Risk factors of Parkinson's disease in Indian patients

Role of PON1 L55M Gene Polymorphism in Parkinson's Disease among North Indian Population

BACKGROUND AND OBJECTIVES

The role of various genetic markers including alpha synuclein, Parkin, etc., is known in the pathogenesis of Parkinson's disease (PD). Novel genetic markers including paraoxonase 1 (PON1) have also been linked to PD pathogenesis in recent studies. The PON1 L55M allele carriers may have defective clearance of environmental toxins and may result in increased susceptibility to PD. Hence, we studied the role of PON1 L55M polymorphism in PD among a North Indian population.

MATERIALS AND METHOD

Seventy-four PD patients and 74 age- and sex-matched controls were recruited in this hospital-based case-control study. Baseline characteristics were recorded using structured questionnaire. DNA was extracted from 3-4 ml of venous blood, followed by PCR and restriction digestion. PON1 L55M genotypes were visualized as bands: LL (177 bp), LM (177, 140 bp) and MM (140,44 bp) on 3% agarose gel. Mann-Whitney U test and Chi-squared test were used for comparing two groups of skewed and categorical variables, respectively. Measures of strength of association were calculated by binary regression analysis. P value < 0.05 was considered as significant.

RESULTS

Parkinson's disease patients had significantly higher exposure to pesticides (12.2%; P (organophosphate exposure) < 0.001) and well water drinking (28.4%; P = 0.006) compared to controls. Frequency distribution of LL, LM, MM genotypes was 67.5% (50/74), 28.4% (21/74), and 4.1% (3/74), respectively, for cases and 72.6% (54/74), 26% (19/74) and 1.4% (1/74), respectively, for controls. PON1 L55M genotype distribution between Parkinson's disease cases and controls was not significant (P = 0.53). PON1 L55M polymorphism was not associated with PD after adjusting for confounders by binary regression analysis.

CONCLUSION

There was no significant association between PON1 L55M polymorphism and PD. Larger population-based studies would be required from India before drawing any definite conclusions.

Dysbiosis of the Beneficial Gut Bacteria in Patients with Parkinson's Disease from India

Objectives

Recent advancement in understanding neurological disorders has revealed the involvement of dysbiosis of the gut microbiota in the pathophysiology of Parkinson's disease (PD). We sequenced microbial DNA using fecal samples collected from PD cases and healthy controls (HCs) to evaluate the role of gut microbiota.

Methods

Full-length bacterial 16S rRNA gene sequencing of fecal samples was performed using amplified polymerase chain reaction (PCR) products on the GridION Nanopore sequencer. Sequenced data were analyzed using web-based tools BugSeq and MicrobiomeAnalyst.

Results

We found that certain bacterial families like Clostridia UCG 014, Cristensenellaceae, and Oscillospiraceae are higher in abundance, and Lachinospiracea, Coriobacteriaceae and genera associated with short-chain fatty acid production, Faecalibacterium, Fusicatenibacter, Roseburia and Blautia, are lower in abundance among PD cases when compared with the HC. Genus Akkermansia, Dialister, Bacteroides, and Lachnospiraceae NK4A136 group positively correlated with constipation in PD.

Conclusion

Observations from this study support the other global research on the PD gut microbiome background and provide fresh insight into the gut microbial composition of PD patients from a south Indian population. We report a higher abundance of Clostridia UCG 014 group, previously not linked to PD.

Alcohol and Parkinson's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

A substantial body of research has examined the relationship between alcohol consumption and risk of Parkinson's disease (PD).

OBJECTIVE

To provide an updated systematic review and meta-analysis of observational studies examining the relationship between alcohol consumption and risk of PD.

METHODS

Eligible studies comparing PD risk in ever vs. never alcohol drinkers were sourced from six databases. Outcomes were pooled using standard meta-analysis techniques. Separate female and male estimates were generated from studies reporting sex-specific data. Additionally, cohort studies stratifying participants by quantity of alcohol intake were integrated in a dose-response analysis.

RESULTS

52 studies were included, totaling 63,707 PD patients and 9,817,924 controls. Our meta-analysis supported a statistically significant overrepresentation of never drinkers among PD subjects; odds ratio (OR) for ever drinking alcohol 0.84 (95% confidence interval (CI) 0.76 - 0.92). A subgroup analysis revealed similar effect estimates in females and males. A further synthesis of seven cohort studies suggested a negative, dose-dependent association between alcohol and risk of PD.

CONCLUSION

In the absence of a known neuroprotective pathway, there may be reason to doubt a true biological effect. The role of survivor bias, selection and recall bias, misclassification, and residual confounding requires consideration. Alternatively, observations might be attributable to reverse causation if those predestined for PD alter their alcohol habits during the preclinical phase. Major limitations of our study include high between-study heterogeneity (I2 = 93.2%) and lack of adjustment for key confounders, namely smoking status.

Sex Differences in Dopaminergic Vulnerability to Environmental Toxicants - Implications for Parkinson's Disease

PURPOSE OF REVIEW

Sex dimorphism in Parkinson's disease (PD) is an ostensible feature of the neurological disorder, particularly as men are 1.5-2 times more likely to develop PD than women. Clinical features of the disease, such as presentation at onset, most prevalent symptoms, and response to treatment, are also affected by sex. Despite these well-known sex differences in PD risk and phenotype, the mechanisms that impart sex dimorphisms in PD remain poorly understood.

RECENT FINDINGS

As PD incidence is influenced by environmental factors, an intriguing pattern has recently emerged in research studies suggesting a male-specific vulnerability to dopaminergic neurodegeneration caused by neurotoxicant exposure, with relative protection in females. These new experimental data have uncovered potential mechanisms that provide clues to the source of sex differences in dopaminergic neurodegeneration and other PD pathology such as alpha-synuclein toxicity. In this review, we discuss the emerging evidence of increased male sensitivity to neurodegeneration from environmental exposures. We examine mechanisms underlying dopaminergic neurodegeneration and PD-related pathologies with evidence supporting the roles of estrogen, SRY expression, the vesicular glutamate transporter VGLUT2, and the microbiome as prospective catalysts for male vulnerability. We also highlight the importance of including sex as a biological variable, particularly when evaluating dopaminergic neurotoxicity in the context of PD.

Risk Factors for Brain Health in Agricultural Work: A Systematic Review

Certain exposures related to agricultural work have been associated with neurological disorders. To date, few studies have included brain health measurements to link specific risk factors with possible neural mechanisms. Moreover, a synthesis of agricultural risk factors associated with poorer brain health outcomes is missing. In this systematic review, we identified 106 articles using keywords related to agriculture, occupational exposure, and the brain. We identified seven major risk factors: non-specific factors that are associated with agricultural work itself, toluene, pesticides, heavy metal or dust exposure, work with farm animals, and nicotine exposure from plants. Of these, pesticides are the most highly studied. The majority of qualifying studies were epidemiological studies. Nigral striatal regions were the most well studied brain area impacted. Of the three human neuroimaging studies we found, two focused on functional networks and the third focused on gray matter. We identified two major directions for future studies that will help inform preventative strategies for brain health in vulnerable agricultural workers: (1) the effects of moderators such as type of work, sex, migrant status, race, and age; and (2) more comprehensive brain imaging studies, both observational and experimental, involving several imaging techniques.

Nutritional aspects in Parkinson's disease

The links between diet and Parkinson's disease (PD) are unclear and incomprehensible. However, numerous studies have demonstrated the correlation between diet, nutrients and health condition in PD patients. They indicate the possibility of management of the disease, which might be possible through nutrition. Pharmaceutical treatment as well as a complementary holistic approach to the patients should be considered. It is of critical importance to understand how the diet and nutrients might influence PD. A better understanding of the relationship between diet and PD could help to better manage the disease explain promising therapeutic approaches, minimize motor and nonmotor symptoms and disease progression based on a personalized diet. In this review, the recent literature on the observed nutrition disorders and the possible role of diet and nutrients in the prevention and potential regression of PD, as well as dietary interventions and supplementation used to manage the disease is revised.

Vegetarianism and veganism compared with mental health and cognitive outcomes: a systematic review and meta-analysis

CONTEXT

Vegetarian and vegan diets are increasing in popularity. Although they provide beneficial health effects, they may also lead to nutritional deficiencies. Cognitive impairment and mental health disorders have a high economic burden.

OBJECTIVE

A meta-analysis was conducted to examine the relationship between vegan or vegetarian diets and cognitive and mental health.

DATA SOURCES

PubMed, Scopus, ScienceDirect, and Proquest databases were examined from inception to July 2018.

STUDY SELECTION

Original observational or interventional human studies of vegan/vegetarian diets were selected independently by 2 authors.

DATA EXTRACTION

Raw means and standard deviations were used as continuous outcomes, while numbers of events were used as categorical outcomes.

RESULTS

Of 1249 publications identified, 13 were included, with 17 809 individuals in total. No significant association was found between diet and the continuous depression score, stress, well-being, or cognitive impairment. Vegans/vegetarians were at increased risk for depression (odds ratio = 2.142; 95%CI, 1.105-4.148) and had lower anxiety scores (mean difference = -0.847; 95%CI, -1.677 to -0.018). Heterogeneity was large, and thus subgroup analyses showed numerous differences.

CONCLUSIONS

Vegan or vegetarian diets were related to a higher risk of depression and lower anxiety scores, but no differences for other outcomes were found. Subgroup analyses of anxiety showed a higher risk of anxiety, mainly in participants under 26 years of age and in studies with a higher quality. More studies with better overall quality are needed to make clear positive or negative associations.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42018097204.

Well-Water Consumption and Risk of Parkinson's Disease: A Meta-Analysis of 15 Observational Studies

INTRODUCTION

The relationship between the risk of Parkinson disease and well-water consumption has been extensively studied, but the results have been contradictory. Therefore, we conducted a meta-analysis of observational studies to systematically assess the relationship between well-water consumption and Parkinson disease risk.

METHODS

We followed the PRISMA checklist in completing the meta-analysis. We searched two electronic databases (PubMed, EBSCO, EMBASE and Cochrane) from establishment to October, 2021, to identify relevant studies linking well-water drinking to Parkinson risk. We used a random-effects model to calculate the overall odds ratio (OR) with 95% confidence interval (CI). To reduce intragroup heterogeneity, we conducted subgroup analyses according to the research design and geographic area.

RESULTS

After careful review, a total of 15 case-control-designed studies included data suitable for our meta-analysis. The total number of cases and total controls that contribute to the combined OR were 2182 and 2456. The combined OR for ever well-water drinkers versus non-drinkers was 1.16 (95% CI: 0.97-1.39, I² = 44.52%). In subgroup analysis by geographic area, a significant association was observed in studies conducted in Asia (OR 1.29, 95% CI: 1.05-1.58, I² = 0.0%, p for heterogeneity = 0.460) but not in studies conducted in America (OR 0.97, 95% CI: 0.76-1.24, I² = 41.2%, p for heterogeneity = 0.164). In subgroup analysis by study design, a borderline significant association emerged in hospital-based case-control studies (OR 1.31, 95% CI: 1.04-1.65, I² = 40.9%, p for heterogeneity = 0.118) but not in population-based case-control studies (OR 0.96, 95% CI: 0.73-1.26, I² = 41.1%, p for heterogeneity = 0.165).

DISCUSSION

Our results indicate that there is no significant correlation between well-water consumption and PD risk.

Novel and reported variants in Parkinson's disease genes confer high disease burden among Indians

BACKGROUND

Genetic heterogeneity in Parkinson's disease (PD) has been unambiguously reported across different populations. Assuming a higher genetic load, we tested variant burden in PD genes to an early onset PD cohort from India.

METHODS

Whole exome sequencing was performed in 250 PD patients recruited following MDS-UPDRS criteria. The number of rare variants in the 20 known PD genes per exome were used to calculate average rare variant burden with the 616 non-PD exomes available in-house as a comparison group. SKAT-O test was used for gene level analysis.

RESULTS

80 patients harboured rare variants in 20 PD genes, of which six had known pathogenic variants accounting for 2.4% of the cohort. Of 80 patients, 12 had homozygous and nine had likely compound heterozygous variants in recessive PD genes and 59 had heterozygous variants in only dominant PD genes. Of the 16 novel variants of as yet unknown significance identified, four homozygous across ATP13A2, PRKN, SYNJ1 and PARK7; and 12 heterozygous among LRRK2, VPS35, EIF4G1 and CHCHD2 were observed. SKAT-O test suggested a higher burden in GBA (p_unadjusted = 0.002). Aggregate rare variant analysis including 75 more individuals with only heterozygous variants in recessive PD genes (excluding GBA), with an average of 0.85 protein-altering rare variants per PD patient exome versus 0.51 in the non-PD group, revealed a significant enrichment (p < 0.0001).

CONCLUSION

This first study in an early onset PD cohort among Indians identified 16 novel variants in known genes and also provides evidence for a high genetic burden in this ethnically distinct population.

Saccadic Eye Movements in Young-Onset Parkinson's Disease - A BOLD fMRI Study

The objective of the present study was to understand control of saccadic eye movements in patients with young onset Parkinson's disease (YOPD) where onset of disease symptoms appears early in life (<40 years of age). Functional magnetic resonance imaging (fMRI) was performed in patients with YOPD and control subjects while they performed saccadic tasks, which consisted of a reflexive task and another task that required inhibitory control of eye movements (Go-NoGo task). Functional imaging related to saccadic eye movements in this group of patients has not been widely reported. A 1.5T MR scanner was used for structural and functional imaging. Analysis of blood-oxygen-level-dependent (BOLD) fMRI was performed using Statistical Parametric Mapping (SPM) software and compared in patients and controls. In patients with YOPD greater activation was seen significantly in the middle frontal gyrus, medial frontal gyrus, angular gyrus, cingulate gyrus, precuneus and cerebellum, when compared with the control group, during the saccadic tasks. Gap and overlap protocols revealed differential activation patterns. The abnormal activation during reflexive saccades was observed in the overlap condition, while during Go-NoGo saccades in the gap condition. The results suggest that impaired circuitry in patients with YOPD results in recruitment of more cortical areas. This increased frontal and parietal cortical activity possibly reflects compensatory mechanisms for impaired cognitive and saccadic circuitry.

Well Water and Parkinson's Disease in Medicare Beneficiaries: A Nationwide Case-Control Study

BACKGROUND

Well water frequently is considered a risk factor for Parkinson's disease (PD), but few studies were designed appropriately to test whether geographic factors affect PD risk.

OBJECTIVE

To determine the risk of PD in relation to residential use of private well water.

METHODS

In a nationwide, population-based case-control study, we identified all incident PD cases (N = 89,790) and all comparable controls (N = 21,549,400) age 66-90 who solely relied on Medicare coverage in the U.S. in 2009. We estimated the probability of use of private well water using zip code of residence at diagnosis/reference and U.S. Census data on household water source. We modeled this exposure linearly in logistic regression to calculate the odds ratio (OR) and 95% confidence interval (CI) of PD risk in relation to well water use. We adjusted for age, sex and race/ethnicity, and verified that smoking and use of medical care did not confound results. We repeated analyses with a 2-year exposure lag and separately within each U.S. state.

RESULTS

Use of well water was inversely associated with PD risk (OR = 0.87, 95% CI 0.85-0.89). We confirmed this association in a Cox survival analysis in which we followed controls for 5 years, death or PD diagnosis. There was little evidence that well water use increased risk of PD in any individual state.

CONCLUSIONS

Although it remains possible that exposures in well water in more narrow geographic regions increase PD risk, in general these results suggest that exposures more common in urban/suburban areas might also be relevant.

Association between depression and the subsequent risk of Parkinson's disease: A meta-analysis

BACKGROUND

Observational studies, including recent large cohort studies, have reported an association between depression and the risk of Parkinson's disease (PD); however, conclusions were inconsistent. Clarifying this relation might improve the understanding of risk factors for and the disease mechanisms in PD. Therefore, we performed a meta-analysis to examine whether depression is associated with an increased risk of PD.

METHODS

A literature search in the PubMed, EMBASE, Scopus, PsycINFO and Web of Science databases was undertaken through March 2018, looking for observational studies evaluating the association between depression and the risk of PD. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using a random-effects model. Subgroup analyses and sensitivity analyses were also performed.

RESULTS

A random-effects meta-analysis of 5 cohort studies and 6 case-control studies demonstrated a significant positive association between depression and a subsequent risk of PD (RR, 2.20; 95% CI, 1.87-2.58), and it was consistent across subgroups. Furthermore, sensitivity analysis confirmed the stability of the results; visual examination of funnel plots and Begg's and Egger's tests showed no evidence of publication bias.

CONCLUSIONS

Our meta-analysis demonstrated that persons with depression exhibited an increased risk of a subsequent PD diagnosis. The pathophysiological and psychological mechanisms underlying this association are still unclear and warrant further research.

Alcohol consumption and risk for Parkinson's disease: a systematic review and meta-analysis

The possibility that alcohol consumption should be considered as a "protective factor" for Parkinson's disease (PD) has been suggested by several case-control studies. However, other case-control studies and data from prospective longitudinal cohort studies have been inconclusive. We carried out a systematic review which included all the eligible studies published on PD risk related with alcohol consumption, and conducted a meta-analysis according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The systematic review was performed using two databases, and the meta-analysis of the eligible studies with the software Meta-Disc1.1.1. Heterogeneity between studies was tested with the Q-statistic. The meta-analysis included 26 eligible retrospective case-control studies (8798 PD patients, 15,699 controls) and 5 prospective longitudinal cohort studies (2404 PD patients, 600,592 controls) on alcohol consumption and PD. In retrospective case-control studies the frequency of PD patients never drinkers was higher and the frequency of heavy + moderate drinkers was lower [diagnostic OR (95% CI) 1.33(1.20-1.48) and 0.74(0.64-0.85)], respectively, when compared to healthy controls. In contrast, in prospective studies, the differences were not significant with the exception of a trend towards a higher frequency of non-drinkers in PD women and a significantly lower frequency of moderate + heavy drinkers in PD men in those studies which stratified data by gender. The present meta-analysis suggests an inverse association between alcohol consumption and PD, which is supported by the results of case-control studies but not clearly by prospective ones.

Clinical Profile of Parkinson's Disease: Experience of Niger

Background:

Parkinson's disease (PD) is a chronic neurodegenerative pathology with unknown etiology. It is characterized clinically by the classic triad that associated tremors, bradykinesia, and rigidity. In Niger, there are no data on PD.

Aims:

We aimed to provide the demographic and clinical profile of PD in patients from Niger to create a database on PD in Niger.

Patients and Methods:

We conducted a retrospective study at the Neurology Outpatient Clinic of the Hôpital National de Niamey (HNN, Niger) over a period of 4.42 years from February 2009 to July 2013 collecting all cases of PD. The demographic and clinical features of all patients were collected and analyzed.

Results:

During the period of the study, 1695 patients consulted at the Neurology Outpatient Clinic of the HNN, among which 76 patients (4.48%) had secondary parkinsonism and 25 patients (1.47%) had features compatible with PD. Only patients with PD were included in this study. The mean age at onset of symptoms was 58 years (range: 42–74 years). The male sex was predominant (60%) with a sex ratio of 1.5. The mean time interval from the onset of symptoms to diagnosis of PD was 1.8 years (range: 1–5 years). The tremor was the most common symptom (84%). Bradykinesia represented 64% of the symptoms and rigidity 20%. At the time of the diagnosis of PD, 8 patients (32%) were in Stage I of the classification of Hoehn and Yahr, 16 patients (64%) in Stage II, and 1 patient (4%) in Stage III. The levodopa/carbidopa combination was the most used antiparkinsonian drug in our patients (88%). The mean time of follow-up of the patients was 2.5 years (range: 1–4.42 years). During the course of the disease, 9 patients (36%) were in Stage II of the classification of Hoehn and Yahr, 13 patients (52%) in Stage III, and 3 patients (12%) in Stage IV.

Conclusion:

Our study provides demographic and clinical data of PD in patients from Niger and shows that the hospital frequency of this disease is low (1.47%). The demographic and clinical features of our patients are similar to those of the patients of the prior studies reported in sub-Saharan Africa.

Vertebrate food products as a potential source of prion-like α-synuclein

The aberrant aggregation of the protein α-synuclein is thought to be involved in Parkinson’s disease (PD). However, the factors that lead to initiation and propagation of α-synuclein aggregation are not clearly understood. Recently, the hypothesis that α-synuclein aggregation spreads via a prion-like mechanism originating in the gut has gained much scientific attention. If α-synuclein spreads via a prion-like mechanism, then an important question becomes, what are the origins of this prion-like species? Here we review the possibility that α-synuclein aggregation could be seeded via the ingestion of a prion-like α-synuclein species contained within food products originating from vertebrates. To do this, we highlight current evidence for the gut-to-brain hypothesis of PD, and put this in context of available routes of α-synuclein prion infectivity via the gastrointestinal (GI) tract. We then discuss meat as a ready exogenous source of α-synuclein and how certain risk factors, including inflammation, may allow for dietary α-synuclein to pass from the GI lumen into the host to induce pathology. Lastly, we review epidemiological evidence that dietary factors may be involved in PD. Overall, research to date has yet to directly test the contribution of dietary α-synuclein to the mechanism of initiation and progression of the disease. However, numerous experimental findings, including the potent seeding and spreading behavior of α-synuclein fibrils, seem to support, at least in part, the feasibility of an infection with a prion α-synuclein particle via the GI tract. Further studies are required to determine whether dietary α-synuclein contributes to seeding pathology in the gut.

Nutritional habits, risk, and progression of Parkinson disease

Parkinson disease (PD) is a multifactorial disease, where a genetic predisposition combines with putative environmental risk factors. Mounting evidence suggests that the initial PD pathological manifestations may be located in the gut to subsequently affect brain areas. Moreover, several lines of research demonstrated that there are bidirectional connections between the central nervous system and the gut, the "gut-brain axis" that influences both brain and gastrointestinal function. This opens a potential therapeutic window suggesting that specific dietary strategies may interact with the disease process and influence the risk of PD or modify its course. Dietary components can also theoretically modulate the chronic activation of the inflammatory response that is associated with aging, the strongest risk factor for PD, that has been suggested to hasten the underlying neurodegenerative process in PD. Here, we reviewed the evidence supporting an association between certain dietary compound and either the risk or progression of PD and have provided an overview of the possible pathomechanisms linking nutrition and neurodegeneration. The results of our review would not support a clear role for any dietary components in reducing the risk or progression of PD. However, the evidence favouring a connection between gut abnormalities, inflammation, and neurodegeneration in PD have become too compelling to be ignored, so that further research, also in the field of nutritional genomics, is highly warranted.

Associations between Lifestyle Factors and Parkinson's Disease in an Urban Sri Lankan Clinic Study

BACKGROUND

Associations between certain environmental and lifestyle factors and Parkinson's disease (PD) have been reported in several studies, but information on these factors and Parkinson's Disease (PD) in South Asia, is limited.

OBJECTIVE

To determine associations between lifestyle factors and PD in an urban clinic-based study in Sri Lanka.

METHODS

In this case-control study, demographic and lifestyle factor data (including diet, coffee/tea drinking, smoking, alcohol status) was collected from an unselected cohort of PD patients and age and gender-matched controls attending clinics in Greater Colombo, Sri Lanka. Associations between lifestyle factors and PD status were assessed using Logistic Regression analysis, while links with age of PD onset were explored with Kaplan Meier and Cox Regression survival analyses. Results with p<0.05 were considered to be statistically significant.

FINDINGS

Of 229 patients with parkinsonism, 144 had Idiopathic PD using standard diagnostic criteria. Controls numbered 102. Coffee drinkers and smokers were significantly less likely to have PD (coffee, p<0.001; Odds Ratio (OR)=0.264; smoking, p=0.043; OR=0.394). Coffee drinkers were older at PD onset (p<0.001). Similar trends seen with tea drinking were not statistically significant.

CONCLUSIONS

This is the first formal study of PD and these lifestyle factors in South Asia. It demonstrates an inverse association between coffee drinking, smoking and PD, and an association between coffee drinking and later age of PD onset. This is in line with other studies done worldwide, suggesting biological associations with global relevance.

Alcohol Consumption and Parkinson's Disease Risk: A Review of Recent Findings

Background: The association between Parkinson’s disease and lifestyle exposures such as smoking, coffee and alcohol consumption have been the focus of research for several decades, with varying and often conflicting results.

Objective: This paper reviews the key features of observational studies investigating the relationship between alcohol drinking and PD risk, to determine potential sources of variability between the results.

Methods: Relevant literature from 2000–2014 was systematically retrieved using three databases. Primary research articles were included if they reported a measure of association between quantity and frequency of alcohol intake and PD risk, and adjusted at least for the potential confounding factors of smoking and age.

Results: Sixteen articles were identified. The seven case-control studies were more likely to report a weak protective association by level of alcohol consumption compared to the studies with prospective designs. Two studies reported the relationship between heavy (harmful to health) drinking and PD. There was weak evidence that associations varied by type of alcoholic beverage. Smoking may modify the association between alcohol intake and PD risk, however, the evidence does not support the theory that a confounder (such as an addiction-avoiding personality trait) produced the inverse associations between smoking, coffee and alcohol intake and PD risk. Methodological weaknesses of the studies, including selection and recall bias, residual confounding and lack of statistical power may in part account for their differences.

Conclusion: The weak association between alcohol drinking and PD risk was found in studies at greater risk of selection and recall bias.

Association between Parkinson's Disease and Cigarette Smoking, Rural Living, Well-Water Consumption, Farming and Pesticide Use: Systematic Review and Meta-Analysis

Objective

Bradford Hill’s viewpoints were used to conduct a weight-of-the-evidence assessment of the association between Parkinson’s disease (PD) and rural living, farming and pesticide use. The results were compared with an assessment based upon meta-analysis. For comparison, we also evaluated the association between PD and cigarette smoking as a “positive control” because a strong inverse association has been described consistently in the literature.

Methods

PubMed was searched systematically to identify all published epidemiological studies that evaluated associations between Parkinson’s disease (PD) and cigarette smoking, rural living, well-water consumption, farming and the use of pesticides, herbicides, insecticides, fungicides or paraquat. Studies were categorized into two study quality groups (Tier 1 or Tier 2); data were abstracted and a forest plot of relative risks (RRs) was developed for each risk factor. In addition, when available, RRs were tabulated for more highly exposed individuals compared with the unexposed. Summary RRs for each risk factor were calculated by meta-analysis of Tier 1, Tier 2 and all studies combined, with sensitivity analyses stratified by other study characteristics. Indices of between-study heterogeneity and evidence of reporting bias were assessed. Bradford Hill’s viewpoints were used to determine if a causal relationship between PD and each risk factor was supported by the weight of the evidence.

Findings

There was a consistent inverse (negative) association between current cigarette smoking and PD risk. In contrast, associations between PD and rural living, well-water consumption, farming and the use of pesticides, herbicides, insecticides, fungicides or paraquat were less consistent when assessed quantitatively or qualitatively.

Conclusion

The weight of the evidence and meta-analysis support the conclusion that there is a causal relationship between PD risk and cigarette smoking, or some unknown factor correlated with cigarette smoking. There may be risk factors associated with rural living, farming, pesticide use or well-water consumption that are causally related to PD, but the studies to date have not identified such factors. To overcome the limitations of research in this area, future studies will have to better characterize the onset of PD and its relationship to rural living, farming and exposure to pesticides.

Research in Parkinson's disease in India: A review

Parkinson's disease (PD) is a common neurodegenerative disorder affecting patients in large numbers throughout the world. In this article, we review all the published data on PD based on studies in Indian population. We have tried to consolidate the contribution of Indian studies in PD research. We found 95 articles, of which 92 were original research papers. This is a relatively less number, but in the last decade, there has been an increase in research on PD from this country. But most of them seem to be restricted to only a few research institutes. The nonmotor symptoms and genetics are the most commonly studied aspects. The systematic review of the articles reveals that the epidemiology in India may be different with relatively lesser incidence here. Most of the genetic mutations found to cause PD in other population are not found in India, revealing that other genetic factors may be involved. Further research needs to be encouraged to understand the disease in Indian patients better, as all the results cannot be extrapolated from the Western literature to this heterogeneous Indian population. There need to be more studies on therapeutic aspects of the disease.

Neuroprotective effect of fucoidan from Turbinaria decurrens in MPTP intoxicated Parkinsonic mice

Fucoidan is one of the dominant sulfated polysaccharide which was extracted from the brown seaweed Turbinaria decurrens. In the behavioral study mice treated with fucoidan showed better response than the MPTP treated mice. Antioxidants and dopamine level has been increased in the fucoidan treated mice when compared to MPTP induced mice. In Immunohistochemistry, the increase of TH positive cells in the fucoidan treated group is correlated with the TH protein levels in substantia nigra and corpus striatum. The increase is greater than the content of dopamine and DOPAC, which may be explained that the dopaminergic terminals are more sensitive to MPTP toxicity and therefore are more severely damaged than the dopaminergic cell bodies. In immunoblotting TH and DAT was used, both the antibodies expression in MPTP was reduced and reversed in other groups. From the results it was conformed that the fucoidan has a neuroprotective effect without any side effects.

Parkinson's Disease Prevalence and Proximity to Agricultural Cultivated Fields

The risk for developing Parkinson's disease (PD) is a combination of multiple environmental and genetic factors. The Negev (Southern Israel) contains approximately 252.5 km² of agricultural cultivated fields (ACF). We aimed to estimate the prevalence and incidence of PD and to examine possible geographical clustering and associations with agricultural exposures. We screened all “Clalit” Health Services members in the Negev (70% of the population) between the years 2000 and 2012. Individual demographic, clinical, and medication prescription data were available. We used a refined medication tracer algorithm to identify PD patients. We used mixed Poisson models to calculate the smoothed standardized incidence rates (SIRs) for each locality. We identified ACF and calculate the size and distance of the fields from each locality. We identified 3,792 cases of PD. SIRs were higher than expected in Jewish rural localities (median SIR [95% CI]: 1.41 [1.28; 1.53] in 2001–2004, 1.62 [1.48; 1.76] in 2005–2008, and 1.57 [1.44; 1.80] in 2009–2012). Highest SIR was observed in localities located in proximity to large ACF (SIR 1.54, 95% CI 1.32; 1.79). In conclusion, in this population based study we found that PD SIRs were higher than expected in rural localities. Furthermore, it appears that proximity to ACF and the field size contribute to PD risk.

Epidemiology of neurological disorders in India: review of background, prevalence and incidence of epilepsy, stroke, Parkinson's disease and tremors

Growth and development of neuroepidemiology in India during the last four decades has been documented highlighting the historical milestones. The prevalence rates of the spectrum of neurological disorders from different regions of the country ranged from 967-4,070 with a mean of 2394 per 100,000 population, providing a rough estimate of over 30 million people with neurological disorders (excluding neuroinfections and traumatic injuries). Prevalence and incidence rates of common disorders including epilepsy, stroke, Parkinson's disease and tremors determined through population-based surveys show considerable variation across different regions of the country. The need for a standardized screening questionnaire, uniform methodology for case ascertainment and diagnosis is an essential requiste for generating robust national data on neurological disorders. Higher rates of prevalence of neurological disorders in rural areas, 6-8 million people with epilepsy and high case fatality rates of stroke (27-42%) call for urgent strategies to establish outreach neurology services to cater to remote and rural areas, develop National Epilepsy Control Program and establish stroke units at different levels of health care pyramid.

A study on risk factors for Parkinson׳s disease in Indian population

Parkinson׳s disease is the second most common neurodegenerative disorder. The exact cause of selective dopaminergic neurodegeneration is unknown, but it is supposed that etiology of Parkinson׳s disease is multifactorial and consists of an interaction between environmental factors and genetic predisposition. To find out the association between environmental factors and risk of Parkinson׳s disease, a case control study was designed including 97 Parkinson׳s disease patients and 97 controls. Logistic regression analysis was used to determine the risk factors for Parkinson׳s disease. Results from the present study showed that gender, religion, education, place of living, occupation, dietary habits, tobacco chewing, smoking, alcohol intake, and head injury had no association with PD. However, chemical exposure and well water drinking were significantly associated with PD, which concluded that environmental factors could act as a risk factor for PD in some way.

Considerations on the role of environmental toxins in idiopathic Parkinson's disease pathophysiology

Neurodegenerative diseases are characterized by a progressive dysfunction of the nervous system. Often associated with atrophy of the affected central or peripheral nervous structures, they include diseases such as Parkinson’s Disease (PD), Alzheimer’s Disease and other dementias, Genetic Brain Disorders, Amyotrophic Lateral Sclerosis (ALS or Lou Gehrig’s Disease), Huntington’s Disease, Prion Diseases, and others. The prevalence of neurodegenerative diseases has increased over the last years. This has had a major impact both on patients and their families and has exponentially increased the medical bill by hundreds of billions of Euros. Therefore, understanding the role of environmental and genetic factors in the pathogenesis of PD is crucial to develop preventive strategies. While some authors believe that PD is mainly genetic and that the aging of the society is the principal cause for this increase, different studies suggest that PD may be due to an increased exposure to environmental toxins. In this article we review epidemiological, sociological and experimental studies to determine which hypothesis is more plausible. Our conclusion is that, at least in idiopathic PD (iPD), the exposure to toxic environmental substances could play an important role in its aetiology.

Parkinson's disease and pesticide exposure--a new assessment

Parkinson's disease (PD) is an idiopathic disease and its pathological feature is a loss of pigmented neurons in the substantia nigra. Some commonly used pesticides possess neurotoxicity, and exposure to such compounds may trigger mechanisms similar to those in the development of idiopathic PD. We conducted a systematic review of epidemiological studies, aiming at a critical evaluation of the association between the development of PD and pesticide exposure. Reported effect sizes (ES) in the relevant studies were pooled into the meta-analysis to derive summary ES. The summary ES suggested a significantly positive association between PD and overall pesticide use (non-occupational and/or occupational pesticide use) [1.42; 95% confidence interval (CI) 1.32 to 1.52, the fixed-effects model], as well as between PD and occupational pesticide exposure (1.49 with a 95% CI of 1.34-1.66). Both occupational herbicide and occupational insecticide exposure showed a significant association with PD. The results of the meta-analysis reported in this study suggest the existence of a statistically positive association between PD and pesticide exposure. The majority of the studies that were pooled in the meta-analysis were case-control design with very few cohort studies and most with poor exposure characterization thus, any further case-control studies using similar methodologies are unlikely to have a significant impact or understanding on the currently-reported association between pesticide exposure and the development of idiopathic PD. Therefore, we believe that if further epidemiological studies are going to be conducted in the area, they should be prospective cohort studies that will include accurate exposure assessment.

Psychiatric diseases predated the occurrence of Parkinson disease: a retrospective cohort study

PURPOSE

The influence of mental illness early in life on the subsequent risk of Parkinson disease (PD) and its clinical picture remain obscure. This study investigated the effects of psychiatric diseases on a subsequent PD diagnosis.

METHODS

We used the Longitudinal Health Insurance Database 2000 of Taiwan to identify 73,597 patients who visited ambulatory care centers or were hospitalized with a first-time diagnosis of anxiety, affective disorders, or schizophrenia between 2001 and 2003 as the study cohort. We also randomly selected 220,791 enrollees matched with the study cohort for comparison. Each patient was individually tracked for 6 years to identify a subsequent PD diagnosis. Stratified Cox proportional hazard regressions were performed for the analysis.

RESULTS

The incidence rate of PD per 1000 person-years was 4.91 (95% confidence interval [CI], 4.71-5.12) and 1.63 (95% CI, 1.56-1.70) for the psychiatric and comparison groups, respectively. Patients with psychiatric illnesses were more vulnerable to developing PD than nonpsychiatric individuals, exhibiting a 2.38-fold increased risk (95% CI, 2.23-2.53) after other covariates were considered. Furthermore, patients with schizophrenia exhibited the highest risk for developing PD.

CONCLUSIONS

We suggest effective monitoring of patients with psychiatric disturbances for potential long-term neurodegenerative diseases.

The role of α-synuclein in the pathophysiology of alcoholism

Alcoholism has complex etiology and there is evidence for both genetic and environmental factors in its pathophysiology. Chronic, long-term alcohol abuse and alcohol dependence are associated with neuronal loss with the prefrontal cortex being particularly susceptible to neurotoxic damage. This brain region is involved in the development and persistence of alcohol addiction and neurotoxic damage is likely to exacerbate the reinforcing effects of alcohol and may hinder treatment. Understanding the mechanism of alcohol's neurotoxic effects on the brain and the genetic risk factors associated with alcohol abuse are the focus of current research. Because of its well-established role in neurodegenerative and neuropsychological disorders, and its emerging role in the pathophysiology of addiction, here we review the genetic and epigenetic factors involved in regulating α-synuclein expression and its potential role in the pathophysiology of chronic alcohol abuse. Elucidation of the mechanisms of α-synuclein regulation may prove beneficial in understanding the role of this key synaptic protein in disease and its potential for therapeutic modulation in the treatment of substance use disorders as well as other neurodegenerative diseases.

Alcohol and risk of Parkinson's disease in a large, prospective cohort of men and women

Addictive behaviors, such as cigarette smoking and coffee drinking, have been associated with a reduced risk of Parkinson's disease (PD). Whether alcohol consumption is also associated with PD risk is less certain. We prospectively followed 132,403 participants in the Cancer Prevention Study II Nutrition Cohort from 1992 to 2005. Alcohol intake was assessed at baseline. Incident cases of PD (n = 605; 389 male and 216 female) were confirmed by treating physicians and medical record review. Relative risks (RRs) were estimated using proportional hazards models, adjusting for age, smoking, and other risk factors. Alcohol consumption was not significantly associated with PD risk. After adjustment for age, smoking, and other risk factors, the RR comparing men consuming 30 or more grams of alcohol per day (highest category) to nondrinker men was 1.29 (95% confidence interval [CI]: 0.90, 1.86; P trend: 0.40), and the RR comparing women consuming 15 or more grams of alcohol (highest category) per day to nondrinker women was 0.77 (95% CI: 0.41, 1.45; P trend: 0.87). Consumption of beer, wine, or liquor was also not associated with PD risk. The results of this large, prospective study do not support an association between alcohol intake and risk of PD.

Risk factors of dementia in North India: a case-control study

OBJECTIVE

The prevalence of dementia in northern India is among the lowest in the world but reasons are unclear. The aim of the study was to evaluate the risk and protective factors for dementia in North India.

METHODS

In a case-control study, we investigated demographic, medical, genetic, dietary, lifestyle, and sociocultural protective and risk factors associated with dementia.

RESULTS

150 patients of dementia (118 males and 32 females) and 150 healthy controls (112 males and 38 females) were included in the study. Diabetes, depression, hyperhomocysteinemia, hyperlipidemia, APOE ε4 gene, BMI, use of saturated fatty acids, pickles in diet, urban living, and lack of exercise were associated with independent risk of dementia. Various dietary factors and sociocultural factors, like cognitively stimulating activities, active socialization, living in joint families, increased intake of polyunsaturated fats, fruits, and salads conferred protection against dementia.

CONCLUSIONS

Dietary, lifestyle, and sociocultural interventions may be protective against dementia.

Is pesticide use related to Parkinson disease? Some clues to heterogeneity in study results

BACKGROUND

Previous systematic reviews have indicated that pesticide exposure is possibly associated with Parkinson disease (PD). However, considerable heterogeneity has been observed in study results.

OBJECTIVE

We aimed at providing an update of the literature published on PD and exposure to pesticides by performing a systematic review and meta-analysis. In addition, we investigated whether methodological differences between studies could explain the heterogeneity in study results.

METHODS

We identified studies through a systematic literature search. We calculated summary risk ratios (sRRs) for pesticide exposure and subcategories using random effects meta-analyses and investigated sources of heterogeneity by meta-regression and stratified analyses.

RESULTS

Thirty-nine case-control studies, four cohort studies, and three cross-sectional studies were identified. An sRR of 1.62 [95% confidence interval (CI): 1.40, 1.88] for pesticide exposure (ever vs. never) was found. Summary estimates for subclasses of pesticides indicated a positive association with herbicides and insecticides, but not with fungicides. Heterogeneity in individual study results was not related to study design, source of control population, adjustment of results for potential confounders, or geographical area. However, results were suggestive for heterogeneity related to differences in the exposure assessment. Job title-based exposure assignment resulted in a higher sRR (2.5; 95% CI: 1.5, 4.1) than did assignment based on self-reported exposure (e.g., for self-reported ever/never exposure, sRR = 1.5; 95% CI: 1.3, 1.8).

CONCLUSIONS

This review affirms the evidence that exposure to herbicides and insecticides increase the risk of PD. Future studies should focus on more objective and improved methods of pesticide exposure assessment.

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.

Parkinson’s disease in sub-Saharan Africa: step-by-step into the challenge

SUMMARY Nowadays, most developing countries are experiencing a demographic transition characterized by an increase in mean life expectancy, thus the prevalence of age-related disorders such as Parkinson’s disease (PD) are expected to increase accordingly. Previous reports suggest that PD is still largely underdiagnosed and undertreated in low-income areas because of the limited availability of trained staff and medication, as well as inadequate patient follow-up and education. In this article, we performed a step-by-step assessment of the main challenges encountered in the management of patients with PD in developing countries, ranging from diagnostic to therapeutic issues. These issues stem from published literature and, mostly, from our direct experience of PD management in Ghana and Zambia through personal contribution of local physicians who face this challenge in their routine clinical practice.

Epidemiology and etiology of Parkinson's disease: a review of the evidence

The etiology of Parkinson's disease (PD) is not well understood but likely to involve both genetic and environmental factors. Incidence and prevalence estimates vary to a large extent-at least partly due to methodological differences between studies-but are consistently higher in men than in women. Several genes that cause familial as well as sporadic PD have been identified and familial aggregation studies support a genetic component. Despite a vast literature on lifestyle and environmental possible risk or protection factors, consistent findings are few. There is compelling evidence for protective effects of smoking and coffee, but the biologic mechanisms for these possibly causal relations are poorly understood. Uric acid also seems to be associated with lower PD risk. Evidence that one or several pesticides increase PD risk is suggestive but further research is needed to identify specific compounds that may play a causal role. Evidence is limited on the role of metals, other chemicals and magnetic fields. Important methodological limitations include crude classification of exposure, low frequency and intensity of exposure, inadequate sample size, potential for confounding, retrospective study designs and lack of consistent diagnostic criteria for PD. Studies that assessed possible shared etiological components between PD and other diseases show that REM sleep behavior disorder and mental illness increase PD risk and that PD patients have lower cancer risk, but methodological concerns exist. Future epidemiologic studies of PD should be large, include detailed quantifications of exposure, and collect information on environmental exposures as well as genetic polymorphisms.

Environmental and familial risk factors of Parkinsons disease: case-control study

BACKGROUND

While the cause of Parkinson's disease (PD) remains unknown, evidence suggests certain environmental factors, such as well water drinking, herbicides, pesticides exposure and neurotoxins, may trigger the chain of oxidative reactions culminating in the death of dopaminergic neurons in substantia nigra to cause Parkinsonism. To investigate the possible impact of environmental risk factors for idiopathic PD, a case-control study was performed in the Eastern India.

METHODS

During the period from January 1st, 2006 and December 10th, 2009, 175 PD patients (140 men, 35 women) and 350 non-Parkinson age-sex matched controls were included in the study. Subjects were given a structured neurological examination and completed an administered questionnaire which elicited detailed information on demographic data, pesticides, herbicides family history, occupation, dietary and smoking habits.

RESULTS

The multivariate analysis revealed that family history of PD, pesticide exposure, exposure to toxins other than pesticides and herbicides, rural living and previous history of depression were associated with increased risk of PD, whereas, smoking appeared to be a protective factor. Well water drinking for at least five years, though a significant risk factor on univariate analysis (OR = 4.5, 95% CI = 2.1-9.9), could not be proved significant in multivariate analysis. Head trauma, vegetarian dietary habit, occupation involving physical exertion and exposure to domestic pets were not as significant risk factors.

CONCLUSION

Results of our study support the hypothesis of multifactorial etiology of PD with environmental factors acting on a genetically susceptible host.

Familial aggregation of Parkinson's disease in a multiethnic community-based case-control study

To assess the familial aggregation of Parkinson's disease (PD), we compared the cumulative incidence of PD among first-degree relatives of PD cases and controls. We identified newly diagnosed patients with PD (n = 573) during 1994 to 1995 within Kaiser Permanente Medical Care Program of Northern California and recruited 496 cases (87%) for the case-control study. Of 720 eligible controls matched by birth year and sex to cases, 541 (75%) agreed to participate. Information on family history of PD and other neurodegenerative diseases was obtained by in-person structured interview. We used the reconstructed cohort approach that provides a better estimate of the risk. The cumulative incidence of PD was significantly higher among relatives of PD patients compared with relatives of controls (2.0 vs. 0.7%; relative risk (RR) = 3.4, 95% confidence interval (CI) 1.9-5.9; P = 0.0001). The degree of familial aggregation was higher among first-degree relatives of Hispanic PD cases compared with Hispanic controls (3.7% vs. 0.4%; RR = 8.5, 95% CI 1.0-68.9) than it was among non-Hispanic Caucasian cases and controls (2.0% vs. 0.8%; RR = 2.7, 95% CI 1.5-5.1; P = 0.02). The familial aggregation of PD was stronger among the siblings of PD cases (RR = 5.4, 95% CI 1.8-16.0) than among parents (RR = 2.7, 95% CI 1.3-5.2). The incidence and familial aggregation of PD is highest among Hispanics, warranting further studies of genetic and environmental risk factors in the Hispanic population.

Depression and the subsequent risk of Parkinson's disease in the NIH-AARP Diet and Health Study

We conducted a case-control study to examine the association between depression and Parkinson's disease (PD). Participants included 992 PD cases diagnosed after 2,000 and 279,958 individuals without PD from the NIH-AARP Diet and Health Study follow-up survey. Physician-diagnosed depression and PD were self-reported with information on the year of diagnosis in the following categories: before 1985, 1985-1994, 1995-1999, and 2000-present. Only PD cases diagnosed after 2000 were included in the analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived from logistic regression models, adjusted for age, gender, educational level, marital status, smoking, and coffee drinking. Individuals with depression diagnosed after 2000 were more likely to report a concurrent diagnosis of PD than those without depression (OR = 4.7, 95% CI = 3.9, 5.7). Depression diagnosed before 2000 was also associated with higher odds of PD diagnosed after 2000 (OR = 2.0, 95% CI = 1.6, 2.4). This association was stronger for depression diagnosed in 1995-1999 (OR = 2.7, 95% CI = 2.0, 3.6), but was also noted for depression diagnosed in 1985-1994 (OR = 1.6, 95% CI = 1.1, 2.3) or even before 1985 (OR = 1.7, 95% CI = 1.3, 2.3). This association was not modified by other factors and persisted in an analysis excluding participants who reported poor health status. The results suggest that depression may either be a very early symptom of PD or share common etiological factors with PD.

Occurrence of depression and anxiety prior to Parkinson's disease

OBJECTIVE

To assess the relationship between depression and anxiety and Parkinson's disease (PD).

BACKGROUND

Many people with PD suffer from depression and anxiety prior to the onset of motor symptoms. Studies suggest these psychiatric conditions may be risk factors for PD or prodromal non-motor symptoms.

METHODS

Using a population-based approach in three California counties, we recruited 371 incident PD cases, 402 population and 115 sibling controls. We recorded self-reports of lifetime depression/anxiety diagnoses and use of psychotropic medications. We adjusted for age, race, sex, pack-years of smoking, and education, and also conducted analyses after excluding (lagging) both diagnoses and medication use first occurring within 2, 5, 10, and 20 years of the index/diagnosis date.

RESULTS

Cases were more likely to have received a diagnosis of depression or anxiety at any time prior to index date (OR 1.42, 95% CI 1.01, 2.00), but were not more likely to have been both diagnosed and treated (OR 1.11, 95% CI 0.77, 1.60). Male PD patients received diagnoses combined with treatment more often than population controls within 5 years of PD diagnosis (OR 2.21, 95% CI 1.21, 4.04; 2 year lag: OR 2.44, 95% CI 1.29, 4.61; 5 year lag: OR 1.67, 95% CI 0.80, 3.49). We did not see any differences for females. Results for cases compared to sibling controls were similar to those for population controls.

CONCLUSION

These results suggest that depression and anxiety may be early symptoms during the prodromal phase of PD.

Epidemiology of Parkinson disease in the city of Kolkata, India: a community-based study

OBJECTIVE

No well-designed longitudinal study on Parkinson disease (PD) has been conducted in India. Therefore, we planned to determine the prevalence, incidence, and mortality rates of PD in the city of Kolkata, India, on a stratified random sample through a door-to-door survey.

METHOD

This study was undertaken between 2003 to 2007 with a validated questionnaire by a team consisting of 4 trained field workers in 3 stages. Field workers screened the cases, later confirmed by a specialist doctor. In the third stage, a movement disorders specialist undertook home visits and reviewed all surviving cases after 1 year from last screening. Information on death was collected through verbal autopsy. A nested case-control study (1:3) was also undertaken to determine putative risk factors. The rates were age adjusted to the World Standard Population.

RESULT

A total population of 100,802 was screened. The age-adjusted prevalence rate (PR) and average annual incidence rate were 52.85/100,000 and 5.71/100,000 per year, respectively. The slum population showed significantly decreased PR with age compared with the nonslum population. The adjusted average annual mortality rate was 2.89/100,000 per year. The relative risk of death was 8.98. The case-control study showed that tobacco chewing protected and hypertension increased PD occurrence.

CONCLUSION

This study documented lower prevalence and incidence of PD as compared with Caucasian and a few Oriental populations. The mortality rates were comparable. The decreased age-specific PR among slum populations and higher relative risk of death need further probing.

Environmental factors and Parkinson's disease: a case-control study in Belgrade, Serbia

A case-control study was performed in Belgrade in order to investigate the association between Parkinson's disease (PD) and some environmental factors. During the period 2001-2005, 110 new PD cases and 220 hospital controls were interviewed. Cases and controls were matched by sex, age (+/-2 years), and place of residence (urban/rural). According to multivariate conditional logistic regression analysis, PD was positively asssociated with exposure to insecticides (odds ratio (OR) 3.22, 95% confidence interval (95% CI) 1.32-7.87), dyes (OR 25.33; 95% CI, 2.89-222.0), and naphtha and its derivates (OR 9.53; 95% CI, 1.04-86.96), and with gardening (OR 5.51; 95% CI, 3.04-10.01), well water drinking (OR 2.62; 95% CI, 1.40-4.90), and spring water drinking (OR 2.19; 95% CI, 1.15-4.16). Negative association was found for service-sector working (OR 0.15; 95% CI, 0.04-0.59). The results obtained did not changed after adjustment for smoking. The findings of the present study support the role of environmental factors in the occurence of PD.

Familial aggregation of Parkinson's disease: a meta-analysis

We sought to determine the relative risk (RR) of Parkinson's disease (PD) for having a first-degree relative with PD versus having no first-degree relative with PD. Studies of familial aggregation of PD were identified by searching Medline and other sources. From each study, RRs were extracted or calculated based on the published data. Studies were categorized according to methodological characteristics, as well as by first-degree relationship type and age at PD onset restrictions. Meta-analyses and meta-regressions were based on random effect models. Twenty-nine studies of familial aggregation of PD were identified with results for first-degree relatives. The best estimate of the RR of PD for having a first-degree relative with PD was 2.9 (95% CI: 2.2, 3.8; P = 2.2 E-14), based on the studies with the most rigorous methods. The RR for sibling pairs was 4.4 (95% CI: 3.1, 6.1; P < 1.0 E-30), while for child-parent pairs it was 2.7 (95% CI: 2.0, 3.7; P = 3.6 E-10). The RR for early onset PD was 4.7 (95% CI: 3.2, 6.8; P = 6.7 E-16), while for late onset PD it was 2.7 (95% CI: 1.9, 3.9; P = 1.8 E-8). Inclusion of methodologically less rigorous investigations tended to increase the RR estimates. Summary RRs were clearly elevated above one for all study methods, all first-degree relationship types, and all age at onset categories. Familial aggregation of PD is strong and unlikely to be due to chance or to deficiencies in study methodology.

Smoking and tea consumption delay onset of Parkinson's disease

Cigarette smoking, coffee and tea drinking may protect against Parkinson's disease (PD). These factors were assessed, retrospectively, to measure their effect on the age of PD onset. The study population consisted of 278 consecutive PD patients. Smoking > or =10 pack-years delayed age of PD onset by 3.2 years (p<0.05). Consumption of tea more than 3 cups per day delayed age of motor symptoms onset by 7.7 years (p<0.01). Coffee consumption exceeding 3 cups per day advanced the age of PD onset by 4.8 years (p=0.03). Thus, tea consumption and smoking can delay the age of PD onset, while coffee drinking may have the opposite effect.

A systematic review of nutritional risk factors of Parkinson's disease

A wide variety of nutritional exposures have been proposed as possible risk factors for Parkinson's disease (PD) with plausible biological hypotheses. Many studies have explored these hypotheses, but as yet no comprehensive systematic review of the literature has been available. MEDLINE, EMBASE, and WEB OF SCIENCE databases were searched for existing systematic reviews or meta-analyses of nutrition and PD, and one meta-analysis of coffee drinking and one meta-analysis of antioxidants were identified. The databases were searched for primary research articles, and articles without robust methodology were excluded by specified criteria. Seven cohort studies and thirty-three case–control (CC) studies are included in the present systematic review. The majority of studies did not find significant associations between nutritional factors and PD. Coffee drinking and alcohol intake were the only exposures with a relatively large number of studies, and meta-analyses of each supported inverse associations with PD. Factors that were reported by at least one CC study to have significantly increased consumption among cases compared with controls were: vegetables, lutein, xanthophylls, xanthins, carbohydrates, monosaccharides, junk food, refined sugar, lactose, animal fat, total fat, nuts and seeds, tea, Fe, and total energy. Factors consumed significantly less often among cases were: fish, egg, potatoes, bread, alcohol, coffee, tea, niacin, pantothenic acid, folate and pyridoxine. In three cohort studies, two reported borderline decreased relative risks and one a significant increased risk with vitamin C intake. One cohort reported an inverse association between caffeine intake and PD. Three cohorts reported significant positive association in men between dairy products and PD.

Efficacy of catalpol as protectant against oxidative stress and mitochondrial dysfunction on rotenone-induced toxicity in mice brain

Rotenone, a specific inhibitor of mitochondrial complex I, reproduces many features of Parkinson's disease. The aim of the study was carried out to investigate how rotenone affected the mitochondrial function and antioxidant/oxidant parameters of mouse striatum, and secondly, to evaluate the ameliorating effects of catalpol against rotenone-induced damage. Our results showed that rotenone induced significant changes in mitochondrial function such as complex I activity and mitochondrial membrane potential decreased, and enhanced antioxidant status as glutathione depletion, enzymatic (glutathione peroxidase and superoxide dismutase) disorders, and increased lipid peroxidation. Catalpol increased complex I, superoxide dismutase and glutathione peroxidase activities, reduced lipid peroxidation and loss of mitochondrial membrane potential in rotenone-treated mice. These in vivo data indicated that catalpol might have protection against deleterious mouse damage caused by rotenone.