Stroke and Coronary Artery Disease Are Associated With Parkinson’s Disease

Causal effects for neurodegenerative diseases on the risk of myocardial infarction: a two-sample Mendelian randomization study

Several studies have demonstrated a correlation between neurodegenerative diseases (NDDs) and myocardial infarction (MI), yet the precise causal relationship between these remains elusive. This study aimed to investigate the potential causal associations of genetically predicted Alzheimer's disease (AD), dementia with Lewy bodies (DLB), Parkinson's disease (PD), and multiple sclerosis (MS) with MI using two-sample Mendelian randomization (TSMR). Various methods, including inverse variance weighted (IVW), weighted median (WM), MR-Egger regression, weighted mode, and simple mode, were employed to estimate the effects of genetically predicted NDDs on MI. To validate the analysis, we assessed pleiotropic effects, heterogeneity, and conducted leave-one-out sensitivity analysis. We identified that genetic predisposition to NDDs was suggestively associated with higher odds of MI (OR_IVW=1.07, OR_MR-Egger=1.08, OR_WM=1.07, OR_weighted mode=1.07, OR_simple mode=1.10, all P<0.05). Furthermore, we observed significant associations of genetically predicted DLB with MI (OR_IVW=1.07, OR_MR-Egger=1.11, OR_WM=1.09, OR_weighted mode=1.09, all P<0.05). However, there was no significant causal evidence of genetically predicted PD and MS in MI. Across all MR analyses, no horizontal pleiotropy or statistical heterogeneity was observed (all P>0.05). Additionally, results from MRPRESSO and leave-one-out sensitivity analysis confirmed the robustness of the causal effect estimations for genetically predicted AD, DLB, PD, and MS on MI. This study provides further support for the causal effects of AD on MI and, for the first time, establishes robust causal evidence for the detrimental effect of DLB on the risk of MI. Our findings emphasize the importance of monitoring the cardiovascular function of the elderly experiencing neurodegenerative changes.

Use of antiviral drugs and incidence of Parkinson's disease in Taiwan

Patients infected with herpes zoster might be at risk for Parkinson's disease (PD). However, antiviral drugs may impede viral deoxyribonucleic acid (DNA) synthesis. This study aimed to determine whether the currently observed association between herpes zoster and PD is consistent with previous findings, and whether antiviral drug use is associated with PD. This retrospective cohort study used the Longitudinal Generation Tracking Database. We included patients aged 40 years and above and applied propensity score matching at 1:1 ratio for study comparability. PD risk was evaluated using Cox proportional hazards regression methods. A total of 234,730 people were analyzed. The adjusted hazard ratio (aHR) for PD in patients with herpes zoster was 1.05. Furthermore, the overall incidence of PD was lower in those treated with antiviral drugs than in the untreated ones (3.17 vs. 3.76 per 1,000 person-years); the aHR was 0.84. After stratifying for sex or age, a similar result was observed. In conclusion, herpes zoster may increase the risk of PD, particularly among females, but receiving antiviral treatment reduces the risk by 16%. Therefore, using antiviral drugs may help prevent PD. However, additional research is required to determine the underlying mechanism(s).

Risk of Parkinson disease in stroke patients: A nationwide cohort study in South Korea

BACKGROUND AND PURPOSE

Previous studies have examined the risk of stroke in patients with Parkinson disease (PD), but the incidence of PD onset among stroke patients and its risk according to severity of poststroke disabilities have scarcely been investigated. This study aims to determine whether the risk of PD is increased among stroke patients using a retrospective cohort with a large population-based database.

METHODS

We used data collected by the Korean National Health Insurance Service from 2010 to 2018 and examined 307,361 stroke patients and 380,917 sex- and age-matched individuals without stroke to uncover the incidence of PD. Cox proportional hazards regression was used to calculate the hazard ratio (HR) and 95% confidence interval (CI), and the risk of PD was compared according to presence and severity of disability.

RESULTS

During 4.31 years of follow-up, stroke patients had a 1.67 times higher risk of PD compared to individuals without stroke (adjusted HR = 1.67, 95% CI = 1.57-1.78). The risk of PD was greater among stroke patients with disabilities than among those without disabilities, even after adjustment for multiple covariates (adjusted HR = 1.72, 95% CI = 1.55-1.91; and adjusted HR = 1.66, 95% CI = 1.56-1.77, respectively).

CONCLUSIONS

Our study demonstrated an increased risk of PD among stroke patients. Health professionals need to pay careful attention to detecting movement disorders as clues for diagnosing PD.

Molecular mechanism of cognitive impairment associated with Parkinson's disease: A stroke perspective

Parkinson's disease (PD) is a common neurological illness that causes several motor and non-motor symptoms, most characteristically limb tremors and bradykinesia. PD is a slowly worsening disease that arises due to progressive neurodegeneration of specific areas of the brain, especially the substantia nigra of the midbrain. Even though PD has continuously been linked to a higher mortality risk in numerous epidemiologic studies, there have been significant discoveries regarding the connection between PD and stroke. The incidence of strokes such as cerebral infarction and hemorrhage is substantially associated with the development of PD. Moreover, cognitive impairments, primarily dementia, have been associated with stroke and PD. However, the underlying molecular mechanism of this phenomenon is still obscure. This concise review focuses on the relationship between stroke and PD, emphasizing the molecular mechanism of cognition deficit and memory loss evident in PD and stroke. Furthermore, we are also highlighting some potential drug molecules that can target both PD and stroke.

Potential risk of proton pump inhibitors for Parkinson's disease: A nationwide nested case-control study

Proton pump inhibitor (PPI) use is a potential risk factor for neurodegenerative disease development; however, its role in Parkinson's disease (PD) remains unclear. This study aimed to investigate the association between PPI use and PD risk. A total of 31,326 patients with newly diagnosed PD were matches by age, sex, body mass index, diabetes, and hypertension with 125,304 controls at a ratio of 1:4. The data were collected from the Korean National Health Insurance Services Database from January 2010 to December 2019. Cumulative defined daily doses of PPIs were extracted from treatment claims. We examined the association between PPI use and PD risk using conditional logistic regression. To prevent protopathic bias, we excluded patients diagnosed with PD within a 1-year lag period after PPI exposure. We applied 2- and 3-year lag periods for sensitivity analysis. PPI use was associated with an increased risk of PD when a 1-year lag period was applied between PPI exposure and PD development (adjusted odds ratio, 1.10; 95% confidence interval, 1.07-1.13). A significant positive dose-response relationship existed between the cumulative defined daily doses of PPIs and PD development (P<0.001). Similar results were obtained for the 2- or 3-year lag periods. The association did not vary based on gender. Older age, a higher Charlson Comorbidity Index score, no alcohol consumption, and a non-smoking status were associated with a significantly increased PD risk with PPI use. We observed an association between PPI use and PD risk, although long-term follow-up studies are necessary to verify this association.

Relationship between Parkinson's disease and cardio-cerebrovascular diseases: a Mendelian randomized study

Parkinson's disease (PD) and cardio-cerebrovascular diseases are related, according to earlier studies, but these studies have some controversy. Our aim was to assess the impact of PD on cardiocerebrovascular diseases using a Mendelian randomization (MR) method. The data for PD were single nucleotide polymorphisms (SNPs) from a publicly available genome-wide association study (GWAS) dataset containing data on 482,730 individuals. And the outcome SNPs data is were derived from five different GWAS datasets. The basic method for MR analysis was the inverse variance weighted (IVW) approach. We use the weighted median method and the MR-Egger method to supplement the MR analysis conclusion. Finally, We used Cochran's Q test to test heterogeneity, MR-PRESSO method and leave-one-out analysis method to perform sensitivity analysis. We used ratio ratios (OR) to assess the strength of the association between exposure and outcome, and 95% confidence intervals (CI) to show the reliability of the results. Our findings imply that PD is linked to a higher occurrence of coronary artery disease (CAD) (OR = 1.055, 95% CI 1.020-1.091, P = 0.001), stroke (OR = 1.039, 95% CI 1.007-1.072, P = 0.014). IVW analyses for stroke's subgroups of ischemic stroke (IS) and 95% CI 1.007-1.072, P = 0.014). IVW analyses for stroke's subgroups of ischemic stroke (IS) and cardioembolic stroke (CES) also yielded positive results, respectively (OR = 1.043, 95% CI 1.008-1.079, P = 0.013), (OR = 1.076, 95% CI 1.008-1.149, P = 0.026). There is no evidence of a relationship between PD and other cardio-cerebrovascular diseases. Additionally, sensitivity analysis revealed reliable outcomes. Our MR study analysis that PD is related with an elevated risk of CAD, stroke, IS, and CES.

Clinical and Non-Clinical Cardiovascular Disease Associated Pathologies in Parkinson's Disease

Despite considerable breakthroughs in Parkinson's disease (PD) research, understanding of non-motor symptoms (NMS) in PD remains limited. The lack of basic level models that can properly recapitulate PD NMS either in vivo or in vitro complicates matters. Even so, recent research advances have identified cardiovascular NMS as being underestimated in PD. Considering that a cardiovascular phenotype reflects sympathetic autonomic dysregulation, cardiovascular symptoms of PD can play a pivotal role in understanding the pathogenesis of PD. In this study, we have reviewed clinical and non-clinical published papers with four key parameters: cardiovascular disease risks, electrocardiograms (ECG), neurocardiac lesions in PD, and fundamental electrophysiological studies that can be linked to the heart. We have highlighted the points and limitations that the reviewed articles have in common. ECG and pathological reports suggested that PD patients may undergo alterations in neurocardiac regulation. The pathological evidence also suggested that the hearts of PD patients were involved in alpha-synucleinopathy. Finally, there is to date little research available that addresses the electrophysiology of in vitro Parkinson's disease models. For future reference, research that can integrate cardiac electrophysiology and pathological alterations is required.

Hypoxic stress accelerates the propagation of pathological alpha-synuclein and degeneration of dopaminergic neurons

AIMS

The etiology of Parkinson's disease (PD) is complex and the mechanism is unclear. It has become a top priority to find common factors that induce and affect PD pathology. We explored the key role of hypoxia in promoting the pathological propagation of α-synuclein (α-syn) and the progression of PD.

METHODS

We performed PD modeling by conducting intracranial stereotaxic surgery in the unilateral striatum of mice. We then measured protein aggregation in vitro. The rotarod and pole tests were employed next to measure the damage of the phenotype. Pathological deposition and autophagy were also observed by immunofluorescence staining and protein levels measured by western blotting.

RESULTS

We demonstrated that short-term hypoxia activated phosphorylated (p)-α-syn in mice. We confirmed that p-α-syn was more readily formed aggregates than α-syn in vitro. Furthermore, we found that hypoxia promoted the activation and propagation of endogenous α-syn, contributing to the earlier degeneration of dopaminergic neurons in the substantia nigra and the deposition of p-α-syn in our animal model. Finally, autophagy inhibition contributed to the above pathologies.

CONCLUSION

Hypoxia was shown to accelerate the pathological progression and damage phenotype in PD model mice. The results provided a promising research target for determining common interventions for PD in the future.

Association Between Parkinson's Disease and Coronary Artery Disease: A Systematic Review and Meta-Analysis

BACKGROUND

The relationship between Parkinson's disease (PD) and coronary artery disease (CAD) is unclear.

OBJECTIVE

This study aims to investigate whether PD and CAD are associated through systematic review and meta-analysis of observational studies.

METHODS

Electronic database search of PubMed, EMBASE, and Web of Science for observational studies published from 1 January 2010 to 1 August 2021 was conducted using terms related to PD and CAD. Unadjusted risk ratios (RR) and odds ratios (OR) of included cohort and case-control studies respectively were used to ascertain the association between PD and CAD. Study heterogeneity was evaluated using the I2 test.

RESULTS

Forty-one full-text studies were initially retrieved for eligibility assessment. Five studies that satisfied the inclusion criteria, consisting of three cohort and two case-control studies, were eventually included in this meta-analysis. The five studies enrolled 35,237 PD patients and 650,866 non-PD patients. PD and CAD were found to be significantly associated in cohort studies (RR = 2.23, 95% CI = 1.08-4.59, p = 0.03; Fig. 2), which held after sensitivity analysis (RR = 1.45, 95% CI = 1.31-1.60, p < 0.001; Fig. 3). Case-control studies found a trend towards association of PD and CAD approaching significance (OR = 1.47, 95% CI = 0.84-2.56, p = 0.18; Fig. 2).

CONCLUSION

Overall, this meta-analysis suggests that PD is associated with CAD. The underlying mechanisms, as well as the role of ethnicity and other comorbidities on the relationship between PD and CAD should be further explored.

Deep Learning Paradigm for Cardiovascular Disease/Stroke Risk Stratification in Parkinson's Disease Affected by COVID-19: A Narrative Review

Background and Motivation: Parkinson's disease (PD) is one of the most serious, non-curable, and expensive to treat. Recently, machine learning (ML) has shown to be able to predict cardiovascular/stroke risk in PD patients. The presence of COVID-19 causes the ML systems to become severely non-linear and poses challenges in cardiovascular/stroke risk stratification. Further, due to comorbidity, sample size constraints, and poor scientific and clinical validation techniques, there have been no well-explained ML paradigms. Deep neural networks are powerful learning machines that generalize non-linear conditions. This study presents a novel investigation of deep learning (DL) solutions for CVD/stroke risk prediction in PD patients affected by the COVID-19 framework. Method: The PRISMA search strategy was used for the selection of 292 studies closely associated with the effect of PD on CVD risk in the COVID-19 framework. We study the hypothesis that PD in the presence of COVID-19 can cause more harm to the heart and brain than in non-COVID-19 conditions. COVID-19 lung damage severity can be used as a covariate during DL training model designs. We, therefore, propose a DL model for the estimation of, (i) COVID-19 lesions in computed tomography (CT) scans and (ii) combining the covariates of PD, COVID-19 lesions, office and laboratory arterial atherosclerotic image-based biomarkers, and medicine usage for the PD patients for the design of DL point-based models for CVD/stroke risk stratification. Results: We validated the feasibility of CVD/stroke risk stratification in PD patients in the presence of a COVID-19 environment and this was also verified. DL architectures like long short-term memory (LSTM), and recurrent neural network (RNN) were studied for CVD/stroke risk stratification showing powerful designs. Lastly, we examined the artificial intelligence bias and provided recommendations for early detection of CVD/stroke in PD patients in the presence of COVID-19. Conclusion: The DL is a very powerful tool for predicting CVD/stroke risk in PD patients affected by COVID-19.

The Inflamm-Aging Model Identifies Key Risk Factors in Atherosclerosis

Background: Atherosclerosis, one of the main threats to human life and health, is driven by abnormal inflammation (i.e., chronic inflammation or oxidative stress) during accelerated aging. Many studies have shown that inflamm-aging exerts a significant impact on the occurrence of atherosclerosis, particularly by inducing an immune homeostasis imbalance. However, the potential mechanism by which inflamm-aging induces atherosclerosis needs to be studied more thoroughly, and there is currently a lack of powerful prediction models.

Methods: First, an improved inflamm-aging prediction model was constructed by integrating aging, inflammation, and disease markers with the help of machine learning methods; then, inflamm-aging scores were calculated. In addition, the causal relationship between aging and disease was identified using Mendelian randomization. A series of risk factors were also identified by causal analysis, sensitivity analysis, and network analysis.

Results: Our results revealed an accelerated inflamm-aging pattern in atherosclerosis and suggested a causal relationship between inflamm-aging and atherosclerosis. Mechanisms involving inflammation, nutritional balance, vascular homeostasis, and oxidative stress were found to be driving factors of atherosclerosis in the context of inflamm-aging.

Conclusion: In summary, we developed a model integrating crucial risk factors in inflamm-aging and atherosclerosis. Our computation pipeline could be used to explore potential mechanisms of related diseases.

Cardiovascular Risk Factors and Phenoconversion to Neurodegenerative Synucleinopathies in Idiopathic REM Sleep Behavior Disorder

Several studies have suggested that atherosclerotic diseases and diabetes may be risk factors for α-synucleinopathies. This prospective cohort study evaluated whether cardiovascular diseases and metabolic risk factors alter the rate or type of phenoconversion from idiopathic/isolated REM sleep behavior disorder (iRBD) to parkinsonism or dementia. Polysomnography-confirmed iRBD patients recruited between 2004 and 2020 were followed annually. Baseline history of cardiovascular disorders, hypertension, hypercholesterolemia, and diabetes were compared among patients who developed outcomes versus those who remained outcome-free. No atherosclerotic risk factors were associated with development of α-synucleinopathies. Patients with hypercholesterolemia were somewhat more likely to develop dementia with Lewy bodies rather than Parkinson's disease.

Cardiovascular/Stroke Risk Stratification in Parkinson's Disease Patients Using Atherosclerosis Pathway and Artificial Intelligence Paradigm: A Systematic Review

Parkinson’s disease (PD) is a severe, incurable, and costly condition leading to heart failure. The link between PD and cardiovascular disease (CVD) is not available, leading to controversies and poor prognosis. Artificial Intelligence (AI) has already shown promise for CVD/stroke risk stratification. However, due to a lack of sample size, comorbidity, insufficient validation, clinical examination, and a lack of big data configuration, there have been no well-explained bias-free AI investigations to establish the CVD/Stroke risk stratification in the PD framework. The study has two objectives: (i) to establish a solid link between PD and CVD/stroke; and (ii) to use the AI paradigm to examine a well-defined CVD/stroke risk stratification in the PD framework. The PRISMA search strategy selected 223 studies for CVD/stroke risk, of which 54 and 44 studies were related to the link between PD-CVD, and PD-stroke, respectively, 59 studies for joint PD-CVD-Stroke framework, and 66 studies were only for the early PD diagnosis without CVD/stroke link. Sequential biological links were used for establishing the hypothesis. For AI design, PD risk factors as covariates along with CVD/stroke as the gold standard were used for predicting the CVD/stroke risk. The most fundamental cause of CVD/stroke damage due to PD is cardiac autonomic dysfunction due to neurodegeneration that leads to heart failure and its edema, and this validated our hypothesis. Finally, we present the novel AI solutions for CVD/stroke risk prediction in the PD framework. The study also recommends strategies for removing the bias in AI for CVD/stroke risk prediction using the PD framework.

Protective Effect of Renin-Angiotensin System Inhibitors on Parkinson's Disease: A Nationwide Cohort Study

Background: Renin-angiotensin system (RAS) inhibitors have been suggested as protective agents in Parkinson's disease (PD). However, epidemiological evidence on the association between RAS inhibitors and the development of PD is inconsistent. Objectives: To investigate the effect of RAS inhibitors on PD risk in patients with ischemic heart disease (IHD) by type and cumulative duration of RAS inhibitors and their degree of blood-brain barrier (BBB) penetration ability. Methods: This was a propensity score-matched retrospective cohort study using 2008-2019 healthcare claims data from the Korean Health Insurance Review and Assessment database. The association between RAS inhibitor use and PD in patients with IHD was evaluated using multivariate Cox proportional hazard regression analysis. The risks are presented as adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Results: Over a 10-year follow-up, 1,086 of 62,228 IHD patients developed PD. The Cox regression model showed that the use of RAS inhibitors was significantly associated with a lower risk of PD (aHR = 0.75; 95% CI 0.66-0.85) than the non-use of RAS inhibitors. Specifically, this reduced risk of PD only remained with the use of BBB-crossing angiotensin II receptor blockers (ARBs) (aHR = 0.62; 95% CI = 0.53-0.74), and this association was more definite with an increasing cumulative duration. A significantly reduced risk of PD was not observed with the use of BBB-crossing angiotensin-converting enzyme inhibitors. Conclusions: The use of ARBs with BBB-penetrating properties and a high cumulative duration significantly reduces the risk of PD in IHD patients. This protective effect could provide insight into disease-modifying drug candidates for PD.

Tinnitus and risk of Alzheimer's and Parkinson's disease: a retrospective nationwide population-based cohort study

Tinnitus has been implied as a “soft” sign of neurodegenerative disease, which is characterized by progressive loss of neuronal function, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). This study aimed to determine whether the risk of developing AD/PD increases after having tinnitus. We conducted a retrospective matched cohort study with 12,657 tinnitus patients and 25,314 controls from the National Health Insurance Research Database (NHIRD) in Taiwan with almost 10 years follow-up. Tinnitus-related risk on developing AD/PD followingly was determined by the Cox regression to identify potential confounding factors. Through the 10-year follow-up period, 398 individuals with tinnitus (3.1%) and 501 control individuals (2.0%) developed AD (P < 0.001), and 211 tinnitus patients (1.7%) and 249 control patients (1.0%) developed PD (P < 0.001). Compared with controls, patients with tinnitus were 1.54 times more likely to develop AD (95% confidence interval (CI) 1.34–1.78, P < 0.001) and 1.56 times more likely to develop PD (95% CI 1.29–1.89, P < 0.001), after adjusting confounding factors. Our results indicate an association between tinnitus and higher risk of developing AD and PD. Additional physical comorbidities may also increase the risk of developing AD and PD.

β-Adrenoceptor Drugs and Parkinson's Disease: A Nationwide Nested Case-Control Study

BACKGROUND

Potential relationships between β-adrenergic drugs and α-synuclein synthesis in Parkinson's disease (PD) have been recently suggested.

OBJECTIVE

This study investigated the putative association between β-adrenoceptor drug exposure and PD occurrence.

METHODS

A nested case-control study was performed in the Echantillon Généraliste des Bénéficiaires (EGB) (a 1/97th random sample of affiliates to the French Insurance System). Incident PD patients diagnosed between 01/01/2008 and 31/12/2017 (index date) were matched 1:1 to controls by gender, birth year, and insurance scheme. Exposure to any β-agonist and to any β-antagonist was compared between cases and controls within 1-2 years before the index date, and exposure to salbutamol and to propranolol was individualized. The association between PD and β-adrenoceptor drugs was investigated through conditional logistic regression models adjusted for potential confounding factors. Because of a statistical interaction between β-agonists and diabetes, results were stratified according to the presence of diabetes.

RESULTS

Among the 2225 incident PD patients identified in the EGB (mean age 75.6 ± 10.2 years, sex ratio 1.04), no significant association was found between PD and β-antagonists (adjusted odds ratio [aOR] 1.05 [95% confidence interval 0.91-1.20]), except for propranolol (aOR 2.11 [1.38-3.23]). For β-agonists, a protective association in non-diabetic patients (aOR 0.75 [0.60-0.93]) and an opposite and significant association in diabetic patients (aOR 1.61 [1.02-2.55]) were observed. Similar results were found with salbutamol.

CONCLUSION

This study did not identify an increased risk of PD occurrence after β-antagonist exposure, except for propranolol (potential protopathic bias). The discordant results observed with β-agonists in patients with or without diabetes deserve further exploration of the influence of diabetic comorbidity on PD occurrence and evolution.

Expanding the search for genetic biomarkers of Parkinson's disease into the living brain

Altered gene expression related to Parkinson's Disease (PD) has not been described in the living brain, yet this information may support novel discovery pertinent to disease pathophysiology and treatment. This study compared the transcriptome in brain biopsies obtained from living PD and Control patients. To evaluate the novelty of this data, a comprehensive literature review also compared differentially expressed gene (DEGs) identified in the current study with those reported in PD cadaveric brain and peripheral tissues. RNA was extracted from rapidly cryopreserved frontal lobe specimens collected from PD and Control patients undergoing neurosurgical procedures. RNA sequencing (RNA-Seq) was performed and validated using quantitative polymerase chain reaction. DEG data was assessed using bioinformatics and subsequently included within a comparative analysis of PD RNA-Seq studies. 370 DEGs identified in living brain specimens reflected diverse gene groups and included key members of trophic signaling, apoptosis, inflammation and cell metabolism pathways. The comprehensive literature review yielded 7 RNA-Seq datasets generated from blood, skin and cadaveric brain but none from a living brain source. From the current dataset, 123 DEGs were identified only within the living brain and 267 DEGs were either newly found or had distinct directional change in living brain relative to other tissues. This is the first known study to analyze the transcriptome in brain tissue from living PD and Control patients. The data produced using these methods offer a unique, unexplored resource with potential to advance insight into the genetic associations of PD.

Association Between Stroke and Parkinson's Disease: a Meta-analysis

Parkinson's disease (PD) and stroke are both associated with aging, but the relationship between these two disorders remains unclear. Recent evidence has shown that they frequently co-occur and are influenced by each another, although some studies have found inconsistent results. We performed this meta-analysis of patients with PD on stroke risk to clarify the relationship between these two disorders on the basis of the studies published from 1975 to July 2019 in the PubMed, EMBASE, and Cochrane Library databases. In total, 13 case-control studies met the inclusion criteria for meta-analysis. The pooled odds ratio (OR) for PD in relation to the stroke risk was 1.72 (95% confidence interval (CI) 1.19-2.49). The OR for the presence of cerebral infarct among PD in the four studies was 1.35 (95% CI 1.04-1.74). Moreover, the OR for the presence of stroke pathology among PD in the four postmortem studies was 1.86 (95% CI 1.17-2.98). In conclusion, our meta-analysis suggests that there is an association between stroke and PD. Sensitivity analysis was used to test the robustness of our results through the sequential removal of each one study at time, in order to investigate if a single study was driving the study results. These results indicate that PD and stroke may have a common pathogenesis and may share preventive treatment measures.