the potential relevance of the identified metabolites to disease pathogenesis. Lifestyle, clinical variables, and medication were most important in determining these metabolites' blood levels, with lifestyle, explaining up to 28.6% of the variance. Smoking was associated with ten metabolites linked to G-factor, while diabetes and antidiabetic medication were associated with 13 metabolites linked to MRI markers, including N-lactoyltyrosine. Antacid medication strongly affected ergothioneine levels. Mediation analysis revealed that lower ergothioneine levels may partially mediate negative effects of antacids on cognition (31.5%). Gut microbial factors were more important for the blood levels of metabolites that were more strongly associated with cognition and incident AD in the older replication cohort (beta-cryptoxanthin, imidazole propionate), suggesting they may be involved later in the disease process. The detailed results on how multiple modifiable factors affect blood levels of cognition- and brain imaging-related metabolites in dementia-free participants may help identify new AD prevention strategies.

Potential Protective Effects of Pungent Flavor Components in Neurodegenerative Diseases

Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD) have become a major global health burden, but the detailed pathogeneses of neurodegenerative diseases are still unknown, and current treatments are mainly aimed at controlling symptoms; there are no curative treatments for neurodegenerative diseases or treatments for the progressive cognitive, behavioral, and functional impairments that they cause. Studies have shown that some plant extracts with pungent flavor components have a certain neuroprotective effect in neurodegenerative diseases, and their mechanisms mainly involve inhibiting neuronal apoptosis, promoting neuronal regeneration, reducing mitochondrial degeneration, and reducing the production of oxides such as reactive oxygen species in cells, which are of great significance for exploring the treatment of neurodegenerative diseases. In this review, we searched the PubMed database for relevant literature collected in the past 15 years. Finally, we summarized the protective effects of pungent flavor components such as capsaicin, piperine, curcumin, cannabinoids, allicin, and nicotine on the nervous system, focusing on the molecular mechanisms and signaling pathways that they activate. In addition, we also compiled and summarized the laboratory experiments, preclinical experiments, and effects of various pungent flavor components in neurodegenerative diseases. The goal is to further explore their potential as effective drugs for the treatment of neurodegenerative diseases and provide new ideas for further research on the specific protective mechanisms of these substances for the treatment of neurodegenerative diseases and the targets of drug action in the future.

Identification of novel risk genes for Alzheimer's disease by integrating genetics from hippocampus

Alzheimer's disease (AD) stands as the most prevalent neurodegenerative ailment, presently lacking a definitive cure. Given that primary medications for AD patients in the early or middle stages demonstrate optimal efficacy, it becomes crucial to delve into the identification of risk genes associated with early onset. In our study, we compiled and integrated three transcriptomics datasets (GSE48350, GSE36980, GSE5281) originating from the hippocampus of 37 AD patients and 66 healthy controls (CTR) for comprehensive bioinformatics analysis. Comparative analysis with CTR revealed 25 up-regulated genes and 291 down-regulated genes in AD. Those down-regulated genes were notably enriched in processes related to the transmission and transport of synaptic signals. Intriguingly, 27 differentially expressed genes implicated in AD were also correlated with the Braak stage, establishing a connection with various immune cell types that exhibit differences in AD, including cytotoxic T cells, neutrophils, CD4 T cells, Th1, Th2, and Tfh. Significantly, a Cox model, constructed using nine feature genes, effectively stratified AD samples (HR = 2.72, 95% CI 1.94 ~ 3.81, P = 3.6e-10), highlighting their promising potential for risk assessment. In conclusion, our investigation sheds light on novel genes intricately linked to the onset and progression of AD, offering potential biomarkers for the early detection of this debilitating condition. This study contributes valuable insights toward enhancing the strategies for preventing and treating AD.

Alzheimer's Disease as Type 3 Diabetes: Understanding the Link and Implications

Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) are two prevalent conditions that present considerable public health issue in aging populations worldwide. Recent research has proposed a novel conceptualization of AD as "type 3 diabetes", highlighting the critical roles of insulin resistance and impaired glucose metabolism in the pathogenesis of the disease. This article examines the implications of this association, exploring potential new avenues for treatment and preventive strategies for AD. Key evidence linking diabetes to AD emphasizes critical metabolic processes that contribute to neurodegeneration, including inflammation, oxidative stress, and alterations in insulin signaling pathways. By framing AD within this metabolic context, we can enhance our understanding of its etiology, which in turn may influence early diagnosis, treatment plans, and preventive measures. Understanding AD as a manifestation of diabetes opens up the possibility of employing novel therapeutic strategies that incorporate lifestyle modifications and the use of antidiabetic medications to mitigate cognitive decline. This integrated approach has the potential to improve patient outcomes and deepen our comprehension of the intricate relationship between neurodegenerative diseases and metabolic disorders.

Pilot implementation of the revised criteria for staging of Alzheimer's disease by the Alzheimer's Association Workgroup in a tertiary memory clinic

INTRODUCTION

We aimed to evaluate the feasibility of the 2024 Alzheimer's Association Workgroup's integrated clinical-biological staging scheme in outpatient settings within a tertiary memory clinic.

METHODS

The 2018 syndromal cognitive staging system, coupled with a binary biomarker classification, was implemented for 236 outpatients with cognitive concerns. The 2024 numeric clinical staging framework, incorporating biomarker staging, was specifically applied to 154 individuals within the Alzheimer's disease (AD) continuum.

RESULTS

The 2024 staging scheme accurately classified 95.5% AD. Among these, 56.5% exhibited concordant clinical and biological stages (canonical), 34.7% demonstrated more advanced clinical stages than biologically expected (susceptible), and 8.8% displayed the inverse pattern (resilient). The susceptible group was characterized by a higher burden of neurodegeneration and inflammation than anticipated from tau, whereas the resilient group showed the opposite.

DISCUSSION

The 2024 staging scheme is generally feasible. A discrepancy between clinical and biological stages is relatively frequent among symptomatic patients with AD.

HIGHLIGHTS

The 2024 AA staging scheme is generally feasible in a tertiary memory clinic. A discrepancy between clinical and biological stages is relatively frequent in AD. The mismatch may be influenced by a non-specific pathological process involved in AD. Individual profiles like aging and lifestyles may contribute to such a mismatch. Matched and mismatched cases converge toward similar clinical outcomes.

Association of modifiable risk factors with progression to dementia in relation to amyloid and tau pathology

BACKGROUND

Dementia preventive interventions targeting multiple modifiable risk factors are a promising approach. However, the impact of modifiable risk factors in the presence of beta-amyloid or phosphorylated-tau (p-tau) pathology is unclear.

METHODS

The objective of the study was to examine the role of modifiable risk factors (vascular factors, depression, and smoking) in the progression to mild cognitive impairment (MCI) or dementia among 434 cognitively unimpaired (CU) and 611 individuals with MCI from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Vascular risk factors were summarized with the Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) score, dichotomized into higher versus lower risk. Depression and smoking (yes/no) were categorised according to medical history or current symptoms. Analyses were stratified by beta-amyloid negative (A-) and positive (A +), p-tau negative (T-) and positive (T +), or beta-amyloid and p-tau negative (A-T-) and positive (A + T +) biomarker status. Cox proportional hazard models were adjusted for age, sex, education, baseline MMSE score, baseline hippocampal volume and ApoE4 carrier status.

RESULTS

Higher CAIDE score was associated with increased risk of progression to all-cause dementia in most MCI subgroups: adjusted hazard ratios (aHR) [95% CI] were 3.1 [1.43; 6.53] in the A- subgroup, 1.7 [1.20-2.27] in T + , 2.6 [1.06-6.59] in A-T-, and 1.6 [1.15-2.22] in the A + T + subgroup. Smoking (yes/no) was associated with increased dementia aHR in the A + MCI subgroup: 1.6 [1.07-2.34]. Depression increased dementia aHR in the T + MCI subgroup: 1.5 [1.06-2.02]. No significant associations were found in the CU biomarker subgroups.

CONCLUSION

Addressing modifiable risk factors carries an important potential for reducing the risk of dementia even after the onset of Alzheimer's pathology. Knowledge of biomarker status can further optimize prevention strategies.

Linking Environmental Genotoxins to Neurodegenerative Diseases Through Transcriptional Mutagenesis

Numerous lines of evidence suggest that DNA damage contributes to the initiation, progression, and severity of neurodegenerative diseases. However, the molecular mechanisms responsible for this relationship remain unclear. This review integrates historical data with contemporary findings to propose that DNA damage exacerbates neurodegenerative diseases by inducing transcription errors. First, we describe the scientific rationale and basic biological concepts that underpin this hypothesis. Then, we provide epidemiological, cellular, and molecular data to support this idea, and we describe new and recently published observations that suggest that the former high incidence of neurodegenerative disease in Guam may have been driven by DNA damage-induced transcription errors. Finally, we explore the long-term implications of these findings on our understanding of the impact of genotoxic stress on human aging and disease.

Nasal lymphatic obstruction of CSF drainage as a possible cause of Alzheimer's disease and dementia

Alzheimer's disease, the most common form of dementia among older adults, slowly destroys memory and thinking skills. In recent years, scientists have made tremendous progress in understanding Alzheimer's disease, still, they do not yet fully understand what causes the disease. This article proposes a novel etiology for Alzheimer's disease. Our hypothesis developed from a review of nuclear medicine scans, in which the authors observed a significant increase in nasal turbinate vasodilation and blood pooling in patients with hypertension, sleep apnea, diabetes and/or obesity, all risk factors for Alzheimer's disease. The authors propose that nasal turbinate vasodilation and resultant blood pooling lead to the obstruction of normal nasal lymphatic clearance of cerebrospinal fluid and its waste products from the brain. The nasal turbinate vasodilation, due to increased parasympathetic activity, occurs alongside the well-established increased sympathetic activity of the cardiovascular system as seen in patients with hypertension. The increased parasympathetic activity is likely due to an autonomic imbalance secondary to the increase in worldwide consumption of highly processed food associated with dysregulation of the glucose regulatory system. The authors' hypothesis offers a novel mechanism and a new paradigm for the etiology of Alzheimer's disease and helps explain the rapid worldwide rise in the disease and other dementias which are expected to double in the next 20 years. This new paradigm provides compelling evidence for the modulation of the parasympathetic nervous system as a novel treatment strategy for Alzheimer's disease and other degenerative brain diseases, specifically targeting nasal turbinate lymphatic flow.

Tobacco-enhanced biofilm formation by Porphyromonas gingivalis and other oral microbes

Microbial biofilms promote pathogenesis by disguising antigens, facilitating immune evasion, providing protection against antibiotics and other antimicrobials and, generally, fostering survival and persistence. Environmental fluxes are known to influence biofilm formation and composition, with recent data suggesting that tobacco and tobacco-derived stimuli are particularly important mediators of biofilm initiation and development in vitro and determinants of polymicrobial communities in vivo. The evidence for tobacco-augmented biofilm formation by oral bacteria, tobacco-induced oral dysbiosis, tobacco-resistance strategies, and bacterial physiology is summarized herein. A general overview is provided alongside specific insights gained through studies of the model and archetypal, anaerobic, Gram-negative oral pathobiont, Porphyromonas gingivalis.

Comparative evaluation of cigarette smoke and a heated tobacco product on microglial toxicity, oxidative stress and inflammatory response

BACKGROUND

Tobacco smoking is the leading cause of preventable death and disease worldwide, with over 8 million annual deaths attributed to cigarette smoking. This study investigates the impact of cigarette smoke and heated tobacco products (HTPs) on microglial function, focusing on toxicological profiles, inflammatory responses, and oxidative stress using ISO standard and clinically relevant conditions of exposure.

METHODS

We assessed cell viability, reactive oxygen species (ROS) production, lipid peroxidation, mitochondrial function, unfolded protein response, and inflammation in human microglial cells (HMC3) exposed to cigarette smoke, HTP aerosol or nicotine.

RESULTS

Our findings show that cigarette smoke significantly reduces microglial viability, increases ROS formation, induces lipid peroxidation, and reduces intracellular glutathione levels. Cigarette smoke also alters the expression of genes involved in mitochondrial dynamics and biogenesis, leading to mitochondrial dysfunction. Additionally, cigarette smoke impairs the unfolded protein response, activates the NF-κB pathway, and induces a pro-inflammatory state characterized by increased TNF and IL-18 expression. Furthermore, cigarette smoke causes DNA damage and decreases the expression of the aging marker Klotho β. In contrast, HTP, exhibited a lesser degree of microglial toxicity, with reduced ROS production, lipid peroxidation, and mitochondrial dysfunction compared to conventional cigarettes.

CONCLUSION

These results highlight the differential toxicological profile of cigarette smoke and HTP on microglial cells, suggesting a potential harm reduction strategy for neurodegenerative disease for smokers unwilling or unable to quit.

Nongenetic and Genetic Factors Associated with White Matter Brain Aging: Exposome-Wide and Genome-Wide Association Study

BACKGROUND/OBJECTIVES

Human brain aging is a complex process that affects various aspects of brain function and structure, increasing susceptibility to neurological and psychiatric disorders. A number of nongenetic (e.g., environmental and lifestyle) and genetic risk factors are found to contribute to the varying rates at which the brain ages among individuals.

METHODS

In this paper, we conducted both an exposome-wide association study (XWAS) and a genome-wide association study (GWAS) on white matter brain aging in the UK Biobank, revealing the multifactorial nature of brain aging. We applied a machine learning algorithm and leveraged fractional anisotropy tract measurements from diffusion tensor imaging data to predict the white matter brain age gap (BAG) and treated it as the marker of brain aging. For XWAS, we included 107 variables encompassing five major categories of modifiable exposures that potentially impact brain aging and performed both univariate and multivariate analysis to select the final set of nongenetic risk factors.

RESULTS

We found current tobacco smoking, dietary habits including oily fish, beef, lamb, cereal, and coffee intake, length of mobile phone use, use of UV protection, and frequency of solarium/sunlamp use were associated with the BAG. In genetic analysis, we identified several SNPs on chromosome 3 mapped to genes IP6K1, GMNC, OSTN, and SLC25A20 significantly associated with the BAG, showing the high heritability and polygenic architecture of human brain aging.

CONCLUSIONS

The critical nongenetic and genetic risk factors identified in our study provide insights into the causal relationship between white matter brain aging and neurodegenerative diseases.

Clinical and Sociodemographic Factors Related to Amyotrophic Lateral Sclerosis in Spain: A Pilot Study

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of unknow etiology. Male sex is a well stablished risk factor, but other factors such as early and adult life expositions show contradictory evidence. Aim: to explore the link of clinical, sociodemographic, and occupational factors with ALS patients in Spain and the impact of these factors in functionality. Methods: A cross-sectional study was conducted with ALS patients and healthy controls. Registered variables were smoking, arterial hypertension, diabetes mellitus type 2, previous cancer to reproductive organs or breast, occupational exposure, and early life exposures. Functionality in ALS patients was compared according to each exposure. Results: The ALS group consisted of 59 participants and the control group of 90 participants. ALS patients showed a significant association with previous cancer (p = 0.011), occupational exposure (p < 0.001), and older siblings (p = 0.029). ALS patients presented significant differences in BMI according to hypertension and older-sibling factors. Moreover, respiratory function was affected in patients with previous cancer (p = 0.031). Conclusions: Occupational exposure and previous cancer to reproductive organs or breast could be linked to ALS patients. In addition, hypertension and previous cancer could affect their BMI and respiratory function. Other factors such as longer smoking periods and exposition to older siblings could also characterize ALS patients.

Association of education attainment, smoking status, and alcohol use disorder with dementia risk in older adults: a longitudinal observational study

BACKGROUND

Previous research on the risk of dementia associated with education attainment, smoking status, and alcohol use disorder (AUD) has yielded inconsistent results, indicating potential heterogeneous treatment effects (HTEs) of these factors on dementia risk. Thus, this study aimed to identify the important variables that may contribute to HTEs of these factors in older adults.

METHODS

Using 2005-2021 data from the National Alzheimer's Coordinating Center (NACC), we included older adults (≥ 65 years) with normal cognition at the first visit. The exposure of interest included college education or above, current smoking, and AUD and the outcome was all-cause dementia. We applied doubly robust learning to estimate risk differences (RD) and 95% confidence intervals (CI) between exposed and unexposed groups in the overall cohort and subgroups identified through a decision tree model.

RESULTS

Of 10,062 participants included, 929 developed all-cause dementia over a median 4.4-year follow-up. College education or above was associated with a lower risk of all-cause dementia in the overall population (RD, -1.5%; 95%CI, -2.8 to -0.3), especially among the subpopulations without hypertension, regardless of the APOE4 status. Current smoking was not related to increased dementia risk overall (2.8%; -1.5 to 7.2) but was significantly associated with increased dementia risk among men with (21.1%, 3.1 to 39.1) and without (8.4%, 0.9 to 15.8) cerebrovascular disease. AUD was not related to increased dementia risk overall (2.0%; -7.7 to 11.7) but was significantly associated with increased dementia risk among men with neuropsychiatric disorders (31.5%; 7.4 to 55.7).

CONCLUSIONS

Our studies identified important factors contributing to HTEs of education, smoking, and AUD on risk of all-cause dementia, suggesting an individualized approach is needed to address dementia disparities.

Neuropathology and neuroinflammation in Alzheimer's disease via bidirectional lung-brain axis

Alzheimer's disease (AD) is the most common form of age-related dementia worldwide. Although the neuropathology of AD is clear, its pathogenesis remains unclear. Recently, conceptualising AD as brain-centred has reoriented many scientists because the close functional relationship between the peripheral and central nerves is increasingly recognised. Recently, various studies have focused on the crosstalk between peripherals and centrals. A new hotspot of research and new therapeutic strategies have emerged from this great progress. This mini-review is an overview of the potential molecular mechanism in AD via the bidirectional lung-brain axis, providing a new perspective for the systemic understanding of AD onset.

Association between Life's Essential 8 and cognitive function among older adults in the United States

The American Heart Association (AHA) recently redefined cardiovascular health (CVH) with the introduction of Life's Essential 8 (LE8), which encompasses eight areas (diet, physical activity, nicotine exposure, sleep duration body mass index, non-HDL cholesterol, blood glucose, and blood pressure). This study aimed to explore the relationships between both the aggregate and individual CVH metrics, as defined by Life's Essential 8, and cognitive function in older adults in the United States. This cross-sectional, population-based study analyzed data from the National Health and Nutrition Examination Survey conducted between 2011 and 2014, focusing on individuals aged 60 years and older. CVH was categorized as low (0-49), moderate (50-79), or high (80-100). Cognitive function was assessed through the CERAD tests, Animal Fluency test, and Digit Symbol Substitution test. Multivariable logistic models and restricted cubic spline models were employed to investigate these associations. This study included a total of 2279 older adults in the United States. Only 11% of adults achieved a high total CVH score, while 12% had a low score. After further adjustment for potential confounding factors, higher LE8 scores were significantly associated with higher scores on CERAD: delayed recall score (0.02[0.01, 0.03]; P < 0.001), CERAD: total score (3 recall trials) (0.04[0.02, 0.06]; P < 0.001), animal fluency: total score (0.09[0.05, 0.12]; P < 0.001), and digit symbol: score (0.29[0.18, 0.41]; P < 0.001), demonstrating a linear dose-response relationship. Similar patterns were also observed in the associations between health behavior and health factor scores with cognitive function tests. LE8 scores exhibited positive linear associations with cognitive function. Maintaining better levels of CVH may be associated with higher levels of cognitive function in older Americans, but further research is needed to confirm the causal and temporal relationships between LE8 and cognitive function.

Could the Early Detection of Atrial Fibrillation Reduce the Risk of Developing Dementia?

Atrial fibrillation (AF) and dementia are major global public health issues and share common risk factors, especially after the age of 65 and regardless of the presence of stroke. Despite accounting for potential confounders, AF appears to be an independent risk factor for cognitive decline and dementia. The mechanisms are likely to be multifactorial and may include AF-related ischemic stroke, cerebral hypoperfusion, microbleeds, systemic inflammation, genetic factors, and small vessel disease, leading to brain atrophy and white matter damage. The early aggressive management of AF and comorbidities may reduce the risk of dementia. Indeed, the early detection of AF-related cognitive impairment should allow for the early implementation of measures to prevent the development of dementia, mainly through integrative approaches involving the correction of risk factors and maintenance of rhythm control. Well-designed prospective studies are needed to determine whether early detection and AF treatment can prevent dementia and identify whether optimal integrative measures are effective in preventing cognitive impairment and dementia.

Neurological Disorders Induced by Drug Use: Effects of Adolescent and Embryonic Drug Exposure on Behavioral Neurodevelopment

Clinical studies demonstrate that the risk of developing neurological disorders is increased by overconsumption of the commonly used drugs, alcohol, nicotine and cannabis. These drug-induced neurological disorders, which include substance use disorder (SUD) and its co-occurring emotional conditions such as anxiety and depression, are observed not only in adults but also with drug use during adolescence and after prenatal exposure to these drugs, and they are accompanied by long-lasting disturbances in brain development. This report provides overviews of clinical and preclinical studies, which confirm these adverse effects in adolescents and the offspring prenatally exposed to the drugs and include a more in-depth description of specific neuronal systems, their neurocircuitry and molecular mechanisms, affected by drug exposure and of specific techniques used to determine if these effects in the brain are causally related to the behavioral disturbances. With analysis of further studies, this review then addresses four specific questions that are important for fully understanding the impact that drug use in young individuals can have on future pregnancies and their offspring. Evidence demonstrates that the adverse effects on their brain and behavior can occur: (1) at low doses with short periods of drug exposure during pregnancy; (2) after pre-conception drug use by both females and males; (3) in subsequent generations following the initial drug exposure; and (4) in a sex-dependent manner, with drug use producing a greater risk in females than males of developing SUDs with emotional conditions and female offspring after prenatal drug exposure responding more adversely than male offspring. With the recent rise in drug use by adolescents and pregnant women that has occurred in association with the legalization of cannabis and increased availability of vaping tools, these conclusions from the clinical and preclinical literature are particularly alarming and underscore the urgent need to educate young women and men about the possible harmful effects of early drug use and to seek novel therapeutic strategies that might help to limit drug use in young individuals.

Pro-atherogenic medical conditions are associated with widespread regional brain metabolite abnormalities in those with alcohol use disorder

AIMS

Widespread brain metabolite abnormalities in those with alcohol use disorder (AUD) were reported in numerous studies, but the effects of the pro-atherogenic conditions of hypertension, type 2 diabetes mellitus, hepatitis C seropositivity, and hyperlipidemia on metabolite levels were not considered. These conditions were associated with brain metabolite abnormalities in those without AUD. We predicted treatment-seeking individuals with AUD and pro-atherogenic conditions (Atherogenic+) demonstrate lower regional metabolite markers of neuronal viability [N-acetylaspartate (NAA)] and cell membrane turnover/synthesis [choline-containing compounds (Cho)], compared with those with AUD without pro-atherogenic conditions (Atherogenic-) and healthy controls (CON).

METHODS

Atherogenic+ (n = 59) and Atherogenic- (n = 51) and CON (n = 49) completed a 1.5 T proton magnetic resonance spectroscopic imaging study. Groups were compared on NAA, Cho, total creatine, and myoinositol in cortical gray matter (GM), white matter (WM), and select subcortical regions.

RESULTS

Atherogenic+ had lower frontal GM and temporal WM NAA than CON. Atherogenic+ showed lower parietal GM, frontal, parietal and occipital WM and lenticular nuclei NAA level than Atherogenic- and CON. Atherogenic- showed lower frontal GM and WM NAA than CON. Atherogenic+ had lower Cho level than CON in the frontal GM, parietal WM, and thalamus. Atherogenic+ showed lower frontal WM and cerebellar vermis Cho than Atherogenic- and CON.

CONCLUSIONS

Findings suggest proatherogenic conditions in those with AUD were associated with increased compromise of neuronal integrity and cell membrane turnover/synthesis. The greater metabolite abnormalities observed in Atherogenic+ may relate to increased oxidative stress-related compromise of neuronal and glial cell structure and/or impaired arterial vasoreactivity/lumen viability.

Association of modified dementia risk score with cerebrospinal fluid biomarkers and cognition in adults without dementia

Introduction

This study aimed to investigate the cognitive profile and prospective cognitive changes in non-demented adults with elevated Modified Dementia Risk Scores (MDRS), while also exploring the potential relationship between these associations and cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) pathology and neuroinflammation.

Methods

Within the Chinese Alzheimer's Biomarker and LifestylE (CABLE) database, 994 participants without dementia were assessed on MDRS, CSF biomarkers and cognition. We examined the associations of the MDRS with CSF biomarkers and cognitive scores using linear regressions. Causal mediation analyses were conducted to analyze the associations among MDRS, brain pathologies, and cognition. The Alzheimer's Disease Neuroimaging Initiative (ADNI) study was used to validate the mediation effects and to investigate the longitudinal association between MDRS and cognitive decline.

Results

The results revealed that higher MDRS were linked to poorer cognitive performance (Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001) and increases in CSF levels of phosphorylated tau (P-tau, Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001), total tau (T-tau, Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001), P-tau/Aβ42 ratio (Model 1: PFDR  = 0.023; Model 2: PFDR  = 0.028), T-tau/Aβ42 ratio (Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001) and soluble triggering receptor expressed on myeloid cells 2 (sTrem2, Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001) in the CABLE study. The impact of MDRS on cognition was partially mediated by neuroinflammation and tau pathology. These mediation effects were replicated in the ADNI study. Baseline MDRS were significantly associated with future cognitive decline, as indicated by lower scores on the Mini-Mental State Examination (MMSE, Model 1: PFDR  = 0.045; Model 2: PFDR  < 0.001), ADNI composite memory score (ADNI-MEM, Model 1: PFDR  = 0.005; Model 2: PFDR  < 0.001), ADNI composite executive function score (ADNI-EF, Model 1: PFDR  = 0.045; Model 2: PFDR  < 0.001), and higher score on the Alzheimer's Disease Assessment Scale (ADAS13, Model 1: PFDR  = 0.045; Model 2: PFDR  < 0.001).

Discussion

The findings of this study revealed significant associations between MDRS and cognitive decline, suggesting a potential role of tau pathology and neuroinflammation in the link between MDRS and poorer cognitive performance in individuals without dementia. Consequently, the MDRS holds promise as a tool for targeted preventive interventions in individuals at high risk of cognitive impairment.

Increased molar ratio of free fatty acids to albumin in blood as cause and early biomarker for the development of cataracts and Alzheimer's disease

Cataracts and Alzheimer's disease (AD) are closely linked and are associated with aging and with systemic diseases that increase the molar ratio of free fatty acids to albumin (mFAR) in the blood. From the results of our earlier studies on the development of senile cataracts and from results recently published in the literature on the pathogenesis of Alzheimer's disease, we suggest that there is a common lipotoxic cascade for both diseases, explaining the strong connection between aging, an elevated mFAR in the blood, cataract formation, and AD. Long-chain free fatty acids (FFA) are transported in the blood as FFA/albumin complexes. In young people, vascular albumin barriers in the eyes and brain, very similar in their structure and effect, reduce the FFA/albumin complex concentration from around 650 μmol/l in the blood to 1-3 μmol/l in the aqueous humour of the eyes as well as in the cerebrospinal fluid of the brain. At such low concentrations the fatty acid uptake of the target cells - lens epithelial and brain cells - rises with increasing FFA/albumin complex concentrations, especially when the fatty acid load of albumin molecules is mFAR>1. At higher albumin concentrations, for instance in blood plasma or the interstitial tissue spaces, the fatty acid uptake of the target cells becomes increasingly independent of the FFA/albumin complex concentration and is mainly a function of the mFAR (Richieri et al., 1993). In the blood plasma of young people, the mFAR is normally below 1.0. In people over 40 years old, aging increases the mFAR by decreasing the plasma concentration of albumin and enhancing the plasma concentrations of FFA. The increase in the mFAR in association with C6-unsaturated FFA are risk factors for the vascular albumin barriers (Hennig et al., 1984). Damage to the vascular albumin barrier in the eyes and brain increases the concentration of FFA/albumin complex in the aqueous humour as well as in the cerebrospinal fluid, leading to mitochondrial dysfunction and the death of lens epithelial and brain cells, the development of cataracts, and AD. An age-dependent increase in the concentration of FFA/albumin complex has been found in the aqueous humour of 177 cataract patients, correlating with the mitochondria-mediated apoptotic death of lens epithelial cells, lens opacification and cataracts (Iwig et al., 2004). Mitochondrial dysfunction is also an early crucial event in Alzheimer's pathology, closely connected with the generation of amyloid beta peptides (Leuner et al., 2012). Very recently, amyloid beta production has also been confirmed in the lenses of Alzheimer's patients, causing cataracts (Moncaster et al., 2022). In view of this, we propose that there is a common lipotoxic cascade for senile cataract formation and senile AD, initiated by aging and/or systemic diseases, leading to an mFAR>1 in the blood.

Early- and Late-Onset Alzheimer's Disease: Two Sides of the Same Coin?

Early-onset Alzheimer's disease (EOAD), defined as Alzheimer's disease onset before 65 years of age, has been significantly less studied than the "classic" late-onset form (LOAD), although EOAD often presents with a more aggressive disease course, caused by variants in the APP, PSEN1, and PSEN2 genes. EOAD has significant differences from LOAD, including encompassing diverse phenotypic manifestations, increased genetic predisposition, and variations in neuropathological burden and distribution. Phenotypically, EOAD can be manifested with non-amnestic variants, sparing the hippocampi with increased tau burden. The aim of this article is to review the different genetic bases, risk factors, pathological mechanisms, and diagnostic approaches between EOAD and LOAD and to suggest steps to further our understanding. The comprehension of the monogenic form of the disease can provide valuable insights that may serve as a roadmap for understanding the common form of the disease.

Associations of vitamin D receptor polymorphisms with risk of Alzheimer's disease, Parkinson's disease, and mild cognitive impairment: a systematic review and meta-analysis

Vitamin D is a lipid soluble steroid hormone, which plays a critical role in the calcium homeostasis, neuronal development, cellular differentiation, and growth by binding to vitamin D receptor (VDR). Associations between VDR gene polymorphism and Alzheimer's disease (AD), Parkinson's disease (PD), and mild cognitive impairment (MCI) risk has been investigated extensively, but the results remain ambiguous. The aim of this study was to comprehensively assess the correlations between four VDR polymorphisms (FokI, BsmI, TaqI, and ApaI) and susceptibility to AD, PD, and MCI. Crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to determine the relationship of interest. Pooled analyses suggested that the ApaI polymorphism decreased the overall AD risk, and the TaqI increased the overall PD susceptibility. In addition, the BsmI and ApaI polymorphisms were significantly correlated with the overall MCI risk. Stratified analysis by ethnicity further showed that the TaqI and ApaI genotypes reduced the AD predisposition among Caucasians, while the TaqI polymorphism enhanced the PD risk among Asians. Intriguingly, carriers with the BB genotype significantly decreased the MCI risk in Asian descents, and the ApaI variant elevated the predisposition to MCI in Caucasians and Asians. Further studies are need to identify the role of VDR polymorphisms in AD, PD, and MCI susceptibility.

Influence of Cigarette Aerosol in Alpha-Synuclein Oligomerization and Cell Viability in SH-SY5Y: Implications for Parkinson's Disease

Although cigarette aerosol exposure is associated with various adverse health issues, its impact on Parkinson's disease (PD) remains elusive. Here, we investigated the effect of cigarette aerosol extract (CAE) on SH-SY5Y cells for the first time, both with and without α-synuclein (α-Syn) overexpression. We found that α-Syn aggravates CAE-induced cell death, oxidative stress, and mitochondrial dysfunction. Fluorescence cross-correlation spectroscopy (FCCS) revealed a dual distribution of α-Syn within the cells, with homogeneous regions indicative of monomeric α-Syn and punctated regions, suggesting the formation of oligomers. Moreover, we observed colocalization of α-Syn oligomers with lysosomes along with a reduction in autophagy activity. These findings suggest that α-Syn overexpression exacerbates CAE-induced intracellular cytotoxicity, mitochondrial dysfunction, and autophagy dysregulation, leading to elevated cell mortality. Our findings provide new insights into the pathogenic mechanisms linking exposure to cigarette aerosols with neurodegenerative diseases.

Exploring the link between comorbidities and Alzheimer's dementia in the Australian Imaging, Biomarker & Lifestyle (AIBL) study

INTRODUCTION

Mounting evidence suggests that certain comorbidities may influence the clinical evolution of Alzheimer's dementia (AD).

METHODS

We conducted logistic regression analyses on the medical history and cognitive health diagnoses of participants in the Australian Imaging, Biomarker & Lifestyle study (n = 2443) to investigate cross-sectional associations between various comorbidities and mild cognitive impairment (MCI)/AD.

RESULTS

A mixture of associations were observed. Higher comorbidity of anxiety and other neurological disorders was associated with higher odds of AD, while arthritis, cancer, gastric complaints, high cholesterol, joint replacement, visual defect, kidney and liver disease were associated with lower odds of AD.

DISCUSSION

This study underscores the links between specific comorbidities and MCI/AD. Further research is needed to elucidate the longitudinal comorbidity-MCI/AD associations and underlying mechanisms of these associations.

Highlights

Comorbidities that significantly increased AD odds included anxiety and other neurological disorders.Arthritis, cancer, gastric complaints, high cholesterol, joint replacement, visual defect, kidney and liver disease were associated with lower odds of AD.Alcohol consumption had the most significant confounding effect in the study.Visual-AD association was modified by age, sex, and APOE ε4 allele status.Anxiety-AD and depression-AD associations were modified by sex.

Genetic causal role of body mass index in multiple neurological diseases

Body mass index (BMI) is a crucial health indicator for obesity. With the progression of socio-economic status and alterations in lifestyle, an increasing number of global populations are at risk of obesity. Given the complexity and severity of neurological diseases, early identification of risk factors is vital for the diagnosis and prognosis of such diseases. In this study, we employed Mendelian randomization (MR) analysis utilizing the most comprehensive genome-wide association study (GWAS) data to date. We selected single nucleotide polymorphisms (SNPs) that are unaffected by confounding factors and reverse causality as instrumental variables. These variables were used to evaluate the genetic and causal relationships between Body Mass Index (BMI) and various neurological diseases, including Parkinson's Disease (PD), Alzheimer's Disease (AD), Amyotrophic Lateral Sclerosis (ALS), Multiple Sclerosis (MS), Ischemic Stroke (IS), and Epilepsy (EP). The Inverse Variance Weighted (IVW) analysis indicated that there was no significant causal relationship between Body Mass Index (BMI) indicators and PD (P-value = 0.511), AD (P-value = 0.076), ALS (P-value = 0.641), EP (P-value = 0.380). However, a causal relationship was found between BMI indicators and MS (P-value = 0.035), and IS (P-value = 0.000), with the BMI index positively correlated with the risk of both diseases. The Cochran's Q test for MR-IVW showed no heterogeneity in the MR analysis results between the BMI index and the neurological diseases (P > 0.05). The Egger intercept test for pleiotropy revealed no horizontal pleiotropy detected in any of the neurological diseases studied (P > 0.05). It was found that there was no causal relationship between BMI and PD, AD, ALS, EP, and a genetic causal association with MS, and IS. Meanwhile, the increase in BMI can lead to a higher risk of MS and IS, which reveals the critical role of obesity as a risk factor for specific neurological diseases in the pathogenesis of the diseases.

In Vitro Evaluation of the Antioxidant Capacity of 3,3-Disubstituted-3H-benzofuran-2-one Derivatives in a Cellular Model of Neurodegeneration

Oxidative stress represents a hallmark for many degenerative pathologies of the Central Nervous System. Throughout life, the constant pressure of noxious stimuli and/or episodes of traumatic events may expose the brain to a microenvironment where the non-balanced reactive oxygen species inevitably lead to neuronal loss and cognitive decline. HO-1, a 32 kDa heat-shock protein catalyzing the degradation of heme into carbon monoxide (CO), iron and biliverdin/bilirubin is considered one of the main antioxidant defense mechanisms playing pivotal roles in neuroprotection. Restoring the redox homeostasis is the goal of many natural or synthetic antioxidant molecules pursuing beneficial effects on brain functions. Here, we investigated the antioxidant capacity of four selected benzofuran-2-one derivatives in a cellular model of neurodegeneration represented by differentiated SH-SY5Y cells exposed to catechol-induced oxidative stress. Our main results highlight how all the molecules have antioxidant properties, especially compound 9, showing great abilities in reducing intracellular ROS levels and protecting differentiated SH-SY5Y cells from catechol-induced death. This compound above all seems to boost HO-1 mRNA and perinuclear HO-1 protein isoform expression when cells are exposed to the oxidative insult. Our findings open the way to consider benzofuran-2-ones as a novel and promising adjuvant antioxidant strategy for many neurodegenerative disorders.

Putative Molecular Mechanisms Underpinning the Inverse Roles of Mitochondrial Respiration and Heme Function in Lung Cancer and Alzheimer's Disease

Mitochondria are the powerhouse of the cell. Mitochondria serve as the major source of oxidative stress. Impaired mitochondria produce less adenosine triphosphate (ATP) but generate more reactive oxygen species (ROS), which could be a major factor in the oxidative imbalance observed in Alzheimer's disease (AD). Well-balanced mitochondrial respiration is important for the proper functioning of cells and human health. Indeed, recent research has shown that elevated mitochondrial respiration underlies the development and therapy resistance of many types of cancer, whereas diminished mitochondrial respiration is linked to the pathogenesis of AD. Mitochondria govern several activities that are known to be changed in lung cancer, the largest cause of cancer-related mortality worldwide. Because of the significant dependence of lung cancer cells on mitochondrial respiration, numerous studies demonstrated that blocking mitochondrial activity is a potent strategy to treat lung cancer. Heme is a central factor in mitochondrial respiration/oxidative phosphorylation (OXPHOS), and its association with cancer is the subject of increased research in recent years. In neural cells, heme is a key component in mitochondrial respiration and the production of ATP. Here, we review the role of impaired heme metabolism in the etiology of AD. We discuss the numerous mitochondrial effects that may contribute to AD and cancer. In addition to emphasizing the significance of heme in the development of both AD and cancer, this review also identifies some possible biological connections between the development of the two diseases. This review explores shared biological mechanisms (Pin1, Wnt, and p53 signaling) in cancer and AD. In cancer, these mechanisms drive cell proliferation and tumorigenic functions, while in AD, they lead to cell death. Understanding these mechanisms may help advance treatments for both conditions. This review discusses precise information regarding common risk factors, such as aging, obesity, diabetes, and tobacco usage.

Elevated serum LDL-C increases the risk of Lewy body dementia: a two-sample mendelian randomization study

BACKGROUND

Lewy body dementia (LBD) ranks second among prevalent neurodegenerative dementias. Previous studies have revealed associations of serum lipid measures with several neurodegenerative diseases. Nevertheless, the potential connection between serum lipids and LBD remains undetermined. In this study, Mendelian randomization (MR) analyses were carried out to assess the causal relationships of several serum lipid measures with the risk of developing LBD.

METHODS

Genome-wide association study (GWAS) data for serum lipids and LBD in European descent individuals were acquired from publicly available genetic summary data. A series of filtering procedures were conducted to identify the genetic variant candidates that are related to serum lipids, including high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). The causal effects were primarily determined through inverse-variance weighting (IVW)-based analyses.

RESULTS

Neither TG (odds ratio [OR] = 1.149; 95% confidence interval [CI], 0.887-1.489; P = 0.293) nor HDL-C (OR = 0.864; 95% CI, 0.718-1.041; P = 0.124) had causal effects on LBD. However, a causal relationship was identified between LDL-C and LBD (OR = 1.343; 95% CI, 1.094-1.649; P = 0.005), which remained significant (OR = 1.237; 95% CI, 1.015-1.508; P = 0.035) following adjustment for HDL-C and TG in multivariable MR.

CONCLUSIONS

Elevated serum LDL-C increases the risk of LBD, while HDL-C and TG have no significant causal effects on LBD.

Correlation analysis between smoke exposure and serum neurofilament light chain in adults: a cross-sectional study

BACKGROUND

Smoke exposure is a prevalent and well-documented risk factor for various diseases across different organ systems. Serum neurofilament light chain (sNfL) has emerged as a promising biomarker for a multitude of nervous system disorders. However, there is a notable paucity of research exploring the associations between smoke exposure and sNfL levels.

METHODS

We conducted a comprehensive analysis of the National Health and Nutrition Examination Survey (NHANES) cross-sectional data spanning the years 2013 to 2014. Serum cotinine levels were classified into the following three groups: < 0.05, 0.05-2.99, and ≥ 3 ng/ml. Multiple linear regression models were employed to assess the relationships between serum cotinine levels and sNfL levels. Additionally, we utilized restricted cubic spline analyses to elucidate the potential nonlinear relationship between serum cotinine and sNfL levels.

RESULTS

A total of 2053 participants were included in our present research. Among these individuals, the mean age was 47.04 ± 15.32 years, and males accounted for 48.2% of the total study population. After adjusting the full model, serum cotinine was positively correlated with sNfl in the second group (β = 0.08, 95%CI 0.01-0.15) and in the highest concentration of serum cotinine (β = 0.10, 95%CI 0.01-0.19) compared to the group with the lowest serum cotinine concentrations. Current smokers, in comparison to non-smokers, exhibited a trend toward elevated sNfL levels (β = 0.07, 95%CI 0.01-0.13). Furthermore, subgroup analyses revealed interactions between serum cotinine levels and different age groups (P for interaction = 0.001) and gender stratification (P for interaction = 0.015) on sNfL levels.

CONCLUSION

The study suggested that serum cotinine was significantly and positively associated with sNfl levels in adult participants. Furthermore, current smokers tend to exhibit elevated sNfL levels. This research sheds light on the potential implications of smoke exposure on neurological function impairment and underscores the importance of further exploration in this area.

Association of Chronic Obstructive Pulmonary Disease with Risk of Psychiatric Disorders: A Two-Sample Mendelian Randomization Study

Background

Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory disorder often accompanied by comorbidities. Although the past few years have witnessed significant scientific progress, the potential relationship between COPD and mental illness remains a subject of debate.

Materials and Methods

We retrieved COPD data from the genome-wide association studies (GWAS) directory and data on mental illnesses, including Alzheimer's disease, schizophrenia, panic disorder, attention deficit hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder, multiple disabilities, obsessive-compulsive disorder, post-traumatic stress disorder, and schizophrenia, from the Psychiatric Genomics Consortium. A two-sample Mendelian randomization (MR) approach was applied to explore the association between COPD and mental illnesses, with subgroup analyses based on smoking history.

Results

Our two-sample MR analysis revealed no causal link between overall COPD and the development of common psychiatric disorders. Subgroup analyses based on smoking history showed no causal association between never-smokers with COPD and the occurrence of psychiatric disorders. However, ever-smokers with COPD were associated with a significantly increased risk of ADHD (OR: 2.303, 95% CI: 1.558-3.403, P = 0.001) and a modestly reduced risk of Alzheimer's disease (OR: 0.994, 95% CI: 0.988-0.999, P = 0.034).

Conclusion

COPD patients with a history of smoking face a higher risk of developing ADHD but may experience a slight reduction in the risk of Alzheimer's disease. Conversely, there was no observed causal association between COPD and psychiatric disorders among patients who never smoked.