Inverse Association of Parkinson Disease With Systemic Lupus Erythematosus: A Nationwide Population-based Study

Investigation of the causal association between Parkinson's disease and autoimmune disorders: a bidirectional Mendelian randomization study

Background

To date, an increasing number of epidemiological evidence has pointed to potential relationships between Parkinson's disease (PD) and various autoimmune diseases (AIDs), however, no definitive conclusions has been drawn about whether PD is causally related to AIDs risk.

Methods

By employing summary statistics from the latest and most extensive genome-wide association studies (GWAS), we performed a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the causal associations between PD and a variety of 17 AIDs, encompassing multiple sclerosis, neuromyelitis optica spectrum disorder, myasthenia gravis, asthma, inflammatory bowel disease, Crohn's disease, ulcerative colitis, irritable bowel syndrome, celiac disease, primary biliary cirrhosis, primary sclerosing cholangitis, type 1 diabetes, ankylosing spondylitis, rheumatoid arthritis, systemic lupus erythematosus, psoriasis and vitiligo. Inverse-variance weighted (IVW) was adopted as the main statistical approach to obtain the causal estimates of PD on different AIDs, supplemented by a series of complementary analyses (weighted median, MR Egger regression, and MR-PRESSO) for further strengthening the robustness of results.

Results

Our MR findings suggested that genetically predicted higher liability to PD was causally associated with a decreased risk of irritable bowel syndrome (OR = 0.98; 95% CI: 0.96-0.99; P = 0.032). On the contrary, IVW analysis showed a potential positive correlation between genetically determined PD and the incidence of type 1 diabetes (OR = 1.10; 95%CI: 1.02-1.19; P = 0.010). Subsequent MR tests ended up in similar results, confirming our findings were reliable. Additionally, in the reverse MR analyses, we did not identify any evidence to support the causal relationship of genetic predisposition to AIDs with PD susceptibility.

Conclusion

In general, a bifunctional role that PD exerted on the risk of developing AIDs was detected in our studies, both protecting against irritable bowel syndrome occurrence and raising the incidence of type 1 diabetes. Future studies, including population-based observational studies and molecular experiments in vitro and in vivo, are warranted to validate the results of our MR analyses and refine the underlying pathological mechanisms involved in PD-AIDs associations.

Inflammation, Autoimmunity and Neurodegenerative Diseases, Therapeutics and Beyond

Neurodegenerative disease (ND) incidence has recently increased due to improved life expectancy. Alzheimer's (AD) or Parkinson's disease (PD) are the most prevalent NDs. Both diseases are poly genetic, multifactorial and heterogenous. Preventive medicine, a healthy diet, exercise, and controlling comorbidities may delay the onset. After the diseases are diagnosed, therapy is needed to slow progression. Recent studies show that local, peripheral and age-related inflammation accelerates NDs' onset and progression. Patients with autoimmune disorders like inflammatory bowel disease (IBD) could be at higher risk of developing AD or PD. However, no increase in ND incidence has been reported if the patients are adequately diagnosed and treated. Autoantibodies against abnormal tau, β amyloid and α- synuclein have been encountered in AD and PD and may be protective. This discovery led to the proposal of immune-based therapies for AD and PD involving monoclonal antibodies, immunization/ vaccines, pro-inflammatory cytokine inhibition and anti-inflammatory cytokine addition. All the different approaches have been analysed here. Future perspectives on new therapeutic strategies for both disorders are concisely examined.

Disease mechanisms as subtypes: Immune dysfunction in Parkinson's disease

In recent years, the contraposition between inflammatory and neurodegenerative processes has been increasingly challenged. Inflammation has been emphasized as a key player in the onset and progression of Parkinson disease (PD) and other neurodegenerative disorders. The strongest indicators of the involvement of the immune system derived from evidence of microglial activation, profound imbalance in phenotype and composition of peripheral immune cells, and impaired humoral immune responses. Moreover, peripheral inflammatory mechanisms (e.g., involving the gut-brain axis) and immunogenetic factors are likely to be implicated. Even though several lines of preclinical and clinical studies are supporting and defining the complex relationship between the immune system and PD, the exact mechanisms are currently unknown. Similarly, the temporal and causal connections between innate and adaptive immune responses and neurodegeneration are unsettled, challenging our ambition to define an integrated and holistic model of the disease. Despite these difficulties, current evidence is providing the unique opportunity to develop immune-targeted approaches for PD, thus enriching our therapeutic armamentarium. This chapter aims to provide an extensive overview of past and present studies that explored the implication of the immune system in neurodegeneration, thus paving the road for the concept of disease modification in PD.

Systemic lupus erythematosus is associated with increased risk of Parkinson’s disease

Background:

A small number of studies have suggested an association between systemic lupus erythematosus (SLE) and Parkinson’s disease (PD).

Objectives:

This study aimed to determine the risk of incident PD among Korean patients with SLE.

Design:

A nationwide retrospective cohort study using the claims database of the National Health Insurance Service of Korea was conducted.

Methods:

Patients above 40 years of age diagnosed with SLE between 2010 and 2015 were included in the study. The primary outcome of the study was incident PD, defined by registration in the rare intractable diseases program for PD and an ICD-10 code of G20. Subjects were followed until PD diagnosis or the end of 2017. We estimated the cumulative incidence of PD among the SLE cohort and compared this to that in a 1:5 age- and sex-matched control group.

Results:

Totals of 11,615 SLE cases and 58,075 matched controls were identified. The cumulative incidence rate of PD was 0.7 per 1000 person-years in the SLE cohort. The crude hazard ratio (HR) of incident PD was 1.71 (95% CI: 1.25–2.36) among the SLE cohort compared to the control group. The HR was 1.59 (95% CI: 1.15–2.20) after adjustment for age, sex, income, and baseline comorbidities.

Conclusion:

This study demonstrated that patients with SLE had an increased risk of incident PD compared to non-SLE controls. Further research is required to determine the mechanism underlying this and to elucidate the precise role of systemic inflammation in the development of PD in patients with SLE.

The association between Parkinson's disease and autoimmune diseases: A systematic review and meta-analysis

Parkinson's disease (PD) is a neurodegenerative disorder that frequently occurs in the older population. Previous epidemiological studies have suggested an association between PD and autoimmune diseases (AIDs). However, some studies have shown conflicting results. This study aimed to summarize existing epidemiological studies on the association between PD with AIDs and to conduct a meta-analysis of combinable results. Four electronic databases (PubMed, Embase, Web of Science Core Collection, and MEDLINE) were searched from each database's inception date until December 12, 2022. All studies that explored the relationship between PD and AIDs were included for quantitative analysis and qualitative review. The pooled relative risk with 95% confidence intervals (CIs) was calculated using a random or fixed effects model. A total of 46 observational studies involving 873,643 patients and 13,402,821 controls were included; ultimately, 38 studies were included in the meta-analysis. The risk of PD combined with AIDs was significantly higher (odds ratio [OR]=1.55, 95% CI: 1.33-1.81), and subgroup analysis found no significant differences in risk by study type, gender, age, and race. Regarding the AID types, the results showed an increased risk of PD combined with bullous pemphigoid (OR=2.67, 95% CI: 2.15-3.31), inflammatory bowel disease (OR=1.30, 95% CI: 1.18-1.45), Crohn's disease (OR=1.30, 95% CI: 1.20-1.42), ulcerative colitis (OR=1.31, 95% CI: 1.14-1.50), Sjögren's syndrome (OR=1.61, 95% CI: 1.24-2.09), and Graves' disease (OR=1.45, 95% CI: 1.24-1.70) than controls. However, there appeared to be no significant association between PD and systemic lupus erythematosus (OR=0.82, 95% CI: 0.66-1.03), multiple sclerosis (OR=2.02, 95% CI: 0.87-4.70), rheumatoid arthritis (OR=0.79, 95% CI: 0.61-1.03), or celiac disease (OR=1.16, 95% CI: 0.79-1.69). This study supports the existence of a strong link between AIDs and PD. When PD and AIDs are identified, clinicians need to be aware of the possibility of coexistence. However, there are some limitations of this study, such as the apparent heterogeneity of some of the results and the fact that most of the included study types were retrospective. Therefore, future larger prospective cohort studies are needed to further explore the interaction between PD and AIDs.

Systematic review registration

INPLASY, identifier INPLASY202280088.

Inflammatory rheumatic diseases and the risk of Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

Several studies showed inconsistencies in the relationships between inflammatory rheumatic diseases (IRDs) and the risk of Parkinson's disease (PD). Therefore, we carried out a meta-analysis to investigate the associations between different IRDs and PD risk.

METHODS

A comprehensive search was undertaken on PubMed, Embase, Cochrane Library, and Web of Science databases up to June 2022. Studies reporting the relationships between IRDs and PD risk were included. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated by using random-effects models.

RESULTS

Twenty-two publications covering seven IRDs containing data from 833,004 patients were identified for quantitative analysis. The pooled results indicated that ankylosing spondylitis (RR = 1.55, 95% CI: 1.31-1.83, I2 = 32.1%, P < 0.001), Sjögren's syndrome (RR = 1.34, 95% CI: 1.22-1.47, I2 = 58.5%, P < 0.001), and Behcet's disease (RR = 1.93, 95% CI: 1.07-3.49, I2 = 57.6%, P = 0.030) were associated with an increased PD risk. However, no significant associations were observed between gout, rheumatoid arthritis, systemic lupus erythematosus, as well as polymyalgia rheumatica and the subsequent development of PD.

CONCLUSION

Ankylosing spondylitis, Sjögren's syndrome, and Behcet's disease may increase PD risk.

A Transcriptome Analysis of mRNAs and Long Non-Coding RNAs in Patients with Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder. The number of cases of PD is expected to double by 2030, representing a heavy burden on the healthcare system. Clinical symptoms include the progressive loss of dopaminergic neurons in the substantia nigra of the midbrain, which leads to striatal dopamine deficiency and, subsequently, causes motor dysfunction. Certainly, the study of the transcriptome of the various RNAs plays a crucial role in the study of this neurodegenerative disease. In fact, the aim of this study was to evaluate the transcriptome in a cohort of subjects with PD compared with a control cohort. In particular we focused on mRNAs and long non-coding RNAs (lncRNA), using the Illumina NextSeq 550 DX System. Differential expression analysis revealed 716 transcripts with padj ≤ 0.05; among these, 630 were mRNA (coding protein), lncRNA, and MT_tRNA. Ingenuity pathway analysis (IPA, Qiagen) was used to perform the functional and pathway analysis. The highest statistically significant pathways were: IL-15 signaling, B cell receptor signaling, systemic lupus erythematosus in B cell signaling pathway, communication between innate and adaptive immune cells, and melatonin degradation II. Our findings further reinforce the important roles of mitochondria and lncRNA in PD and, in parallel, further support the concept of inverse comorbidity between PD and some cancers.

A Transcriptome Analysis of mRNAs and Long Non-Coding RNAs in Patients with Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder. The number of cases of PD is expected to double by 2030, representing a heavy burden on the healthcare system. Clinical symptoms include the progressive loss of dopaminergic neurons in the substantia nigra of the midbrain, which leads to striatal dopamine deficiency and, subsequently, causes motor dysfunction. Certainly, the study of the transcriptome of the various RNAs plays a crucial role in the study of this neurodegenerative disease. In fact, the aim of this study was to evaluate the transcriptome in a cohort of subjects with PD compared with a control cohort. In particular we focused on mRNAs and long non-coding RNAs (lncRNA), using the Illumina NextSeq 550 DX System. Differential expression analysis revealed 716 transcripts with padj ≤ 0.05; among these, 630 were mRNA (coding protein), lncRNA, and MT_tRNA. Ingenuity pathway analysis (IPA, Qiagen) was used to perform the functional and pathway analysis. The highest statistically significant pathways were: IL-15 signaling, B cell receptor signaling, systemic lupus erythematosus in B cell signaling pathway, communication between innate and adaptive immune cells, and melatonin degradation II. Our findings further reinforce the important roles of mitochondria and lncRNA in PD and, in parallel, further support the concept of inverse comorbidity between PD and some cancers.

Disease-Modifying Antirheumatic Drugs and Risk of Parkinson Disease: Nested Case-Control Study of People With Rheumatoid Arthritis

BACKGROUND

Epidemiological studies have suggested a link between rheumatoid arthritis and Parkinson's disease (PD). Disease-modifying anti-rheumatic drugs (DMARDs) might explain this association.

OBJECTIVE

To evaluate the association between DMARDs and risk of PD in persons with rheumatoid arthritis.

METHODS

Nested nationwide case-control study was conducted within the Finnish Parkinson's disease (FINPARK) cohort that includes 22,189 Finnish persons with clinically verified PD diagnosed in 1996-2015. The cases had recorded diagnosis of PD in the Special Reimbursement Register and had no exclusion diagnoses whose symptoms may be confused with PD within two years of PD diagnosis. This study included cases with PD diagnosed during 1999-2015 and rheumatoid arthritis diagnosed >3 years before PD. Rheumatoid arthritis was identified using Finnish Care Register for Health Care and Special Reimbursement Register. Cases were matched with up to seven control persons by age, sex, duration of rheumatoid arthritis and region. DMARDs were categorised into five classes and data on purchased prescriptions was identified from the Prescription Register since 1995. Associations were studied with conditional logistic regression adjusted for confounders.

RESULTS

Altogether 315 cases with PD and 1,571 matched controls were included. Majority (> 60%) were women and median duration of rheumatoid arthritis on matching date was 11.6 years for controls and 12.6 years for cases. Use of DMARDs was not associated with risk of PD with three-year lag period applied between exposure and outcome, except chloroquine/hydroxychloroquine which associated with decreased risk (adjusted odds ratio 0.74; 95% confidence interval 0.56-0.97). Other DMARDs, including sulfasalazine, methotrexate, gold preparations and immunosuppressants, were not associated with PD.

DISCUSSION

Our results suggest that the lower risk of PD in people with rheumatoid arthritis is not explained by DMARD use as these drugs in general did not modify the risk of PD among persons with rheumatoid arthritis. Association between chloroquine/hydroxychloroquine and lower risk of PD as well as the possible underlying mechanisms should be further investigated.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in individuals with rheumatoid arthritis using DMARDs, only chloroquine/hydroxychloroquine was associated with a potentially decreased risk of developing PD (adjusted OR 0.74, 95% CI 0.56-0.97).

Epidemiological Evidence for an Immune Component of Parkinson's Disease

There is a growing interest in the role the immune system and inflammatory response play on the pathophysiology of Parkinson's disease (PD). Epidemiological evidence lends support for the hypothesis that PD is an immune-mediated condition. An association between inflammatory bowel disease, including Crohn's and Ulcerative colitis, and the risk of PD has been described and replicated in several population-based cohorts. Other autoimmune conditions, such as Sjogren syndrome, ankylosing spondylitis, and rheumatoid arthritis also seem to be associated with an increased risk of PD. Immunosuppressant medications seem to be associated with a decreased risk of PD. Finally, variants in genes involved in immune system regulation are also shared between PD and autoimmune conditions. In this review, we will provide an overview of epidemiological evidence from population-based cohort studies, meta-analyses, and genome-wide association studies that analyze the association between the immune system and PD, discuss current gaps in the literature and future research directions in this field.

Comprehensive Profiling of Blood Coagulation and Fibrinolysis Marker Reveals Elevated Plasmin-Antiplasmin Complexes in Parkinson's Disease

Parkinson's disease (PD) is the second most common age-related neurodegenerative disease. Accumulating evidence demonstrates that alpha-synuclein (α-Syn), an apparently predominant neuronal protein, is a major contributor to PD pathology. As α-Syn is also highly abundant in blood, particularly in red blood cells (RBCs) and platelets, this in turn raises the question on the function of presumably dysfunctional α-Syn in "peripheral" cells and its putative effect on the other enclosed constituents. Herein, we detected the internal variance in erythrocytes of PD patients by Raman spectroscopy, but no measurable amount of erythrocytic behavioural change (eryptosis) or any haemoglobin variation was noticed. An elevated level of plasmin-antiplasmin complexes (PAP) was observed in the plasma of PD patients, indicating activation of the fibrinolytic system, but platelet activation after thrombin stimulation was not altered. Sex-specific patterns were noticed for blood coagulation factor XIII and factor XII activity in PD patients. Additionally, the alterations in homocysteine levels which have often been observed in PD patients were found to be independent from L-DOPA usage and PAP levels. Furthermore, a selective gene expression analysis identified subsets of genes related to different blood-associated compartments (RBCs, platelets, coagulation-fibrinolysis) also involved in PD-related pathways.

Rheumatoid arthritis decreases risk for Parkinson's disease: a Mendelian randomization study

Epidemiological and clinical studies have suggested comorbidity between rheumatoid arthritis and Parkinson’s disease (PD), but whether there exists a causal association and the effect direction of rheumatoid arthritis on PD is controversial and elusive. To evaluate the causal relationship, we first estimated the genetic correlation between rheumatoid arthritis and PD, and then performed a two-sample Mendelian randomization analysis based on summary statistics from large genome-wide association studies of rheumatoid arthritis (N = 47,580) and PD (N = 482,703). We identified negative and significant correlation between rheumatoid arthritis and PD (genetic correlation: −0.10, P = 0.0033). Meanwhile, one standard deviation increase in rheumatoid arthritis risk was associated with a lower risk of PD (OR: 0.904, 95% CI: 0.866–0.943, P: 2.95E–06). The result was robust under all sensitivity analyses. Our results provide evidence supporting a protective role of rheumatoid arthritis on PD. A deeper understanding of the inflammation and immune response is likely to elucidate the potential pathogenesis of PD and identify therapeutic targets for PD.

Positive association of Parkinson's disease with ankylosing spondylitis: a nationwide population-based study

Background

Ankylosing spondylitis (AS) is characterized by excessive production of inflammatory cytokines. Recent evidence suggests that inflammation underlies the neurodegenerative process of Parkinson’s disease (PD). Whether AS has an influence on the development of PD is unclear. We aimed to examine a relationship, if any exists between AS and PD.

Methods

A population-based matched cohort study was performed using data from the 2000–2010 Taiwan National Health Insurance database. 6440 patients with AS and 25,760 randomly selected, age- and sex-matched controls were included in this study. The risk of PD in the AS cohort was evaluated by using a Cox model.

Results

This study revealed a positive association between AS and the risk of PD regardless of sex and age (aHR 1.75, p < .001). Particularly, AS cohort to non-AS cohort relative risk of PD significantly increased for the patients aged below 49 and above 65 years (aHR 4.70, p < .001; aHR 1.69, p < .001, respectively) and the patients with and without comorbidities (aHR 1.61, p < .001; aHR 2.71, p < .001, respectively). Furthermore, NSAID use was associated with lower risk of PD (aHR 0.69, p < .05). However, the risk of PD was higher (aHR 2.40, p < .01) in patients with AS receiving immunosuppressants than in those not receiving (aHR 1.70, p < .001).

Conclusions

Patients with AS had an increased risk of PD which might be related to underlying chronic inflammation. Further research is required to elucidate the underlying mechanism.

The Functional Roles and Applications of Immunoglobulins in Neurodegenerative Disease

Natural autoantibodies, immunoglobulins (Igs) that target self-proteins, are common in the plasma of healthy individuals; some of the autoantibodies play pathogenic roles in systemic or tissue-specific autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Recently, the field of autoantibody-associated diseases has expanded to encompass neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD), with related studies examining the functions of Igs in the central nervous system (CNS). Recent evidence suggests that Igs have various effects in the CNS; these effects are associated with the prevention of neurodegeneration, as well as induction. Here, we summarize the functional roles of Igs with respect to neurodegenerative disease (AD and PD), focusing on the target antigens and effector cell types. In addition, we review the current knowledge about the roles of these antibodies as diagnostic markers and immunotherapies.

Parkinson disease and the immune system - associations, mechanisms and therapeutics

Multiple lines of evidence indicate that immune system dysfunction has a role in Parkinson disease (PD); this evidence includes clinical and genetic associations between autoimmune disease and PD, impaired cellular and humoral immune responses in PD, imaging evidence of inflammatory cell activation and evidence of immune dysregulation in experimental models of PD. However, the mechanisms that link the immune system with PD remain unclear, and the temporal relationships of innate and adaptive immune responses with neurodegeneration are unknown. Despite these challenges, our current knowledge provides opportunities to develop immune-targeted therapeutic strategies for testing in PD, and clinical studies of some approaches are under way. In this Review, we provide an overview of the clinical observations, preclinical experiments and clinical studies that provide evidence for involvement of the immune system in PD and that help to define the nature of this association. We consider autoimmune mechanisms, central and peripheral inflammatory mechanisms and immunogenetic factors. We also discuss the use of this knowledge to develop immune-based therapeutic approaches, including immunotherapy that targets α-synuclein and the targeting of immune mediators such as inflammasomes. We also consider future research and clinical trials necessary to maximize the potential of targeting the immune system.

Protein Deimination Signatures in Plasma and Plasma-EVs and Protein Deimination in the Brain Vasculature in a Rat Model of Pre-Motor Parkinson's Disease

The identification of biomarkers for early diagnosis of Parkinson’s disease (PD) is of pivotal importance for improving approaches for clinical intervention. The use of translatable animal models of pre-motor PD therefore offers optimal opportunities for novel biomarker discovery in vivo. Peptidylarginine deiminases (PADs) are a family of calcium-activated enzymes that contribute to protein misfolding through post-translational deimination of arginine to citrulline. Furthermore, PADs are an active regulator of extracellular vesicle (EV) release. Both protein deimination and extracellular vesicles (EVs) are gaining increased attention in relation to neurodegenerative diseases, including in PD, while roles in pre-motor PD have yet to be investigated. The current study aimed at identifying protein candidates of deimination in plasma and plasma-EVs in a rat model of pre-motor PD, to assess putative contributions of such post-translational changes in the early stages of disease. EV-cargo was further assessed for deiminated proteins as well as three key micro-RNAs known to contribute to inflammation and hypoxia (miR21, miR155, and miR210) and also associated with PD. Overall, there was a significant increase in circulating plasma EVs in the PD model compared with sham animals and inflammatory and hypoxia related microRNAs were significantly increased in plasma-EVs of the pre-motor PD model. A significantly higher number of protein candidates were deiminated in the pre-motor PD model plasma and plasma-EVs, compared with those in the sham animals. KEGG (Kyoto encyclopedia of genes and genomes) pathways identified for deiminated proteins in the pre-motor PD model were linked to “Alzheimer’s disease”, “PD”, “Huntington’s disease”, “prion diseases”, as well as for “oxidative phosphorylation”, “thermogenesis”, “metabolic pathways”, “Staphylococcus aureus infection”, gap junction, “platelet activation”, “apelin signalling”, “retrograde endocannabinoid signalling”, “systemic lupus erythematosus”, and “non-alcoholic fatty liver disease”. Furthermore, PD brains showed significantly increased staining for total deiminated proteins in the brain vasculature in cortex and hippocampus, as well as increased immunodetection of deiminated histone H3 in dentate gyrus and cortex. Our findings identify EVs and post-translational protein deimination as novel biomarkers in early pre-motor stages of PD.

Defining Depression and Anxiety in Individuals With Rheumatic Diseases Using Administrative Health Databases: A Systematic Review

OBJECTIVE

To conduct a systematic review to describe how administrative health databases have been used to study depression and anxiety in patients with rheumatic diseases and to synthesize the case definitions that have been applied.

METHODS

Search strategies to identify articles evaluating depression and anxiety among individuals with rheumatic diseases were employed in Medline, Embase, CINAHL, Cochrane Database of Systematic Reviews, and PsycINFO. Studies included were those using administrative health data and reporting case definitions for depression and anxiety using International Classification of Diseases (ICD) codes. We extracted information on study design and objectives, administrative health database, specific data sources (e.g., inpatient, pharmacy records), ICD codes, operational definitions, and validity of case definitions.

RESULTS

Of the 36 studies included in this review, all studies assessed depression, and 13 studies (36.1%) evaluated anxiety. A number of specific ICD-9/10 codes were consistently applied to identify depression and anxiety, but the overall combination of ICD codes and operational definitions varied across studies. Twenty-four studies reported operational definitions, and 19 of these studies (79.2%) combined claims from more than 1 type of administrative data source (e.g., inpatient, outpatient). Validated case definitions were used by 6 studies (16.7%), with sensitivity estimates for depression and anxiety case definitions ranging from 33% to 74% and 42% to 76%, respectively.

CONCLUSION

We identified numerous case definitions used to evaluate depression and anxiety among individuals with rheumatic diseases within administrative health databases. Recommendations include using case definitions with demonstrated validity as well as operationalizing case definitions within multiple data sources.

Risk of Parkinson disease in Sjögren syndrome administered ineffective immunosuppressant therapies: A nationwide population-based study

To determine the incidence and risk of Parkinson disease (PD) in patients with Sjögren syndrome (SS) according to a nationwide population-based database.In total, 12,640 patients in the SS cohort and 50,560 in the non-SS cohort were enrolled from Taiwan's National Health Insurance Research Database from 2000 to 2010. We used the Cox multivariable proportional hazards model to determine the risk factors for PD in the SS cohort.We observed an increased incidence of PD in patients with SS, with a crude hazard ratio (HR) of 1.40 and an adjusted HR (aHR) of 1.23. The cumulative incidence of PD was 1.95% higher in the SS cohort than in the non-SS cohort. The SS cohort had an elevated HR under medication use, namely cevimeline and pilocarpine (crude HR, 1.28), hydroxychloroquine (crude HR, 1.43; aHR, 1.46), and methylprednisolone (crude HR, 2.21; aHR, 1.49). Patients receiving other non-hydroxychloroquine immunosuppressant therapies had a lower risk (aHR, 0.86) of PD. Furthermore, patients with SS aged 20 to 49 years had a 1.93-fold higher risk of PD than did those without SS (aHR, 1.93). The risk of PD was higher (aHR, 2.20) in patients with SS without comorbidities than in those with comorbidities. The aHR of PD significantly increased when the follow-up period exceeded 9 years (aHR, 1.93).We determined an increased risk of PD in patients with SS. Further investigation is warranted to determine the possible underlying mechanisms and the potential role of non-hydroxychloroquine immunosuppressants in ameliorating PD.

The Challenge of the Pathogenesis of Parkinson's Disease: Is Autoimmunity the Culprit?

The role of autoimmunity in Parkinson's disease (PD), as one of the most popular research subjects, has been intensively investigated in recent years. Although the ultimate cause of PD is unknown, one major area of interest remains identifying new therapeutic targets and options for patients suffering from PD. Herein, we present a comprehensive review of the impacts of autoimmunity in neurodegenerative diseases, especially PD, and we have composed a logical argument to substantiate that autoimmunity is actively involved in the pathogenesis of PD through several proteins, including α-synuclein, DJ-1, PINK1, and Parkin, as well as immune cells, such as dendritic cells, microglia, T cells, and B cells. Furthermore, a detailed analysis of the relevance of autoimmunity to the clinical symptoms of PD provides strong evidence for the close correlation of autoimmunity with PD. In addition, the previously identified relationships between other autoimmune diseases and PD help us to better understand the disease pattern, laying the foundation for new therapeutic solutions to PD. In summary, this review aims to integrate and present currently available data to clarify the pathogenesis of PD and discuss some controversial but innovative research perspectives on the involvement of autoimmunity in PD, as well as possible novel diagnostic methods and treatments based on autoimmunity targets.

Does nephrotic syndrome without chronic kidney disease increase the risk of Parkinson's disease and secondary parkinsonism? A nationwide population-based study in Taiwan

OBJECTIVES

Previous research has shown that patients with nephrotic syndrome (NS) have a higher risk of cognitive impairment, dementia or neurodegenerative disorder. The present study aimed to examine a relationship, if any exists between NS and Parkinson's disease (PD), a neurodegenerative disorder and secondary parkinsonism (sPS).

METHODS

A nationwide retrospective observational study conducted using data from the 2000-2010 Taiwan National Health Insurance Research Database. This study included 3663 patients with NS and 14 652 randomly selected, age-matched and sex-matched patients without NS. A Cox multivariable proportional hazards model was used to evaluate the risk of PD and sPS (PDsPS) in the NS cohort.

RESULTS

This study identified a positive association between NS and the risk of PDsPS in both men and women and in all age groups (adjusted HR 1.51; 95% CI 1.37 to 1.66). Compared with patients without NS and comorbidities, those with NS with two or more comorbidities exhibited an 8.23-fold higher risk of PDsPS (95% CI 6.22 to 10.9) and patients with NS and one comorbidity exhibited a 2.93-fold higher risk of PDsPS (95% CI 2.37 to 3.63).

CONCLUSIONS

Patients with NS have an increased risk of PDsPS. This increased risk may be related to brain vascular damage or blood-brain barrier impairment. Further research is necessary to explore the underlying relationship between NS and PDsPS.

Predictable biomarkers of developing lymphoma in patients with Sjögren syndrome: a nationwide population-based cohort study

Sjögren syndrome (SS) is commonly known to be correlated with lymphoma. This study included 16,396 individuals in the SS cohort and 65,584 individuals in the non-SS cohort, all of whom were enrolled in the Taiwan National Health Insurance database between 2000 and 2010. We evaluated the risk factors of non-Hodgkin's lymphoma (NHL) in the primary SS cohort by applying a Cox multivariable proportional-hazards model. We increased the correlation of patients with SS and NHL, with an adjusted HR of 4.314 (95% CI 2.784 – 6.685). Of the 16,396 SS patients, 66 individuals had salivary gland slices without NHL development, while the other 16,330 individuals that did not have salivary gland slices revealed 30 individuals that developed NHL. Of the 16,396 SS patients, 128 individuals underwent immunomodulator agent therapy (including hydroxychloroquine, azathioprine, cyclosporine, methotrexate, and rituximab) without NHL development. None of the 30 individuals that developed NHL from SS received immunomodulator agents. We found that patients with SS were at an increased risk of developing NHL, with the most common NHL subgroup being diffused large B-cell lymphoma. SS patients who were candidates for salivary gland slices or immunomodulator agents were associated with a lower risk of developing lymphoma over time. We recommend that patients at a higher risk upon diagnosis of SS receive close follow-up and aggressive treatment.

Autoimmune rheumatic diseases and the risk of Parkinson disease: a nationwide population-based cohort study in Taiwan

BACKGROUNDS

In autoimmune rheumatic diseases (ARDs), the levels of inflammatory mediators are increased and microglia may be activated, resulting in an inflammatory state and the degeneration of dopaminergic neurons. We investigated the association between ARDs and Parkinson disease (PD).

METHODS

We identified ARD patients through the Taiwan National Health Insurance Research Database from 2001 to 2012. From the general population, we randomly selected a comparison cohort that was frequency-matched by age (in 5-year increments), sex and index year. We analysed the risk of PD, stratified by sex, age and comorbidities, by using a Cox regression model.

RESULTS

The risk of PD was 1.37 times greater in ARD patients than in controls after adjustment for age, sex, and comorbidities. ARD subgroups, such as the rheumatoid arthritis and Sjogren syndrome (SS) cohorts, were associated with a significantly higher risk of PD (adjusted hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.03-1.2 and adjusted HR, 1.56; 95% CI, 1.35-1.79, respectively). Furthermore, primary and secondary SS patients had significantly higher risks of PD (adjusted HR, 1.58; 95% CI, 1.32-1.88 and adjusted HR, 1.53, 95% CI, 1.23-1.90, respectively).

CONCLUSIONS

The risk of PD was significantly higher in the ARD patients. Prospective studies are needed to confirm whether ARDs indeed increase the risk of PD.

Risk of infertility following pelvic angiographic embolization in female patients with pelvic fractures: A nationwide population-based cohort study in Taiwan

Pelvic angiographic embolization is an effective procedure to provide haemostasis in patients with pelvic fractures. However, management with repeated follow-up radiographs may result in infertility. The study aimed to evaluate the risk of infertility following pelvic fracture treated with pelvic angiographic embolization in female patients. We used data from the National Health Insurance Research Database (NHIRD) provided by the Bureau of National Health Insurance of the Department of Health in Taiwan from the period of 1997–2010. A total of 36 and 18,029 patients were included in the case and control cohorts, respectively. The risk estimations for the case and control cohorts were compared using a Cox’s proportional hazards regression model. The significance level was set at <0.05. After adjusting for possible confounding factors, the incidence of infertility in the case cohort was nearly 30.7-fold higher than that in the control cohort (adjust hazard ratio [HR] = 30.7, 95% confidence interval [CI] = 10.643–70.109). Patients between 15–35 years of age had a much higher incidence of infertility in the case cohort than in the control cohort (adjusted HR = 49.9, 95% CI = 15.177–64.099). Taken together, pelvic fractures in female patients treated with arterioembolization for haemostasis might be associated with a higher risk of infertility in Taiwan. Physicians should be aware of the link and inform patients of this risk prior to arterioembolization.

Reduced Risk of Parkinson Disease in Patients With Rheumatoid Arthritis: A Nationwide Population-Based Study

OBJECTIVE

To investigate the association between rheumatoid arthritis (RA) and the risk of developing Parkinson disease (PD).

PATIENTS AND METHODS

This retrospective cohort study was conducted from January 1, 1998, through December 31, 2010, using data from the Taiwan National Health Insurance Research Database. We identified 33,221 patients with newly diagnosed RA and 132,884 randomly selected age- and sex-matched patients without RA. A multivariable Cox proportional hazards regression model was used to evaluate the risk of developing PD in the RA cohort.

RESULTS

The multivariable Cox proportional hazards regression analysis revealed an adjusted hazard ratio of 0.65 (95% CI, 0.58-0.73) for the development of PD in the RA cohort relative to the non-RA cohort. The cumulative incidence of PD was 2.42% lower in the RA cohort than in the non-RA cohort. The risk reduction of PD development in patients affected with RA was independent of treatment with disease-modifying antirheumatic drugs (DMARDs); subgroup analysis of patients treated with biologic DMARDs revealed further risk reduction (adjusted hazard ratio, 0.57; 95% CI, 0.41-0.79).

CONCLUSION

Patients with RA have a reduced risk of developing PD. This risk reduction was independent of treatment with DMARDs; however, biologic DMARDs appear to further reduce this risk. Further research is necessary to explore the underlying mechanism.

Risk of Esophageal Cancer Following Percutaneous Endoscopic Gastrostomy in Head and Neck Cancer Patients: A Nationwide Population-Based Cohort Study in Taiwan

Esophageal cancers account for majority of synchronous or metachronous head and neck cancers. This study examined the risk of esophageal cancer following percutaneous endoscopic gastrostomy (PEG) in head and neck cancer patients using the Taiwan National Health Insurance Research Database. From 1997 to 2010, we identified and analyzed 1851 PEG patients and 3702 sex-, age-, and index date-matched controls. After adjusting for esophagitis, esophagus stricture, esophageal reflux, and primary sites, the PEG cohort had a higher adjusted hazard ratio (2.31, 95% confidence interval [CI] = 1.09-4.09) of developing esophageal cancer than the controls. Primary tumors in the oropharynx, hypopharynx, and larynx were associated with higher incidence of esophageal cancer. The adjusted hazard ratios were 1.49 (95% CI = 1.01-1.88), 3.99 (95% CI = 2.76-4.98), and 1.98 (95% CI = 1.11-2.76), respectively. Head and neck cancer patients treated with PEG were associated with a higher risk of developing esophageal cancer, which could be fixed by surgically placed tubes.