Chronic renal dysfunction, proteinuria, and risk of Parkinson's disease in the elderly

Mid- and Late-Life Chronic Kidney Disease Is Associated with Parkinson's Disease, Not with an Increased Risk of Alzheimer's Disease

Chronic kidney disease (CKD) is strongly associated with dementia. However, its independent association with Alzheimer's or Parkinson's disease remains unclear. This study investigated the prospective association of patients with CKD aged ≥55 years with an increased risk of Alzheimer's or Parkinson's disease. We conducted a retrospective cohort analysis using a national cohort sample of approximately one million patients. Primary outcome indicators measured included incidence of all-cause dementia, Alzheimer's disease, and Parkinson's disease events using person-years at risk. The hazard ratio was adjusted using the Cox proportional hazards model. We included 952 patients without CKD and 476 with CKD over 55 years using propensity score matching. The CKD group exhibited higher incidences of all-cause dementia, Parkinson's disease, and Alzheimer's disease than the non-CKD group. Furthermore, the CKD group had an elevated risk of all-cause dementia and a significantly increased risk of Parkinson's disease, especially among older women. Notably, the risk of Parkinson's disease was higher within the first 3 years of CKD diagnosis. These findings emphasize the link between CKD in mid- and late-life individuals and a higher incidence of all-cause dementia and Parkinson's disease rather than Alzheimer's disease.

Proteinuria and risk of ocular motor cranial nerve palsy: a nationwide population-based study

Understanding the association between dipstick-detected proteinuria and oculomotor cranial nerve palsy (CNP) could have significant implications for understanding the mechanism of CNP development and for developing preventive strategies against CNP development in patients with proteinuria. This study aimed to determine the relationship between dipstick-determined proteinuria and ocular motor CNP using National Sample Cohort (NSC) database from Korea's National Health Insurance Service (NHIS). A nationwide population-based cohort study was conducted using data from the NSC database of Korea's NHIS. These data were collected from 2009 to 2018. A one-year time lag was established to prevent a situation in which the causal link was inverted. Participants aged 20 years or more who were diagnosed with proteinuria in 2009 were included. Individuals with specific pre-existing CNP, missing data, and those who were newly diagnosed with CNP or who died within one year of being tested were excluded. The study population was classified into six groups according to the degree of proteinuria (negative, trace, or between 1 + and 4 +) based on the urine dipstick test. A Cox proportional hazard regression analysis was performed to determine the linkage between the degree of proteinuria and ocular motor CNP. A total of 5,807 (0.14% of subjects) with ocular motor CNP were assigned to the ocular motor CNP group and 4,047,205 subjects were assigned to the control group. After full adjustment of comorbidities, hazard ratios (HRs) for 1 + , 2 + , 3 + and 4 + proteinuria groups were 1.449 (95% confidence interval [CI] 1.244-1.687), 2.081 (1.707-2.538), 1.96 (1.322-2.904), and 3.011 (1.507-6.014), respectively, for developing ocular motor CNP compared to the proteinuria-negative group. In subgroup analysis, the HR of patients with proteinuria for the development of ocular motor CNP was higher in the younger age group (less than 40 years) (P = 0.0242) and the group with DM (P = 0.04). Our population-based cohort study demonstrated a significant association between proteinuria and the incidence of CNP, suggesting that urine protein level could be a new clinical marker for predicting the development of CNP.

Racial disparities in hospitalization characteristics among Native Hawaiians, Pacific Islanders and Asian American subgroups with Parkinson's disease

BACKGROUND

Differences among Native Hawaiians/Pacific Islanders (NHPI) and Asian American (AA) subgroups have not been adequately studied in Parkinson's disease (PD).

OBJECTIVE

To determine differences in demographics, comorbidities, and healthcare utilization among NHPI, AA subgroups, and White hospitalized PD patients.

METHODS

We conducted a retrospective cross-sectional analysis of Hawai'is statewide registry (2016-2020). Patients with PD were identified using ICD10 code G20 and categorized as White, Japanese, Filipino, Chinese, NHPI, or Other. Variables collected included: age, sex, residence (county), primary source of payment, discharge status, length of stay, in-hospital expiration, Charlson Comorbidity Index (CCI) and Deep Brain Stimulation (DBS) utilization. Bivariate analyses were performed: differences in age and CCI were further examined by multivariable linear regression and proportional odds models.

RESULTS

Of 229,238 hospitalizations, 2428 had PD (Japanese: 31.3 %, White: 30.4 %, Filipino: 11.3 %, NHPI: 9.6 %, Chinese: 8.0 %). NHPI were younger compared to rest of the subgroups [estimate in years (95 % CI): Whites: 4.4 (3.0-5.8), Filipinos: 4.3 (2.7-5.9), Japanese: 7.7 (6.4-9.1), Chinese: 7.9 (6.1-9.7), p < 0.001)]. NHPI had a higher CCI compared to White, Japanese, and Chinese (p < 0.001). Among AA subgroups, Filipinos were younger and had a higher CCI compared to Japanese and Chinese (p < 0.001). There were no significant differences in DBS utilization among subgroups.

CONCLUSIONS

NHPI and Filipinos with PD were hospitalized at a younger age and had a greater comorbidity burden compared to other AAs and Whites. Further research, ideally prospective studies, are needed to understand these racial disparities.

Study on the Correlation between Blood Urea Nitrogen, Creatinine Level, Proteinuria and Parkinson's Disease

Introduction

Parkinson's disease (PD) is related to renal insufficiency. The purpose of this study was to explore the correlation between PD and blood urea nitrogen, creatinine, and proteinuria.

Methods

The case-control study method was adopted in this study. In total, 200 patients with PD who were hospitalized in the Department of Neurology of the Second Affiliated Hospital of Anhui Medical University were selected as the PD group, and 110 healthy patients during the same period were selected as the control group. The differences in clinical data and laboratory results between the two groups were compared. Logistic regression analysis, ROC curve, and Spearman correlation analysis were used to determine the correlation between PD and blood urea nitrogen, creatinine, and urine protein.

Results

The levels of cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL-C), and apolipoprotein B in the PD group were lower than those in the control group. The levels of creatinine, urea nitrogen, and proteinuria in the PD group were higher than those in the control group. Multivariate logistic regression analysis showed that elevated blood urea nitrogen, creatinine, and urine protein levels were risk factors for PD, and elevated LDL-C levels were protective factors for PD. The blood urea nitrogen level of patients with PD was positively correlated with the course of PD, Hoehn-Yahr staging, and UPDRS exercise score (r = 0.309, 0.434, and 0.540, respectively; P < 0.01). Serum creatinine level was positively correlated with the course of PD, Hoehn-Yahr staging, and UPDRS exercise score (r = 0.139, 0.320, and 0.290, respectively; P < 0.01).

Conclusion

Blood urea nitrogen, creatinine levels, and proteinuria can be regarded as the onset of PD and a biomarker of disease progression.

Increased risk of Parkinson's disease amongst patients with age-related macular degeneration and visual disability: A nationwide cohort study

BACKGROUND AND PURPOSE

The association between Parkinson's disease (PD) and age-related macular degeneration (AMD) has been shown in previous reports. However, the association between the severity of AMD and PD development is unknown. The aim was to evaluate the association of AMD with/without visual disability (VD) with the risk of PD occurrence using the National Health Insurance data in South Korea.

METHODS

A total of 4,205,520 individuals, 50 years or older and without a previous diagnosis of PD, participated in the Korean National Health Screening Program in 2009. AMD was verified using diagnostic codes, and participants with VD were defined as those with loss of vision or visual field defect as certified by the Korean Government. The participants were followed up until 31 December 2019, and incident cases of PD were identified using registered diagnostic codes. The hazard ratio was calculated for groups (control and AMD with/without VD) using multivariable adjusted Cox regression analysis.

RESULTS

In total, 37,507 participants (0.89%) were diagnosed with PD. Amongst individuals with AMD, the risk of PD development was higher in individuals with VD (adjusted hazard ratio [aHR] 1.35, 95% confidence interval [CI] 1.09-1.67) than in those without (aHR 1.22, 95% CI 1.15-1.30) compared with controls. Additionally, an increased risk of PD was observed in individuals with AMD compared with controls, regardless of the presence of VD (aHR 1.23, 95% CI 1.16-1.31).

CONCLUSIONS

Visual disability in AMD was associated with the development of PD. This suggests that neurodegeneration in PD and AMD may have common pathways.

Exploring the Link between Chronic Kidney Disease and Parkinson's Disease: Insights from a Longitudinal Study Using a National Health Screening Cohort

Chronic kidney disease (CKD) and Parkinson's disease (PD) are common illnesses found in the geriatric population. A potential link between CKD and PD emergence has been hypothesized; however, existing conclusions are disputed. In this longitudinal research, we analyzed data acquired from the Korean National Health Insurance Service-Health Screening Cohort. The dataset comprised the health information of 16,559 individuals clinically diagnosed with CKD and 66,236 control subjects of comparable ages, all aged ≥40 years. These subjects participated in health examinations from 2002 to 2019. To assess the correlation between CKD and PD, we employed overlap-weighted Cox proportional hazard regression models. The unadjusted, crude hazard ratio for PD was greater in the CKD group than in the control group (crude hazard ration (HR) 1.20; 95% confidence interval (CI) = 1.04-1.39; p = 0.011). However, the Cox proportional hazard regression analysis, incorporating propensity score overlap weighting, revealed no significant discrepancy after considering confounding variables such as demographic factors, socio-economic status, lifestyle, and concurrent health conditions (adjusted HR (aHR), 1.09; 95% CI = 0.97-1.22; p = 0.147). Subgroup analyses showed a higher probability of PD development among certain CKD individuals, including those who resided in rural areas (aHR, 1.19; 95% CI = 1.03-1.37; p = 0.022), maintained a normal weight (aHR, 1.29; 95% CI = 1.08-1.56; p = 0.006), or had fasting blood glucose levels ≥100 mg/dL (aHR, 1.18; 95% CI = 1.00-1.39; p = 0.046). Therefore, these clinical or environmental factors may influence the incidence of PD in CKD patients. In conclusion, our results suggest that the general CKD population may not exhibit a greater propensity for PD than their non-CKD counterparts. However, this might be contingent upon specific lifestyle and comorbid conditions. Thus, certain lifestyle alterations could be crucial in mitigating the potential manifestation of PD in patients diagnosed with CKD.

Estimated glomerular filtration rate is a biomarker of cognitive impairment in Parkinson's disease

Backgrounds

The relationship between kidney function and cognitive impairment in Parkinson's disease (PD) is poorly understood and underexplored. This study aims to explore whether renal indices can serve as indicators to monitor the cognitive impairment of PD.

Methods

A total of 508 PD patients and 168 healthy controls from the Parkinson's Progression Markers Initiative (PPMI) were recruited, and 486 (95.7%) PD patients underwent longitudinal measurements. The renal indicators including serum creatinine (Scr), uric acid (UA), and urea nitrogen, as well as UA/Scr ratio and estimated glomerular filtration rate (eGFR), were measured. Cross-sectional and longitudinal associations between kidney function and cognitive impairment were evaluated using multivariable-adjusted models.

Results

eGFR was associated with lower levels of cerebrospinal fluid (CSF) Aβ_1-42 (p = 0.0156) and α-synuclein (p = 0.0151) and higher serum NfL (p = 0.0215) in PD patients at baseline. Longitudinal results showed that decreased eGFR predicted a higher risk of cognitive impairment (HR = 0.7382, 95% CI = 0.6329-0.8610). Additionally, eGFR decline was significantly associated with higher rates of increase in CSF T-tau (p = 0.0096), P-tau (p = 0.0250), and serum NfL (p = 0.0189), as well as global cognition and various cognitive domains (p < 0.0500). The reduced UA/Scr ratio was also linked to higher NfL levels (p = 0.0282) and greater accumulation of T-tau (p = 0.0282) and P-tau (p = 0.0317). However, no significant associations were found between other renal indices and cognition.

Conclusion

eGFR is altered in PD subjects with cognitive impairment, and predict larger progression of cognitive decline. It may assist identifying patients with PD at risk of rapid cognitive decline and have the potential to monitoring responses to therapy in future clinical practice.

Chronic kidney disease prevention campaign: relationship between proteinuria and elderly people

OBJECTIVE

To verify the relationship between the presence of proteinuria as a renal injury marker in elderly without history of systemic arterial hypertension and cardiovascular diseases. A cross-sectional study was developed from January 2014 to December 2019, through kidney disease prevention campaigns promoted by the Federal University of Ceará in the city of Fortaleza.

METHODS

The sample consisted of 417 elderlies. A questionnaire was used to characterize individuals and assess previous diseases, and urinalysis reagent strips were used to assess proteinuria.

RESULTS

Statistically significant differences (p < 0.05) and moderate effect sizes were found for blood pressure levels (CI 0.53-0.93), systolic blood pressure, and diastolic blood pressure (CI 0.21-0.61). Significant differences in capillary glycemia were also found between groups (p = 0.033), but with a low effect size (0.02-0.42). The group with comorbidities was 2.94 times more likely to have proteinuria than those without comorbidities (OR 2.94, CI 1.55-4.01; p < 0.05). In the group without cardiovascular disease/high blood pressure, a statistically significant association was found for previous diabetes and proteinuria (p = 0.037), presenting 2.68 times higher risk of proteinuria in those with diabetes mellitus (OR 2.68, CI 1.05-6.85). Significant association was also found between age groups, with the older group having 2.69 times higher risk of developing proteinuria (75 to 90 compared to 60 to 74 years) (CI 1.01-7.16; p = 0.045).

CONCLUSION

Even without systemic arterial hypertension or cardiovascular disease, diabetes and older age can be considered high risk factors for proteinuria.

A nationwide cohort study on diabetes severity and risk of Parkinson disease

There is growing evidence that patients with type 2 diabetes mellitus (DM) have an increased risk of developing Parkinson's disease (PD) and share similar dysregulated pathways. We aimed to determine whether the risk of PD increases as diabetes progresses among patients with type 2 DM. Using a nationally representative database from the Korean National Health Insurance System, 2,362,072 individuals (≥40 years of age) with type 2 DM who underwent regular health checkups during 2009-2012 were followed up until the end of 2018. The diabetes severity score parameters included the number of oral hypoglycemic agents, diabetes duration, insulin use, or presence of chronic kidney disease, diabetic retinopathy, or cardiovascular disease. Each of these characteristics was scored as one unit of diabetes severity and their sum was defined as a diabetes severity score from 0-6. We identified 17,046 incident PD cases during the follow-up. Each component of the diabetes severity score showed a similar intensity for the risk of PD. Compared with subjects with no parameters, HR values (95% confidence intervals) of PD were 1.09 (1.04-1.15) in subjects with one diabetes severity score parameter, 1.28 (1.22-1.35) in subjects with two parameters, 1.55 (1.46-1.65) in subjects with three parameters, 1.96 (1.82-2.11) in subjects with four parameters, 2.08 (1.83-2.36) in subjects with five parameters, and 2.78 (2.05-3.79) in subjects with six parameters. Diabetes severity was associated with an increased risk of developing PD. Severe diabetes may be a risk factor for the development of PD.

Mortality of Deep Brain Stimulation and Risk Factors in Patients With Parkinson's Disease: A National Cohort Study in Korea

BACKGROUND

This study aimed to investigate 1) long-term outcomes of deep brain stimulation (DBS), such as mortality after DBS as well as the causes of death, 2) demographic and socioeconomic factors influencing mortality, and 3) comorbidities affecting mortality after DBS in patients with Parkinson's disease (PD).

METHODS

This study analyzed the National Health Insurance Service-National Health Information Database. Data on patients with PD diagnosis codes from 2002 to 2019 were extracted and analyzed. Data on the causes of death were obtained by linking the causes of death to data from Statistics Korea. The Kaplan-Meier method with the log-rank test was used for survival analysis. Multivariate Cox regression analyses were used to estimate hazard ratios (HRs) and their 95% confidence intervals. Regarding comorbidities such as PD dementia and fracture, which did not satisfy the assumption for the proportional HR, time-dependent Cox analysis with the Mantel-Byar method was used.

RESULTS

From 2005 to 2017, among 156,875 patients diagnosed with PD in Korea, 1,079 patients underwent DBS surgery, and 251 (23.3%) had died by 2019. The most common cause of death (47.1%) was PD. In the multivariate Cox regression analysis, the higher the age at diagnosis and surgery, the higher the mortality rate. The men and medical aid groups had significantly higher mortality rates. PD dementia and fracture were identified as risk factors for mortality.

CONCLUSION

Older age at diagnosis and surgery, being male, the use of medical aid, and the comorbidity of dementia and fractures were associated with a higher risk of mortality after DBS in patients with PD. Neurologists should consider these risk factors in assessing the prognosis of PD patients undergoing DBS.

Movement Disorders in Chronic Kidney Disease Patients on Hemodialysis in Mosul City

BACKGROUND: Movement disorders are not rare in patients with chronic kidney disease (CKD) on hemodialysis (HD). The prevalence and the exact mechanism of these disorders are unknown. Iron deficiency and dopamine dysregulation are implicated from one perspective, whereas chronic inflammation and calcium dysmetabolism may be involved from another perspective. AIM: We studied the prevalence, delay in the diagnosis and the role of iron deficiency, inflammation, and bone abnormalities on some movement disorders in patients with CKD on HD. METHODS: A cross-sectional study examined the prevalence, among patients with CKD on HD in Mosul city, of restless leg syndrome (RLS), periodic limb movement syndrome (PLMS), Parkinsonism, asterixis, and myoclonus. Delay in diagnosis of these disorders was also studied. Validated questionnaires and specified neurological examination were applied to define patients with these disorders. Using IBM® SPSS® v. 23 statistical software, we compared between the different groups of patients by different parameters (case–control design). RESULTS: Among 281 enrolled CKD patients on HD in Mosul city, the prevalence of RLS, PLMS, Parkinsonism, asterixis, and myoclonus was 28.72%, 17.02%, 2.84%, 20.92%, and 24.11% respectively. Average delay in diagnoses was 2.6 (±3.09) years, 3.02 (±3.13) years, 1 (±0.78) year, 1.23 (±1.51) years, and 2.28 (±2.34) years, respectively. Median duration of dialysis in patients with PLMS and Parkinsonism tended to be higher than in those without PLMS or Parkinsonism. Neither inflammation, ferritin level nor bone dysmetabolism discriminated patients with CKD on HD with and without these movement disorders. CONCLUSIONS: Movement disorders are prevalent in patients with CKD on HD. In Mosul city, there would be still delay in diagnosis and treatment of these movement disorders. The longer the duration on HD, the more frequent the PLMS and Parkinsonism cases.

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.

Campanha de prevenção de doença renal crônica: relação entre proteinúria e idosos

Resumo Objetivo: Verificar a relação entre a presença de proteinúria como marcador de lesão renal em idosos sem histórico de hipertensão arterial sistêmica e doenças cardiovasculares. Um estudo transversal foi desenvolvido de Janeiro de 2014 a Dezembro de 2019, por meio de campanhas de prevenção a doenças renais promovidas pela Universidade Federal do Ceará, na cidade de Fortaleza. Métodos: A amostra foi composta por 417 idosos. Um questionário foi usado para caracterizar indivíduos e avaliar doenças prévias, e foram utilizadas tiras reagentes de urinálise para avaliar proteinúria. Resultados: Diferenças estatisticamente significativas (p < 0,05) e tamanhos de efeito moderados foram encontrados para níveis de pressão arterial (IC 0,53-0,93), pressão arterial sistólica e pressão arterial diastólica (IC 0,21-0,61). Também foram encontradas diferenças significativas na glicemia capilar entre grupos (p = 0,033), mas com um tamanho de efeito baixo (0,02–0,42). O grupo com comorbidades apresentou 2,94 vezes mais probabilidade de ter proteinúria do que aqueles sem comorbidades (OR 2,94; IC 1,55-4,01; p < 0,05). No grupo sem doença cardiovascular/hipertensão, foi encontrada uma associação estatisticamente significativa para diabetes anterior e proteinúria (p = 0,037), apresentando risco 2,68 vezes maior de proteinúria naqueles com diabetes mellitus (OR 2,68; IC 1,05-6,85). Também foi encontrada uma associação significativa entre faixas etárias, com o grupo mais velho apresentando risco 2,69 vezes maior de desenvolver proteinúria (75 a 90 em comparação com 60 a 74 anos) (IC 1,01-7,16; p = 0,045). Conclusão: Mesmo sem hipertensão arterial sistêmica ou doença cardiovascular, o diabetes e a idade avançada podem ser considerados fatores de alto risco para proteinúria.

The risk of Parkinson's disease according to diabetic kidney disease status in a Korean population

INTRODUCTION

Type 2 diabetes is a risk factor for Parkinson's disease (PD). Recently, it has been reported that proteinuria without reduced estimated glomerular filtration rate (eGFR) can increase the risk of PD development. The objective of this study was to evaluate the risk of PD among Korean adults with type 2 diabetes stratified by proteinuria (PU) and eGFR levels.

METHODS

Using the Korean National Health Insurance Service database, a total of 2,217,326 patients with type 2 diabetes who underwent regular health check-ups from 2009 to 2012 were included. These patients were classified into four groups (no-diabetic kidney disease (DKD) (PU^-GFR^-), proteinuric DKD with normal eGFR (PU⁺GFR^-), nonproteinuric DKD (PU^-GFR⁺), and proteinuric DKD with reduced eGFR (PU⁺GFR⁺) and followed up until 2018. PD was defined using International Classification of Diseases, 10th revision.

RESULTS

The prevalence of PU^-GFR^-, PU⁺GFR^-, PU^-GFR⁺, or PU⁺GFR⁺ phenotype was 83.3%, 5.0%, 10.1%, or 1.6%, respectively. During a median follow-up of 7.2 years, 16,079 participants developed PD. Hazard ratios for PD were 1.10 (95% confidence interval [CI]: 1.01-1.21, p = 0.0091), 1.15 (95% CI: 1.09-1.21, p < 0.0001), and 1.23 (95% CI: 1.09-1.39, p < 0.0001) for participants in PU⁺GFR^-, PU^-GFR⁺, and PU⁺GFR⁺ groups relative to those in the PU^-GFR^- group, respectively. Effects of DKD on PD were more pronounced in those aged less than 65 years.

CONCLUSION

Reduced eGFR and/or proteinuria might be independent risk factors for boosting PD development among patients with type 2 diabetes. More attention should be paid to PD in patients with DKD, even in a younger aged population.

Chronic kidney disease and neurological disorders: are uraemic toxins the missing piece of the puzzle?

Chronic kidney disease (CKD) perturbs the crosstalk with others organs, with the interaction between the kidneys and the heart having been studied most intensively. However, a growing body of data indicates that there is an association between kidney dysfunction and disorders of the central nervous system. In epidemiological studies, CKD is associated with a high prevalence of neurological complications, such as cerebrovascular disorders, movement disorders, cognitive impairment and depression. Along with traditional cardiovascular risk factors (such as diabetes, inflammation, hypertension and dyslipidaemia), non-traditional risk factors related to kidney damage (such as uraemic toxins) may predispose patients with CKD to neurological disorders. There is increasing evidence to show that uraemic toxins, for example indoxyl sulphate, have a neurotoxic effect. A better understanding of factors responsible for the elevated prevalence of neurological disorders among patients with CKD might facilitate the development of novel treatments. Here, we review (i) the potential clinical impact of CKD on cerebrovascular and neurological complications, (ii) the mechanisms underlying the uraemic toxins' putative action (based on pre-clinical and clinical research) and (iii) the potential impact of these findings on patient care.

Prognostic biomarkers of Parkinson's disease in the Spanish EPIC cohort: a multiplatform metabolomics approach

The lack of knowledge about the onset and progression of Parkinson's disease (PD) hampers its early diagnosis and treatment. Metabolomics might shed light on the PD imprint seeking a broader view of the biochemical remodeling induced by this disease in an early and pre-symptomatic stage and unveiling potential biomarkers. To achieve this goal, we took advantage of the great potential of the European Prospective Study on Nutrition and Cancer (EPIC) cohort to apply metabolomics searching for early diagnostic PD markers. This cohort consisted of healthy volunteers that were followed for around 15 years until June 2011 to ascertain incident PD. For this untargeted metabolomics-based study, baseline preclinical plasma samples of 39 randomly selected individuals that developed PD (Pre-PD group) and the corresponding control group were analyzed using a multiplatform approach. Data were statistically analyzed and exposed alterations in 33 metabolites levels, including significantly lower levels of free fatty acids (FFAs) in the preclinical samples from PD subjects. These results were then validated by adopting a targeted HPLC-QqQ-MS approach. After integrating all the metabolites affected, our finding revealed alterations in FFAs metabolism, mitochondrial dysfunction, oxidative stress, and gut-brain axis dysregulation long before the development of PD hallmarks. Although the biological purpose of these events is still unknown, the remodeled metabolic pathways highlighted in this work might be considered worthy prognostic biomarkers of early prodromal PD. The findings revealed by this work are of inestimable value since this is the first study conducted with samples collected many years before the disease development.

Evaluation of the association between periodontitis and risk of Parkinson's disease: a nationwide retrospective cohort study

The objective of this study was to examine the association between periodontitis and risk of incident Parkinson’s disease using large-scale cohort data on the entire population of South Korea. Health checkup data from 6,856,180 participants aged 40 and older were provided by the National Health Insurance Service of South Korea between January 1, 2009, and December 31, 2009, and the data were followed until December 31, 2017. The hazard ratio (HR) of Parkinson’s disease and 95% confidence interval (CI) were estimated using a Cox proportional hazards model adjusted for potential confounders. The incidence probability of Parkinson’s disease was positively correlated with the presence of periodontitis. The HR of Parkinson’s disease for the participants without the need of further dentist visits was 0.96 (95% CI 0.921–1.002); the HR of Parkinson’s disease increased to 1.142 (95% CI 1.094–1.193) for the individuals who needed further dentist visits. Compared to individuals without periodontitis and without metabolic syndrome, the HR of incident Parkinson’s disease gradually increased for individuals with periodontitis, with metabolic syndrome, and with both periodontitis and metabolic syndrome. People with periodontitis and metabolic syndrome had the highest HR of incident Parkinson’s disease, at 1.167 (95% CI 1.118–1.219). In conclusion, a weak association between periodontitis and Parkinson’s disease was suggested after adjusting for confounding factors from the population-based large-scale cohort of the entire South Korean population.

Incident Parkinson's disease in kidney transplantation recipients: a nationwide population-based cohort study in Korea

This nation-wide population based retrospective cohort study evaluated risk of incident Parkinson’ disease in kidney transplant (KT) recipients in Korea. From Korean National Health Insurance Service database, we identified incident KT recipients aged ≥ 40 years without any history of Parkinson’s disease between 2007 and 2015. We established two control cohorts without a history of Parkinson’ disease: (1) General population (GP) cohort of insured subjects without a history of kidney disease, (2) end-stage renal disease (ESRD) cohort of incident ESRD subjects, with frequency matched for age, sex, and inclusion year. Parkinson’s disease data were obtained from baseline until December 2017. We followed 8372 KT recipients, ESRD patients, and GP for 45,723, 38,357, and 47,476 patient-years, respectively. Their mean age was 51.2 years and 60.1% were men. During follow-up period, 19 KT recipients, 53 ESRD patients, and 15 GP developed Parkinson’ disease. Risk of incident Parkinson’s disease in KT recipients was similar to that in GP (adjusted hazard ratio [HR] 0.86, 95% confidence interval [CI] 0.35 to 2.13, P = 0.75) and significantly lower than that in ESRD patients (adjusted HR 0.31, 95% CI 0.18 to 0.52, P < 0.001). Older age was the strongest predictor for incident Parkinson’s disease in KT recipients.

Potential Fluid Biomarkers and a Prediction Model for Better Recognition Between Multiple System Atrophy-Cerebellar Type and Spinocerebellar Ataxia

Objective

This study screened potential fluid biomarkers and developed a prediction model based on the easily obtained information at initial inspection to identify ataxia patients more likely to have multiple system atrophy-cerebellar type (MSA-C).

Methods

We established a retrospective cohort with 125 ataxia patients from southwest China between April 2018 and June 2020. Demographic and laboratory variables obtained at the time of hospital admission were screened using Least Absolute Shrinkage and Selection Operator (LASSO) regression and logistic regression to construct a diagnosis score. The receiver operating characteristic (ROC) and decision curve analyses were performed to assess the accuracy and net benefit of the model. Also, independent validation using 25 additional ataxia patients was carried out to verify the model efficiency. Then the model was translated into a visual and operable web application using the R studio and Shiny package.

Results

From 47 indicators, five variables were selected and integrated into the prediction model, including the age of onset (AO), direct bilirubin (DBIL), aspartate aminotransferase (AST), eGFR, and synuclein-alpha. The prediction model exhibited an area under the curve (AUC) of 0.929 for the training cohort and an AUC of 0.917 for the testing cohort. The decision curve analysis (DCA) plot displayed a good net benefit for this model, and external validation confirmed its reliability. The model also was translated into a web application that is freely available to the public.

Conclusion

The prediction model that was developed based on laboratory and demographic variables obtained from ataxia patients at admission to the hospital might help improve the ability to differentiate MSA-C from spinocerebellar ataxia clinically.

Proteinuria Is Associated with the Development of Crohn's Disease: A Nationwide Population-Based Study

BACKGROUND AND AIMS

The impact of proteinuria and its severity on the incidence of inflammatory bowel disease (IBD) has not yet been studied. We aimed to determine the association between proteinuria measured by urine dipstick tests and the development of IBD.

METHODS

This nationwide population-based study was conducted using the Korean National Health Insurance Service (NHIS) database. A total of 9,917,400 people aged 20 years or older who had undergone a national health examination conducted by the NHIS in 2009 were followed up until 2017. The study population was classified into four groups-negative, trace, 1+, and ≥ 2+-according to the degree of proteinuria measured by the urine dipstick test. The primary endpoint was newly diagnosed IBD, Crohn's disease (CD), or ulcerative colitis (UC) during the follow-up period.

RESULTS

Compared with the dipstick-negative group, the incidence of CD significantly increased according to the degree of proteinuria (adjusted hazard ratio [aHR] with 95% confidence interval [CI], 1.01 [0.703-1.451], 1.515 [1.058-2.162], and 2.053 [1.301-3.24] in the trace, 1+, and ≥ 2+ dipstick groups, respectively; p for trend 0.007). However, there was no significant difference in the incidence of UC according to the degree of proteinuria (aHR with 95% CI, 1.12 [0.949-1.323], 0.947 [0.764-1.174], and 1.009 [0.741-1.373] in the trace, 1+, and ≥ 2+ dipstick groups, respectively; p for trend 0.722). In the subgroup analysis, dipstick-positive proteinuria independently increased the incidence of CD regardless of the subgroup. However, dipstick-positive proteinuria was associated with the risk of UC in those with diabetes mellitus and not in those without diabetes mellitus (aHR, 1.527 vs. 0.846; interaction p-value 0.004). The risk of CD was increased or decreased according to proteinuria changes but not associated with the risk of UC.

CONCLUSION

Proteinuria, measured by the dipstick test, is strongly associated with the development of CD.

Microalbuminuria as a potential biomarker for Parkinson's disease severity: A hypothesis

Parkinson's disease (PD) is the second most common neurodegenerative condition characterized by motor and non-motor symptoms causing a great burden in patients' quality of life. PD has been associated with various metabolic factors such as diabetes, hypertension, and more recently chronic kidney disease where proteinuria has been associated with an increased risk. The presence of small amounts of albumin in urine, microalbuminuria, is a common biomarker for endothelial damage and a predictive factor for not only cardiovascular but also neurological dysfunction. Multiple studies have assessed potential biomarkers for PD progression with great heterogeneity, we hypothesize the use of microalbuminuria as a potential marker that correlates with PD severity and might represent a feasible and simple method of evaluating PD patients in clinical practice. Evidence supporting the present hypothesis comes from oxidative stress, insulin resistance, and endothelial dysfunction. Oxidative stress is a key element in PD pathogenesis; studies have shown lower antioxidant capacity as PD progresses. On the other side, insulin signaling plays an important role in neuronal growth and survival, with its resistance being associated with PD. Microalbuminuria has been associated with both processes; increased levels of oxidative stress markers and decreased insulin sensitivity, hence its screening in PD might reflect these common pathological mechanisms. Moreover, the low vitamin D levels observed in PD patients, which are correlated with endothelial dysfunction and disease severity, might contribute to microalbuminuria induction. More evidence on this vascular approach comes from white matter lesions (WML), observed in brain imaging, which have been significantly associated with motor and non-motor function in PD patients and are independently associated with microalbuminuria. In this manner, an oxidant and insulin resistant environment, along with low vitamin D levels in PD patients, which are associated with microalbuminuria, might contribute altogether to WML. As the latter are correlated with motor and non-motor function, microalbuminuria might thus give insight on PD status. Prospective cohort studies with an adequate sample size, follow-up, and a thorough battery of clinical tests for PD are needed to confirm this hypothesis.

Biochemical markers for severity and risk in GBA and LRRK2 Parkinson's disease

BACKGROUND

The phenotype of Parkinson's disease (PD) is variable with mutations in genes such as LRRK2 and GBA explaining part of this heterogeneity. Additional genetic and environmental factors contribute to disease variability.

OBJECTIVE

To assess the association between biochemical markers, PD severity and probability score for prodromal PD, among GBA and LRRK2 mutation carriers.

METHODS

Levels of uric acid, vitamin D, C-reactive protein, microalbumin/creatinine ratio (ACR), white blood count (WBC), hemoglobin, platelets, neutrophil/lymphocyte ratio and estimated glomerular filtration rate (eGFR) were assessed from patients with PD and non-manifesting carriers (NMC) of mutations in GBA and LRRK2, together with disease related questionnaires enabling the construction of the MDS prodromal probability score.

RESULT

A total of 241 patients with PD: 105 idiopathic PD (iPD), 49 LRRK2-PD and 87 GBA-PD and 412 non-manifesting subjects; 74 LRRK2-NMC, 118 GBA-NMC and 220 non-manifesting non-carriers (NMNC), participated in this study. No significant differences in biochemical measures were detected among patients with PD or non-manifesting carriers. Among GBA-PD patients, worse motor performance was associated with ACR (B = 4.68, 95% CI (1.779-7.559); p = 0.002). The probability score for prodromal PD among all non-manifesting participants was associated with eGFR; NMNC (B = - 0.531 95% CI (- 0.879 to - 0.182); p < 0.001, LRRK2-NMC (B = - 1.014 95% CI (- 1.663 to - 0.366); p < 0.001) and GBA-NMC (B = - 0.686 95% CI (1.300 to - 0.071); p = 0.029).

CONCLUSION

Sub-clinical renal impairment is associated with increased likelihood for prodromal PD regardless of genetic status. While the mechanism behind this finding needs further elucidation, it suggests that kidney function might play a role in PD pathogenesis.

Linking chronic kidney disease and Parkinson's disease: a literature review

Chronic kidney disease (CKD) has been typically implicated in cardiovascular risk, considering the function the kidney has related to blood pressure, vitamin D, red blood cell metabolism, and electrolyte and acid-base regulation. However, neurological consequences are also attributed to this disease. Among these, recent large epidemiological studies have demonstrated an increased risk for Parkinson's disease (PD) in patients with CKD. Multiple studies have evaluated individually the association of blood pressure, vitamin D, and red blood cell dysmetabolism with PD, however, no study has reviewed the potential mechanisms related to these components in context of CKD and PD. In this review, we explored the association of CKD and PD and linked the components of the former to propose potential pathways explaining a future increased risk for PD, where renin-angiotensin system, oxidative stress, and inflammation have a main role. Potential preventive and therapeutic interventions based on these associations are also explored. More preclinical studies are needed to confirm the potential link of CKD conditions and future PD risk, whereas more interventional studies targeting this association are warranted to confirm their potential benefit in PD.

Changes of protein levels in human urine reflect the dysregulation of signaling pathways of chronic kidney disease and its complications

The increasing prevalence of chronic kidney disease (CKD) seriously is threatening human health and overall quality of life. The discovery of biomarkers of pathogenesis of CKD and the associated complications are very important for CDK diagnosis and treatment. In this paper, urine protein biomarkers were investigated because urine sample collection is convenient and non-invasive. We analyzed the protein concentrations in the urine of CKD patients and extracted abnormal protein signals comparing with the healthy control groups. The enriched signaling pathways that may characterize CKD pathology were identified from these proteins. We applied surface-enhanced laser desorption and ionization time of flight mass spectrometry technology to detect different protein peaks in urine samples from patients with CKD and healthy controls. We searched the proteins corresponding to protein peaks through the UniProt database and identified the signaling pathways of CKD and its complications by using the NIH DAVID database. 42 low abundance proteins and 46 high abundance proteins in the urine samples from CKD patients were found by comparing with healthy controls. Seven KEGG pathways related to CKD and its complications were identified from the regulated proteins. These pathways included chemokine signaling pathway, cytokine-cytokine receptor interaction, oxidative phosphorylation, cardiac muscle contraction, Alzheimer's disease, Parkinson's disease, and salivary secretion. In CKD stages 2, 3, 4, and 5, five proteins showed significantly differential abundances. The differential protein signals and regulated signaling pathways will provide new insight for the pathogenesis of CKD and its complications. These altered proteins may also be used as novel biomarkers for the noninvasive and convenient diagnosis methods of CKD and its complications through urine testing in the future.

p-Cresol Sulfate Caused Behavior Disorders and Neurodegeneration in Mice with Unilateral Nephrectomy Involving Oxidative Stress and Neuroinflammation

Protein-bound uremic toxins, such as p-cresol sulfate (PCS), can be accumulated with declined renal function and aging and is closely linked with central nervous system (CNS) diseases. In the periphery, PCS has effects on oxidative stress and inflammation. Since oxidative stress and inflammation have substantial roles in the pathogenesis of neurological disorders, the CNS effects of PCS were investigated in unilateral nephrectomized C57/BL/6 mice. Unlike intact mice, unilateral nephrectomized mice showed increased circulating levels of PCS after exogenous administration. Upon PCS exposure, the unilateral nephrectomized mice developed depression-like, anxiety-like, and cognitive impairment behaviors with brain PCS accumulation in comparison with the nephrectomy-only group. In the prefrontal cortical tissues, neuronal cell survival and neurogenesis were impaired along with increased apoptosis, oxidative stress, and neuroinflammation. Circulating brain-derived neurotrophic factors (BDNF) and serotonin were decreased in association with increased corticosterone and repressor element-1 silencing transcription factor (REST), regulators involved in neurological disorders. On the contrary, these PCS-induced changes were alleviated by uremic toxin absorbent AST-120. Taken together, PCS administration in mice with nephrectomy contributed to neurological disorders with increased oxidative stress and neuroinflammation, which were alleviated by PCS chelation. It is suggested that PCS may be a therapeutic target for chronic kidney disease-associated CNS diseases.

Association Between Glycemic Status and the Risk of Parkinson Disease: A Nationwide Population-Based Study

OBJECTIVE

Previous studies have suggested that diabetes increases the risk of Parkinson disease (PD); however, this has not been conclusively established. We analyzed the risk of PD based on baseline glucose tolerance status in a large-scale cohort representative of the general Korean population.

RESEARCH DESIGN AND METHODS

This analysis was performed in a cohort of 15,168,021 adults aged ≥40 years who underwent health checkups under the National Health Insurance Service between January 2009 and December 2010. The clinical course of subjects was monitored until December 2016. Subjects were classified into the following groups: no diabetes, impaired fasting glucose (IFG), diabetes duration <5 years, and diabetes duration ≥5 years. We analyzed the adjusted hazard ratio of PD for each group.

RESULTS

During the observation period of 49,076,148.74 person-years, PD occurred in 31,577 patients. Compared with the nondiabetes group, the adjusted hazard ratio was 1.038 (95% CI, 1.009-1.067) in the IFG group, 1.185 (95% CI, 1.143-1.229) in the diabetes duration <5 years group, and 1.618 (95% CI, 1.566-1.672) in the diabetes duration ≥5 years group. These results were consistent with those of the subgroup analysis, and the presence of diabetes further increased the risk of PD regardless of comorbidities such as cardiovascular, cerebrovascular, and chronic kidney diseases.

CONCLUSIONS

This population-based cohort study suggests that diabetes is an independent risk factor for PD.

Visual Acuity and Development of Parkinson's Disease: A Nationwide Cohort Study

BACKGROUND

Visual dysfunction in Parkinson's disease (PD) is well known from previous reports, but the association of visual deficits with PD development has not yet been studied. The aim of this research was to evaluate the association of visual acuity with the risk of PD occurrence using a nationwide cohort in South Korea.

METHODS

Among the population participating in the National Health Insurance Service, which is mandatory for all South Koreans, 6,055,113 individuals who had taken part in health screening programs between January 1, 2009, and December 31, 2012, were included in the cohort and followed until December 31, 2017. The hazard ratio was calculated for groups with high and low visual acuity using multivariate adjusted Cox regression analysis.

RESULTS

A total of 22,872 subjects (0.38%) were diagnosed as having PD within the study period. Groups with low visual acuity showed a higher incidence of PD compared with groups with good visual acuity. Compared with the reference group (visual acuity better than 20/20), the adjusted hazard ratios and 95% confidence intervals (CIs) was 1.315 (95% CI, 1.261-1.371) for the group with visual acuity between 20/20 and 20/60, 1.357 (95% CI, 1.277-1.442) for the group with visual acuity between 20/60 and 10/100, and 1.267 (95% CI, 1.193-1.343) for the group with visual acuity less than 10/100.

CONCLUSIONS

Low visual acuity was associated with the development of PD. This suggests that visual dysfunction is one of the premotor symptoms for PD development. © 2020 International Parkinson and Movement Disorder Society.

Is sudoscan a reliable tool in detecting small fiber neuropathy in Parkinson's disease patients?

Aim: Previous studies have revealed uncertainties concerning the utility of sudoscan in identifying small fiber neuropathy in Parkinson's disease (PD). Patients & methods: We searched for a significant reduction of electrochemical skin conductance (ESC) in 67 PD patients versus 66 controls with similar characteristics. We conducted analysis of the subgroups of PD patients without diabetes using sudoscan technology. Results: There is no discrimination between patients and controls relative to feet ESC, the modified Hoehn and Yahr Scale and/or Unified Parkinson's Disease Rating Scale. ESC in patients did not differ significantly according to the Unified Parkinson's Disease Rating Scale score. The oldest PD patients with cardiovascular risk factors have more marked small fibers dysfunction. Conclusion: The sudoscan procedure did not show advantage in the diagnosis of small fiber neuropathy. Its diagnostic value increases in some subgroups of patients with cardiovascular co-morbidity.

Anemia and the risk of Parkinson's disease in Korean older adults: A nationwide population-based study

Evidence of the association between anemia and risk of PD (Parkinson’s disease) have been accumulating. This study aimed to examine the relationship between anemia and risk of PD in Korean older adults. Korean adults aged 50 years or older who participated in the Korean National Screening Program (n = 12,342,278) between 2009 and 2013 were followed until 2015. Cox proportional hazards regression models were used to calculate the hazard ratio (HR) of PD, and participants were followed for a mean period of 5.0 years. At the end of follow-up, 3,844 adults were diagnosed with PD. After adjusting for potential confounders, participants with anemia had decreased risk of PD compared to adults without anemia (adjusted HR (aHR) 0.894, 95% CI: 0.809–0.989). Furthermore, aHR of PD was 0.698 (95% CI: 0.546–0.891) in moderate to severe anemia and 0.938 (95% CI: 0.843–1.044) in mild anemia. The protective effect of anemia was also more profound in men (aHR 0.888, 95% CI: 0.774–1.02) than in women (aHR 0.905, 95% CI: 0.782–1.048). In conclusion, anemia was associated with lower risk of PD, particularly for patients with moderate to severe anemia. Our study suggests that further studies may be needed to clarify the relationship between anemia and PD.

Body mass index, diabetes, and the risk of Parkinson's disease

BACKGROUND

There are conflicting findings in the literature regarding the association of body mass index and incidence of PD.

OBJECTIVES

This study aimed to investigate the association of body mass index with the risk of PD incidence while considering diabetes mellitus as a major confounding factor.

METHODS

We examined 6,800,601 individuals (aged ≥40 years) who were free of PD using the database of the Korean National Health Insurance Service. Cox proportional hazard regression was used to assess adjusted hazard ratios for PD with adjustment for potential confounders. Stratified analyses by diabetes status were also performed.

RESULTS

A total of 33,443 individuals were diagnosed with PD during the follow-up period (7.3 years). An increased risk of PD incidence was observed in the underweight group versus the normal group (adjusted hazard ratio: 1.28; 95% confidence interval: 1.21-1.36), whereas a decreased risk of PD incidence was observed (adjusted hazard ratio: 0.88; 95% confidence interval: 0.88-0.93) in the obese group and (adjusted hazard ratio: 0.77; 95% confidence interval: 0.72-0.82) in the severely obese group. This association consistently persisted after stratification by diabetes mellitus status, with the steepest downward slope for PD risk present with increasing body mass index in patients with severe diabetes mellitus (i.e., long duration or complication).

CONCLUSIONS

Being underweight and diabetes mellitus were associated with an increased risk of PD incidence, and effect of being underweight was more prominent in those with diabetes mellitus, with a dose-response relationship existing according to diabetes mellitus status. Further research is warranted to understand the clinical implications of the significant interaction between being underweight and diabetes mellitus status in the development of PD. © 2020 International Parkinson and Movement Disorder Society.