Risk of dementia among patients with asthma: a nationwide longitudinal study

House dust mite-induced asthma exacerbates Alzheimer's disease changes in the brain of the AppNL-G-F mouse model of disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) plaques, neuroinflammation, and neuronal death. Besides aging, various comorbidities increase the risk of AD, including obesity, diabetes, and allergic asthma. Epidemiological studies have reported a 2.17-fold higher risk of dementia in asthmatic patients. However, the molecular mechanism(s) underlying this asthma-associated AD exacerbation is unknown. This study was designed to explore house dust mite (HDM)-induced asthma effects on AD-related brain changes using the AppNL-G-F transgenic mouse model of disease. Male and female 8-9 months old C57BL/6J wild type and AppNL-G-F mice were exposed to no treatment, saline sham, or HDM extract every alternate day for 16 weeks for comparison across genotypes and treatment. Mice were euthanized at the end of the experiment, and broncho-alveolar lavage fluid (BALF), blood, lungs, and brains were collected. BALF was used to quantify immune cell phenotype, cytokine levels, total protein content, lactate dehydrogenase (LDH) activity, and total IgE. Lungs were sectioned and stained with hematoxylin and eosin, Alcian blue, and Masson's trichrome. Serum levels of cytokines and soluble Aβ1-40/42 were quantified. Brains were sectioned and immunostained for Aβ, GFAP, CD68, and collagen IV. Finally, frozen hippocampi and temporal cortices were used to perform Aβ ELISAs and cytokine arrays, respectively. HDM exposure led to increased levels of inflammatory cells, cytokines, total protein content, LDH activity, and total IgE in the BALF, as well as increased pulmonary mucus and collagen staining in both sexes and genotypes. Levels of serum cytokines increased in all HDM-exposed groups. Serum from the AppNL-G-F HDM-induced asthma group also had significantly increased soluble Aβ1-42 levels in both sexes. In agreement with this peripheral change, hippocampi from asthma-induced male and female AppNL-G-F mice demonstrated elevated Aβ plaque load and increased soluble Aβ 1-40/42 and insoluble Aβ 1-40 levels. HDM exposure also increased astrogliosis and microgliosis in both sexes of AppNL-G-F mice, as indicated by GFAP and CD68 immunoreactivity, respectively. Additionally, HDM exposure elevated cortical levels of several cytokines in both sexes and genotypes. Finally, HDM-exposed groups also showed a disturbed blood-brain-barrier (BBB) integrity in the hippocampus of AppNL-G-F mice, as indicated by decreased collagen IV immunoreactivity. HDM exposure was responsible for an asthma-like condition in the lungs that exacerbated Aβ pathology, astrogliosis, microgliosis, and cytokine changes in the brains of male and female AppNL-G-F mice that correlated with reduced BBB integrity. Defining mechanisms of asthma effects on the brain may identify novel therapeutic targets for asthma and AD.

LRRK2 G2019S enhances immune response pathways and aggravates asthma in mouse models

Asthma is a complex inflammatory airway disease that arises from the interplay between genetic predisposition and environmental influences. Leucine-rich repeat kinase 2 (LRRK2), a gene commonly associated with Parkinson's disease, has recently gained attention for its role in immune regulation and inflammation beyond the brain. However, its involvement in asthma has not yet been reported. In this study, we used LRRK2 G2019S transgenic mice and LRRK2 knockout mice to establish asthmatic models to explore LRRK2 impact on asthma. We found that LRRK2 G2019S transgenic mice showed exacerbated airway hyperresponsiveness (AHR) and airway inflammation in asthma mouse models induced by house dust mite. RNA sequencing data unveiled that the LRRK2 G2019S mutation enhanced immune response pathways, including NOD-like receptor, cellular response to interferon β and activation of innate immune response signaling. Conversely, LRRK2 deficiency attenuated AHR and airway inflammation in the same asthma models. Our study offers new insights into the role of LRRK2 in allergic inflammation and highlights its potential as a therapeutic target for asthma.

Alzheimer incidence and prevalence with and without asthma: A Medicare cohort study

BACKGROUND

International data suggest that asthma, like other inflammatory diseases, might increase Alzheimer disease (AD) risk.

OBJECTIVE

We sought to explore risk pathways and future mitigation strategies by comparing diagnostic claims-based AD incidence and prevalence among US patients with asthma with those without asthma.

METHODS

This cohort study included a national Medicare 20% random sample (2013-2015). Adult patients with asthma with more than 12 months continuous Medicare were compared with subjects without asthma overall and as matched. Asthma was defined by 1 inpatient or 2 outpatient codes for asthma. The main outcomes were 2-year incident or prevalent AD defined by International Classification of Diseases, Ninth Revision code 331.0 or Tenth Revision code G30.0, G30.1, G30.8, or G30.9.

RESULTS

Among 5,460,732 total beneficiaries, 678,730 patients were identified with baseline asthma and more often identified as Black or Hispanic, were Medicaid eligible, or resided in a highly disadvantaged neighborhood than those without asthma. Two-year incidence of AD was 1.4% with asthma versus 1.1% without asthma; prevalence was 7.8% versus 5.4% (both P ≤ .001). Per 100,000 patients over 2 years, 303 more incident AD diagnoses occurred in those with asthma, with 2,425 more prevalent cases (P < .001). Multivariable models showed that asthma had greater odds of 2-year AD incidence (adjusted odds ratio, 1.33 [95% CI, 1.29-1.36]; matched 1.2 [95% CI, 1.17-1.24]) and prevalence (adjusted odds ratio, 1.48 [95% CI, 1.47-1.50]; matched 1.25 [95% CI, 1.22-1.27]).

CONCLUSIONS

Asthma was associated with 20% to 33% increased 2-year incidence and 25% to 48% increased prevalence of claims-based AD in this nationally representative US sample. Future research should investigate risk pathways of underlying comorbidities and social determinants as well as whether there are potential asthma treatments that may preserve brain health.

Potential association between obstructive lung diseases and cognitive decline

Introduction

Chronic obstructive lung diseases, such as asthma and COPD, appear to have a more extensive impact on overall functioning than previously believed. The latest data from clinical trials suggests a potential link between cognitive deterioration and chronic obstructive inflammatory lung disease. This raises the question of whether these diseases affect cognitive functions and whether any relevant biomarker may be identified.

Methods

This prospective observational study included 78 patients divided equally into asthma, COPD, and control groups (n=26, 27 and 25 respectively). The participants underwent identical examinations at the beginning of the study and after at least 12 months. The test battery comprised 16 questionnaires (11 self-rated, 5 observer-rated, assessing cognition and mental state), spirometry, and blood samples taken for PKA and CREB mRNA evaluation.

Results

A 2.3-fold increase in CREB mRNA was observed between examinations (p=0.014) for all participants; no distinctions were observed between the asthma, COPD, and control groups. Pooled, adjusted data revealed a borderline interaction between diagnosis and CREB expression in predicting MMSE (p=0.055) in COPD, CREB expression is also associated with MMSE (β=0.273, p=0.034) like with the other conducted tests (β=0.327, p=0.024) from COPD patients. No correlations were generally found for PKA, although one significant negative correlation was found between the first and second time points in the COPD group (β=-0.4157, p=0.049),.

Discussion

Chronic obstructive lung diseases, such as asthma and COPD, may have some linkage to impairment of cognitive functions. However, the noted rise in CREB mRNA expression might suggest a potential avenue for assessing possible changes in cognition, especially in COPD; such findings may reveal additional transcription factors linked to cognitive decline.

Systemic Inflammation in Asthma: What Are the Risks and Impacts Outside the Airway?

Airway inflammation in asthma has been well recognized for several decades, with general agreement on its role in asthma pathogenesis, symptoms, propensity toward exacerbation, and decline in lung function. This has led to universal recommendation in asthma management guidelines to incorporate the use of inhaled corticosteroid as an anti-inflammatory therapy for all patients with persistent asthma symptoms. However, there has been limited attention paid to the presence and potential impact of systemic inflammation in asthma. Accumulating evidence from epidemiological observations and cohort studies points to a host of downstream organ dysfunction in asthma especially among patients with longstanding or more severe disease, frequent exacerbations, and underlying risk factors for organ dysfunction. Most studies to date have focused on cognitive impairment, depression/anxiety, metabolic syndrome, and cardiovascular abnormalities. In this review, we summarize some of the evidence demonstrating these abnormalities and highlight the proposed mechanisms and potential benefits of treatment in limiting these extrapulmonary abnormalities in patients with asthma. The goal of this commentary is to raise awareness of the importance of recognizing potential extrapulmonary conditions associated with systemic inflammation of asthma. This area of treatment of patients with asthma is a large unmet need.

Asthma aggravates alzheimer's disease by up-regulating NF- κB signaling pathway through LTD4

Clinical studies have shown that asthma is a risk factor for dementia or Alzheimer's disease (AD). To investigate whether asthma aggravates AD in APP/PS1 mice and explore the potential mechanisms, an asthma model was established using six-month-old APP/PS1 mice, and montelukast was used as a therapeutic agent in APP/PS1 mice with asthma. The Morris water maze test showed that asthma aggravates spatial learning and memory abilities. Asthma also upregulates the NF-κB inflammatory pathway in APP/PS1 mice and promotes the expression of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), amyloid-β (Aβ) deposition, neuronal damage, synaptic plasticity deficiency, activation of microglia and astrocytes. The level of LTD4 and its receptor CysLT1R in the hippocampus of APP/PS1 mice after the asthma modeling was established was higher than that in APP/PS1 mice, suggesting that asthma may affect the pathology of AD through LTD4 and its receptor Cys-LT1R. Montelukast ameliorates these pathological changes and cognitive impairment. These results suggest that asthma aggravates AD pathology and cognitive impairment of APP/PS1 mice via upregulation of the NF-κB inflammatory pathway, and montelukast ameliorates these pathological changes.

Causal Association Between Allergic Diseases and Dementia: Evidence from Multivariate Mendelian Randomization Study

Background

The link between allergic diseases and dementia remains controversial, and the genetic causality of this link is unclear.

Objective

This study investigated the causal relationship between allergic diseases and dementia using univariate and multivariate Mendelian randomization (MR) methods.

Methods

We selected genome-wide association studies including 66,645 patients with allergic diseases and 12,281 patients with dementia, with statistical datasets derived from the FinnGen Consortium of European origin. After a rigorous screening process for single nucleotide polymorphisms to eliminate confounding effects, MR estimation was performed mainly using the inverse variance weighting method and the MR-Egger method. Sensitivity analyses were performed using Cochran's Q test, MR-PRESSO test, MR Pleiotropy residuals and leave-one-out analysis.

Results

Univariate and multivariate MR together demonstrated a causal relationship between atopic dermatitis and reduced vascular dementia (VaD) risk (OR = 0.89, 95% CI: 0.81-0.99, p = 0.031; OR = 0.85, 95% CI: 0.76-0.95, p = 0.003). MVMR confirmed asthma was associated with a reduction in the risk of Alzheimer's disease (AD) (OR = 0.82, 95% CI: 0.71-0.94, p = 0.005) and may be associated with a reduction in the risk of VaD (OR = 0.80, 95% CI: 0.65-0.99, p = 0.042); allergic rhinitis may be causally associated with an increased risk of AD (OR = 1.16, 95% CI: 1.00-1.35, p = 0.046) and VaD (OR = 1.29, 95% CI: 1.03-1.62, p = 0.027). In sensitivity analyses, these findings were reliable.

Conclusions

MR methods have only demonstrated that allergic rhinitis dementia is associated with an increased risk of developing dementia. Previously observed associations between other allergic diseases and dementia may be influenced by comorbidities and confounding factors rather than causality.

Molecular pathways underlying lung-brain axis signaling in asthma: Relevance for psychopathology and neuroinflammation

BACKGROUND

Accumulating evidence indicates that asthma has systemic effects and affects brain function. Although airway inflammation is proposed to initiate afferent communications with the brain, the signaling pathways have not been established.

OBJECTIVE

We sought to identify the cellular and molecular pathways involved in afferent lung-brain communication during airway inflammation in asthma.

METHODS

In 23 adults with mild asthma, segmental bronchial provocation with allergen (SBP-Ag) was used to provoke airway inflammation and retrieve bronchoalveolar lavage fluid for targeted protein analysis and RNA sequencing to determine gene expression profiles. Neural responses to emotional cues in nodes of the salience network were assessed with functional magnetic resonance imaging at baseline and 48 hours after SBP-Ag.

RESULTS

Cell deconvolution and gene coexpression network analysis identified 11 cell-associated gene modules that changed in response to SBP-Ag. SBP-Ag increased bronchoalveolar lavage eosinophils and expression of an eosinophil-associated module enriched for genes related to TH17-type inflammation (eg, IL17A), as well as cell proliferation in lung and brain (eg, NOTCH1, VEGFA, and LIF). Increased expression of genes in this module, as well as several TH17-type inflammation-related proteins, was associated with an increase from baseline in salience network reactivity.

CONCLUSIONS

Our results identify a specific inflammatory pathway linking asthma-related airway inflammation and emotion-related neural function. Systemically, TH17-type inflammation has been implicated in both depression and neuroinflammation, with impacts on long-term brain health. Thus, our data emphasize that inflammation in the lung in asthma may have profound effects outside of the lung that may be targetable with novel therapeutic approaches.

Impact of asthma on the brain: evidence from diffusion MRI, CSF biomarkers and cognitive decline

Chronic systemic inflammation increases the risk of neurodegeneration, but the mechanisms remain unclear. Part of the challenge in reaching a nuanced understanding is the presence of multiple risk factors that interact to potentiate adverse consequences. To address modifiable risk factors and mitigate downstream effects, it is necessary, although difficult, to tease apart the contribution of an individual risk factor by accounting for concurrent factors such as advanced age, cardiovascular risk, and genetic predisposition. Using a case-control design, we investigated the influence of asthma, a highly prevalent chronic inflammatory disease of the airways, on brain health in participants recruited to the Wisconsin Alzheimer's Disease Research Center (31 asthma patients, 186 non-asthma controls, aged 45-90 years, 62.2% female, 92.2% cognitively unimpaired), a sample enriched for parental history of Alzheimer's disease. Asthma status was determined using detailed prescription information. We employed multi-shell diffusion weighted imaging scans and the three-compartment neurite orientation dispersion and density imaging model to assess white and gray matter microstructure. We used cerebrospinal fluid biomarkers to examine evidence of Alzheimer's disease pathology, glial activation, neuroinflammation and neurodegeneration. We evaluated cognitive changes over time using a preclinical Alzheimer cognitive composite. Using permutation analysis of linear models, we examined the moderating influence of asthma on relationships between diffusion imaging metrics, CSF biomarkers, and cognitive decline, controlling for age, sex, and cognitive status. We ran additional models controlling for cardiovascular risk and genetic risk of Alzheimer's disease, defined as a carrier of at least one apolipoprotein E (APOE) ε4 allele. Relative to controls, greater Alzheimer's disease pathology (lower amyloid-β42/amyloid-β40, higher phosphorylated-tau-181) and synaptic degeneration (neurogranin) biomarker concentrations were associated with more adverse white matter metrics (e.g. lower neurite density, higher mean diffusivity) in patients with asthma. Higher concentrations of the pleiotropic cytokine IL-6 and the glial marker S100B were associated with more salubrious white matter metrics in asthma, but not in controls. The adverse effects of age on white matter integrity were accelerated in asthma. Finally, we found evidence that in asthma, relative to controls, deterioration in white and gray matter microstructure was associated with accelerated cognitive decline. Taken together, our findings suggest that asthma accelerates white and gray matter microstructural changes associated with aging and increasing neuropathology, that in turn, are associated with more rapid cognitive decline. Effective asthma control, on the other hand, may be protective and slow progression of cognitive symptoms.

Strength of association between comorbidities and asthma: a meta-analysis

BACKGROUND

The strength of association between comorbidities and asthma has never been ranked in relation to the prevalence of the comorbidity in the nonasthma population. We investigated the strength of association between comorbidities and asthma.

METHODS

A comprehensive literature search was performed for observational studies reporting data on comorbidities in asthma and nonasthma populations. A pairwise meta-analysis was performed and the strength of association calculated by anchoring odds ratios and 95% confidence intervals with the rate of comorbidities in nonasthma populations via Cohen's d method. Cohen's d=0.2, 0.5 and 0.8 were cut-off values for small, medium and large effect sizes, respectively; very large effect size resulted for Cohen's d >0.8. The review was registered in the PROSPERO database; identifier number CRD42022295657.

RESULTS

Data from 5 493 776 subjects were analysed. Allergic rhinitis (OR 4.24, 95% CI 3.82-4.71), allergic conjunctivitis (OR 2.63, 95% CI 2.22-3.11), bronchiectasis (OR 4.89, 95% CI 4.48-5.34), hypertensive cardiomyopathy (OR 4.24, 95% CI 2.06-8.90) and nasal congestion (OR 3.30, 95% CI 2.96-3.67) were strongly associated with asthma (Cohen's d >0.5 and ≤0.8); COPD (OR 6.23, 95% CI 4.43-8.77) and other chronic respiratory diseases (OR 12.85, 95% CI 10.14-16.29) were very strongly associated with asthma (Cohen's d >0.8). Stronger associations were detected between comorbidities and severe asthma. No bias resulted according to funnel plots and Egger's test.

CONCLUSION

This meta-analysis supports the relevance of individualised strategies for disease management that look beyond asthma. A multidimensional approach should be used to assess whether poor symptom control is related to uncontrolled asthma or to uncontrolled underlying comorbidities.

Hidden Comorbidities in Asthma: A Perspective for a Personalized Approach

Bronchial asthma is the most frequent inflammatory non-communicable condition affecting the airways worldwide. It is commonly associated with concomitant conditions, which substantially contribute to its burden, whether they involve the lung or other districts. The present review aims at providing an overview of the recent acquisitions in terms of asthma concomitant systemic conditions, besides the commonly known respiratory comorbidities. The most recent research has highlighted a number of pathobiological interactions between asthma and other organs in the view of a shared immunological background underling different diseases. A bi-univocal relationship between asthma and common conditions, including cardiovascular, metabolic or neurodegenerative diseases, as well as rare disorders such as sickle cell disease, α1-Antitrypsin deficiency and immunologic conditions with hyper-eosinophilia, should be considered and explored, in terms of diagnostic work-up and long-term assessment of asthma patients. The relevance of that acquisition is of utmost importance in the management of asthma patients and paves the way to a new approach in the light of a personalized medicine perspective, besides targeted therapies.

Associations of Lung Function Decline with Risks of Cognitive Impairment and Dementia: A Meta-Analysis and Systematic Review

BACKGROUND

There are controversies surrounding the effects of lung function decline on cognitive impairment and dementia.

OBJECTIVE

We conducted a meta-analysis and systematic review to explore the associations of lung function decline with the risks of cognitive impairment and dementia.

METHODS

The PubMed, EMBASE, and the Cochrane Library were searched to identify prospective studies published from database inception through January 10, 2023. We pooled relative risk (RR) and 95% confidence intervals (CI) using random-effects models. The Egger test, funnel plots, meta-regression, sensitivity, and subgroup analyses were conducted to detect publication bias and investigate the source of heterogeneity.

RESULTS

Thirty-three articles with a total of 8,816,992 participants were subjected to meta-analysis. Poorer pulmonary function was associated with an increased risk of dementia (FEV: RR = 1.25 [95% CI, 1.17-1.33]; FVC: RR = 1.40 [95% CI, 1.16-1.69]; PEF: RR = 1.84 [95% CI, 1.37-2.46]). The results of the subgroup analyses were similar to the primary results. Individuals with lung diseases had a higher combined risk of dementia and cognitive impairment (RR = 1.39 [95% CI, 1.20-1.61]). Lung disease conferred an elevated risk of cognitive impairment (RR = 1.37 [95% CI, 1.14-1.65]). The relationship between lung disease and an increased risk of dementia was only shown in total study participants (RR = 1.32 [95% CI, 1.11-1.57]), but not in the participants with Alzheimer's disease (RR = 1.39 [95% CI, 1.00-1.93]) or vascular dementia (RR = 2.11 [95% CI, 0.57-7.83]).

CONCLUSION

Lung function decline was significantly associated with higher risks of cognitive impairment and dementia. These findings might provide implications for the prevention of cognitive disorders and the promotion of brain health.

Allergic Diseases and Risk of Incident Dementia and Alzheimer's Disease

OBJECTIVE

To examine the associations between the allergic triad (asthma, allergic rhinitis, atopic dermatitis) and risk of dementia.

METHODS

Participants comprised 6,785,948 adults aged ≥40 years who participated in a national health examination in 2009 without any history of dementia before baseline. From 2009 to 2017, we prospectively investigated the associations between physician-diagnosed allergic diseases and risk of incident dementia (all-cause, Alzheimer's disease [AD], vascular dementia [VaD]) ascertained using national health insurance claims data.

RESULTS

During 8.1 years of follow-up, 260,705 dementia cases (195,739 AD, 32,789 VaD) were identified. Allergic diseases were positively associated with dementia risk. Compared with individuals without allergic diseases, multivariable hazard ratios (HRs) of all-cause dementia were 1.20 (95% confidence interval [CI] 1.19-1.22) in those with asthma, 1.10 (95% CI 1.09-1.12) with allergic rhinitis, 1.16 (95% CI 1.11-1.21) with atopic dermatitis, and 1.13 (95% CI 1.12-1.14) with any of these allergies. Similarly, individuals with any of the allergic triad had a higher risk of AD (HR 1.16, 95% CI 1.14-1.17) and VaD (HR 1.04; 95% CI 1.01-1.06) than those without any allergic disease. As the number of comorbid allergic diseases increased, the risk of dementia increased linearly (P_trend  ≤ 0.002). Compared with individuals without allergies, those with all three allergic diseases had substantially increased risk of all-cause dementia (HR 1.54, 95% CI 1.35-1.75), AD (HR 1.46; 95% CI 1.25-1.70), and VaD (HR 1.99, 95% CI 1.44-2.75).

INTERPRETATION

Asthma, allergic rhinitis, and atopic dermatitis were significantly associated with increased risk of all-cause dementia and subtypes, with dose-effect relationships with the severity of allergic diseases. ANN NEUROL 2023;93:384-397.

Association between non-cystic fibrosis bronchiectasis and the risk of incident dementia: A nationwide cohort study

BACKGROUND

Chronic lung diseases, such as chronic obstructive pulmonary disease or asthma, are associated with an increased risk of dementia. However, few data are available regarding the risk of dementia in individuals with bronchiectasis.

OBJECTIVES

To explore the association between bronchiectasis and the risk of incident dementia using a longitudinal population-based cohort.

METHODS

A total of 4,068,560 adults older than 50 years without previous dementia were enrolled from the Korean National Health Insurance Service database in 2009. They were followed up until the date of the diagnosis of dementia or December 31, 2020. The study exposure was the diagnosis of bronchiectasis, and the primary outcome was incident dementia comprising Alzheimer's disease and vascular dementia.

RESULTS

During the median follow-up duration of 9.3 years, the incidence of all-cause dementia was 1.6-fold higher in individuals with bronchiectasis than in those without bronchiectasis (15.0 vs. 9.3/1000 person-years, p < .001). In the multivariable Cox regression analysis, the risk of all dementia was significantly higher in individuals with bronchiectasis than in those without bronchiectasis (adjusted hazard ratio [aHR] 1.09, 95% confidence interval [CI] 1.04-1.14). In a subgroup analysis by dementia type, individuals with bronchiectasis had an increased risk of Alzheimer's disease compared to those without bronchiectasis (aHR 1.07, 95% CI 1.01-1.12); the risk of vascular dementia did not significantly differ between the two groups (aHR 1.05, 95% CI 0.90-1.21).

CONCLUSION

Bronchiectasis was associated with an increased risk of dementia, especially Alzheimer's disease.

Brain-Airway Interactions in Asthma

Asthma and brain interactions have long been appreciated and initially centered on increased anxiety and depression. Epidemiology studies have shown that early life stressors and situational disadvantages are risk factors for asthma. Conversely, the presence of asthma is a risk for mood and anxiety disorders, thus indicating a bidirectional effect between asthma and brain-related health. To substantiate asthma-brain interactions, validated instruments indicate and elucidate that communication likely exists between asthma and the brain. For example, provocation of an asthmatic response with an allergen challenge modulates how the brain responds to emotion-laden information. As detected by imaging studies, emotion-related brain activation is associated with generating airway inflammation. However, the specific mediators and processes mediating airway communication with the brain have yet to be established.Systemic inflammation is also associated with asthma and can affect other organ systems such as the cardiovascular system and the brain. Epidemiology studies have shown that asthma is a risk factor for dementia and Alzheimer's disease. In support of the importance of asthma as a risk factor for impaired cognitive function, imaging studies have shown changes to the white matter of the brain in asthma patients that resemble neuroinflammation changes seen in Alzheimer's disease and other neurodegenerative diseases. Therefore, bidirectional links between asthma and the brain exist with an important next research step to define asthma-brain interactions linked to neurodegeneration and dementia and explore whether treatments directed toward asthma-related inflammation can prevent the deleterious effects of asthma on brain health.

The causes and consequences of Alzheimer's disease: phenome-wide evidence from Mendelian randomization

Alzheimer's disease (AD) has no proven causal and modifiable risk factors, or effective interventions. We report a phenome-wide association study (PheWAS) of genetic liability for AD in 334,968 participants of the UK Biobank study, stratified by age. We also examined the effects of AD genetic liability on previously implicated risk factors. We replicated these analyses in the HUNT study. PheWAS hits and previously implicated risk factors were followed up in a Mendelian randomization (MR) framework to identify the causal effect of each risk factor on AD risk. A higher genetic liability for AD was associated with medical history and cognitive, lifestyle, physical and blood-based measures as early as 39 years of age. These effects were largely driven by the APOE gene. The follow-up MR analyses were primarily null, implying that most of these associations are likely to be a consequence of prodromal disease or selection bias, rather than the risk factor causing the disease.

Asthma amplifies dementia risk: Evidence from CSF biomarkers and cognitive decline

Introduction

Evidence from epidemiology, neuroimaging, and animal models indicates that asthma adversely affects the brain, but the nature and extent of neuropathophysiological impact remain unclear.

Methods

We tested the hypothesis that asthma is a risk factor for dementia by comparing cognitive performance and cerebrospinal fluid biomarkers of glial activation/neuroinflammation, neurodegeneration, and Alzheimer's disease (AD) pathology in 60 participants with asthma to 315 non-asthma age-matched control participants (45-93 years), in a sample enriched for AD risk.

Results

Participants with severe asthma had higher neurogranin concentrations compared to controls and those with mild asthma. Positive relationships between cardiovascular risk and concentrations of neurogranin and α-synuclein were amplified in severe asthma. Severe asthma also amplified the deleterious associations that apolipoprotein E ε4 carrier status, cardiovascular risk, and phosphorylated tau181/amyloid beta42 have with rate of cognitive decline.

Discussion

Our data suggest that severe asthma is associated with synaptic degeneration and may compound risk for dementia posed by cardiovascular disease and genetic predisposition.

Highlights

Those with severe asthma showed evidence of higher dementia risk than controls evidenced by: higher levels of the synaptic degeneration biomarker neurogranin regardless of cognitive status, cardiovascular or genetic risk, and controlling for demographics.steeper increase in levels of synaptic degeneration biomarkers neurogranin and α-synuclein with increasing cardiovascular risk.accelerated cognitive decline with higher cardiovascular risk, genetic predisposition, or pathological tau.

Sex-Differential Associations Between Body Mass Index and the Incidence of Dementia

BACKGROUND

Little is known about the sex differences in the association between body mass index (BMI) and dementia in late life.

OBJECTIVE

Therefore, this retrospective cohort study aimed to analyze associations between BMI and dementia in older women and men separately in general practices in Germany.

METHODS

This study included patients followed in one of 832 general practices in Germany between 2006 and 2019 (index date: first visit date). Study variables included dementia (dependent variable), BMI (independent variable), age, sex, and comorbidities (control variables). Kaplan-Meier curves and adjusted Cox regression analyses were conducted to analyze associations between BMI and the 10-year incidence of dementia in women and men, separately.

RESULTS

There were 296,767 patients included in this study (mean [standard deviation] age 70.2 [5.9] years; 54.3% women). The proportion of underweight, normal weight, overweight, and obesity was 0.9%, 25.5%, 41.5%, and 32.1%, respectively. The 10-year incidence of dementia significantly decreased with increasing BMI, from 11.5% in women with underweight to 9.1% in those with obesity (log-rank p <  0.001). Respective figures in men were 12.0% and 8.2% (log-rank p <  0.001). In women, only overweight (versus normal weight) was significantly associated with dementia (HR = 0.93, 95% CI = 0.88-0.97). In contrast, in men, the only BMI category significantly associated with the incidence of dementia was underweight (HR = 1.58, 95% CI = 1.11-2.25).

CONCLUSION

In this study conducted in Germany, overweight was negatively associated with dementia in women, whereas there was a positive underweight-dementia relationship in men. More data are needed to confirm or refute these findings in other settings.

Neuroimaging and biomarker evidence of neurodegeneration in asthma

BACKGROUND

Epidemiologic studies have shown that Alzheimer's disease (AD) and related dementias (ADRD) are seen more frequently with asthma, especially with greater asthma severity or exacerbation frequency.

OBJECTIVE

To examine the changes in brain structure that may underlie this phenomenon, we examined diffusion-weighted magnetic resonance imaging (dMRI) and blood-based biomarkers of AD (phosphorylated tau 181, p-Tau181), neurodegeneration (neurofilament light chain, NfL), and glial activation (glial fibrillary acidic protein, GFAP).

METHODS

dMRI data were obtained in 111 individuals with asthma, ranging in disease severity from mild to severe, and 135 healthy controls. Regression analyses were used to test the relationships between asthma severity and neuroimaging measures, as well as AD pathology, neurodegeneration, and glial activation, indexed by plasma p-Tau181, NfL, and GFAP, respectively. Additional relationships were tested with cognitive function.

RESULTS

Asthma participants had widespread and large-magnitude differences in several dMRI metrics, which were indicative of neuroinflammation and neurodegeneration, and which were robustly associated with GFAP and, to a lesser extent, NfL. The AD biomarker p-Tau181 was only minimally associated with neuroimaging outcomes. Further, asthma severity was associated with deleterious changes in neuroimaging outcomes, which in turn were associated with slower processing speed, a test of cognitive performance.

CONCLUSIONS

Asthma, particularly when severe, is associated with characteristics of neuroinflammation and neurodegeneration, and may be a potential risk factor for neural injury and cognitive dysfunction. There is a need to determine how asthma may affect brain health and whether treatment directed toward characteristics of asthma associated with these risks can mitigate these effects.

Immune modulations and immunotherapies for Alzheimer's disease: a comprehensive review

Alzheimer's disease (AD), the most common cause of dementia, is characterized by progressive cognitive and memory impairment ensued from neuronal dysfunction and eventual death. Intraneuronal deposition of tau proteins and extracellular senile amyloid-β plaques have ruled as the supreme postulations of AD for a relatively long time, and accordingly, a wide range of therapeutics, especially immunotherapies have been implemented. However, none of them resulted in significant positive cognitive outcomes. Especially, the repetitive failure of anti-amyloid therapies proves the inefficiency of the amyloid cascade hypothesis, suggesting that it is time to reconsider this hypothesis. Thus, for the time being, the focus is being shifted to neuroinflammation as a third core pathology in AD. Neuroinflammation was previously considered a result of the two aforementioned phenomena, but new studies suggest that it might play a causal role in the pathogenesis of AD. Neuroinflammation can act as a double-edged sword in the pathogenesis of AD, and the activation of glial cells is indispensable for mediating such attenuating or detrimental effects. The association of immune-related genes polymorphisms with the clinical phenotype of AD as well as the protective effect of anti-inflammatory drugs like nonsteroidal anti-inflammatory drugs supports the possible causal role of neuroinflammation in AD. Here, we comprehensively review immune-based therapeutic approaches toward AD, including monoclonal antibodies and vaccines. We also discuss their efficacy and underlying reasons for shortcomings. Lastly, we highlight the capacity of modulating the neuroimmune interactions and targeting neuroinflammation as a promising opportunity for finding optimal treatments for AD.

Towards Understanding COVID-19: Molecular Insights, Co-infections, Associated Disorders, and Aging

BACKGROUND

COVID-19 can be related to any diseases caused by microbial infection(s) because 1) co-infection with COVID-19-related virus and other microorganism(s) and 2) because metabolites produced by microorganisms such as bacteria, fungi, and protozoan can be involved in necrotizing pneumonia and other necrotizing medical conditions observed in COVID-19.

OBJECTIVE

By way of illustration, the microbial metabolite of aromatic amino acid tryptophan, a biogenic amine tryptamine inducing neurodegeneration in cell and animal models, also induces necrosis.

METHODS

This report includes analysis of COVID-19 positivity by zip codes in Florida and relation of the positivity to population density, possible effect of ecological and social factors on spread of COVID-19, autopsy analysis of COVID-19 cases from around the world, serum metabolomics analysis, and evaluation of autoantigenome related to COVID-19.

RESULTS

In the present estimations, COVID-19 positivity percent per zip code population varied in Florida from 4.65% to 44.3% (February 2021 data). COVID-19 analysis is partially included in my book Microbial Metabolism and Disease (2021). The autoantigenome related to COVID-19 is characterized by alterations in protein biosynthesis proteins including aminoacyl-tRNA synthetases. Protein biosynthesis alteration is a feature of Alzheimer's disease. Serum metabolomics of COVID-19 positive patients show alteration in shikimate pathway metabolism, which is associated with the presence of Alzheimer's disease-associated human gut bacteria.

CONCLUSION

Such alterations in microbial metabolism and protein biosynthesis can lead to toxicity and neurodegeneration as described earlier in my book Protein Biosynthesis Interference in Disease (2020).

Network and co-expression analysis of airway smooth muscle cell transcriptome delineates potential gene signatures in asthma

Airway smooth muscle (ASM) is known for its role in asthma exacerbations characterized by acute bronchoconstriction and remodeling. The molecular mechanisms underlying multiple gene interactions regulating gene expression in asthma remain elusive. Herein, we explored the regulatory relationship between ASM genes to uncover the putative mechanism underlying asthma in humans. To this end, the gene expression from human ASM was measured with RNA-Seq in non-asthmatic and asthmatic groups. The gene network for the asthmatic and non-asthmatic group was constructed by prioritizing differentially expressed genes (DEGs) (121) and transcription factors (TFs) (116). Furthermore, we identified differentially connected or co-expressed genes in each group. The asthmatic group showed a loss of gene connectivity due to the rewiring of major regulators. Notably, TFs such as ZNF792, SMAD1, and SMAD7 were differentially correlated in the asthmatic ASM. Additionally, the DEGs, TFs, and differentially connected genes over-represented in the pathways involved with herpes simplex virus infection, Hippo and TGF-β signaling, adherens junctions, gap junctions, and ferroptosis. The rewiring of major regulators unveiled in this study likely modulates the expression of gene-targets as an adaptive response to asthma. These multiple gene interactions pointed out novel targets and pathways for asthma exacerbations.

Glucocorticoid Therapy is Associated with a Lower Risk of Dementia

BACKGROUND

Recent evidence indicates an important role for neuroinflammation in the pathological cascade of Alzheimer's disease (AD), and neuroinflammation is increasingly being recognized as a potential therapeutic target.

OBJECTIVE

To assess the impact of glucocorticoids on the risk of developing dementia.

METHODS

We used health insurance data of the largest German health insurer from 2004-2013 with a baseline sample of 176,485 persons aged 50 years and older to study the association of glucocorticoid treatment and incidence of dementia. Cox proportional-hazard models were calculated adjusting for sex, age, and comorbidities known to be major risk factors for dementia and were given as hazard ratios (HR) with 95% confidence intervals (CI). We further stratified glucocorticoid treatment by route of application and treatment duration.

RESULTS

Of the 176,485 dementia-free persons, 19,938 were diagnosed with dementia by the end of 2013. The risk of suffering from dementia was significantly lower for glucocorticoid users compared to non-users (HR = 0.81, CI = 0.78-0.84). The lowest risk was found among users of inhaled glucocorticoid (HR = 0.65, CI = 0.57-0.75), followed by nasal (HR = 0.76, CI = 0.66-0.87), other (HR = 0.84, CI = 0.80-0.88), and oral users (HR = 0.83, CI = 0.78-0.88). We found no difference in risk reduction between long- and short-term-users.

CONCLUSION

Longitudinal German health insurance data indicate that the use of glucocorticoids is associated with a lower risk of dementia. Prospective clinical trials will be necessary to determine whether glucocorticoids can have a positive impact on neuroinflammation and thus protect persons against dementia.

Atopic dermatitis and dementia risk: A nationwide longitudinal study

BACKGROUND

Retrospective studies have suggested that patients with dementia have higher prevalence of atopic dermatitis (AD) than those without dementia. However, the temporal association of AD with subsequent dementia remains unknown.

OBJECTIVE

To assess the temporal association of AD with subsequent dementia.

METHODS

We included data of patients with AD aged 45 years and older (n = 1059) and 1:10 age, sex, residence, income, and dementia-related comorbidity-matched controls (n = 10,590) from the Taiwan National Health Insurance Research Database and reviewed their subsequent dementia development from the enrollment date to the end of 2013.

RESULTS

After adjustments for dementia-related comorbidities, patients with AD were found to be more likely to develop any dementia (hazard ratio [HR], 2.02; 95% confidence interval [CI], 1.24-3.29), particularly Alzheimer's disease (HR, 3.74; 95% CI, 1.17-11.97), during the follow-up period than those in the control group. Moderate-to-severe AD was associated with a high subsequent dementia risk (HR, 4.64; 95% CI, 2.58-8.33). Sensitivity analyses with the exclusion of the first 3 (HR, 2.20; 95% CI, 1.28-3.80) or 5 (HR, 2.05; 95% CI, 1.08-3.89) years of observation revealed consistent findings.

CONCLUSION

AD may be an independent risk factor for new-onset dementia. Clinicians may monitor the trajectory of neurocognitive function among elderly patients with AD. Additional studies elucidating the pathomechanisms between AD and subsequent dementia are warranted.

The Interplay Between Asthma and Other Diseases: Role of Ca2+/cAMP Signalling

OBJECTIVE

Asthma is correlated with a higher risk of manifesting other diseases, including hypertension, diabetes, obesity, psychiatric and neurological diseases, and cancer. Therefore, revealing this interplay between asthma and these illnesses may provide novel insights into their pathogenesis.

RESULTS

It is highly debated that dysregulation of Ca2+ homeostasis is involved in the pathogenesis of these maladies. Not surprisingly, calcium (Ca2+) channel blockers (CCBs), classically used as antihypertensive medicines, have been demonstrating off-label effects such as alleviating asthma symptoms, in addition to antidiabetic, antiobesity, anticancer and antineurodegenerative effects. Our studies about Ca2+/cAMP signalling may shed some new light on this field.

CONCLUSION

Thus, considering that asthma and associated illnesses such as hypertension, diabetes, obesity, cancer and neurodegenerative diseases have become highly prevalent medical problems in the world, the comprehension of this interplay between asthma and other disorders could improve drug therapy.

A possible effect of montelukast on neurological aging examined by the use of register data

Background The leukotriene receptor antagonist montelukast has been shown to rejuvenate aged brains in rats; however, data on humans are still scarce. Objective To investigate if montelukast may alleviate degenerative neurological changes using a register data. Setting Norwegian registry data analyses. Method The present observational study was based on data from the Norwegian Prescription Database and the Tromsø Study. The former has information regarding the use of prescription medicine; the latter includes tests for brain function such as subjective memory and finger-tapping. Multivariate linear regression analyses were performed to see how the use of various medications correlated with the test results, correcting for likely confounders. Main outcome measure Results on seven different tests considered relevant for neurological health were used as outcome. Results Previous use of montelukast correlated with improved scores on cognitive or neurological functioning (F = 2.20, p = 0.03 in a multivariate test). A range of other medications were tested with the same algorithm, including drugs acting on the immune system, but none of them correlated with (overall) significantly improved test results. Conclusion The present data suggest that montelukast may alleviate degenerative neurological changes associated with human aging.

Chronic Respiratory Disease and Cognitive Impairment in Older Mexican Adults

Background

Cognitive impairment has emerged as an important concern in clinical practice in aging population. Several comorbid factors contribute to etiopathogenesis; one disease of interest is chronic respiratory disease.

Aim

The aim of this study is to investigate the association of chronic respiratory disease with risk of cognitive impairment in older Mexicans.

Materials and Methods

Data were obtained from 2782 Mexicans, aged ≥60 years, enrolled in waves I (2001) and III (2012) of the Mexican Health and Aging Study, a prospective cohort of nationally representative sample of older Mexicans. Participants' self-reported responses were used to categorize them into having respiratory disease or not. Study outcome included participants categorized into "cognitively impaired" or "cognitively normal" groups. Multivariable logistic regression models were used to investigate the relationship.

Results

Overall, 16% of cohort participants reported cognitively impaired at Wave III. Compared with older Mexicans without chronic respiratory disease diagnosis, those diagnosed were not significantly associated with risk of cognitive impairment [adjusted odds ratio (OR): 0.94, 95% confidence interval (CI): 0.58-1.58].

Conclusion

Chronic respiratory disease is not significantly associated with risk of cognitive impairment in older Mexican adults.

Respiratory Disease and Lower Pulmonary Function as Risk Factors for Dementia: A Systematic Review With Meta-analysis

BACKGROUND

In addition to affecting the oxygen supply to the brain, pulmonary function is a marker of multiple insults throughout life (including smoking, illness, and socioeconomic deprivation). In this meta-analysis of existing longitudinal studies, the hypothesis that lower pulmonary function and respiratory illness are linked to an elevated risk of dementia was tested.

METHODS

A systematic review was conducted of longitudinal studies using PubMed until April 1, 2019, and, where possible, results were pooled in random effects meta-analyses.

RESULTS

Ten studies relating pulmonary function to later dementia risk and 11 studies of respiratory illness and dementia (including one that assessed both factors) were identified. The lowest quartile of FEV₁ compared with the highest was associated with a 1.4-fold (hazard ratio [HR], 1.46; 95% CI, 0.77-2.75) increased dementia risk (N_total = 62,209; two studies). A decrease of 1 SD in FEV₁ was associated with a 28% increase in dementia risk (HR, 1.28; 95% CI, 1.03-1.60; N_total = 67,505; six studies). Respiratory illness was also associated with increased dementia risk to a similar degree (pooled HR, 1.54; 95% CI, 1.30-1.81; N_total = 288,641; 11 studies).

CONCLUSIONS

Individuals with poor pulmonary function experience an increased risk of dementia. The extent to which the association between poor pulmonary function and dementia is causal remains unclear and requires examination.

Risk of neurodegenerative dementia in asthma patients: a nested case-control study using a national sample cohort

OBJECTIVES

This study investigated the risk of neurodegenerative dementia following asthma.

DESIGN

A nested case-control study SETTING: The ≥60-year-old population was selected from the Korean Health Insurance Review and Assessment Service - National Sample Cohort from 2002 to 2013.

PARTICIPANTS AND INTERVENTIONS

The 11 442 dementia cases were matched with 45 768 control cases for age, sex, income, region of residence, hypertension, diabetes and dyslipidaemia. Asthma was classified using International Classification of Disease-10 (ICD-10) codes (J45 and J46) and medication history. Dementia was identified based on ICD-10 codes (G30 and F00).

PRIMARY AND SECONDARY OUTCOME MEASURES

The ORs of a previous history of asthma in patients with dementia were analysed using conditional logistic regression analysis stratified for age, sex, income, region of residence, hypertension, diabetes and dyslipidaemia. Subgroup analysis was performed according to age and sex.

RESULTS

Overall, 22.6% (2587/11 442) and 22.3% (10 229/45 768) of the cases in the dementia and control groups, respectively, had a previous history of asthma. The OR for asthma in the dementia group was not higher than that in the control group (adjusted OR=0.97, 95% CI 0.92 to 1.02, p=0.207). All age and sex subgroups demonstrated consistent results.

CONCLUSIONS

Asthma was not related to an increased risk of dementia.

Learning Impairments, Memory Deficits, and Neuropathology in Aged Tau Transgenic Mice Are Dependent on Leukotrienes Biosynthesis: Role of the cdk5 Kinase Pathway

Previous studies showed that the leukotrienes pathway is increased in human tauopathy and that its manipulation may modulate the onset and development of the pathological phenotype of tau transgenic mice. However, whether interfering with leukotrienes biosynthesis is beneficial after the behavioral deficits and the neuropathology have fully developed in these mice is not known. To test this hypothesis, aged tau transgenic mice were randomized to receive zileuton, a specific leukotriene biosynthesis inhibitor, or vehicle starting at 12 months of age for 16 weeks and then assessed in their functional and pathological phenotype. Compared with baseline, we observed that untreated tau mice had a worsening of their memory and spatial learning. By contrast, tau mice treated with zileuton had a reversal of these deficits and behaved in an undistinguishable manner from wild-type mice. Leukotriene-inhibited tau mice had an amelioration of synaptic integrity, lower levels of neuroinflammation, and a significant reduction in tau phosphorylation and pathology, which was secondary to an involvement of the cdk5 kinase pathway. Taken together, our findings represent the first demonstration that the leukotriene biosynthesis is functionally involved at the later stages of the tau pathological phenotype and represents an ideal target with viable therapeutic potential for treating human tauopathies.

Atopic diseases/diathesis and subsequent ischemic stroke among patients with bipolar disorder: A nationwide longitudinal study

INTRODUCTION

Previous studies have suggested that both bipolar disorder and atopy are associated with an increased risk of stroke. However, the role of atopic diseases/diathesis in the risk of stroke among patients with bipolar disorder remains unclear.

METHODS

Using Taiwan's National Health Insurance Research Database, we selected 55,593 patients with bipolar disorder between 2002 and 2008, divided them into patients with atopic diseases/diathesis (n = 21,050) and patients without atopic diseases/diathesis (n = 34,543), and observed them until the end of 2011. Patients who experienced a stroke during the follow-up period were identified.

RESULTS

Patients with bipolar disorder and atopic diseases/diathesis had an elevated risk of ischemic stroke (hazard ratio [HR]: 1.44, 95% confidence interval [CI]: 1.25-1.59) compared with patients with only bipolar disorder; a dose-dependent relationship was observed between the number of allergic comorbidities and the risk of ischemic stroke (1 atopic disease, HR: 1.30, 95% CI: 1.13-1.49; 2 atopic diseases, HR: 1.59, 95% CI: 1.33-1.91; ≥ 3 atopic diseases, HR: 2.09, 95% CI: 1.50-2.91).The role of atopic diseases in the risk of hemorrhagic stroke among patients with bipolar disorder was nonsignificant (HR: 0.84, 95% CI: 0.64-1.09).

CONCLUSIONS

Patients with bipolar disorder and atopic diseases/diathesis are more prone to ischemic stroke later in life than are those without atopic diseases/diathesis. Further study is required to investigate the underlying mechanism linking atopy, bipolar disorder, and stroke.

Increased risk of dementia in patients with Schizophrenia: A population-based cohort study in Taiwan

Background:

The extent to which schizophrenia is associated with the risk of all-cause dementia is controversial. This study investigated the risk of dementia by type in patients with schizophrenia.

Methods:

Data were collected from the Taiwanese National Health Insurance Database 2005 and analyzed using multivariate Cox proportional hazard regression models to determine the effect of schizophrenia on the dementia risk after adjusting for demographic characteristics, comorbidities, and medications. Fine and Gray's competing risk analysis was used to determine the risk of dementia, as death can act as a competing risk factor for dementia.

Results:

We assessed 6040 schizophrenia patients and 24,160 propensity scale-matched control patients. Schizophrenia patients exhibited a 1.80-fold risk of dementia compared to controls (adjusted hazard ratio [aHR] = 1.80, 95% confidence interval [CI] = 1.36 ∼ 2.21,p <0.001) after adjusting for covariates. Cardiovascular disease (aHR = 5.26; 95% CI = 4.50 ∼ 6.72;p <0.001), hypertension (aHR = 1.83; 95% CI = 1.77 ∼ 2.04;p= 0.002), traumatic head injury (aHR = 1.35; 95% CI = 1.24 ∼ 1.78;p <0.001), chronic lung diseases (aHR = 1.64; 95% CI = 1.13 ∼ 2.56;p <0.001), alcohol-related disorders (aHR = 3.67; 95% CI = 2.68 ∼ 4.92;p <0.001), and Parkinson’s disease (aHR = 1.72; 95% CI = 1.25 ∼ 2.40;p <0.001) were significantly associated with dementia risk. Notably, first-generation antipsychotics (aHR = 0.80; 95% CI = 0.56 ∼ 0.95;p=0.044) and second-generation antipsychotics (aHR = 0.24; 95% CI = 0.11 ∼ 0.60;p <0.001) were associated with a lower dementia risk. Sensitivity tests yielded consistent findings after excluding the first year and first 3 years of observation. Patients with schizophrenia had the highest risk of developing Alzheimer’s [dementia/disease?] among dementia subtypes (aHR = 2.10; 95% CI = 1.88 ∼ 3.86;p< 0.001), followed by vascular dementia (aHR = 1.67; 95% CI = 1.27 ∼ 2.12;p< 0.001) and unspecified dementia (aHR = 1.30; 95% CI = 1.04 ∼ 2.01;p< 0.001).

Conclusions:

Schizophrenia was significantly associated with the risk of all-cause dementia. Data are scarce on the mechanisms through which antipsychotic agents protect persons with schizophrenia from developing dementia. Further research is recommended to elucidate the neurobiological mechanisms underlying the association between schizophrenia and dementia, and whether antipsychotics protect against the development of dementia in schizophrenia.

Prevalence of asthma among the adult general population of five Middle Eastern countries: results of the SNAPSHOT program

BACKGROUND

Asthma is a common chronic respiratory disease leading to morbidity, mortality and impaired quality of life worldwide. Information on asthma prevalence in the Middle East is fragmented and relatively out-dated. The SNAPSHOT program was conducted to obtain updated information.

METHODS

SNAPSHOT is a cross-sectional epidemiological program carried out in five Middle Eastern countries (Egypt, Turkey, Kuwait, Saudi Arabia, and the United Arab Emirates, the latter three grouped into a Gulf cluster) to collect data on asthma, allergic rhinitis, benign prostatic hyperplasia and bipolar disorder. The survey was carried out by telephone in a random sample of the adult general population with quotas defined according to country demographics. The analysis presented in this paper focuses on asthma. Subjects were screened for asthma based on criteria from the global Asthma Insights and Reality studies. Current prevalence (last 12 months) was estimated. Multivariate logistic regression analyses were used to investigate risk factors related to asthma and the association with allergic rhinitis and other co-morbidities. Quality of life was assessed using the three-level EQ-5D questionnaire.

RESULTS

2124 out of the 33,486 subjects enrolled in the SNAPSHOT program fulfilled the criteria for asthma. The adjusted prevalence of asthma ranged from 4.4% [95% CI: 4.0-4.8%] in Turkey, to 6.7% [95% CI: 6.2-7.2%] in Egypt and 7.6% [95% CI: 7.1-8.0%] in the Gulf cluster. Prevalence was higher (p < 0.0001) in women than men and increased with age (p < 0.0001). Co-morbidities occurred more frequently in asthma subjects compared to the non-asthma population (38% vs. 15% p < 0.0001). Subjects with asthma reported a lower (p < 0.0001) EQ-VAS score (68.2 ± 22.9) compared to the general population (78.1 ± 17.5). The risk factors associated with asthma were age, gender, country, and certain co-morbidities, namely respiratory, cardiovascular, gastrointestinal, nervous, and neurological diseases.

CONCLUSION

The observed adjusted prevalence of asthma in the Middle East ranges from 4.4% to 7.6%, which is comparatively lower than the reported prevalence in Europe and North America. Asthma has a negative impact on quality of life, and is associated with high levels of co-morbid diseases, indicating a need for physicians to check for co-morbidities and ensure they are managed correctly in all asthma patients.

Increased Risk of Psychiatric Disorders in Allergic Diseases: A Nationwide, Population-Based, Cohort Study

BACKGROUND/OBJECTIVE

Allergic diseases, such as bronchial asthma, allergic rhinitis, atopic dermatitis, and psychiatric disorders, are major health issues. There have been reports that allergic diseases were associated with depression or anxiety disorders. This study aimed to investigate the association between these allergic diseases and the risk of developing overall psychiatric disorders in patients from Taiwan.

METHODS

This cohort study used the database of the Taiwan National Health Insurance Program. A total of 186,588 enrolled patients, with 46,647 study subjects who had suffered from allergic diseases, and 139,941 controls matched for sex and age, from the Longitudinal Health Insurance Dataset of 2000-2015, were selected from a sub-dataset of the National Health Insurance Research Database. Fine and Gray's competing risk model analysis was used to explore the hazard ratio (HR), and 95% confidence interval, for the risk of allergic diseases being associated with the risk of developing psychiatric disorders during the 15 years of follow-up.

RESULTS

Of the study subjects, 5,038 (10.8%) developed psychiatric disorders when compared to 9,376 (6.7%) in the control group, with significant difference (p < 0.001). Fine and Gray's competing risk model analysis revealed that the adjusted HR was 1.659 (95% CI = 1.602-1.717, p < 0.001). In this study, we found that the groups of atopic dermatitis alone and the allergic rhinitis + atopic dermatitis were associated with a lower risk of psychiatric disorders, but all the other four groups, such as bronchial asthma alone, allergic rhinitis alone, bronchial asthma + allergic rhinitis, bronchial asthma + atopic dermatitis, and the combination of all these three allergic diseases, were associated with a higher risk of psychiatric disorders.

CONCLUSION

Allergic diseases are therefore associated with a 1.66-fold increased hazard of psychiatric disorders in Taiwan.

Mast Cell Activation in Brain Injury, Stress, and Post-traumatic Stress Disorder and Alzheimer's Disease Pathogenesis

Mast cells are localized throughout the body and mediate allergic, immune, and inflammatory reactions. They are heterogeneous, tissue-resident, long-lived, and granulated cells. Mast cells increase their numbers in specific site in the body by proliferation, increased recruitment, increased survival, and increased rate of maturation from its progenitors. Mast cells are implicated in brain injuries, neuropsychiatric disorders, stress, neuroinflammation, and neurodegeneration. Brain mast cells are the first responders before microglia in the brain injuries since mast cells can release prestored mediators. Mast cells also can detect amyloid plaque formation during Alzheimer's disease (AD) pathogenesis. Stress conditions activate mast cells to release prestored and newly synthesized inflammatory mediators and induce increased blood-brain barrier permeability, recruitment of immune and inflammatory cells into the brain and neuroinflammation. Stress induces the release of corticotropin-releasing hormone (CRH) from paraventricular nucleus of hypothalamus and mast cells. CRH activates glial cells and mast cells through CRH receptors and releases neuroinflammatory mediators. Stress also increases proinflammatory mediator release in the peripheral systems that can induce and augment neuroinflammation. Post-traumatic stress disorder (PTSD) is a traumatic-chronic stress related mental dysfunction. Currently there is no specific therapy to treat PTSD since its disease mechanisms are not yet clearly understood. Moreover, recent reports indicate that PTSD could induce and augment neuroinflammation and neurodegeneration in the pathogenesis of neurodegenerative diseases. Mast cells play a crucial role in the peripheral inflammation as well as in neuroinflammation due to brain injuries, stress, depression, and PTSD. Therefore, mast cells activation in brain injury, stress, and PTSD may accelerate the pathogenesis of neuroinflammatory and neurodegenerative diseases including AD. This review focusses on how mast cells in brain injuries, stress, and PTSD may promote the pathogenesis of AD. We suggest that inhibition of mast cells activation and brain cells associated inflammatory pathways in the brain injuries, stress, and PTSD can be explored as a new therapeutic target to delay or prevent the pathogenesis and severity of AD.

Prescription database analyses indicates that the asthma medicine montelukast might protect against dementia: a hypothesis to be verified

BACKGROUND

It has recently been shown that the leukotriene receptor antagonist montelukast rejuvenates aged brains in rats. The question is whether this commonly used, systemic, anti-asthmatic medicine has a similar effect in humans?

RESULTS

We approached this issue by doing statistical analyses based on the Norwegian Prescription Database. The Database lists all prescription-based medications in Norway, but not drugs given to people who are in hospitals or nursing homes. The question asked was whether users of montelukast, compared to users of inhalation asthma medicine, live longer, and are less likely to develop dementia. A small, non-significant protective effect on the use of dementia medicine became significant when adjusting for other prescriptions (based on the notion that montelukast users on average are less healthy). A possible protective effect was substantiated by looking at the lack of prescriptions as a proxy for dementia-related residency in nursing homes, and the risk of death.

CONCLUSIONS

The present results suggest that montelukast may alleviate the cognitive decline associated with human aging. However, further data, preferably based on controlled clinical trials, are required.

Comorbidity and dementia: A nationwide survey in Taiwan

BACKGROUND

Comorbid medical diseases are highly prevalent in the geriatric population, imposing hardship on healthcare services for demented individuals. Dementia also complicates clinical care for other co-existing medical conditions. This study investigated the comorbidities associated with dementia in the elderly population aged 65 years and over in Taiwan.

METHODS

We conducted a nationwide, population-based, cross-sectional survey; participants were selected by computerized random sampling from all 19 Taiwan counties between December 2011 and March 2013. After exclusion of incomplete or erroneous data, 8,456 subjects were enrolled. Of them, 6,183 were cognitively normal (control group), 1,576 had mild cognitive impairment (MCI), and 697 had dementia. We collected information about types of comorbidities (i.e., vascular risk factors, lung diseases, liver diseases, gastrointestinal diseases, and cancers), Charlson comorbidity index score, and demographic variables to compare subjects with normal cognition, MCI, and dementia.

RESULTS

Regardless of the cognitive condition, over 60% of the individuals in each group had at least one comorbid disease. The proportion of subjects possessing at least three comorbidities was higher in those with cognitive impairment (MCI 20.9%, dementia 27.3%) than in control group (15%). Hypertension and diabetes mellitus were the most common comorbidities. The mean number of comorbidities and Charlson comorbidity index score were greater in MCI and dementia groups than in control group. Logistic regression demonstrated that the comorbidities significantly associated with MCI and dementia were cerebrovascular disease (OR 3.35, CI 2.62-4.28), cirrhosis (OR 3.29, CI 1.29-8.41), asthma (OR 1.56, CI 1.07-2.27), and diabetes mellitus (OR 1.24, CI 1.07-1.44).

CONCLUSION

Multiple medical comorbid diseases are common in older adults, especially in those with cognitive impairment. Cerebrovascular disease, cirrhosis, asthma, and diabetes mellitus are important contributors to cognitive deterioration in the elderly. Efforts to lower cumulative medical burden in the geriatric population may benefit cognitive function.

Arthritis and Risk of Cognitive and Functional Impairment in Older Mexican Adults

OBJECTIVE

This study investigated the risk of cognitive and functional impairment in older Mexicans diagnosed with arthritis. Participants included 2,681 Mexicans, aged ≥60 years, enrolled in the Mexican Health and Aging Study cohort.

METHOD

Participants were categorized into arthritis and no arthritis exposure groups. Primary outcome included participants categorized into "cognitively impaired" or "cognitively normal" groups. Secondary outcomes included participants categorized into Normal, Functionally Impaired only, Cognitively Impaired only, or Dementia (both cognitively and functionally impaired) groups. Multivariable logistic and multinomial regression models were used to assess the relationships.

RESULTS

Overall, 16% or 7% were diagnosed with cognitive impairment or dementia. Compared with older Mexicans without arthritis, those who were diagnosed with arthritis had significantly increased risk of functional impairment (adjusted odds ratio [OR] 1.82, 95% confidence interval [CI] = [1.45, 2.29]), but not of dementia.

CONCLUSION

Arthritis is associated with increased risk of functional impairment, but not with dementia after 11 years in older Mexicans.

Asthma, corticosteroid use and schizophrenia: A nationwide population-based study in Taiwan

OBJECTIVE

Asthma and corticosteroid use have been implicated as possible risk factors for schizophrenia. The retrospective cohort study herein aimed to investigate the association between asthma, corticosteroid use, and schizophrenia.

METHOD

Longitudinal data (2000 to 2007) from adults with asthma (n = 50,046) and without asthma (n = 50,046) were compared on measures of schizophrenia incidence using Taiwan's National Health Insurance Research Database (NHIRD). Incidence of schizophrenia diagnosis (ICD-9 codes 295.XX) between 2000 and 2007 were compared between groups. Competing risk-adjusted Cox regression analyses were conducted, adjusting for sex, age, residence, socioeconomic status, corticosteroid use, outpatient and emergency room visit frequency, Charlson comorbidity index, and total length of hospital stays days for any disorder.

RESULTS

Of the 75,069 subjects, 238 received a diagnosis of schizophrenia. The mean (SD) follow-up interval for all subjects was 5.8 (2.3) years. After adjusting for potential confounding factors, asthma was associated with significantly greater hazard ratio for incident schizophrenia 1.40 (95% CI = 1.05, 1.87). Additional factors associated with greater incidence of schizophrenia were rural residence, lower economic status, and poor general health. Older age (i.e. ≥65 years) was negatively associated with schizophrenia incidence. Corticosteroid use was not associated with increased risk for schizophrenia.

CONCLUSIONS

Asthma was associated with increased risk for schizophrenia. The results herein suggest that a convergent disturbance in the immune-inflammatory system may contribute to the pathoetiology of asthma and schizophrenia.

Lifetime Modulation of the Pain System via Neuroimmune and Neuroendocrine Interactions

Chronic pain is a debilitating condition that still is challenging both clinicians and researchers. Despite intense research, it is still not clear why some individuals develop chronic pain while others do not or how to heal this disease. In this review, we argue for a multisystem approach to understand chronic pain. Pain is not only to be viewed simply as a result of aberrant neuronal activity but also as a result of adverse early-life experiences that impact an individual's endocrine, immune, and nervous systems and changes which in turn program the pain system. First, we give an overview of the ontogeny of the central nervous system, endocrine, and immune systems and their windows of vulnerability. Thereafter, we summarize human and animal findings from our laboratories and others that point to an important role of the endocrine and immune systems in modulating pain sensitivity. Taking "early-life history" into account, together with the past and current immunological and endocrine status of chronic pain patients, is a necessary step to understand chronic pain pathophysiology and assist clinicians in tailoring the best therapeutic approach.

Alzheimer's disease as an inflammatory disease

Alzheimer's disease (AD) is a neurodegenerative condition characterized by the formation of amyloid-β plaques, aggregated and hyperphosphorylated tau protein, activated microglia and neuronal cell death, ultimately leading to progressive dementia. In this short review, we focus on neuroinflammation in AD. Specifically, we describe the participation of microglia, as well as other factors that may contribute to inflammation, in neurodegeneration.

Influence of Allergy on Immunoglobulins and Amyloid-β in the Cerebrospinal Fluid of Patients with Alzheimer's Disease

BACKGROUND

Peripheral inflammation has been suggested to influence the development of Alzheimer's disease (AD). Elevated levels of pro-inflammatory markers in the plasma of patients with AD indicate that a systemic pro-inflammatory status occurs concomitantly with inflammatory changes in the brain.

OBJECTIVE

To investigate whether allergy influences the levels of immunoglobulins (Ig) and of pro- and anti-inflammatory cytokines in the serum and cerebrospinal fluid (CSF) from patients with AD, mild cognitive impairment (MCI), and subjective cognitive impairment (SCI).

METHODS

IgA, IgG, and its subclasses, IgM, and cytokines were analyzed in CSF and serum from patients with SCI, MCI, and AD, with or without allergy. The relation between allergy and Mini-Mental State Examination (MMSE) scores, and between allergy and CSF biomarkers for AD (phosphorylated (p)-tau, total (t)-tau, amyloid-β 42 (Aβ₄₂), were analyzed.

RESULTS

In MCI, the CSF levels of IgG2 were lower in allergic patients, and in AD, the levels of IgA and the IgG1/total IgG ratio were lower in allergic patients, compared to patients without allergy. MCI subjects with allergy had higher serum IgM levels compared to those without allergy. CSF levels of Aβ₄₂ were lower and MMSE scores were higher in AD patients with allergy than in those without allergy.

CONCLUSIONS

The presence of allergy was associated with seemingly beneficial effects on AD as suggested by higher Aβ₄₂ levels in CSF, and higher MMSE scores. Higher IgM levels and lower other Ig classes suggest that allergy may influence senescence of the immune response.

Microglial priming through the lung-brain axis: the role of air pollution-induced circulating factors

Air pollution is implicated in neurodegenerative disease risk and progression and in microglial activation, but the mechanisms are unknown. In this study, microglia remained activated 24 h after ozone (O3) exposure in rats, suggesting a persistent signal from lung to brain. Ex vivo analysis of serum from O3-treated rats revealed an augmented microglial proinflammatory response and β-amyloid 42 (Aβ42) neurotoxicity independent of traditional circulating cytokines, where macrophage-1 antigen-mediated microglia proinflammatory priming. Aged mice exhibited reduced pulmonary immune profiles and the most pronounced neuroinflammation and microglial activation in response to mixed vehicle emissions. Consistent with this premise, cluster of differentiation 36 (CD36)(-/-) mice exhibited impaired pulmonary immune responses concurrent with augmented neuroinflammation and microglial activation in response to O3 Further, aging glia were more sensitive to the proinflammatory effects of O3 serum. Together, these findings outline the lung-brain axis, where air pollutant exposures result in circulating, cytokine-independent signals present in serum that elevate the brain proinflammatory milieu, which is linked to the pulmonary response and is further augmented with age.-Mumaw, C. L., Levesque, S., McGraw, C., Robertson, S., Lucas, S., Stafflinger, J. E., Campen, M. J., Hall, P., Norenberg, J. P., Anderson, T., Lund, A. K., McDonald, J. D., Ottens, A. K., Block, M. L. Microglial priming through the lung-brain axis: the role of air pollution-induced circulating factors.

[Association of decreased external pulmonary function with cognitive impairments]

AIM

To examine the association between the basic indicators of external respiratory function (ERF) and cognitive impairments (CIs).

MATERIALS AND METHODS

The materials of a population-based cross-sectional study were used in the investigation; a representative sample consisted of 3818 men and women aged 45-69 years. Forced expiratory volume in the first second (FEV1), the ratio of FEV1 to forced vital capacity (FVC) were determined to assess ERF. CIs were evaluated using the 10-word test described by A.R. Luria, Cog-sum indices (the sum of correctly reproduced words with 3 attempts), and Cog-mean=Cog-sum/3.

RESULTS

In patients with an FEV1/FVC <70%, the probability of a Cog-sum of <20 scores was twice higher than in those with an FEV1/FVC ≥70%; in patients with an FEV1 <80%, the probability of a Cog-sum of <20 scores was also 2 times higher than in those with an FEV1 ≥80%. Multiple regression analysis revealed no significant associations between Cog-sum index and smoking index, body mass index, and blood pressure. Cog-sum was inversely related to age and directly related to FEV1 and female sex. Binary logistic regression analysis showed that gender, age, and FEV1 were statistically significant variables. The relative risk of a Cog-sum of <20 that was 1.7 times higher in the men than in the women, 1.8 times higher in the patients with an FEV1 <80% than in those with an FEV1 ≥80% (model 1), 1.7 times higher in the patients with an FEV1/FVC <70% than in those with FEV1/FVC ≥70% (model 2) increased with age.

CONCLUSION

The decrease in the basic indicators of ERF (FEV1, FEV1/FVC) is an independent predictor of CIs.

Challenges in the management of severe allergic asthma in the elderly

Little is known about the features of asthma and allergy in the elderly. A significant number of elderly patients with asthma have uncontrolled and severe asthma. This review aims to provide an analysis of the literature on the assessment and phenotype of severe allergic asthma in the elderly. Gaps and pitfalls in diagnostic and therapeutic approaches, as well as management of severe allergic asthma in the elderly, are also discussed.

Risk of developing Parkinson's disease among patients with asthma: a nationwide longitudinal study

BACKGROUND

A cross-sectional retrospective study suggested a link between allergic diseases and Parkinson's disease. However, the temporal association between asthma and Parkinson's disease remains unknown.

METHODS

From the Taiwan National Health Insurance Research Database, 10 455 patients who were diagnosed with asthma between 1998 and 2008 and aged ≥45 years and 41 820 age- and sex-matched controls were selected for our study and observed until the end of 2011. Those who developed Parkinson's disease during the follow-up period were identified. We also examined the asthma severity, as indicated by the frequency of admission (times per year) for asthma exacerbation, and the risk of subsequent Parkinson's disease.

RESULTS

Patients with asthma had an increased risk of developing Parkinson's disease (hazard ratio [HR]: 3.10, 95% confidence interval [CI]: 2.20-4.36) after we adjusted for demographic data, health system use, medical comorbidities, and medication use. Sensitivity tests yielded consistent findings after we excluded observations on the first year (HR: 2.90, 95% CI: 2.04-4.13) and first 3 years (HR: 2.46, 95% CI: 1.64-3.69). Patients with asthma who had more frequent admissions (times per year) during the follow-up period exhibited a greater risk of subsequent Parkinson's disease (>2: HR: 16.42, 95% CI: 5.88-45.91; 1-2: 12.69, 95% CI: 5.03-31.71; 0-1: HR: 2.92, 95% CI: 1.91-4.49).

CONCLUSION

Patients with asthma had an elevated risk of developing Parkinson's disease later in life, and we observed a dose-dependent relationship between greater asthma severity and a higher risk of subsequent Parkinson's disease.

Serum Amyloid-Beta Levels are Increased in Patients with Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is associated with cognitive decline, but the molecular link between COPD and dementia or Alzheimer's disease (AD) remains unclear. This study was aimed to investigate whether serum Aβ levels are correlated with COPD. 77 cognitively normal COPD patients and 45 age- and gender-matched normal controls were admitted to the study. Serum Aβ40 and Aβ42 levels were measured using ELISA kits. Serum C-reactive protein (CRP), interleukin 6 (IL-6), and procalcitonin (PCT) measurements were done using standard laboratory methods. Pulmonary function tests were performed to assess the pulmonary function and determine the degree of lung damage. Significantly increased levels of serum Aβ40, Aβ42, and total Aβ levels were found in patients with COPD in comparison with normal controls. In COPD patients, serum Aβ levels were higher in subjects with serum CRP, IL-6, and PCT upper the limit of normal. Moreover, serum Aβ levels were dramatically higher in COPD patients with worse pulmonary function. Our study suggests that cognitively normal COPD patients may undergo AD-related pathological changes, and COPD might facilitate AD-type pathogenesis.