Compassionate open-label use of rituximab following a randomised clinical trial against neuromyelitis optica (RIN-2 study): B cell monitoring-based administration.

OBJECTIVE: The aim of the RIN-2 study was a compassionate use of rituximab (RTX) for patients who completed the RIN-1 study, a multicentre, randomised, double-blind, placebo-controlled trial of RTX. We also investigated the long-term safety and efficacy of RTX. METHODS: A study design was a prospective open-label extension study following the RIN-1 study. RTX was infused repeatedly under monthly monitoring of CD19-positive and CD 20-positive B cell lymphocyte subsets from 24 weeks after an infusion. RESULTS: Thirty-three (87%) of 38 patients of the RIN-1 study were enrolled from February 2016 to March 2019 at six sites in Japan. In RIN-2, RTX was administered three times (median, range 1-5 times), and the interval of RTX administrations were 9.5 [2.5] months (mean [SD]). The observation period was 20.5 [10.1] months. During the trial, three patients dropped out due to two withdrawals and one adverse event. During the study, 28 (90%) of 31 patients were treated with RTX monotherapy. Neuromyelitis optica (NMO) relapses were observed in two patients. The annualized relapse rate (ARR) was 0.035 counts per person-years, ∼1/10th compared with 0.321 in the placebo arm of the RIN-1 study. We observed 14 severe adverse events in six (18%) and 156 adverse events, of which 135 were grade 1, 11 were grade 2 and 10 were grade 3. CONCLUSIONS: Under B cell monitoring, the interval of RTX re-infusion was elongated to nine months, and NMO relapses were suppressed with 0.035 of ARR.

Safety and efficacy of rituximab in neuromyelitis optica spectrum disorders (RIN-1 study): a multicentre, randomised, double-blind, placebo-controlled trial.

BACKGROUND: Pharmacological prevention against relapses in patients with neuromyelitis optica spectrum disorder (NMOSD) is developing rapidly. We aimed to investigate the safety and efficacy of rituximab, an anti-CD20 monoclonal antibody, against relapses in patients with NMOSD. METHODS: We did a multicentre, randomised, double-blind, placebo-controlled clinical trial at eight hospitals in Japan. Patients aged 16-80 years with NMOSD who were seropositive for aquaporin 4 (AQP4) antibody, were taking 5-30 mg/day oral steroids, and had an Expanded Disability Status Scale (EDSS) score of 7·0 or less were eligible for the study. Individuals taking any other immunosuppressants were excluded. Participants were randomly allocated (1:1) either rituximab or placebo by a computer-aided dynamic random allocation system. The doses of concomitant steroid (converted to equivalent doses of prednisolone) and relapses in previous 2 years were set as stratification factors. Participants and those assessing outcomes were unaware of group assignments. Rituximab (375 mg/m2) was administered intravenously every week for 4 weeks, then 6-month interval dosing was done (1000 mg every 2 weeks, at 24 weeks and 48 weeks after randomisation). A matching placebo was administered intravenously. Concomitant oral prednisolone was gradually reduced to 2-5 mg/day, according to the protocol. The primary outcome was time to first relapse within 72 weeks. Relapses were defined as patient-reported symptoms or any new signs consistent with CNS lesions and attributable objective changes in MRI or visual evoked potential. The primary analysis was done in the full analysis set (all randomly assigned patients) and safety analyses were done in the safety analysis set (all patients who received at least one infusion of assigned treatment). The primary analysis was by intention-to-treat principles. This trial is registered with the UMIN clinical trial registry, UMIN000013453. FINDINGS: Between May 10, 2014, and Aug 15, 2017, 38 participants were recruited and randomly allocated either rituximab (n=19) or placebo (n=19). Three (16%) patients assigned rituximab discontinued the study and were analysed as censored cases. Seven (37%) relapses occurred in patients allocated placebo and none were recorded in patients assigned rituximab (group difference 36·8%, 95% CI 12·3-65·5; log-rank p=0·0058). Eight serious adverse events were recorded, four events in three (16%) patients assigned rituximab (lumbar compression fracture and infection around nail of right foot [n=1], diplopia [n=1], and uterine cancer [n=1]) and four events in two (11%) people allocated to placebo (exacerbation of glaucoma and bleeding in the right eye chamber after surgery [n=1], and visual impairment and asymptomatic white matter brain lesion on MRI [n=1]); all patients recovered. No deaths were reported. INTERPRETATION: Rituximab prevented relapses for 72 weeks in patients with NMOSD who were AQP4 antibody-positive. This study is limited by its small sample size and inclusion of participants with mild disease activity. However, our results suggest that rituximab could be useful maintenance therapy for individuals with NMOSD who are AQP4 antibody-positive. FUNDING: Japanese Ministry of Health, Labour and Welfare, Japan Agency for Medical Research and Development, and Zenyaku Kogyo.

Vitamin D receptor gene polymorphisms, smoking, and risk of sporadic Parkinson's disease in Japan.

Epidemiological evidence on the relationships between the vitamin D receptor (VDR) single nucleotide polymorphisms (SNPs) rs731236 (TaqI), rs7975232 (ApaI), rs1544410 (BsmI), and rs2228570 (FokI) and Parkinson's disease (PD) is inconsistent. We investigated these relationships in 229 sporadic PD patients within six years of onset in Japan. Controls were 357 patients without neurodegenerative disease. Adjustment was made for sex, age, region of residence, and smoking. A significant inverse association was found between SNP rs2228570 and the risk of sporadic PD under the additive but not the co-dominant or dominant model (P=0.048); however, this fell below significance after adjustment for multiple comparisons (adjusted P=0.46). No significant relationships were found between SNPs rs731236, rs7975232, or rs1544410 and the risk of sporadic PD in any genetic model. VDR haplotypes inferred in the current study were not associated with sporadic PD. Compared with subjects with the GA or AA genotype of SNP rs2228570 who had ever smoked, those with the GG genotype who had never smoked had a 3.78-fold increased risk of sporadic PD; however, no significant interaction was observed. VDR SNP rs2228570 may be associated with sporadic PD in Japan. Smoking did not significantly modify the relationship between SNP rs2228570 and sporadic PD.

PARK16 polymorphisms, interaction with smoking, and sporadic Parkinson's disease in Japan.

Epidemiological evidence on the relationships between PARK16 single nucleotide polymorphisms (SNPs) and Parkinson's disease (PD) is inconsistent. We examined this issue in Japan. Included were 229 cases within six years of PD onset. Controls were 356 patients without neurodegenerative disease. Compared with subjects with the AA genotype of SNP rs823128, those with the AG genotype, but not the GG genotype, had a significantly reduced risk of sporadic PD. Compared with the AA genotype of SNP rs947211, both the AG genotype and the GG genotype were significantly related to an increased risk of sporadic PD. Using subjects with the AA genotype of SNP rs823156 as a reference group, there were significant inverse relationships under the additive and dominant models. No significant relationships were found between SNPs rs16856139 or rs11240572 and sporadic PD. The CAAAC, the TGAGA, and the CAGAC haplotypes were significantly related to sporadic PD. The additive interaction between SNP rs823128 and smoking affecting sporadic PD was significant, although the multiplicative interaction was not significant. The PARK16 SNPs rs823128, rs947211, and rs823156 and the CAAAC, TGAGA, and CAGAC haplotypes may be significantly associated with sporadic PD in Japan. New evidence of an additive interaction between SNP rs823156 and smoking is suggested.

Baseline C-Reactive Protein Levels and Life Prognosis in Parkinson Disease.

BACKGROUND: C-reactive protein (CRP) is a biomarker of inflammation, and high levels of CRP correlate with vascular death. Chronic inflammation is considered to be involved in neurodegeneration, although there is no evidence linking it with the process of neurodegenerative diseases. OBJECTIVE: To determine the role of baseline CRP levels in the prognosis of patients with Parkinson disease (PD). METHODS: A cohort of 313 patients with a mean age of 69.1 and mean PD duration of 7.9 years was retrospectively followed for a mean observation time of 1,753 days. CRP was measured when patients were not diagnosed with any infections, and levels were repetitively measured to investigate a tendency of "regression to mean." The primary outcome measure was a survival time from study enrollment to death. RESULTS: During the observation period 56 patients died. Baseline CRP was log-linearly associated with a risk of death in PD. Mean survival time was 3,149 (95% confidence interval; 3,009-3,289) days in patients with CRP ≤ 0.8mg/L (lower two thirds) and 2,620 (2,343-2,897) days in those with CRP > 0.8 mg/L (top third, p < 0.001, log-rank test). The adjusted hazard ratio (HR) per two-fold higher CRP concentration for all deaths was 1.29 (1.10-1.52), and after excluding PD-unrelated deaths, such as cancer or stroke, HR was 1.23 (1.01-1.49) (adjusted for age, sex, PD duration, modified Hohen-Yahr stages, MMSE scores, and serum albumin). CONCLUSIONS: Baseline CRP concentrations were associated with the risk of death and predicted life prognosis of patients with PD. The associations were independent from PD duration, PD severity, cognitive function, ages, and nutritional conditions, suggesting the possibility that subclinical chronic inflammation is associated with a neurodegenerative process in PD.

[A case of refractory generalized myasthenia gravis with anti-acetylcholine receptor antibodies treated with rituximab].

We report a case of a 57-year-old woman with thymoma-associated generalized myasthenia gravis (MG) showing severe bulbar and respiratory symptoms, moderate weakness of the neck muscles, and mild weakness of extremity muscles. Corticosteroid treatment with various types of immunosuppressive agents, such as cyclosporine, tacrolimus, and azathioprine, did not improve her symptoms. Plasma exchange transiently improved her symptoms, and she was required to undergo plasmapheresis every 4 weeks. At first, cyclophosphamide pulse therapy was administered, which improved her symptoms transiently. Thereafter, rituximab (RTX) was administered. Six months after RTX administration, respiratory distress and dysphagia improved gradually, and reduction in the dosage of corticosteroids from 30 mg/day to 10 mg/day did not result in symptom deterioration. Therefore, the interval between successive plasmapheresis treatments was increased from 4 to 9 weeks 19 months after the first RTX administration. During a 26-month period from the first administration of RTX, the number of CD20+ B cells in peripheral blood decreased and remained at 0% to 26% of that before RTX treatment. The titer of anti-acetylcholine receptor antibodies did not change during the first course of treatment (0.6-0.9 nmol/l). The clinical symptom worsened with the increase of the number of CD20+ B cells in peripheral blood in the 27 month after 1st RTX administration. Therefore, RTX was administered a second time, after which the patient's clinical symptoms again improved gradually. The titer of anti-acetylcholine receptor antibodies came to be stable with 0.5-0.7 nmol and low level during the 2nd course. Corticosteroids could be discontinued in the 16th month. The findings suggest that RTX can be one of the choices for pharmacological therapy in patients with intractable MG accompanied by the presence of anti-acetylcholine receptor antibodies.

MDR1 C3435T polymorphism and interaction with environmental factors in risk of Parkinson's disease: a case-control study in Japan.

It has been suggested that P-glycoprotein (P-gp), the product of multidrug resistance 1 (MDR1) gene, regulates the brain entry of various xenobiotics. Impaired function of P-gp may be associated with an increased risk of Parkinson's disease (PD). The aim of this study was to investigate the impact of a MDR1 C3435T polymorphism on PD risk alone or in combination with environmental factors. A total of 238 patients with PD and 368 controls were genotyped for the MDR1 C3435T polymorphism. Subjects with the TT genotype of the C3435T polymorphism showed a nonsignificantly increased risk of PD [odds ratio (OR)=1.49, 95% confidence interval (CI)=0.85-2.25] compared with those with the CC genotype. A gene-environment interaction was suggested, with a combination of at least one T allele and ever drinking conferring significantly higher risk (OR=1.83, 95% CI=1.07-3.15, p=0.029), compared with the CC genotype and never drinking. No significant interaction of smoking or occupational pesticide use with the C3435T polymorphism was observed. Our results suggest that the C3435T polymorphism may not play an important role in PD susceptibility in Japanese. Evidence of an interaction between the C3435T polymorphism and alcohol consumption was suggested.

Lack of association between BST1 polymorphisms and sporadic Parkinson's disease in a Japanese population.

Several genome-wide association studies and case-control studies have investigated the relationships between single nucleotide polymorphisms (SNPs) in the BST1 gene and Parkinson's disease (PD), but the results have been inconsistent. We examined the relationships between SNPs rs11931532, rs12645693, and rs11724635 and the risk of sporadic PD in Japan. Included were 229 cases within 6years of onset of PD as defined according to the UK PD Society Brain Bank clinical diagnostic criteria. Controls were 357 inpatients and outpatients without neurodegenerative disease. SNPs rs11931532 and rs12645693 were not significantly related to sporadic PD. Compared with a reference group of subjects with the CC genotype of SNP rs11724635, those with the AA genotype had a marginally significantly increased risk of sporadic PD: the adjusted OR was 1.57 (95% CI: 0.95-2.61, P=0.08). No significant interactions were found between BST1 SNP rs11724635 and smoking or caffeine intake with respect to sporadic PD. The current study failed to detect significant relationships between BST1 SNPs rs11931532, rs12645693, and rs11724635 and sporadic PD; however, the relationship between SNP rs11724635 and sporadic PD was of borderline significance. We do not find evidence for interactions between smoking or caffeine intake and SNP rs11724635 affecting sporadic PD.

UCHL1 S18Y variant is a risk factor for Parkinson's disease in Japan.

BACKGROUND: A recent meta-analysis on the UCHL1 S18Y variant and Parkinson's disease (PD) showed a significant inverse association between the Y allele and PD; the individual studies included in that meta-analysis, however, have produced conflicting results. We examined the relationship between UCHL1 S18Y single nucleotide polymorphism (SNP) and sporadic PD in Japan. METHODS: Included were 229 cases within 6 years of onset of PD, defined according to the UK PD Society Brain Bank clinical diagnostic criteria. Controls were 357 inpatients and outpatients without neurodegenerative disease. Adjustment was made for sex, age, region of residence, smoking, and caffeine intake. RESULTS: Compared with subjects with the CC or CA genotype of UCHL1 S18Y SNP, those with the AA genotype had a significantly increased risk of sporadic PD: the adjusted OR was 1.57 (95 % CI: 1.06 - 2.31). Compared with subjects with the CC or CA genotype of UCHL1 S18Y and the CC or CT genotype of SNCA SNP rs356220, those with the AA genotype of UCHL1 S18Y and the TT genotype of SNP rs356220 had a significantly increased risk of sporadic PD; the interaction, however, was not significant. Our previous investigation found significant inverse relationships between smoking and caffeine intake and PD in this population. There were no significant interactions between UCHL1 S18Y and smoking or caffeine intake affecting sporadic PD. CONCLUSIONS: This study reveals that the UCHL1 S18Y variant is a risk factor for sporadic PD. We could not find evidence for interactions affecting sporadic PD between UCHL1 S18Y and SNCA SNP rs356220, smoking, or caffeine intake.

SNCA polymorphisms, smoking, and sporadic Parkinson's disease in Japanese.

Several case-control studies and genome-wide association studies have examined the relationships between single nucleotide polymorphisms (SNPs) in the SNCA gene and Parkinson's disease (PD), and have provided inconsistent results. We investigated the relationships between SNPs rs356229, rs356219, rs356220, rs7684318, and rs2736990 and the risk of sporadic PD in Japan using data from a multicenter hospital-based case-control study. Included were 229 cases within 6 years of onset of PD as defined according to the UK PD Society Brain Bank clinical diagnostic criteria. Controls were 357 inpatients and outpatients without neurodegenerative disease. Adjustment was made for sex, age, region of residence, and smoking. Based on the recessive model, compared with subjects with the CC or CT genotype of SNP rs356220, those with the TT genotype had a significantly increased risk of sporadic PD: the adjusted OR was 1.42 (95% CI: 1.002-2.02). In the additive model, SNP rs2736990 was significantly related to the risk of sporadic PD: the adjusted OR was 1.30 (95% CI: 1.002-1.68). There were no significant relationships between SNP rs356229, rs356219, or rs7684318 and the risk of sporadic PD in any genetic model. The additive interactions between SNPs rs356219 and rs356220 and smoking with respect to sporadic PD were significant although the multiplicative interactions were not significant. This study suggests that SNCA SNPs rs356220 and rs2736990 are significantly associated with the risk of sporadic PD in Japanese. We also present new evidence for biological interactions between SNPs rs356219 and rs356220 and smoking that affect sporadic PD.

Occupational risk factors for Parkinson's disease: a case-control study in Japan.

BACKGROUND: The evidence for associations between occupational factors and the risk of Parkinson's disease (PD) is inconsistent. We assessed the risk of PD associated with various occupational factors in Japan. METHODS: We examined 249 cases within 6 years of onset of PD. Control subjects were 369 inpatients and outpatients without neurodegenerative disease. Information on occupational factors was obtained from a self-administered questionnaire. Relative risks of PD were estimated using odds ratios (ORs) and 95% confidence intervals (CIs) based on logistic regression. Adjustments were made for gender, age, region of residence, educational level, and pack-years of smoking. RESULTS: Working in a professional or technical occupation tended to be inversely related to the risk of PD: adjusted OR was 0.59 (95% CI: 0.32-1.06, P = 0.08). According to a stratified analysis by gender, the decreased risk of PD for persons in professional or technical occupations was statistically significant only for men. Adjusted ORs for a professional or technical occupation among men and women were 0.22 (95% CI: 0.06-0.67) and 0.99 (0.47-2.07), respectively, and significant interaction was observed (P = 0.048 for homogeneity of OR). In contrast, risk estimates for protective service occupations and transport or communications were increased, although the results were not statistically significant: adjusted ORs were 2.73 (95% CI: 0.56-14.86) and 1.74 (95% CI: 0.65-4.74), respectively. No statistical significance was seen in data concerning exposure to occupational agents and the risk of PD, although roughly a 2-fold increase in OR was observed for workers exposed to stone or sand. CONCLUSION: The results of our study suggest that occupational factors do not play a substantial etiologic role in this population. However, among men, professional or technical occupations may decrease the risk of PD.

Genetic polymorphisms involved in dopaminergic neurotransmission and risk for Parkinson's disease in a Japanese population.

BACKGROUND: Parkinson's disease (PD) is characterized by alterations in dopaminergic neurotransmission. Genetic polymorphisms involved in dopaminergic neurotransmission may influence susceptibility to PD. METHODS: We investigated the relationship of catechol-O-methyltransferase (COMT), monoamine oxidase B (MAOB), dopamine receptor (DR) D2 and DRD4 polymorphisms and PD risk with special attention to the interaction with cigarette smoking among 238 patients with PD and 369 controls in a Japanese population. RESULTS: Subjects with the AA genotype of MAOB rs1799836 showed a significantly increased risk of PD (odds ratio (OR) = 1.70, 95% confidence interval (CI) = 1.12 - 2.58) compared with the AG and GG genotypes combined. The AA genotype of COMT rs4680 was marginally associated with an increased risk of PD (OR = 1.86, 95% CI = 0.98 - 3.50) compared with the GG genotype. The DRD2 rs1800497 and DRD4 rs1800955 polymorphisms showed no association with PD. A COMT -smoking interaction was suggested, with the combined GA and AA genotypes of rs4680 and non-smoking conferring significantly higher risk (OR = 3.97, 95% CI = 2.13 - 7.41) than the AA genotype and a history of smoking (P for interaction = 0.061). No interactions of smoking with other polymorphisms were observed. CONCLUSIONS: The COMT rs4680 and MAOB rs1799836 polymorphisms may increase susceptibility to PD risk among Japanese. Future studies involving larger control and case populations and better pesticide exposure histories will undoubtedly lead to a more thorough understanding of the role of the polymorphisms involved in the dopamine pathway in PD.

Intake of Japanese and Chinese teas reduces risk of Parkinson's disease.

Studies that have addressed the association between the intake of coffee or caffeine and Parkinson's disease (PD) were conducted mainly in Western countries. Little is known about this relationship in an Asian population. Therefore, we performed an assessment of the association of the intake of coffee, other caffeine-containing beverages, and caffeine with the risk of PD in Japan. The study involved 249 PD cases and 368 control subjects. Information on dietary factors was obtained through a self-administered diet history questionnaire. Adjustment was made for sex, age, region of residence, educational level, pack-years of smoking, body mass index, the dietary glycemic index, and intake of cholesterol, vitamin E, ß-carotene, vitamin B(6,) alcohol, and iron. Intake of coffee, black tea, and Japanese and Chinese teas was significantly inversely associated with the risk of PD: the adjusted odds ratios in comparison of the highest with the lowest quartile were 0.52, 0.58, and 0.59, respectively (95% confidence intervals = 0.30-0.90, 0.35-0.97, and 0.35-0.995, respectively). A clear inverse dose-response relationship between total caffeine intake and PD risk was observed. We confirmed that the intake of coffee and caffeine reduced the risk of PD. Furthermore, this is the first study to show a significant inverse relationship between the intake of Japanese and Chinese teas and the risk of PD.

Alcohol drinking and risk of Parkinson's disease: a case-control study in Japan.

BACKGROUND: Although some epidemiologic studies found inverse associations between alcohol drinking and Parkinson's disease (PD), the majority of studies found no such significant associations. Additionally, there is only limited research into the possible interactions of alcohol intake with aldehyde dehydrogenase (ALDH) 2 activity with respect to PD risk. We examined the relationship between alcohol intake and PD among Japanese subjects using data from a case-control study. METHODS: From 214 cases within 6 years of PD onset and 327 controls without neurodegenerative disease, we collected information on "peak", as opposed to average, alcohol drinking frequency and peak drinking amounts during a subject's lifetime. Alcohol flushing status was evaluated via questions, as a means of detecting inactive ALHD2. The multivariate model included adjustments for sex, age, region of residence, smoking, years of education, body mass index, alcohol flushing status, presence of selected medication histories, and several dietary factors. RESULTS: Alcohol intake during peak drinking periods, regardless of frequency or amount, was not associated with PD. However, when we assessed daily ethanol intake separately for each type of alcohol, only Japanese sake (rice wine) was significantly associated with PD (adjusted odds ratio of ≥66.0 g ethanol per day: 3.39, 95% confidence interval: 1.10-11.0, P for trend = 0.001). There was no significant interaction of alcohol intake with flushing status in relation to PD risk. CONCLUSIONS: We did not find significant associations between alcohol intake and PD, except for the daily amount of Japanese sake. Effect modifications by alcohol flushing status were not observed.

LRRK2 Gly2385Arg polymorphism, cigarette smoking, and risk of sporadic Parkinson's disease: a case-control study in Japan.

Previous case-control studies in Japanese and ethnic Chinese populations reported that the LRRK2 Gly2385Arg variant is a risk factor for Parkinson's disease (PD). We aimed to validate the previous findings and investigate whether cigarette smoking influences the relationship between the Gly2385Arg variant and PD. Included were 229 cases within 6years of onset of sporadic PD. Controls were 358 inpatients and outpatients without a neurodegenerative disease. The frequency of the heterozygous genotype was 13.1% of cases and 6.4% of controls: adjusted OR for the GA genotype was 2.06 (95% CI: 1.15-3.69). Compared with subjects with the GG genotype who had ever smoked, those with the GA genotype who had never smoked had a 5.8-fold increased risk of sporadic PD. The multiplicative interaction between the SNP and smoking was not statistically significant. With respect to the additive interaction, the estimated attributable proportion due to interaction (AP), but not relative excess risk due to interaction or the synergy index, was statistically significant (AP=0.50, 95% CI: 0.05-0.94), suggesting the presence of a biological interaction. The present study confirms that the LRRK2 Gly2385Arg variant is a risk factor for sporadic PD. In addition, we provide new evidence for the biological interaction between the polymorphism and smoking with regard to the risk of sporadic PD.

Case-control study of risk of Parkinson's disease in relation to hypertension, hypercholesterolemia, and diabetes in Japan.

This case-control study investigated the associations of a history of hypertension, hypercholesterolemia, and diabetes mellitus with the risk of Parkinson's disease (PD) in Japan. Included were 249 cases within 6 years of onset of PD. Controls were 368 inpatients and outpatients without a neurodegenerative disease. Data on the vascular risk factors and confounders were obtained from a self-administered questionnaire. The vascular risk factors were defined based on drug treatment. Adjustment was made for sex, age, region of residence, pack-years of smoking, years of education, leisure-time exercise, body mass index, dietary intake of energy, cholesterol, vitamin E, alcohol, and coffee and the dietary glycemic index. The proportions of hypertension, hypercholesterolemia, and diabetes mellitus prior to the onset of PD were 23.7%, 9.6%, and 4.0%, respectively, in cases. Hypertension, hypercholesterolemia, and diabetes mellitus were significantly associated with a decreased risk of PD: the adjusted ORs were 0.43 (95% CI: 0.29-0.64), 0.58 (95% CI: 0.33-0.97), and 0.38 (95% CI: 0.17-0.79), respectively. No significant differences were observed in the association of vascular risk factors with the risk of PD between men and women. We found evidence of significant inverse associations of hypertension, hypercholesterolemia, and diabetes mellitus with the risk of PD in Japan. Further well-designed investigations of the association of vascular risk factors with the risk of PD are needed, particularly large-scale prospective studies in Asia.