Migraine and the risk of all-cause dementia, Alzheimer's disease, and vascular dementia: A prospective cohort study in community-dwelling older adults

Genetic evidence for causal association between migraine and dementia: a mendelian randomization study

BACKGROUND

There is an association between migraine and dementia, however, their causal relationship remains unclear. This study employed bidirectional two-sample Mendelian randomization (MR) to investigate the potential causal relationship between migraine and dementia and its subtypes: Alzheimer's disease (AD), vascular dementia (VaD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB).

METHODS

Summary-level statistics data were obtained from publicly available genome-wide association studies (GWAS) for both migraine and five types of dementia. Single nucleotide polymorphisms (SNPs) associated with migraine and each dementia subtype were selected. MR analysis was conducted using inverse variance weighting (IVW) and weighted median (WM) methods. Sensitivity analyses included Cochran's Q test, MR pleiotropy residual sum and outlier (MR-PRESSO) analysis, the intercept of MR-Egger, and leave-one-out analysis.

RESULTS

Migraine showed a significant causal relationship with AD and VaD, whereas no causal relationship was observed with all-cause dementia, FTD, or DLB. Migraine may be a potential risk factor for AD (odds ratio [OR]: 1.09; 95% confidence interval [CI]: 0.02-0.14; P = 0.007), while VaD may be a potential risk factor for migraine (OR: 1.04; 95% CI: 0.02-0.06; P = 7.760E-5). Sensitivity analyses demonstrated the robustness of our findings.

CONCLUSION

Our study suggest that migraine may have potential causal relationships with AD and VaD. Migraine may be a risk factor for AD, and VaD may be a risk factor for migraine. Our study contributes to unraveling the comprehensive genetic associations between migraine and various types of dementia, and our findings will enhance the academic understanding of the comorbidity between migraine and dementia.

Mind the Metabolic Gap: Bridging Migraine and Alzheimer's disease through Brain Insulin Resistance

Brain insulin resistance has recently been described as a metabolic abnormality of brain glucose homeostasis that has been proven to downregulate insulin receptors, both in astrocytes and neurons, triggering a reduction in glucose uptake and glycogen synthesis. This condition may generate a mismatch between brain's energy reserve and expenditure, mainly during high metabolic demand, which could be involved in the chronification of migraine and, in the long run, at least in certain subsets of patients, in the prodromic phase of Alzheimer's disease, along a putative metabolic physiopathological continuum. Indeed, the persistent disruption of glucose homeostasis and energy supply to neurons may eventually impair protein folding, an energy-requiring process, promoting pathological changes in Alzheimer's disease, such as amyloid-β deposition and tau hyperphosphorylation. Hopefully, the "neuroenergetic hypothesis" presented herein will provide further insight on there being a conceivable metabolic bridge between chronic migraine and Alzheimer's disease, elucidating novel potential targets for the prophylactic treatment of both diseases.

Genetic evidence for the causal relationships between migraine, dementia, and longitudinal brain atrophy

BACKGROUND

Migraine is a neurological disease with a significant genetic component and is characterized by recurrent and prolonged episodes of headache. Previous epidemiological studies have reported a higher risk of dementia in migraine patients. Neuroimaging studies have also shown structural brain atrophy in regions that are common to migraine and dementia. However, these studies are observational and cannot establish causality. The present study aims to explore the genetic causal relationship between migraine and dementia, as well as the mediation roles of brain structural changes in this association using Mendelian randomization (MR).

METHODS

We collected the genome-wide association study (GWAS) summary statistics of migraine and its two subtypes, as well as four common types of dementia, including Alzheimer's disease (AD), vascular dementia, frontotemporal dementia, and Lewy body dementia. In addition, we collected the GWAS summary statistics of seven longitudinal brain measures that characterize brain structural alterations with age. Using these GWAS, we performed Two-sample MR analyses to investigate the causal effects of migraine and its two subtypes on dementia and brain structural changes. To explore the possible mediation of brain structural changes between migraine and dementia, we conducted a two-step MR mediation analysis.

RESULTS

The MR analysis demonstrated a significant association between genetically predicted migraine and an increased risk of AD (OR = 1.097, 95% CI = [1.040, 1.158], p = 7.03 × 10- 4). Moreover, migraine significantly accelerated annual atrophy of the total cortical surface area (-65.588 cm2 per year, 95% CI = [-103.112, -28.064], p = 6.13 × 10- 4) and thalamic volume (-9.507 cm3 per year, 95% CI = [-15.512, -3.502], p = 1.91 × 10- 3). The migraine without aura (MO) subtype increased the risk of AD (OR = 1.091, 95% CI = [1.059, 1.123], p = 6.95 × 10- 9) and accelerated annual atrophy of the total cortical surface area (-31.401 cm2 per year, 95% CI = [-43.990, -18.811], p = 1.02 × 10- 6). The two-step MR mediation analysis revealed that thalamic atrophy partly mediated the causal effect of migraine on AD, accounting for 28.2% of the total effect.

DISCUSSION

This comprehensive MR study provided genetic evidence for the causal effect of migraine on AD and identified longitudinal thalamic atrophy as a potential mediator in this association. These findings may inform brain intervention targets to prevent AD risk in migraine patients.

Independent causal effect of migraines on Alzheimer's disease risk: a multivariate Mendelian randomization study

Background

The observational studies investigated the impact of migraine on Alzheimer's Disease (AD). However, these findings were limited by confounding factors and reverse causation, leading to contradictory results.

Methods

We utilized Univariable Mendelian Randomization (UVMR) to explore the link between migraine (13,971 cases/470,627 controls) and AD risk (Bellenguez et al., 39,106 cases/46,828 controls; FinnGen, 111,471 cases/111,471 controls). Meta-analysis was performed for comprehensive synthesis. Employing Multivariable Mendelian Randomization (MVMR), we created models incorporating migraine and 35 potential AD risk factors, examining migraine's independent impact on AD onset risk under considering these factors.

Results

The meta-analysis of inverse variance weighted MR results, combining data from Bellenguez et al. (odds ratio (OR) [95% confidence interval (CI)]: 1.5717 [1.1868-2.0814], p = 0.0016) and FinnGen (OR [95% CI]: 1.2904 [0.5419-3.0730], p = 0.5646), provided evidence for a causal relationship between genetically predicted migraine and the heightened risk of AD occurrence (OR [95% CI]: 1.54 [1.18, 2.00], p < 0.01). After adjusting for Diastolic blood pressure (OR [95% CI]: 1.4120 [0.8487-2.3493], p = 0.1840) and Tumor necrosis factor alpha (OR [95% CI]: 1.2411 [0.8352-1.8443], p = 0.2852), no discernible association was detected between migraine and the risk of AD.

Conclusion

This study offers compelling evidence indicating a significant correlation between genetically predicted migraine and an elevated risk of AD.

Association between Migraine and Quality of Life, Mental Health, Sleeping Disorders, and Health Care Utilization Among Older African American Adults

PURPOSE

This study examines the associations between migraine headaches, well-being, and health care use among a sample of underserved older African American adults. Controlling for relevant variables, the association between migraine headaches and (1) health care utilization, (2) health-related quality of life (HRQoL), and (3) physical and mental health outcomes was examined.

METHODS

Our sample included 760 older African American adults from South Los Angeles recruited through convenience and snowball sampling. In addition to demographic variables, our survey included validated instruments, such as the SF-12 QoL, Short-Form McGill Pain Questionnaire, and the Geriatric Depression Scale. Data analysis included 12 independent multivariate models using multiple linear regression, log transferred linear regression, binary and multinomial logistic regression, and generalized linear regression with Poisson distribution.

RESULTS

Having migraine was associated with three categories of outcomes: (1) higher level of health care utilization measured by (i) emergency department admissions and (ii) number of medication use; (2) lower level of HRQoL and health status measured by (i) lower self-rated health (ii) physical QoL, and (iii) mental QoL; and (3) worse physical and mental health outcomes measured by (i) higher number of depressive symptoms, (ii) higher level of pain, (iii) sleep disorder, and (iv) being disabled.

CONCLUSIONS

Migraine headache significantly was associated with quality of life, health care utilization, and many health outcomes of underserved African American middle-aged and older adults. Diagnoses and treatments of migraine among underserved older African American adults require multi-faceted and culturally sensitive interventional studies.

Association between chronic pain and dementia: a systematic review and meta-analysis

PURPOSE

Dementia and chronic pain (CP) are prevalent among older adults. However, no study has systematically reviewed the association between dementia and CP. Therefore, we performed this study to gather evidence about the potential relationship between the two.

METHODS

Two authors independently searched PubMed, Embase, and Web of Science to identify all records published up to 1 September 2022 that explored the association between CP and dementia. The methodological quality of the studies was assessed using the Newcastle Ottawa Scale (NOS). A fixed or random-effects model was used to pool the risk estimates.

RESULTS

Among the initial 3296 articles retrieved, 19 were included in the review (1 cross-sectional, and 18 cohort). The pooled result showed the risk of dementia was 1.42 times higher in CP patients (HR = 1.42, 95% CI 1.23-1.64, P < 0.001). dementia and CP subtypes, gender, and age did not significantly affect the results.

CONCLUSION

Our study shows that people who suffered from CP are at an increased risk of developing dementia, regardless of gender, age, and dementia and CP subtypes.

Interictal Dysfunctions of Attention, Vigilance, and Executive Functions in Migraine and Their Reversal by Preventive Treatment: A longitudinal Controlled Study

OBJECTIVE

To assess attention, vigilance, and executive functions in migraine patients during headache-free (interictal) periods and in healthy controls without migraine and to study the impact of migraine preventive treatment on these cognitive functions.

METHODS

Preventive drug-naive migraine patients, aged ≥18 years, without a history of medication overuse were studied and compared to non-migraine controls. Psychiatric comorbidity was screened by Patient Health Questionnaire-9, and those who screened positive were evaluated further by specific scales. The Epworth Sleepiness Scale assessed subjective complaints of sleep quality. Cognitive functions were assessed by Mini-Mental State Examination (MMSE), digit span forward and backward (DS-F, DS-B), trail-making tests (TMT-A and B) and Stroop word (SW), Stroop color (SC), and Stroop interference (SI) tests. Cognitive test scores at the end of 6 months following treatment were compared to baseline scores.

RESULTS

One hundred and fifty migraine patients and controls each were studied. Compared to controls, migraine patients performed significantly worse in DS-B ( P < 0.0001), TMT-A ( P = 0.00004), TMT-B ( P < 0.0001), SW ( P < 0.0001), SC ( P < 0.0001), and SI ( P = 0.0221). MMSE scores did not differ between patients and the controls ( P = 0.3224). Compared to the patients without psychiatric comorbidity, migraine patients with psychiatric comorbidity showed no significant differences in the cognitive test scores. Significant improvement in all cognitive test scores ( P < 0.001) was observed after 6 months of treatment.

CONCLUSION

Migraine patients, compared to non-migraine controls, showed deficits in attention, vigilance, and executive functions during the interictal period, which improved with successful preventive treatment. Psychiatric comorbidities did not have a significant impact on cognitive dysfunctions.

Association between migraine and the risk of vascular dementia: A nationwide longitudinal study in South Korea

OBJECTIVE

We aimed to examine the potential association between migraine and vascular dementia (VaD) using a nationwide population database.

BACKGROUND

Migraine and VaD showed similar structural and functional changes in pathophysiology process and shared common risk factors, However, whether migraine prevalence increases VaD incidence remains controversial.

METHODS

This retrospective population-based cohort study used the medical records from the Korean National Health Insurance System database. Migraine (G43) was defined by using the Tenth Revision of the International Classification of Diseases code. More than two migraine diagnoses at least 3 months apart were defined as "chronic migraine". Cox proportional hazards model estimated hazard ratios (HRs) of VaD for group comparisons.

RESULTS

We included 212,836 patients with migraine and 5,863,348 individuals without migraine. During 10 years of follow-up, 3,914 (1.8%) and 60,258 (1.0%) patients with and without migraine, respectively, were newly diagnosed with VaD. After adjustment, patients with migraine showed a 1.21-fold higher risk of VaD than those without migraine (HR = 1.21; 95% confidence interval (CI): 1.17-1.25). Patients with chronic migraine showed a higher cumulative incidence of VaD than those with episodic migraine. The adjusted HR for the VaD incidence with migraine was higher in: (1) patients aged <65 years; (2) women; (3) patients without hypertension, diabetes, or atrial fibrillation; and (4) non-smokers.

CONCLUSION

Migraine is associated with an increased risk of VaD, particularly in chronic migraine patients. Incidence of VaD in the setting of migraine may have distinct pathophysiology from that of VaD with traditional cardiovascular risks.

Migraine Association with Alzheimer's Disease Risk: Evidence from the UK Biobank Cohort Study and Mendelian Randomization

BACKGROUND

Epidemiological studies on the association between migraine and Alzheimer's disease (AD) risk have yielded inconsistent conclusions. We aimed to characterize the phenotypic and genetic relationships between migraine and AD.

METHODS

To investigate the association between migraine and the risk of AD by analyzing data from a large sample of 404,318 individuals who were initially free from all-cause dementia or cognitive impairment, utilizing the UK Biobank dataset. We employed Cox regression modeling and propensity score matching techniques to examine the relationship between migraine and subsequent occurrences of AD. Additionally, the study utilized Mendelian randomization (MR) analysis to identify the genetic relationship between migraine and the risk of AD.

RESULTS

Migraine patients had a significantly increased risk of developing AD, compared to non-migraine patients (adjusted hazard ratio (HR) = 2.34, 95% confidence interval (CI) = 2.01-0.74, P < 0.001). Moreover, the propensity scores matching analyses found that migraine patients had a significantly higher risk of developing AD compared to non-migraine patients (HR = 1.85, 95%CI = 1,68-2.05, P < 0.001). Additionally, the MR suggested that significant causal effects of migraine on AD risks were observed [odds ratio (OR) = 2.315; 95% confidence interval (CI) = 1.029-5.234; P = 0.002]. Moreover, no evidence supported the causal effects of AD on migraine (OR = 1.000; 95%CI = 0.999-1.006; P = 0.971).

CONCLUSION

The present study concludes that migraine patients, compared to a matched control group, exhibit an increased risk of developing AD. Moreover, migraine patients exhibit an increased predisposition of genetic susceptibility to AD. These findings hold significant clinical value for early intervention and treatment of migraines to reduce the risk of AD.

Is headache a risk factor for dementia? A systematic review and meta-analysis

OBJECTIVE

In this systematic review and meta-analysis, we critically evaluate available evidence regarding the association between primary headaches and subsequent decline of cognitive function and dementia.

BACKGROUND

Recent studies suggested that headache disorders may increase the risk for dementia. However, available studies are conflicting.

METHODS

To identify qualifying studies, we searched scientific databases, including Pubmed, Scopus, Web of Science, Science Direct and BMC, screening for relevant papers. In order to reduce the heterogeneity between different studies, the analyses were further subdivided according to the clinical diagnoses and the study methodologies.

RESULTS

We identified 23 studies investigating the association between primary headaches and the risk of dementia. Of these, 18 met our inclusion criteria for meta-analysis (covering 924.140 individuals). Overall effect-size shows that primary headaches were associated with a small increase in dementia risk (OR = 1,15; CI 95%: 1,03-1,28; p = 0,02). Analyzing subgroups, we found that migraine was associated with both a moderate increased risk of all-cause dementia (OR = 1,26; p = 0,00; 95% CI: 1,13-1,40) as well as a moderate increased risk of Alzheimer's disease (OR = 2,00; p = 0,00; 95% CI: 1,46-2,75). This association was significant in both case-control and retrospective cohort studies but not in prospective studies.

CONCLUSIONS

Our study supports the presence of a link between primary headaches and dementia. However, in the subgroup analysis, only patients with migraine showed a moderate increase risk for all-cause dementia and for Alzheimer's disease. Additional rigorous studies are needed to elucidate the possible role of primary headaches on the risk of developing cognitive impairment and dementia.

Causal influences of neuropsychiatric disorders on Alzheimer's disease

Previous studies have observed a significant comorbidity between Alzheimer's disease (AD) and some other neuropsychiatric disorders. However, the mechanistic connections between neuropsychiatric disorders and AD are not well understood. We conducted a Mendelian randomization analysis to appraise the potential influences of 18 neurodegenerative and neuropsychiatric disorders on AD. We found that four disorders are causally associated with increased risk for AD, including bipolar disorder (BD) (OR: 1.09), migraine (OR: 1.09), schizophrenia (OR: 1.05), and Parkinson's disease (PD) (OR: 1.07), while attention-deficit/hyperactivity disorder (ADHD) was associated with a decreased risk for AD (OR: 0.80). In case of amyotrophic lateral sclerosis (OR: 1.04) and Tourette's syndrome (OR: 1.05), there was suggestive evidence of their causal effects of on AD. Our study shows that genetic components predisposing to BD, migraine, schizophrenia, and PD may promote the development of AD, while ADHD may be associated with a reduced risk of AD. The treatments aimed at alleviating neuropsychiatric diseases with earlier onset may also influence the risk of AD-related cognitive decline, which is typically observed later in life.

Thirty Risk Factors for Alzheimer's Disease Unified by a Common Neuroimmune-Neuroinflammation Mechanism

One of the major obstacles confronting the formulation of a mechanistic understanding for Alzheimer's disease (AD) is its immense complexity-a complexity that traverses the full structural and phenomenological spectrum, including molecular, macromolecular, cellular, neurological and behavioural processes. This complexity is reflected by the equally complex diversity of risk factors associated with AD. However, more than merely mirroring disease complexity, risk factors also provide fundamental insights into the aetiology and pathogenesis of AD as a neurodegenerative disorder since they are central to disease initiation and subsequent propagation. Based on a systematic literature assessment, this review identified 30 risk factors for AD and then extended the analysis to further identify neuroinflammation as a unifying mechanism present in all 30 risk factors. Although other mechanisms (e.g., vasculopathy, proteopathy) were present in multiple risk factors, dysfunction of the neuroimmune-neuroinflammation axis was uniquely central to all 30 identified risk factors. Though the nature of the neuroinflammatory involvement varied, the activation of microglia and the release of pro-inflammatory cytokines were a common pathway shared by all risk factors. This observation provides further evidence for the importance of immunopathic mechanisms in the aetiopathogenesis of AD.

Different Aspects of Aging in Migraine

Migraine is a common neurological disease displaying an unusual dependence on age. For most patients, the peak intensity of migraine headaches occurs in 20s and lasts until 40s, but then headache attacks become less intense, occur less frequently and the disease is more responsive to therapy. This relationship is valid in both females and males, although the prevalence of migraine in the former is 2-4 times greater than the latter. Recent concepts present migraine not only as a pathological event, but rather as a part of evolutionary adaptive response to protect organism against consequences of stress-induced brain energy deficit. However, these concepts do not fully explain that unusual dependence of migraine prevalence on age. Many aspects of aging, both molecular/cellular and social/cognitive, are interwound in migraine pathogenesis, but they neither explain why only some persons are affected by migraine, nor suggest any causal relationship. In this narrative/hypothesis review we present information on associations of migraine with chronological aging, brain aging, cellular senescence, stem cell exhaustion as well as social, cognitive, epigenetic, and metabolic aging. We also underline the role of oxidative stress in these associations. We hypothesize that migraine affects only individuals who have inborn, genetic/epigenetic, or acquired (traumas, shocks or complexes) migraine predispositions. These predispositions weakly depend on age and affected individuals are more prone to migraine triggers than others. Although the triggers can be related to many aspects of aging, social aging may play a particularly important role as the prevalence of its associated stress has a similar age-dependence as the prevalence of migraine. Moreover, social aging was shown to be associated with oxidative stress, important in many aspects of aging. In perspective, molecular mechanisms underlying social aging should be further explored and related to migraine with a closer association with migraine predisposition and difference in prevalence by sex.

Unraveling the link: exploring the causal relationship between diabetes, multiple sclerosis, migraine, and Alzheimer's disease through Mendelian randomization

Introduction

Observational studies suggested that diabetes mellitus [type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM)], multiple sclerosis (MS), and migraine are associated with Alzheimer's disease (AD). However, the causal link has not been fully elucidated. Thus, we aim to assess the causal link between T1DM, T2DM, MS, and migraine with the risk of AD using a two-sample Mendelian randomization (MR) study.

Methods

Genetic instruments were identified for AD, T1DM, T2DM, MS, and migraine respectively from genome-wide association study. MR analysis was conducted mainly using the inverse-variance weighted (IVW) method.

Results

The result of IVW method demonstrated that T2DM is causally associated with risk of AD (OR: 1.237, 95% CI: 1.099-1.391, P: 0.0003). According to the IVW method, there is no causal association between TIDM, MS, migraine, and the risk of AD (all p value > 0.05). Here we show, there is a causal link between T2DM and the risk of AD.

Conclusion

These findings highlight the significance of active monitoring and prevention of AD in T2DM patients. Further studies are required to actively search for the risk factors of T2DM combined with AD, explore the markers that can predict T2DM combined with AD, and intervene and treat early.

Association between migraine and Alzheimer's disease: a nationwide cohort study

Background and objective

Migraine is a common chronic neurological disease characterized by pulsating headaches, photophobia, phonophobia, nausea, and vomiting. The prevalence of dementia in individuals aged over 65 years in Korea is more than 10%, and Alzheimer's disease (AD) dementia accounts for most cases. Although these two neurological diseases account for a large portion of the medical burden in Korea, few studies have examined the relationship between the two diseases. Therefore, this study investigated the incidence and risk of AD in patients with migraines.

Methods

We retrospectively collected nationwide data from a national health insurance claims database governed by Korea's National Health Insurance Service. Among Koreans in the 2009 record, patients with migraine were identified according to the International Classification of Diseases, 10th revision (ICD-10) code G43. First, we screened the database for participants aged over 40 years. Individuals diagnosed with migraine at least twice over more than 3 months in a year were considered to have chronic migraine in this study. Further, all participants with an AD diagnosis (ICD-10 code: Alzheimer's disease F00, G30) were investigated for AD dementia development. The primary endpoint was AD development.

Results

The overall incidence of AD dementia was higher in individuals with a history of migraine than in those with no migraine history (8.0 per 1,000 person-years vs. 4.1 per 1,000 person-years). The risk of AD dementia was higher in individuals diagnosed with migraine (hazard ratio = 1.37 [95% confidence interval, 1.35-1.39]) than in the control group after adjustments for age and sex. Individuals with chronic migraine had a higher incidence of AD dementia than those with episodic migraine. Younger age (<65 years old) was associated with an increased risk of AD dementia compared to older age (≥65  years old). Higher body mass index (BMI) (≥25 kg/m²) was also associated with an increased risk of AD dementia compared to lower BMI (<25 kg/m²) (p < 0.001).

Conclusion

Our results suggest that individuals with a migraine history are more susceptible to AD than those without a migraine history. Additionally, these associations were more significant in younger and obese individuals with migraine than in individuals without migraine.

The Functions and Phenotypes of Microglia in Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease worldwide, but therapeutic strategies to slow down AD pathology and symptoms have not yet been successful. While attention has been focused on neurodegeneration in AD pathogenesis, recent decades have provided evidence of the importance of microglia, and resident immune cells in the central nervous system. In addition, new technologies, including single-cell RNA sequencing, have revealed heterogeneous cell states of microglia in AD. In this review, we systematically summarize the microglial response to amyloid-β and tau tangles, and the risk factor genes expressed in microglia. Furthermore, we discuss the characteristics of protective microglia that appear during AD pathology and the relationship between AD and microglia-induced inflammation during chronic pain. Understanding the diverse roles of microglia will help identify new therapeutic strategies for AD.

Assessment of Joint and Interactive Effects of Multimorbidity and Chronic Pain on ADRD Risk in the Elder Population

Objective

Multimorbidity and non-cancer chronic pain conditions (NCPC) are independently linked to elevated risk for cognitive impairment and incident Alzheimer's Disease and Related Dementias (ADRD)-both - We present the study of potential joint and interactive effects of these conditions on the risk of incident ADRD in older population.

Methods

This retrospective-cohort study drew baseline and 2-year follow-up data from linked Medicare claims and Medicare Current Beneficiary Survey (MCBS). Baseline multimorbidity and NCPC were ascertained using claims data. ADRD was ascertained at baseline and follow-up.

Results

NCPC accompanied by multimorbidity (vs. absence of NCPC or multimorbidity) had a significant and upward association with incident ADRD (adjusted odds ratio (AOR): 1.72, 95% CI 1.38, 2.13, p < 0.0001). Secondary analysis by number of comorbid conditions suggested that the joint effects of NCPC and multimorbidity on ADRD risk may increase with rising number contributing chronic conditions. Interaction analyses indicated significantly elevated excess risk for incident ADRD.

Amyloid oligomers as on-pathway precursors or off-pathway competitors of fibrils

Amyloid Diseases involve the growth of disease specific proteins into amyloid fibrils and their deposition in protein plaques. Amyloid fibril formation is typically preceded by oligomeric intermediates. Despite significant efforts, the specific role fibrils or oligomers play in the etiology of any given amyloid disease remains controversial. In neurodegenerative disease, though, amyloid oligomers are widely considered critical contributors to disease symptoms. Aside from oligomers as inevitable on-pathway precursors of fibril formation, there is significant evidence for off-pathway oligomer formation competing with fibril growth. The distinct mechanisms and pathways of oligomer formation directly affect our understanding under which conditions oligomers emerge in vivo, and whether their formation is directly coupled to, or distinct from, amyloid fibril formation. In this review, we will discuss the basic energy landscapes underlying the formation of on-pathway vs. off-pathway oligomers, their relation to the related amyloid aggregation kinetics, and their resulting implications for disease etiology. We will review evidence on how differences in the local environment of amyloid assembly can dramatically shift the relative preponderance of oligomers vs. fibrils. Finally, we will comment on gaps in our knowledge of oligomer assembly, of their structure, and on how to assess their relevance to disease etiology.

Contribution of pain to subsequent cognitive decline or dementia: A systematic review and meta-analysis of cohort studies

BACKGROUND

Dementia is an urgent public health problem worldwide, and the determination of the contribution of pain to cognitive decline or dementia is significant for the prevention of dementia.

OBJECTIVE

To comprehensively explore the contribution of pain to subsequent cognitive decline or dementia and analyze possible influencing factors.

DESIGN

Systematic review and meta-analysis of cohort studies.

METHODS

We systematically searched MEDLINE, EMBASE, PsycINFO, CINAHL, Cochrane Library, China National Knowledge Internet, WANFANG DATA and VIP for cohort studies from database inception to January 21, 2022. Random-effects meta-analysis was used to pool odds ratios (ORs) and 95% confidence intervals (CIs) of incident cognitive decline or dementia among patients with pain. Subgroup analyses and meta-regression were used to explore the sources of heterogeneity.

RESULTS

A total of 35 cohort studies containing 1,122,503 participants were included. As a whole, pain (OR = 1.24; 95% CI = 1.17-1.31) was a risk factor for subsequent cognitive decline or dementia; headache, migraine, tension-type headache, widespread pain, and irritable bowel syndrome, but not burning mouth syndrome, were also risk factors. Pain increased the risk of all-cause dementia (OR = 1.26; 95% CI = 1.18-1.35), Alzheimer's disease (OR = 1.28; 95% CI = 1.12-1.47), and vascular dementia (OR = 1.31; 95% CI = 1.06-1.62). Pain interference (OR = 1.42; 95% CI = 1.16-1.74) was associated with an increased risk of cognitive decline or dementia, while pain intensity was not. Pooled results from studies with sample sizes less than 2000 or with relatively low quality showed that pain did not increase the risk of cognitive decline or dementia. There was no statistically significant increase in the risk of cognitive decline or dementia in people with pain aged ≥75 years.

CONCLUSIONS

Our results demonstrated that pain increased the risk of subsequent cognitive decline or dementia. Sample size, study methodological quality, types of pain, pain severity (pain interference), and age composition of the study population may affect the relationship between pain and cognitive decline or dementia.

REGISTRATION

PROSPERO (CRD42022316406).

Machine Learning for Dementia Prediction: A Systematic Review and Future Research Directions

Nowadays, Artificial Intelligence (AI) and machine learning (ML) have successfully provided automated solutions to numerous real-world problems. Healthcare is one of the most important research areas for ML researchers, with the aim of developing automated disease prediction systems. One of the disease detection problems that AI and ML researchers have focused on is dementia detection using ML methods. Numerous automated diagnostic systems based on ML techniques for early prediction of dementia have been proposed in the literature. Few systematic literature reviews (SLR) have been conducted for dementia prediction based on ML techniques in the past. However, these SLR focused on a single type of data modality for the detection of dementia. Hence, the purpose of this study is to conduct a comprehensive evaluation of ML-based automated diagnostic systems considering different types of data modalities such as images, clinical-features, and voice data. We collected the research articles from 2011 to 2022 using the keywords dementia, machine learning, feature selection, data modalities, and automated diagnostic systems. The selected articles were critically analyzed and discussed. It was observed that image data driven ML models yields promising results in terms of dementia prediction compared to other data modalities, i.e., clinical feature-based data and voice data. Furthermore, this SLR highlighted the limitations of the previously proposed automated methods for dementia and presented future directions to overcome these limitations.

The association between migraine and dementia - a national register-based matched cohort study

OBJECTIVES

Migraine and dementia, two major public health challenges, are associated, but more knowledge is needed to understand their relationship. Objectives of this study were to investigate 1) the association between non-self-reported measures of migraine and dementia, and whether dementia was associated with 2) migraine without aura (MO) and with aura (MA) in combination with migraine medication use, and 3) migraine severity operationalized as the number of migraine prescriptions.

STUDY DESIGN

Matched cohort study.

METHODS

National register data were obtained from individuals born between 1934 and 1958. Migraine cases (aged 25-58 years) were identified by migraine diagnoses and redeemed migraine medication. Migraine cases were matched with non-cases (N = 340,850) and date of diagnosis or medication redemption was defined as index year. Dementia was identified by dementia diagnoses and redeemed dementia medication.

RESULTS

We observed a 1.46 (95% CI: 1.26-1.69) times higher dementia rate in individuals with a migraine diagnosis and a 0.86 (95% CI: 0.76-0.97) times lower rate when using migraine medication. We found the highest dementia rate among individuals with MA, who also used migraine medication (HR = 2.23; 95% CI: 1.19-4.17), and the lowest rate among individuals with MO, who also used medication (HR = 1.25; 95% CI: 0.75-2.10). The number of migraine medication prescriptions was not associated with dementia.

CONCLUSIONS

Being registered with a migraine diagnosis was associated with a higher dementia rate, while use of prescribed migraine medication was not. The differences in the dementia rate among migraine cases identified via diagnoses versus medications warrants further investigation.

Migraine Pharmacological Treatment and Cognitive Impairment: Risks and Benefits

Migraine is a common neurological disorder impairing the quality of life of patients. The condition requires, as an acute or prophylactic line of intervention, the frequent use of drugs acting on the central nervous system (CNS). The long-term impact of these medications on cognition and neurodegeneration has never been consistently assessed. The paper reviews pharmacological migraine treatments and discusses their biological and clinical effects on the CNS. The different anti-migraine drugs show distinct profiles concerning neurodegeneration and the risk of cognitive deficits. These features should be carefully evaluated when prescribing a pharmacological treatment as many migraineurs are of scholar or working age and their performances may be affected by drug misuse. Thus, a reconsideration of therapy guidelines is warranted. Furthermore, since conflicting results have emerged in the relationship between migraine and dementia, future studies must consider present and past pharmacological regimens as potential confounding factors.

Increased risk of all-cause, Alzheimer's, and vascular dementia in adults with migraine in Korea: a population-based cohort study

BACKGROUND

Studies investigating the association between migraine and dementia have reported inconsistent findings. This study aimed to evaluate whether patients with migraine have an increased risk of dementia compared to individuals without migraine.

METHODS

We obtained data from the 2002-2019 Korean National Health Insurance Health Screening Cohort. Non-migraine controls were selected using a 1:1 risk-set matching with a time-dependent propensity score. The main outcome was the development of all-cause dementia, and the secondary outcome was the development of each cause of dementia (Alzheimer's, vascular, mixed or other specified, and unspecified dementia). The incidence rate of dementia was calculated using Poisson regression, and the association between migraine and dementia was evaluated using Cox proportional hazards regression.

RESULTS

Among 88,390 participants, 66.1% were female, and the mean baseline age was 55.3 ± 9.4 years. During the study period, dementia cases were identified in 4,800 of the 44,195 patients with migraine and 3,757 of the 44,915 matched controls. The incidence rate of dementia was 139.6 (95% confidence interval [CI], 135.7-143.5) and 107.7 (95% CI, 104.3-111.1) cases per 10,000 person-years in patients with migraine and matched controls, respectively. Patients with migraine had a 1.30 (hazard ratio [HR], 1.30; 95% CI, 1.25-1.35), 1.29 (HR, 1.29; 95% CI, 1.23-1.35), 1.35 (HR, 1.35; 95% CI, 1.19-1.54), 1.36 (HR, 1.36; 95% CI, 1.00-1.83), and 1.30 (HR, 1.30; 95% CI, 1.17-1.45) times higher risk of developing all-cause dementia, Alzheimer's dementia, vascular dementia, mixed or other specified dementias, and unspecified dementia than their matched controls, respectively.

CONCLUSION

Our results suggest that migraine is associated with an increased risk of subsequent dementia. Further research is warranted to confirm these findings and to reveal the underlying mechanisms.

Primary headaches increase the risk of dementias: An 8-year nationwide cohort study

Background

Headache, a highly prevalent neurological disorder, has consistently been linked with an elevated risk of dementia. However, most studies are focused on the relationship with migraine in limited age groups. Therefore, the objective of this research was to look at the link between various type of headaches and dementias based on longitudinal population-based data.

Methods and results

Participants diagnosed with headache from 2002 to 2005 were selected and major covariates were collected. The diagnoses of Alzheimer’s disease, vascular dementia, and other dementias were observed from 2006 until 2013. The adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) of dementias according to headache type were calculated by Cox proportional hazards regression. A number of 470,652 participants were observed for a mean of 7.6 years (standard deviation: 1.2), for approximately 3.6 million person-years. Both tension type headache (TTH) and migraine elevated the risk of all-cause dementias (TTH, aHR 1.18, 95% CI 1.13–2.24; migraine, aHR 1.18, 95% CI 1.13–2.24). Headaches had a greater influence in females and non-smokers as a risk factor of dementias. Patients with migraine who consumed alcohol had a higher risk of dementia, however this was not true with TTH patients. Among participants without comorbidities, TTH patients were more susceptible to dementia than migraine patients. Headache patients had a higher proportion of females regardless of headache type and approximately 1.5 times more individuals had three or more comorbidities compared to those without headache.

Conclusions

Headache could be an independent predictor for subsequent dementia risk. Future studies should focus on clarifying pathogenic pathways and possible dementia-related preventive measures in headache populations.

Association between migraine and cognitive impairment

Background

Previous studies revealed inconsistent results regarding association between migraine and cognitive impairment. In addition, previous studies found inconsistent results regarding the association between migraine and risk of dementia. Thus, the study aimed to make a meta-analysis exploring comparison result in different types of cognitive function between migraine patients and non-migraine subjects. In addition, meta-analysis was made to explore the association between migraine and risk of dementia.

Methods

Articles published before June 2022 were searched in the following databases: PubMed, Web of Science, SCOPUS, EMBASE, EBSCO, PROQUEST, ScienceDirect and Cochrane Database of Systematic Reviews. Results were computed using STATA 12.0 software.

Results

Meta-analysis showed lower general cognitive function and language function in migraine group, compared to no migraine group (general cognitive function: standard mean difference (SMD) = − 0.40, 95% CI = − 0.66 to − 0.15; language: SMD = − 0.14, 95% confidence interval (CI) = − 0.27 to − 0.00), whereas the study showed no significant difference in visuospatial function, attention, executive function and memory between migraine group and no migraine group (visuospatial function: SMD = − 0.23, 95% CI = − 0.53 to 0.08; attention: SMD = − 0.01, 95% CI = − 0.10 to 0.08; executive function: SMD = − 0.05, 95% CI = − 0.16 to 0.05; memory: SMD = − 0.14, 95% CI = − 0.30 to 0.03). In addition, the meta-analysis showed a significant association between migraine and risk of dementia (odds ratio (OR)/relative risk (RR) = 1.30, 95% CI = 1.11 to 1.52).

Conclusions

In conclusion, the meta-analysis demonstrated lower general cognitive function and language function in migraine. In addition, migraine is associated with an increased risk of all-cause dementia, VaD and AD. These results suggest a significant association between migraine and cognitive impairment. Because of the association between migraine and cognitive impairment, neurological physician should be vigilant and effectively intervene in migraineurs with high risk factors of cognitive impairment to prevent the development of cognitive impairment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01462-4.

Eptinezumab for migraine prevention in patients 50 years or older

OBJECTIVE

To evaluate the efficacy and safety of eptinezumab versus placebo in patients ≥50 years old with episodic (EM) or chronic migraine (CM).

MATERIALS AND METHODS

This post hoc analysis included data from two phase 3, parallel-group, randomized, double-blind, placebo-controlled studies in adults with EM (PROMISE-1) or CM (PROMISE-2). Patients ≥50 years at baseline treated with eptinezumab 100 mg, 300 mg, or placebo were pooled from both studies to evaluate efficacy and safety.

RESULTS

A total of 385/1960 (19.6%) EM and CM patients who were ≥50 years old at baseline (range, 50-71 and 50-65 years, respectively) received eptinezumab 100 mg (n = 132), 300 mg (n = 127), or placebo (n = 126) over Weeks 1-12. Reductions in mean monthly migraine days (MMDs) in ≥50-year-old EM patients were -3.8 (100 mg) and -4.4 (300 mg) with eptinezumab versus -2.6 with placebo. In ≥50-year-old CM patients, mean changes in MMDs were -7.7 (100 mg) and -8.6 (300 mg) with eptinezumab versus -6.0 with placebo. Changes in MMDs were comparable to total study results. A ≥50% MMD reduction over Weeks 1-12 was achieved by 57.9% of eptinezumab-treated versus 35.7% of patients who received placebo, and a ≥75% reduction by 30.5% versus 13.5%, respectively. The incidence of treatment-emergent adverse events (TEAEs) in EM and CM patients ≥50 years old was similar across treatment groups, with ≥96% of TEAEs mild or moderate in severity.

CONCLUSIONS

Treatment with eptinezumab was efficacious, tolerable, and safe in patients ≥50 years with EM or CM, congruent with results from the overall study population.

Migraine and the risk of dementia: a meta-analysis and systematic review

OBJECTIVES

To conduct a comprehensive systematic review and meta-analysis to explore the correlation between migraine and the risk of dementia.

METHODS

The PubMed, EMBASE, and Cochrane library databases were searched systematically. We selected cohort studies (prospective and retrospective) and case-control studies that reported migraine in patients with dementia, including vascular dementia. The pooled effects were analyzed to evaluate relative risk with 95% confidence intervals.

RESULTS

In total, nine studies (two case-control and seven cohort studies) including 291,549 individuals were identified. These studies indicated that people with migraine (relative risk = 1.33; 95% confidence interval: 1.16-1.53) have an increased risk of all-cause dementia. Additionally, the pooled results of four studies showed that migraine is associated with an increased risk of vascular dementia (relative risk = 1.85; 95% confidence interval: 1.22-2.81; P = 0.004).

CONCLUSIONS

Data from observational studies suggest that migraine may be a risk factor for dementia, particularly vascular dementia. More studies are warranted to explore the association between migraine and dementia and the potential common pathophysiological mechanisms.

Genetic analyses identify pleiotropy and causality for blood proteins and highlight Wnt/β-catenin signalling in migraine

Migraine is a common complex disorder with a significant polygenic SNP heritability (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}_{{SNP}}^{2}$$\end{document}hSNP2). Here we utilise genome-wide association study (GWAS) summary statistics to study pleiotropy between blood proteins and migraine under the polygenic model. We estimate \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}_{{SNP}}^{2}$$\end{document}hSNP2 for 4625 blood protein GWASs and identify 325 unique proteins with a significant \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}_{{SNP}}^{2}$$\end{document}hSNP2 for use in subsequent genetic analyses. Pleiotropy analyses link 58 blood proteins to migraine risk at genome-wide, gene and/or single-nucleotide polymorphism levels—suggesting shared genetic influences or causal relationships. Notably, the identified proteins are largely distinct from migraine GWAS loci. We show that higher levels of DKK1 and PDGFB, and lower levels of FARS2, GSTA4 and CHIC2 proteins have a significant causal effect on migraine. The risk-increasing effect of DKK1 is particularly interesting—indicating a role for downregulation of β-catenin-dependent Wnt signalling in migraine risk, suggesting Wnt activators that restore Wnt/β-catenin signalling in brain could represent therapeutic tools against migraine.

Understanding of the causes and treatment of migraine is incomplete. Here, the authors detect pleiotropic genetic effects and causal relationships between migraine and 58 proteins that are largely distinct from migraine-associated loci identified by GWAS.

Migraine, Cognitive Decline, and Dementia in Older Adults: A Population-Based Study

Background: The potential impact of migraine on cognitive aging among older adults remains controversial. Objective: To examine the relationship of migraine and subtypes with cognitive decline and dementia in an older Swedish population. Methods: This population-based study included 3069 participants (age≥60) from the Swedish National study on Aging and Care in Kungsholmen, Stockholm. Baseline examination was conducted in 2001–2004, and participants were followed every 3 or 6 years until 2013–2016. Data were collected through face-to-face interviews, clinical examinations, laboratory tests, and linkage with registers. Global cognitive function was measured with the Mini-Mental State Examination (MMSE). Dementia was diagnosed according to the DSM-IV criteria. Migraine and subtypes were defined following the international classification system. Data were analyzed using logistic regression, Cox regression, and linear mixed-effects models. Results: At baseline, 305 participants were defined with non-migraine headache and 352 with migraine. The cross-sectional analysis showed that the multivariable-adjusted odds ratio (95% confidence interval) of prevalent dementia was 0.49 (0.20–1.21) for migraine and 0.66 (0.26–1.66) for migraine without aura. The longitudinal analysis showed that the multivariable-adjusted hazard ratios of incident dementia associated with migraine and subtypes ranged 0.68–0.89 (p > 0.05). Furthermore, migraine and subtypes were not significantly associated with either baseline MMSE score or MMSE changes during follow-ups (p > 0.05). The nonsignificant associations did not vary substantially by age, APOE ɛ4 allele, cerebrovascular disease, and antimigraine treatment (p for interactions > 0.05). Conclusion: This study shows no evidence supporting the associations of migraine and its subtypes with cognitive decline and dementia among older adults.

Migraine, Brain Glucose Metabolism and the "Neuroenergetic" Hypothesis: A Scoping Review

Increasing evidence suggests that migraine may be the result of an impaired brain glucose metabolism. Several studies have reported brain mitochondrial dysfunction, impaired brain glucose metabolism and gray matter volume reduction in specific brain areas of migraineurs. Furthermore, peripheral insulin resistance, a condition demonstrated in several studies, may extend to the brain, leading to brain insulin resistance. This condition has been proven to downregulate insulin receptors, both in astrocytes and neurons, triggering a reduction in glucose uptake and glycogen synthesis, mainly during high metabolic demand. This scoping review examines the clinical, epidemiologic and pathophysiologic data supporting the hypothesis that abnormalities in brain glucose metabolism may generate a mismatch between the brain's energy reserve and metabolic expenditure, triggering migraine attacks. Moreover, alteration in glucose homeostasis could generate a chronic brain energy deficit promoting migraine chronification. Lastly, insulin resistance may link migraine with its comorbidities, like obesity, depression, cognitive impairment and cerebrovascular diseases. PERSPECTIVE: Although additional experimental studies are needed to support this novel "neuroenergetic" hypothesis, brain insulin resistance in migraineurs may unravel the pathophysiological mechanisms of the disease, explaining the migraine chronification and connecting migraine with comorbidities. Therefore, this hypothesis could elucidate novel potential approaches for migraine treatment.

Cognitive Impairment in Primary and Secondary Headache Disorders

Purpose of Review

To critically evaluate the recent literature on cognitive impairment and headache.

Recent Findings

Neurocognitive symptoms are prevalent, debilitating, and occur often with both primary and secondary headache disorders.

Summary

This is a “narrative review of the current literature in PubMed on cognitive function and headache.” Migraine is associated with cognitive impairment years before a migraine diagnosis. In young and middle-aged adults, migraine is associated with deficits in attention, executive function, processing speed, and memory. It is unlikely that migraine is associated with dementia. Although methodologically difficult to assess, there does not seem to be an association between tension-type headache and cognitive dysfunction. In early to midlife, cluster headache seems to be associated with executive dysfunction. Several secondary headache syndromes relevant to clinicians managing headache disorders are associated with poorer cognitive performance or distinctive cognitive patterns, including those attributed to chronic cerebral or systemic vascular disorders, trauma, and derangements of intracranial pressure and volume, including frontotemporal brain sagging syndrome.

Association of Headache Disorders and the Risk of Dementia: Meta-Analysis of Cohort Studies

Objectives

The purpose of this meta-analysis is to assess whether there is an association between headache disorders and all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD).

Methods

PubMed, Cochrane Library, Embase, and Web of Science were searched for cohort studies published from database inception to October 8, 2021, using medical subject headings (MeSH) and keywords. All statistical analyses were performed using Stata statistical software version 14.0. If P > 0.1 and I² ≤ 50%, a fixed-effects model was adopted. If I² > 50% (which indicated great heterogeneity), a random-effects model was adopted. The funnel plot and Egger's test were used to evaluate publication bias.

Results

This meta-analysis included 12 cohort studies covering 465,358 individuals, which were published between 2001 and 2020. The pooling analysis shows that a history of any headache disorder is associated with an increased risk of all-cause dementia (OR = 1.35; 95% CI: 1.21–1.50; I² = 81.6%, P < 0.001). The history of any headache was associated with an increased risk of AD (OR = 1.49; 95% CI: 1.08–2.05; I² = 70.0%, P = 0.003) and VaD (OR = 1.72; 95% CI: 1.32–2.25; I² = 0%, P < 0.001). In the subgroup analysis, females with a history of headache have a slightly higher risk of dementia than males (OR = 1.32; 95% CI: 1.16–1.51; I² = 88.3%, P < 0.001) and the risk of dementia in the retrospective cohort was slightly higher than in the prospective cohort (OR = 1.38; 95% CI: 1.22–1.56; I² = 83.4%, P < 0.001).

Conclusions

Our meta-analysis shows that any headache disorder increases the risk of all-cause dementia, AD, or VaD. These findings provide evidence that headache should be recognized as an independent risk factor for dementia, AD, or VaD.

Assessment of neurovascular coupling and cortical spreading depression in mixed mouse models of atherosclerosis and Alzheimer's disease

Neurovascular coupling is a critical brain mechanism whereby changes to blood flow accompany localised neural activity. The breakdown of neurovascular coupling is linked to the development and progression of several neurological conditions including dementia. In this study, we examined cortical haemodynamics in mouse preparations that modelled Alzheimer's disease (J20-AD) and atherosclerosis (PCSK9-ATH) between 9 and 12 m of age. We report novel findings with atherosclerosis where neurovascular decline is characterised by significantly reduced blood volume, altered levels of oxyhaemoglobin and deoxyhaemoglobin, in addition to global neuroinflammation. In the comorbid mixed model (J20-PCSK9-MIX), we report a 3 x increase in hippocampal amyloid-beta plaques. A key finding was that cortical spreading depression (CSD) due to electrode insertion into the brain was worse in the diseased animals and led to a prolonged period of hypoxia. These findings suggest that systemic atherosclerosis can be detrimental to neurovascular health and that having cardiovascular comorbidities can exacerbate pre-existing Alzheimer's-related amyloid-plaques.

Acupuncture Treatment is Associated with Reduced Dementia Risk in Patients with Migraine: A Propensity-Score-Matched Cohort Study of Real-World Data

BACKGROUND

Migraine is a recurrent headache disease that has been identified as a risk factor for subsequent dementia. The present study collected data from Taiwan's National Health Insurance Research Database (NHIRD) to investigate the incidence of dementia in patients with migraine who did or did not concurrently receive acupuncture treatment.

METHODS

A 1:1 propensity score method was used to match an equal number of patients (N = 4813) in the acupuncture and nonacupuncture cohorts based on sex, age, migraine diagnosis year, index year, insurance amount, urbanization level, baseline comorbidities, and medication usage. We employed Cox proportional hazards models to evaluate the risk of dementia.

RESULTS

Patients with migraine who received acupuncture treatment were found to have a lower risk of dementia (adjusted hazard ratio [aHR] = 0.51, 95% CI = 0.40-0.65) than those who did not undergo acupuncture treatment. The cumulative incidence of dementia was significantly lower in the acupuncture cohort than in the nonacupuncture cohort (Log rank test, p < 0.001). This propensity score-matched cohort study demonstrated an association between acupuncture treatment and dementia development in patients with migraine in Taiwan.

CONCLUSION

The results suggest that acupuncture treatment significantly reduced the development of dementia in patients with migraine.

Meta-analysis of association between migraine and risk of dementia

OBJECTIVES

The association between migraine and dementia has rarely been investigated, and available results are conflicting. Thus, the aim of this meta-analysis was to evaluate whether an association exists between migraine and dementia.

MATERIALS & METHODS

We searched for cohort studies from databases including PubMed, EBSCO, Web of Science, and EMBASE database from inception to April 1, 2021, using subject and free words. RevMan 5.1 software was used to calculate the risk ratio (RR) of dementia in patients with migraine. Subgroup and sensitivity analyses were conducted to assess the source of heterogeneity. A random-effects model was used when heterogeneity was present. The Funnel plot and Egger's test were used to evaluate publication bias.

RESULTS

Five published cohort studies covering a total of 249,303 individuals were identified. Pooled analysis showed that migraine was associated with increased risk of all-cause dementia (RR: 1.34, 95% CI: 1.13-1.59) and Alzheimer's disease (AD) (RR: 2.49, 95% CI: 1.16-5.32). However, we did not found any association between migraine and risk of vascular dementia (VaD) (RR: 1.51, 95% CI: 0.77-2.96).

CONCLUSIONS

Our results revealed that migraine was a potential risk indicator for AD and all-cause dementia.

It Is Time to Study Overlapping Molecular and Circuit Pathophysiologies in Alzheimer's and Lewy Body Disease Spectra

Alzheimer's disease (AD) is the leading cause of dementia due to neurodegeneration and is characterized by extracellular senile plaques composed of amyloid β1 - 42 (Aβ) as well as intracellular neurofibrillary tangles consisting of phosphorylated tau (p-tau). Dementia with Lewy bodies constitutes a continuous spectrum with Parkinson's disease, collectively termed Lewy body disease (LBD). LBD is characterized by intracellular Lewy bodies containing α-synuclein (α-syn). The core clinical features of AD and LBD spectra are distinct, but the two spectra share common cognitive and behavioral symptoms. The accumulation of pathological proteins, which acquire pathogenicity through conformational changes, has long been investigated on a protein-by-protein basis. However, recent evidence suggests that interactions among these molecules may be critical to pathogenesis. For example, Aβ/tau promotes α-syn pathology, and α-syn modulates p-tau pathology. Furthermore, clinical evidence suggests that these interactions may explain the overlapping pathology between AD and LBD in molecular imaging and post-mortem studies. Additionally, a recent hypothesis points to a common mechanism of prion-like progression of these pathological proteins, via neural circuits, in both AD and LBD. This suggests a need for understanding connectomics and their alterations in AD and LBD from both pathological and functional perspectives. In AD, reduced connectivity in the default mode network is considered a hallmark of the disease. In LBD, previous studies have emphasized abnormalities in the basal ganglia and sensorimotor networks; however, these account for movement disorders only. Knowledge about network abnormalities common to AD and LBD is scarce because few previous neuroimaging studies investigated AD and LBD as a comprehensive cohort. In this paper, we review research on the distribution and interactions of pathological proteins in the brain in AD and LBD, after briefly summarizing their clinical and neuropsychological manifestations. We also describe the brain functional and connectivity changes following abnormal protein accumulation in AD and LBD. Finally, we argue for the necessity of neuroimaging studies that examine AD and LBD cases as a continuous spectrum especially from the proteinopathy and neurocircuitopathy viewpoints. The findings from such a unified AD and Parkinson's disease (PD) cohort study should provide a new comprehensive perspective and key data for guiding disease modification therapies targeting the pathological proteins in AD and LBD.

Mid- and Late-Life Migraine Is Associated with an Increased Risk of All-Cause Dementia and Alzheimer's Disease, but Not Vascular Dementia: A Nationwide Retrospective Cohort Study

We used a nationwide cohort sample of data from 2002 to 2013, representing approximately 1 million patients to investigate the prospective association between migraine and dementia. The migraine group (n = 1472) included patients diagnosed between 2002 and 2004, aged over 55 years; the comparison group was selected using propensity score matching (n = 5888). Cox proportional hazards regression analyses was used to calculate the hazard ratios (HRs). The incidence of dementia was 13.5 per 1000 person-years in the migraine group. Following adjustment for sociodemographic and comorbidities variables, patients with migraine developed dementia more frequently than those in the comparison group (adjusted HR = 1.37, 95% confidence interval [CI], 1.16–1.61). In the subgroup analysis, we found a higher HR of dementia events in male, the presence of comorbidities, and older age (≥65) patients with migraine, compared to those without migraine. Moreover, patients with migraine had a significantly higher incidence of Alzheimer’s disease (adjusted HR = 1.31, 95% CI, 1.08–1.58), but not vascular dementia, than those without migraine. Therefore, our findings suggest that mid- and late-life migraines may be associated with an increased incidence of all-cause dementia and Alzheimer’s disease, but not vascular dementia.

Increased Odds of Incident Alzheimer's Disease and Related Dementias in Presence of Common Non-Cancer Chronic Pain Conditions in Appalachian Older Adults

BACKGROUND

There is a growing concern regarding the increasing prevalence of common non-cancer chronic pain conditions (NCPCs) and their possible association with Alzheimer's disease and related dementias (ADRD). However, large population-based studies are limited, especially in Appalachian and other predominantly rural, underserved populations who suffer elevated prevalence of both NCPCs and known ADRD risk factors.

OBJECTIVES

We investigated the relation of NCPC to risk of incident ADRD in older Appalachian Medicare beneficiaries and explored the potential mediating effects of mood and sleep disorders.

METHODS

Using a retrospective cohort design, we assessed the overall and cumulative association of common diagnosed NCPCs at baseline to incident ADRD in 161,573 elders ≥65 years, Medicare fee-for-service enrollees, 2013-2015. NCPCs and ADRD were ascertained using claims data. Additional competing risk for death analyses accounted for potential survival bias.

MAIN FINDINGS

Presence of any NCPC at baseline was associated with significantly increased odds for incident ADRD after adjustment for covariates [adjusted odds ratio (AOR) = 1.26 (1.20, 1.32), p < .0001]. The magnitude and strength of this association increased significantly with rising burden of NCPCs at baseline [AOR for ≥4 vs. no NCPC = 1.65 (1.34, 2.03), p-trend = .01]. The addition of depression and anxiety, but not sleep disorders, modestly attenuated these associations [AORs for any NCPC and ≥4 NCPCs, respectively = 1.16 (1.10, 1.22) and 1.39 (1.13, 1.71)], suggesting a partial mediating role of mood impairment. Sensitivity analyses, multinomial logistic regressions accounting for risk of death, yielded comparable findings.

CONCLUSION

In this large cohort of older Appalachian Medicare beneficiaries, baseline NCPCs showed a strong, positive, dose-response relationship to odds for incident ADRD; this association appeared partially mediated by depression and anxiety. Further longitudinal research in this and other high-risk, rural populations are needed to evaluate the causal relation between NCPC and ADRD.

Headache - A Window to Dementia: An Unexpected Twist

Migraine and other types of headaches have several symptoms associated with them. The association between migraine and dementia has been considered. It is a topic of discussion and appears to be multifactorial. Dementia is a cluster of symptoms, with memory loss and cognitive dysfunction being the prominent symptoms. In this review, we discussed the association of headache and cognitive dysfunction in a broader context and how the practiced treatment of headaches may silently lead to dementia. We conducted a thorough literature search using PubMed as our main database. The articles exploring the association between headache (both migraine and non-migraine) and dementia were included. Some risk factors like migraine-induced stroke and inherent vascular diseases in migraine patients channeling to stroke and dementia were not considered. A total of 28 studies were included for review. All the reviewed studies put together showed an association between headache and cognitive dysfunction of any form. They showed that the frequency and duration of headache is a determinant for dementia. Few studies also focused on how treating headaches with certain drugs can lead to dementia. The reviewed published literature showed that headaches of any sort and their treatment are potentially linked to dementia. Not all headache patients will require medical treatment, as the benefit might outweigh the risk sometimes. It is interim to understand these facts and formulate a better protocol for treating headache patients. However, due to some discordant results, further studies are needed.

Risk of ambulance services associated with ambient temperature, fine particulate and its constituents

Short-term adverse health effects of constituents of fine particles with aerodynamic diameters less than or equal to 2.5 μm (PM_2.5) have been revealed. This study aimed to evaluate the real-time health outcome of ambulance services in association with ambient temperature and mass concentrations of total PM_2.5 level and constituents in Kaohsiung City, an industrialized city with the worst air quality in Taiwan. Cumulative 6-day (lag0-5) relative risk (RR) and 95% confidence interval (CI) of daily ambulance services records of respiratory distress, coma and unconsciousness, chest pain, headaches/dizziness/vertigo/fainting/syncope, lying at public, and out-of-hospital cardiac arrest (OHCA) in association with ambient temperature and mass concentrations of total PM_2.5 level and constituents (nitrate, sulfate, organic carbon (OC), and elemental carbon (EC)) from 2006 to 2010 were evaluated using a distributed lag non-linear model with quasi-Poisson function. Ambulance services of chest pain and OHCA were significantly associated with extreme high (30.8 °C) and low (18.2 °C) temperatures, with cumulative 6-day RRs ranging from 1.37 to 1.67 at the reference temperature of 24–25 °C. Daily total PM_2.5 level had significant effects on ambulance services of lying at public and respiratory distress. After adjusting the cumulative 6-day effects of temperature and total PM_2.5 level, RRs of ambulance services of lying at public associated with constituents at 90th percentile versus 25th percentile were 1.35 (95% CI: 1.08, 1.68) for sulfate and 1.20 (95% CI: 1.02, 1.41) for EC, while RR was 1.31 (95% CI: 1.09–1.58) for ambulance services of headache/dizziness/vertigo/fainting/syncope in association with OC at 90th percentile versus 25th percentile. Cause-specific ambulance services had various significant association with daily temperature, total PM_2.5 level, and concentrations of constituents. Elemental carbon may have stronger associations with increased ambulance services than other constituents.

Imaging for central nervous system (CNS) interstitial fluidopathy: disorders with impaired interstitial fluid dynamics

After the introduction of the glymphatic system hypothesis, an increasing number of studies on cerebrospinal fluid and interstitial fluid dynamics within the brain have been investigated and reported. A series of diseases are known which develop due to abnormality of the glymphatic system including Alzheimer's disease, traumatic brain injury, stroke, or other disorders. These diseases or disorders share the characteristics of the glymphatic system dysfunction or other mechanisms related to the interstitial fluid dynamics. In this review article, we propose "Central Nervous System (CNS) Interstitial Fluidopathy" as a new concept encompassing diseases whose pathologies are majorly associated with abnormal interstitial fluid dynamics. Categorizing these diseases or disorders as "CNS interstitial fluidopathies," will promote the understanding of their mechanisms and the development of potential imaging methods for the evaluation of the disease as well as clinical methods for disease treatment or prevention. In other words, having a viewpoint of the dynamics of interstitial fluid appears relevant for understanding CNS diseases or disorders, and it would be possible to develop novel common treatment methods or medications for "CNS interstitial fluidopathies."

Personality and Headaches: Findings From Six Prospective Studies

OBJECTIVE

The present study examined the association between personality traits and concurrent and incident headaches.

METHODS

Participants (n = 34,989), aged 16 to 107 years were from the Midlife in the United States study, the Midlife in Japan study, the Health and Retirement Study, the Wisconsin Longitudinal Study Graduate and Siblings samples, and the Longitudinal Internet Studies for the Social Sciences. Demographic factors, personality traits, and headaches were assessed at baseline. Headaches were assessed again 4 to almost 20 years later.

RESULTS

Across the samples, higher neuroticism was related to a higher likelihood of concurrent (combined odd ratio = 1.41, 95% confidence interval [CI] = 1.28-1.55, p < .001) and incident (combined odd ratio = 1.28, 95% CI = 1.12-1.46, p < .001) headaches, whereas higher extraversion was associated with a lower likelihood of concurrent (combined odd ratio = 0.87, 95% CI = 0.84-0.89, p < .001) and incident (combined odd ratio = 0.90, 95% CI = 0.85-0.96, p = .001) headaches. Higher conscientiousness (combined odd ratio = 0.90, 95% CI = 0.86-0.94, p < .001) and openness (combined odd ratio = 0.95, 95% CI = 0.90-0.99, p = .025) were associated with a lower probability of reporting concurrent headaches. Agreeableness was unrelated to headaches. Sex was not a consistent moderator.

CONCLUSIONS

The present study provides robust evidence that neuroticism and introversion are risk factors for headaches in concurrent and prospective analyses across multiple cohorts.

The Potential Contribution of Chronic Pain and Common Chronic Pain Conditions to Subsequent Cognitive Decline, New Onset Cognitive Impairment, and Incident Dementia: A Systematic Review and Conceptual Model for Future Research

BACKGROUND

Growing evidence suggests that chronic pain and certain chronic pain conditions may increase risk for cognitive decline and dementia.

OBJECTIVE

In this systematic review, we critically evaluate available evidence regarding the association of chronic pain and specific common chronic pain conditions to subsequent decline in cognitive function, new onset cognitive impairment (CI), and incident Alzheimer's disease and related dementias (ADRD); outline major gaps in the literature; and provide a preliminary conceptual model illustrating potential pathways linking pain to cognitive change.

METHODS

To identify qualifying studies, we searched seven scientific databases and scanned bibliographies of identified articles and relevant review papers. Sixteen studies met our inclusion criteria (2 matched case-control, 10 retrospective cohort, 2 prospective cohort), including 11 regarding the association of osteoarthritis (N = 4), fibromyalgia (N = 1), or headache/migraine (N = 6) to incident ADRD (N = 10) and/or its subtypes (N = 6), and 5 investigating the relation of chronic pain symptoms to subsequent cognitive decline (N = 2), CI (N = 1), and/or ADRD (N = 3).

RESULTS

Studies yielded consistent evidence for a positive association of osteoarthritis and migraines/headaches to incident ADRD; however, findings regarding dementia subtypes were mixed. Emerging evidence also suggests chronic pain symptoms may accelerate cognitive decline and increase risk for memory impairment and ADRD, although findings and measures varied considerably across studies.

CONCLUSION

While existing studies support a link between chronic pain and ADRD risk, conclusions are limited by substantial study heterogeneity, limited investigation of certain pain conditions, and methodological and other concerns characterizing most investigations to date. Additional rigorous, long-term prospective studies are needed to elucidate the effects of chronic pain and specific chronic pain conditions on cognitive decline and conversion to ADRD, and to clarify the influence of potential confounding and mediating factors.

Functional gene networks reveal distinct mechanisms segregating in migraine families

Migraine is the most common neurological disorder worldwide and it has been shown to have complex polygenic origins with a heritability of estimated 40-70%. Both common and rare genetic variants are believed to underlie the pathophysiology of the prevalent types of migraine, migraine with typical aura and migraine without aura. However, only common variants have been identified so far. Here we identify for the first time a gene module with rare mutations through a systems genetics approach integrating RNA sequencing data from brain and vascular tissues likely to be involved in migraine pathology in combination with whole genome sequencing of 117 migraine families. We found a gene module in the visual cortex, based on single nuclei RNA sequencing data, that had increased rare mutations in the migraine families and replicated this in a second independent cohort of 1930 patients. This module was mainly expressed by interneurons, pyramidal CA1, and pyramidal SS cells, and pathway analysis showed association with hormonal signalling (thyrotropin-releasing hormone receptor and oxytocin receptor signalling pathways), Alzheimer's disease pathway, serotonin receptor pathway and general heterotrimeric G-protein signalling pathways. Our results demonstrate that rare functional gene variants are strongly implicated in the pathophysiology of migraine. Furthermore, we anticipate that the results can be used to explain the critical mechanisms behind migraine and potentially improving the treatment regime for migraine patients.

Mid- to late-life migraine diagnoses and risk of dementia: a national register-based follow-up study

BACKGROUND

Previous studies found an association between migraine and dementia, which are two leading causes of disability. However, these studies did not differentiate between migraine types and did not investigate all prevalent dementia subtypes. The main objective of this national register-based study was to investigate whether migraine was a risk factor for dementia. Additionally, we explored potential differences in dementia risk for migraine with and without aura.

METHODS

We obtained data on birth cohorts born between 1935 and 1956 (n = 1,657,890) from Danish national registers. Individuals registered with migraine before age 59 (n = 18,135) were matched (1:5) on sex and birthdate with individuals without migraine (n = 1,378,346). Migraine was defined by International Classification of Diseases (ICD) diagnoses and dementia was defined by ICD diagnoses and anti-dementia medication. After matching, 62,578 individuals were eligible for analysis. For the statistical analyses, we used Cox regression models and adjusted for socio-demographic factors and several psychiatric and somatic morbidities.

RESULTS

During a median follow-up time of 6.9 (IQR: 3.6-11.2) years, 207 individuals with migraine developed dementia. Compared with individuals without migraine, we found a 50% higher rate of dementia among individuals with migraine (HR = 1.50; 95% CI: 1.28-1.76). Individuals without aura had a 19% higher rate of dementia (HR = 1.19; 95% CI: 0.84-1.70), and individuals with aura had a two times higher rate of dementia (HR = 2.11; 95% CI: 1.48-3.00).

CONCLUSIONS

Our findings support the hypothesis that migraine is a midlife risk factor for dementia in later life. The higher rate of dementia in individuals with a hospital-based diagnosis of migraine with aura emphasizes the need for studies on pathological mechanisms and potential preventative measures. Furthermore, given that only hospital-based migraine diagnoses were included in this study, future research should also investigate migraine cases derived from the primary healthcare system to include less severe migraine cases.

Non-Cancer Chronic Pain Conditions and Risk for Incident Alzheimer's Disease and Related Dementias in Community-Dwelling Older Adults: A Population-Based Retrospective Cohort Study of United States Medicare Beneficiaries, 2001-2013

Accumulating evidence suggests that certain chronic pain conditions may increase risk for incident Alzheimer's disease and related dementias (ADRD). Rigorous longitudinal research remains relatively sparse, and the relation of overall chronic pain condition burden to ADRD risk remains little studied, as has the potential mediating role of sleep and mood disorders. In this retrospective cohort study, we investigated the association of common non-cancer chronic pain conditions (NCPC) at baseline to subsequent risk for incident ADRD, and assessed the potential mediating effects of mood and sleep disorders, using baseline and 2-year follow-up data using 11 pooled cohorts (2001-2013) drawn from the U.S. Medicare Current Beneficiaries Survey (MCBS). The study sample comprised 16,934 community-dwelling adults aged ≥65 and ADRD-free at baseline. NCPC included: headache, osteoarthritis, joint pain, back or neck pain, and neuropathic pain, ascertained using claims data; incident ADRD (N = 1149) was identified using claims and survey data. NCPC at baseline remained associated with incident ADRD after adjustment for sociodemographics, lifestyle characteristics, medical history, medications, and other factors (adjusted odds ratio (AOR) for any vs. no NCPC = 1.21, 95% confidence interval (CI) = 1.04-1.40; p = 0.003); the strength and magnitude of this association rose significantly with increasing number of diagnosed NCPCs (AOR for 4+ vs. 0 conditions = 1.91, CI = 1.31-2.80, p-trend < 0.00001). Inclusion of sleep disorders and/or depression/anxiety modestly reduced these risk estimates. Sensitivity analyses yielded similar findings. NCPC was significantly and positively associated with incident ADRD; this association may be partially mediated by mood and sleep disorders. Additional prospective studies with longer-term follow-up are warranted to confirm and extend our findings.

Pharmacogenomics of Cognitive Dysfunction and Neuropsychiatric Disorders in Dementia

Symptomatic interventions for patients with dementia involve anti-dementia drugs to improve cognition, psychotropic drugs for the treatment of behavioral disorders (BDs), and different categories of drugs for concomitant disorders. Demented patients may take >6-10 drugs/day with the consequent risk for drug-drug interactions and adverse drug reactions (ADRs >80%) which accelerate cognitive decline. The pharmacoepigenetic machinery is integrated by pathogenic, mechanistic, metabolic, transporter, and pleiotropic genes redundantly and promiscuously regulated by epigenetic mechanisms. CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 geno-phenotypes are involved in the metabolism of over 90% of drugs currently used in patients with dementia, and only 20% of the population is an extensive metabolizer for this tetragenic cluster. ADRs associated with anti-dementia drugs, antipsychotics, antidepressants, anxiolytics, hypnotics, sedatives, and antiepileptic drugs can be minimized by means of pharmacogenetic screening prior to treatment. These drugs are substrates, inhibitors, or inducers of 58, 37, and 42 enzyme/protein gene products, respectively, and are transported by 40 different protein transporters. APOE is the reference gene in most pharmacogenetic studies. APOE-3 carriers are the best responders and APOE-4 carriers are the worst responders; likewise, CYP2D6-normal metabolizers are the best responders and CYP2D6-poor metabolizers are the worst responders. The incorporation of pharmacogenomic strategies for a personalized treatment in dementia is an effective option to optimize limited therapeutic resources and to reduce unwanted side-effects.

Effect of genetic liability to migraine on cognition and brain volume: A Mendelian randomization study

Objective

To investigate potential causality between genetic liability to migraine and Alzheimer’s disease, intelligence, and brain volume using two-sample Mendelian randomization.

Methods

The exposure consisted of independent genetic variants associated with migraine in the largest (59,674 cases/316,078 controls) published genome-wide association study. Outcomes included Alzheimer’s disease (71,880 cases/383,378 controls), a measure of general intelligence (n = 269,867), intracranial volume (n = 11,373), and seven subcortical brain volumes (n ∼ 13,000), all with available genome-wide association study summary statistics. Mendelian randomization effects were estimated using inverse-variance weighted analysis.

Results

Genetic liability to migraine did not associate with Alzheimer’s disease (odds ratio [95% confidence interval] 1.01 [1.00–1.02], p = 0.07), intelligence (standardized beta [95% confidence interval] 0.01 [0.00–0.02], p = 0.13), or any brain volume measures (all p > 0.05). No individual migraine variant associated with any of the outcomes at genome-wide significance.

Conclusions

These data do not support a causal effect of migraine liability on Alzheimer’s disease, intelligence, or brain volume.