Parkinson's disease in Ferrara, Italy, 1967 through 1987

Temporal trends in the prevalence of Parkinson's disease from 1980 to 2023: a systematic review and meta-analysis

BACKGROUND

Parkinson's disease is the second most common neurodegenerative disorder, exhibiting an upward trend in prevalence. We aimed to investigate the prevalence of Parkinson's disease, temporal trends between 1980 and 2023, and variations in prevalence by location, age, sex, survey period, sociodemographic index (SDI), human development index (HDI), and study characteristics (sample size, diagnostic criteria, and data source).

METHODS

In this systematic review and meta-analysis we searched PubMed, Cochrane, Web of Science, Embase, Scopus, and Global Health for observational studies that reported Parkinson's disease prevalence in the general population from database inception to Nov 1, 2023. We included studies if they were original observational investigations, had participants from the general population or community-based datasets, and provided numerical data on the prevalence of Parkinson's disease either with 95% CIs or with sufficient information to calculate 95% CIs. Studies were excluded if they were conducted in a specific population, had a sample size smaller than 1000, or were review articles, case reports, protocols, meeting abstracts, letters, comments, short communications, posters, and reports. The publication characteristics (first author and publication year), study location (countries, WHO regions, SDI, and HDI), survey period, study design, diagnostic criteria, data source, participant information, and prevalence data were extracted from articles using a standard form. Two authors independently evaluated eligibility, and discrepancies were resolved through discussion with the third author. We used random effect models to pool estimates with 95% CIs. Estimated annual percentage change (EAPC) was calculated to assess the temporal trend in prevalence of Parkinson's disease. The study was registered with PROSPERO, CRD42022364417.

FINDINGS

83 studies from 37 countries were eligible for analysis, with 56 studies providing all-age prevalence, 53 studies reporting age-specific prevalence, and 26 studies providing both all-age and age-specific prevalence. Global pooled prevalence of Parkinson's disease was 1·51 cases per 1000 (95% CI 1·19-1·88), which was higher in males (1·54 cases per 1000 [1·17-1·96]) than in females (1·49 cases per 1000 [1·12-1·92], p=0·030). During different survey periods, the prevalence of Parkinson's disease was 0·90 cases per 1000 (0·48-1·44; 1980-89), 1·38 cases per 1000 (1·17-1·61; 1990-99), 1·18 cases per 1000 (0·77-1·67; 2000-09), and 3·81 cases per 1000 (2·67-5·14; 2010-23). The EAPC of Parkinson's disease prevalence was significantly higher in the period of 2004-23 (EAPC 16·32% [95% CI 6·07-26·58], p=0·0040) than in the period of 1980-2003 (5·30% [0·82-9·79], p=0·022). Statistically significant disparities in prevalence were observed across six WHO regions. Prevalence increased with HDI or SDI. Considerable variations were observed in the pooled prevalence of Parkinson's disease based on different sample sizes or diagnostic criteria. Prevalence also increased with age, reaching 9·34 cases per 1000 (7·26-11·67) among individuals older than 60 years.

INTERPRETATION

The global prevalence of Parkinson's disease has been increasing since the 1980s, with a more pronounced rise in the past two decades. The prevalence of Parkinson's disease is higher in countries with higher HDI or SDI. It is necessary to conduct more high-quality epidemiological studies on Parkinson's disease, especially in low SDI countries.

FUNDING

National Nature Science Foundation of China.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Global prevalence and incidence of Young Onset Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

There is a lack of enough evidence regarding the epidemiology of Young-onset Parkinson's disease (YOPD) which is needed by clinicians and healthcare policymakers.

AIM

Herein, in this systematic review and meta-analysis, we aimed to estimate the global prevalence and incidence rates of YOPD.

METHODS

We searched the literature in PubMed, Scopus, and Web of Science in May 2022. We included retrospective, prospective, cross-sectional observational population-based studies that reported the prevalence or incidence of PD in individuals younger than 40 years with known diagnostic criteria.

RESULTS

After two-step screening, 50 studies were eligible to be included in our study. The age-standardized prevalence of YOPD was 10.2 per 100,000 persons globally while it was 14.7 per 100,000 population in European countries. Age-standardized prevalence estimates for 5-year age bands showed that the YOPD prevalence estimates varied from 6.1 per 100,000 population in the group aged 20-24 to 16.1 per 100,000 population in the group aged 35-39. Also, the age-standardized incidence of YOPD was 1.3 per 100,000 person-years population worldwide and 1.2 per 100,000 person-years in the European population.

CONCLUSION

Based on this systematic review and meta-analysis, the overall prevalence of YOPD is 10.2 per 100,000 population, although estimates of the prevalence and incidence in low-income countries remain scarce. To improve monitoring and certain diagnoses of YOPD, healthcare providers and policymakers should be aware that much more effective tools are required.

Age at onset as stratifier in idiopathic Parkinson’s disease – effect of ageing and polygenic risk score on clinical phenotypes

Several phenotypic differences observed in Parkinson’s disease (PD) patients have been linked to age at onset (AAO). We endeavoured to find out whether these differences are due to the ageing process itself by using a combined dataset of idiopathic PD (n = 430) and healthy controls (HC; n = 556) excluding carriers of known PD-linked genetic mutations in both groups. We found several significant effects of AAO on motor and non-motor symptoms in PD, but when comparing the effects of age on these symptoms with HC (using age at assessment, AAA), only positive associations of AAA with burden of motor symptoms and cognitive impairment were significantly different between PD vs HC. Furthermore, we explored a potential effect of polygenic risk score (PRS) on clinical phenotype and identified a significant inverse correlation of AAO and PRS in PD. No significant association between PRS and severity of clinical symptoms was found. We conclude that the observed non-motor phenotypic differences in PD based on AAO are largely driven by the ageing process itself and not by a specific profile of neurodegeneration linked to AAO in the idiopathic PD patients.

Prevalence of Parkinson Disease in Italy: a systematic review and meta-analysis

Introduction:

Parkinson’s disease (PD) is a common disease of unknown etiology. Even though accurate information on the epidemiology of PD is critical for defining appropriate health policies, epidemiological data on Parkinson’s disease (PD) in Italy are often defined as scant or conflicting. Our study attempted to provide an overview on the prevalence of (PD) by means of a systematic review and metanalysis of existing data.

Material and methods:

We searched into two different databases (PubMed and EMBASE), focusing on studies reporting the prevalence of PD in Italy. Data were extracted using a standardized assessment form, and results of such analyses were systematically reported, summarized and compared.

Results:

A total of 16 studies were eventually included in the analyses, with a prevalence rate of 193.7/100,000. Available reports were heterogeneous both in design and in eventual figures, and also prevalence estimates were affected by substantial heterogeneity. Interestingly, prevalence rates ranged from 37.8/100,000 inhabitants in subjects aged 0 to 64 years, to 578.7 in age group 65 to 75 years, and 1235.7 in age group 75 years or older. PD was significantly associated with male sex, but only in older age groups (i.e. Odds Ratio, OR 1.37 95%CI 1.22-1.53, and OR 1.31, 95%CI 1.21-1.42 for age groups 65-74 years and 75 years or more, respectively).

Discussion and conclusion:

While the observed variations in prevalence rates may result from environmental or genetic factors, differences in methodologies for case ascertainment and diagnostic criteria may have significantly affected our estimates. As a consequence, the comparability of existing studies is limited.

Prevalence, Duration and Severity of Parkinson's Disease in Germany: A Combined Meta-Analysis from Literature Data and Outpatient Samples

BACKGROUND

Epidemiological data on the prevalence of Parkinson's disease (PD) in Germany are limited. The aims of this study were to estimate the age- and gender-specific prevalence of PD in Germany as well as the severity and illness duration.

SUMMARY

A systematic literature search was performed in 5 different databases. European studies were included if they reported age- and gender-specific numbers of prevalence rates of PD. Meta-analytic approaches were applied to derive age- and gender-specific pooled prevalence estimates. Data of 4 German outpatient samples were incorporated to calculate the proportion of patients with PD in Germany grouped by Hoehn and Yahr (HY) stages and disease duration. In the German population, 178,169 cases of PD were estimated (prevalence: 217.22/100,000). The estimated relative illness duration was 40% with less than 5 years, 31% with 5-9 years, and 29% with more than 9 years. The proportions for different HY stages were estimated at 13% (I), 30% (II), 35% (III), 17% (IV), and 4% (V), respectively. Key Message: We provide an up-to-date estimation of age- and gender-specific as well as severity-based prevalence figures for PD in Germany. Further community studies are needed to estimate population-based severity distributions and distributions of non-motor symptoms in PD.

Drivers: A Biologically Contextualized, Cross-Inferential View of the Epidemiology of Neurodegenerative Disorders

Background:

Sutherland et al. (2011) suggested that, instead of risk factors for single neurodegenerative disorders (NDDs), there was a need to identify specific “drivers”, i.e., risk factors with impact on specific deposits, such as amyloid-β, tau, or α-synuclein, acting across entities.

Objectives and Methods:

Redefining drivers as “neither protein/gene- nor entity-specific features identifiable in the clinical and general epidemiology of conformational NDDs (CNDDs) as potential footprints of templating/spread/transfer mechanisms”, we conducted an analysis of the epidemiology of ten CNDDs, searching for patterns.

Results:

We identified seven potential drivers, each of which was shared by at least two CNDDs: 1) an age-at-exposure-related susceptibility to Creutzfeldt-Jakob disease (CJD) and several late-life CNDDs; 2) a relationship between age at onset, survival, and incidence; 3) shared genetic risk factors for CJD and late-life CNNDs; 4) partly shared personal (diagnostic, educational, behavioral, and social risk factors) predating clinical onset of late-life CNDDs; 5) two environmental risk factors, namely, surgery for sporadic CJD and amyotrophic lateral sclerosis, and Bordetella pertussis infection for Parkinson’s disease; 6) reticulo-endothelial system stressors or general drivers (andropause or premenopausal estrogen deficiency, APOEɛ4, and vascular risk factors) for late-life CNDDs such as dementia/Alzheimer’s disease, type-2 diabetes mellitus, and some sporadic cardiac and vascular degenerative diseases; and 7) a high, invariant incidence ratio of sporadic to genetic forms of mid- and late-life CNDDs, and type-2 diabetes mellitus.

Conclusion:

There might be a systematic epidemiologic pattern induced by specific proteins (PrP, TDP-43, SOD1, α-synuclein, amyloid-β, tau, Langerhans islet peptide, and transthyretin) or established combinations of these.

Etiologic Framework for the Study of Neurodegenerative Disorders as Well as Vascular and Metabolic Comorbidities on the Grounds of Shared Epidemiologic and Biologic Features

Background: During the last two decades, protein aggregation at all organismal levels, from viruses to humans, has emerged from a neglected area of protein science to become a central issue in biology and biomedicine. This article constitutes a risk-based review aimed at supporting an etiologic scenario of selected, sporadic, protein-associated, i.e., conformational, neurodegenerative disorders (NDDs), and their vascular- and metabolic-associated ailments.

Methods: A rationale is adopted, to incorporate selected clinical data and results from animal-model research, complementing epidemiologic evidences reported in two prior articles.

Findings: Theory is formulated assuming an underlying conformational transmission mechanism, mediated either by horizontal transfer of mammalian genes coding for specific aggregation-prone proteins, or by xeno-templating between bacterial and host proteins. We build a few population-based and experimentally-testable hypotheses focusing on: (1) non-disposable surgical instruments for sporadic Creutzfeldt-Jakob disease (sCJD) and other rapid progressive neurodegenerative dementia (sRPNDd), multiple system atrophy (MSA), and motor neuron disease (MND); and (2) specific bacterial infections such as B. pertussis and E. coli for all forms, but particularly for late-life sporadic conformational, NDDs, type 2 diabetes mellitus (T2DM), and atherosclerosis where natural protein fibrils present in such organisms as a result of adaptation to the human host induce prion-like mechanisms.

Conclusion: Implications for cohort alignment and experimental animal research are discussed and research lines proposed.

Parkinson's Disease Case Ascertainment in the EPIC Cohort: The NeuroEPIC4PD Study

BACKGROUND/AIMS

Large epidemiological prospective studies represent an important opportunity for investigating risk factors for rare diseases such as Parkinson's disease (PD). Here we describe the procedures we used for ascertaining PD cases in the EPIC (European Prospective Investigation into Cancer and Nutrition) study.

METHODS

The following three-phase procedure was used: (1) elaboration of a NeuroEPIC4PD template for clinical data collection, (2) identification of all potential PD cases via record linkage and (3) validation of the diagnosis through clinical record revision, in a population of 220,494 subjects recruited in 7 European countries. All cases were labelled with the NeuroEPIC4PD diagnoses of 'definite', 'very likely', 'probable', or 'possible' PD.

RESULTS

A total of 881 PD cases were identified, with over 2,741,780 person-years of follow-up (199 definite, 275 very likely, 146 probable, and 261 possible). Of these, 734 were incident cases. The mean age at diagnosis was 67.9 years (SD 9.2) and 458 patients (52.0%) were men. Bradykinesia was the most frequent presenting motor sign (76.5%). Tremor-dominant and akinetic rigid forms of PD were the most common types of PD. A total of 289 patients (32.8%) were dead at the time of the last follow-up.

CONCLUSIONS

This exercise proved that it is feasible to ascertain PD in large population-based cohort studies and offers a potential framework to be replicated in similar studies.

Comparative Incidence of Conformational, Neurodegenerative Disorders

Background

The purpose of this study was to identify incidence and survival patterns in conformational neurodegenerative disorders (CNDDs).

Methods

We identified 2563 reports on the incidence of eight conditions representing sporadic, acquired and genetic, protein-associated, i.e., conformational, NDD groups and age-related macular degeneration (AMD). We selected 245 papers for full-text examination and application of quality criteria. Additionally, data-collection was completed with detailed information from British, Swedish, and Spanish registries on Creutzfeldt-Jakob disease (CJD) forms, amyotrophic lateral sclerosis (ALS), and sporadic rapidly progressing neurodegenerative dementia (sRPNDd). For each condition, age-specific incidence curves, age-adjusted figures, and reported or calculated median survival were plotted and examined.

Findings

Based on 51 valid reported and seven new incidence data sets, nine out of eleven conditions shared specific features. Age-adjusted incidence per million person-years increased from ≤1.5 for sRPNDd, different CJD forms and Huntington's disease (HD), to 1589 and 2589 for AMD and Alzheimer's disease (AD) respectively. Age-specific profiles varied from (a) symmetrical, inverted V-shaped curves for low incidences to (b) those increasing with age for late-life sporadic CNDDs and for sRPNDd, with (c) a suggested, intermediate, non-symmetrical inverted V-shape for fronto-temporal dementia and Parkinson's disease. Frequently, peak age-specific incidences from 20–24 to ≥90 years increased with age at onset and survival. Distinct patterns were seen: for HD, with a low incidence, levelling off at middle age, and long median survival, 20 years; and for sRPNDd which displayed the lowest incidence, increasing with age, and a short median disease duration.

Interpretation

These results call for a unified population view of NDDs, with an age-at-onset-related pattern for acquired and sporadic CNDDs. The pattern linking age at onset to incidence magnitude and survival might be explained by differential pathophysiological mechanisms associated with specific misfolded protein deposits.

Gender-related protection from or vulnerability to severe CNS diseases: gonado-structural and/or gonado-activational? A meta-analysis of relevant epidemiological studies

BACKGROUND

A vast scientific literature has dealt with gender-specific risk for brain disorder. That field is evolving toward a consensus to the effect that the estrogen hormone family is outstandingly and uniquely neuroprotective. However, the epidemiology relevant to this general outlook remains piecemeal.

METHOD

The present investigation strategically formats the relevant epidemiological findings around the world in order to quantitatively meta-analyze gender ratio of risk for a variety of relevant severe central nervous system (CNS) diseases at all three gonadal stages of the life cycle, pre pubertal, post adolescent/pre menopausal, and post menopausal.

RESULTS

The data quantitatively establish that (1) no single epidemiological study should be cited as evidence of gender-specific neuroprotection against the most common severe CNS diseases because the gender-specific risk ratios are contradictory from one study to the other; (2) risk for severe CNS disease is indeed significantly gender-specific, but either gender can be protected: it depends on the disease, not at all on the age bracket.

CONCLUSION

Our assay of gender-specific risk for severe brain disease around the world has not been able to support the idea according to which any one gender-prevalent gonadal steroid hormone dominates as a neuroprotective agent at natural concentrations.

Age-, gender-, and socioeconomic status-specific incidence of Parkinson's disease and parkinsonism in northeast Scotland: the PINE study

There have been few high quality incidence studies of Parkinson's disease (PD). We measured age-, gender- and socioeconomic-specific incidence rates for parkinsonism and PD in north-east Scotland, and compared our results with those of previous high quality studies. Incident patients were identified prospectively over three years by several overlapping methods from primary care practices (total population 311,357). Parkinsonism was diagnosed if patients had two or more cardinal motor signs. Drug-induced parkinsonism was excluded. Patients had yearly follow-up to improve diagnostic accuracy. Incidence rates using clinical diagnosis at latest follow-up were calculated for all parkinsonism and for PD by age, gender and socioeconomic status. Meta-analysis with similar studies was performed. Of 377 patients identified at baseline with possible or probable parkinsonism, 363 were confirmed as incident patients after median follow-up of 26 months (mean age 74.8 years, SD 9.8; 61% men). The crude annual incidence of parkinsonism was 28.7 per 100,000 (95% confidence interval (CI) 25.7-31.8) and PD 17.9 per 100,000 (95% CI 15.5-20.4). PD was more common in men (age-adjusted male to female ratio 1.87:1, 95% CI 1.55-2.23) but there was no difference by socioeconomic status. Meta-analysis of 12 studies showed an incidence of PD (adjusted to the 1990 Scottish population) of 14.6 per 100,000 (95% CI 12.2-17.3) with considerable heterogeneity (I(2) 95%), partially explained by population size and recruitment duration. The incidence of PD was similar to other high quality studies. The incidence of PD was not affected by socioeconomic status.

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.

Male/Female differences in neuroprotection and neuromodulation of brain dopamine

The existence of a sex difference in Parkinson's disease (PD) is observed as related to several variables, including susceptibility of the disease, age at onset, and symptoms. These differences between men and women represent a significant characteristic of PD, which suggest that estrogens may exert beneficial effects against the development and the progression of the disease. This paper reviews the neuroprotective and neuromodulator effects of 17β-estradiol and progesterone as compared to androgens in the nigrostriatal dopaminergic (NSDA) system of both female and male rodents. The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mice model of PD and methamphetamine toxicity faithfully reproduce the sex differences of PD in that endogenous estrogen levels appear to influence the vulnerability to toxins targeting the NSDA system. Exogenous 17β-estradiol and/or progesterone treatments show neuroprotective properties against NSDA toxins while androgens fail to induce any beneficial effect. Sex steroid treatments show male and female differences in their neuroprotective action against methamphetamine toxicity. NSDA structure and function, as well as the distribution of estrogen receptors, show sex differences and may influence the susceptibility to the toxins and the response to sex steroids. Genomic and non-genomic actions of 17β-estradiol converge to promote survival factors and the presence of both estrogen receptors α and β are critical to 17β-estradiol neuroprotective action against MPTP toxicity.

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.

Systematic review of the prevalence and incidence of Parkinson's disease in Asia

BACKGROUND

Parkinson's disease (PD) is a common neurodegenerative disorder in older people, and half of the world's older population lives in Asia. However, the epidemiology of PD in Asian countries is poorly understood. This review assembles evidence on the prevalence and incidence of PD in Asian countries and identifies gaps in our present knowledge.

METHODS

A systematic search of studies published from 1965 to October 2008 was conducted using MEDLINE and EMBASE. The selection criteria were defined a priori. Prevalence and incidence were standardized to the WHO World Standard Population 2000. Twenty-one original studies were selected for the review. Two studies that described the ethnic origin of participants and contained Asian populations were also included in the analysis.

RESULTS

Excluding one study with questionably low prevalence and incidence, the remaining studies reported a standardized all-age prevalence of 51.3 to 176.9 per 100,000 in door-to-door surveys; prevalence in record-based studies ranged from 35.8 to 68.3 per 100,000. The standardized incidence rates were 8.7 per 100,000 person-years in door-to-door surveys and 6.7 to 8.3 per 100,000 person-years in record-based surveys.

CONCLUSIONS

The prevalence of PD in Asian countries was slightly lower than that in Western countries. However, comparison of incidence was difficult because of the small number of studies. Varying methodologies, diagnostic criteria, and case-finding strategies contributed to the considerable variation in the reported prevalence and incidence of PD.

Incidence and remaining lifetime risk of Parkinson disease in advanced age

OBJECTIVE

To estimate the incidence and lifetime risk (LTR) of Parkinson disease (PD) in a large cohort of men.

BACKGROUND

Age is the strongest risk factor for PD, but whether its incidence continues to increase after age 80 years remains unclear.

METHODS

Prospective cohort of 21,970 US male physicians aged 40-84 years at baseline who did not report PD before study entry. Participants self-reported PD on yearly follow-up questionnaires, and all deaths were confirmed. We calculated incidence rates and cumulative incidence using a modified Kaplan-Meier analysis. LTR was estimated by adjusting cumulative incidence for competing risks of death.

RESULTS

Five hundred sixty-three cases of PD were identified over 23 years of follow-up. The crude incidence rate of PD was 121 cases/100,000 person-years. Age-specific incidence rates increased sharply beginning at age 60 years, peaked in those aged 85-89 years, and declined beginning at age 90 years. Cumulative incidence substantially overestimated the long-term risk of PD, particularly in those aged 80 years and older. Cumulative incidence was 9.9% (95% confidence interval [CI] 8.48%-11.30%) from ages 45 to 100 years, whereas LTR for the same period was 6.7% (95% CI 6.01%-7.43%). The incidence and LTR of PD decreased with increasing exposure to smoking.

CONCLUSIONS

Our study provides evidence that the incidence of Parkinson disease (PD) in men increases through age 89 years. Whether the subsequent decline represents a true decrease in risk remains to be established. A history of smoking substantially decreased the incidence and lifetime risk of PD. Incidence studies that do not adjust for competing risks of death may overestimate the true risk of PD in the elderly.

Circuit-based framework for understanding neurotransmitter and risk gene interactions in schizophrenia

Many risk genes interact synergistically to produce schizophrenia and many neurotransmitter interactions have been implicated. We have developed a circuit-based framework for understanding gene and neurotransmitter interactions. NMDAR hypofunction has been implicated in schizophrenia because NMDAR antagonists reproduce symptoms of the disease. One action of antagonists is to reduce the excitation of fast-spiking interneurons, resulting in disinhibition of pyramidal cells. Overactive pyramidal cells, notably those in the hippocampus, can drive a hyperdopaminergic state that produces psychosis. Additional aspects of interneuron function can be understood in this framework, as follows. (i) In animal models, NMDAR antagonists reduce parvalbumin and GAD67, as found in schizophrenia. These changes produce further disinhibition and can be viewed as the aberrant response of a homeostatic system having a faulty activity sensor (the NMDAR). (ii) Disinhibition decreases the power of gamma oscillation and might thereby produce negative and cognitive symptoms. (iii) Nicotine enhances the output of interneurons, and might thereby contribute to its therapeutic effect in schizophrenia.

Epidemiology of Parkinson's disease

This chapter discusses the epidemiology of Parkinson's disease (PD). Classically, PD refers to progressive parkinsonism caused by loss of pigmented aminergic brainstem neurons without an identifiable cause, while parkinsonism refers simply to the syndrome of bradykinesia, resting tremor, rigidity and postural reflex impairment. Over nearly two centuries, Parkinson's clinical description has provided the framework for clinical investigations, including epidemiologic ones. Descriptions of PD were limited to selected clinical settings until the middle of the 20th century. Since then, epidemiologic approaches have been used not only to investigate the population distribution of PD, but also as a way to glean clues as to the cause of this “idiopathic” disorder. Because PD is relatively infrequent, a large base population must be surveyed to identify sufficient numbers of cases for a study. In some instances, PD cases can be identified through health service rosters within defined geographic areas or in enumerated populations. In others, cases of PD are sought independently of the health care system, such as through door-to-door surveys. While the latter approach is theoretically least likely to exclude cases, the time and cost involved are also greatest using this approach.

Is electric arc welding linked to manganism or Parkinson's disease?

Manganese and its inorganic compounds are widely used in many industries and have been accepted as occupational neurotoxins that have caused a distinct and disabling clinical entity, manganism, in several types of work, notably where exposure is by way of dust. There is inconclusive and inconsistent evidence that, in these occupations, subclinical neurological effects, detectable only by neurobehavioural studies, may be caused by low doses. This has prompted a re-evaluation of occupational exposure limits. Some countries, including the UK, already demand much higher levels of protection against exposure than 5 years ago. Welding is the most common source of occupational exposure as manganese is an essential component of steel and so its compounds are inevitable components of fume emitted from steel welding processes. There it is found in respirable particles, often as complex oxides (spinels), sometimes within a core protected by a silicon oxide shell - as distinct from the much simpler form of particle formed by disintegration in processes such as mining and ore milling where manganism has been diagnosed convincingly. Millions of workers are at risk of exposure to manganese-containing compounds in fumes from electric arc welding of steel. In recent years it has been asserted that neurological and neurobehavioural disorders may develop consequent to exposure to steel welding fumes and that employment as a welder is associated with the unusually early onset of Parkinson's disease. Causal relationships have been postulated. Welders have been recorded as having been exposed to high levels of manganese-containing fume, especially where they have worked in confined, unventilated spaces, although this appears from limited data to be the exception rather than the rule. Even then the dose received is generally less than in mining or ore crushing. When care is taken to exclude exposures from hardfacing and burning and cutting arc processes, where manganese may form a high percentage of the fume, manganese compounds usually form a relatively low percentage of the composition of welding fume particles, <2.0%, much outweighed by iron. Although these manganese-compound-containing welding fume particles are insoluble in water, the manganese compounds in particles that are retained in the alveoli may be absorbed, at least in part. Manganese concentrations in biological material samples in some exposed groups reflect this relative to unexposed workers. Some of the transfer systems for absorption and transport, including across the blood-brain barrier, are used in competition with iron which is present in abundance in welding fume. This may reduce absorption of manganese in welders and thus reduce the opportunity for sufficient doses to cause neurotoxicological consequences. Scrutiny of the literature covering the last 40 years has revealed only five cases that meet sufficient criteria for manganism to just cross the diagnostic threshold, and even then they carry a degree of doubt with them. This low incidence alone gives notice that welders have not been and are not at high risk of clinically apparent damage from exposure to manganese. If this needs to be further emphasised, there is the fact that the literature contains no confirmed cases of manganism in welders. Assertions of abnormal results in neurobehavioural studies of welders have raised the possibility of there being a subclinical form of manganism with loss of fine motor control as one of its features. While observations of such changes in workers in other industries have caused regulators in some countries to apply more stringent controls of exposure, as yet the results lack convincing consistency and there is no indication of any dose-effect relationship. If welding fume can have these motor effects it would be a heavy and perhaps career-ending blow to those affected. It would not be prudent to dismiss the warnings sounded by the results of studies of welders, no matter how flawed these investigations are, but wiser and better to act with vigour to reduce exposure and monitor the effectiveness of this additional protection whilst conducting high quality research to allow sound conclusions to be drawn as to whether there actually is a subclinical disorder. Idiopathic Parkinson's disease is a common disorder affecting 1-2% of those in the general population aged >65 years. It has been suggested, on flawed and contested evidence, not that welding causes the disease but rather that employment as a welder carries with it the risk of developing this disease at a younger age than if that trade had not been followed. Manganese in welding fume has been nominated as the neurotoxin. This may be biologically feasible if manganese destroys insufficient receptor cells to produce clinical manganism but sufficient to enhance the effects of a reduced supply of dopamine to give the manifestations of already developing idiopathic Parkinson's disease earlier in the course of destruction of the substantia nigra than if all receptors were intact.

The frequency and validity of self-reported diagnosis of Parkinson's Disease in the UK elderly: MRC CFAS cohort

BACKGROUND

Estimates of the incidence and prevalence of chronic diseases can be made using established cohort studies but these estimates may have lower reliability if based purely on self-reported diagnosis.

METHODS

The MRC Cognitive Function & Ageing Study (MRC CFAS) has collected longitudinal data from a population-based random sample of 13004 individuals over the age of 65 years from 5 centres within the UK. Participants were asked at baseline and after a two-year follow-up whether they had received a diagnosis of Parkinson's disease. Our aim was to make estimates of the incidence and prevalence of PD using self-reporting, and then investigate the validity of self-reported diagnosis using other data sources where available, namely death certification and neuropathological examination.

RESULTS

The self-reported prevalence of Parkinson's disease (PD) amongst these individuals increases with age from 0.7% (95%CI 0.5-0.9) for 65-75, 1.4% (95%CI 1.0-1.7) for 75-85, and 1.6% (95%CI 1.0-2.3) for 85+ age groups respectively. The overall incidence of self reported PD in this cohort was 200/100,000 per year (95%CI 144-278). Only 40% of the deceased individuals reporting prevalent PD and 35% of those reporting incident PD had diagnoses of PD recorded on their death certificates. Neuropathological examination of individuals reporting PD also showed typical PD changes in only 40%, with the remainder showing basal ganglia pathologies causing parkinsonism rather than true PD pathology.

CONCLUSION

Self-reporting of PD status may be used as a screening tool to identify patients for epidemiological study, but inevitably identifies a heterogeneous group of movement disorders patients. Within this group, age, male sex, a family history of PD and reduced cigarette smoking appear to act as independent risk factors for self-reported PD.

Prevalence and incidence of Parkinson's disease in Europe

OBJECTIVE

To provide an overview on the prevalence and incidence of Parkinson's disease (PD) in selected European countries.

BACKGROUND

PD is a common disease of unknown etiology. Accurate information on the epidemiology of PD is critical to inform health policy. An aging population will lead to more patients with PD; thus, the high financial burden PD places on society will increase.

MATERIAL AND METHODS

A systematic literature search was performed to identify studies on the prevalence and incidence of PD in the following European countries: Austria, the Czech Republic, France, Germany, Italy, The Netherlands, Portugal, Spain, Sweden and United Kingdom. Only published studies were included. Abstracts, reviews, meta-analyses and letters to the editor were excluded. There were no language restrictions. Data were extracted using a standardized assessment form, and evidence tables were used to systematically report and compare the data.

RESULTS

Of 39 identified studies, most (87%) reported estimates of PD prevalence rates, while only a few (13%) reported estimates of PD annual incidence rates. Crude prevalence rate estimates ranged from 65.6 per 100,000 to 12,500 per 100,000 and annual incidence estimates ranged from 5 per 100,000 to 346 per 100,000. No publications could be identified for Austria or the Czech Republic.

DISCUSSION AND CONCLUSION

The observed variations in prevalence and incidence rates may result from environmental or genetic factors, but might also be a consequence of differences in methodologies for case ascertainment, diagnostic criteria, or age distributions of the study populations. The comparability of existing studies is limited.

Prevalence of Parkinson's disease in the L'Aquila district, central Italy

OBJECTIVE

We estimated the prevalence of Parkinson's disease (PD) in the L'Aquila district.

METHODS

Cases of PD were identified screening all available case sources including general practitioners and antiparkinsonian drug-users by means of pharmacy records. Prevalence of PD was computed considering the prevalence day of December 31, 2001.

RESULTS

On the prevalence day, 682 patients with PD were alive and residing in the L'Aquila district. A total of 354 patients were women and 328 men. The overall crude prevalence rate was 229.3/100,000 (95% CI 212.7-247.1), without any difference between men (227.4/100,000; 95% CI 200.0-257.5) and women (231.1/100,000; 95% CI 202.2-263.1). Prevalence rates increased with age in both sexes and were higher in urban (244.5/100,000; 95% CI 213.7-278.5) than in rural residents (214.7/100,000; 95% CI 189.0-242.9) (SRR = 1.7; 95% CI 1.3-2.1).

CONCLUSIONS

The prevalence of PD in the L'Aquila district was within the range of prevalence rates found in our country and steeply increased with advancing age in both sexes.

Burden of disease related to Parkinson's disease in Spain in the year 2000

We measured the burden caused by Parkinson's disease (PD) in Spain during the year 2000 and compared it against PD burden worldwide and in the European A subregion. Burden of disease (BoD) is an important factor in health policy. Disability-adjusted life years (DALY) as a measure of BoD is the result of adding years of life lost (YLL) and years lived with disability (YLD). The burden of PD (BPD) has not been studied in Spain. YLL were obtained from the Spanish death certificates and YLD from the estimated number of incident PD cases and the average PD duration. PD disability was calculated, using the Disability Weights for Diseases in the Netherlands. Prior PD DALY data for Europe and the world were obtained from the 2001 World Health Organization World Health Report. A discount rate of 3% and age-weighting modulation factor with K = 1 were used. In Spain, PD generated 67,582 DALY, comprising 6,351 (9.4%) YLL and 61,231 (90.6%) YLD. Most PD DALY (57.5%) occurred in the population 60 to 74 years of age. When PD DALY estimates were adjusted using the world population in 2000, Spain registered a PD DALY rate of 84 per 100,000 population, higher than both the world and European A subregion rates (24 and 35 per 100,000 population, respectively). PD burden in Spain in 2000 was high, with disability being the major contributing factor. Although BPD in Spain was greater than both world and European A subregion BPD, these differences should nevertheless be interpreted with caution.

Environmental factors and Parkinson's disease: a case–control study in the Tuscany region of Italy

To date the aetiology of Parkinson's disease (PD) is unknown although both genetic susceptibility and environmental factors appear to play an important role in the development of the disease. Recent data have also indicated that chronic exposure to a common pesticide can reproduce the neurochemical, behavioral and neuropathological features of PD. The epidemiological studies previously carried on the prevalence of PD in population exposed to environmental factors have produced controversial results, probably because of different trial design and different analysis methods. A case-control retrospective study was conducted in a well-defined geographic area in Tuscany-Italy with the aim to identify environmental factors possibly related to PD. No significant difference between PD patients and control subjects was observed in time spent in rural or industrial residence, in well water drinking and in the exposure to herbicides and pesticides. A significant difference between patients with PD and controls was reported for cigarette smoking, controls resulting more likely cigarette smokers in comparison with PD patients. The present findings support the view of a protective effect of cigarette smoking and do not show any significant association between environmental factors and the risk of development of PD.

The cognitive ability of an incident cohort of Parkinson's patients in the UK. The CamPaIGN study

We have used multiple sources to identify a population-representative cohort of newly diagnosed patients with parkinsonism and Parkinson's disease in the UK over a 2-year period. All patients have been invited to participate in a detailed clinical assessment either at home or in an outpatient clinic. These assessments have been used to refine clinical diagnoses of parkinsonism using established criteria, and describe some of the phenotypic variability of Parkinson's disease at the time of diagnosis. The crude incidence of Parkinson's disease was 13.6/10(5yr-1) [confidence interval (CI) 11.8-15.6 and of parkinsonism was 20.9/10(5yr-1) (CI 18.7-23.3). Age-standardized to the 1991 European population, the incidence figures become 10.8/10(5yr-1) (CI 9.4-12.4) for Parkinson's disease and 16.6/10(5yr-1) (CI 14.8-18.6) for parkinsonism. Thirty-six per cent of the Parkinson's disease patients had evidence of cognitive impairment based on their performance in the Mini-Mental State Examination, a pattern recognition task, and the Tower of London task. The pattern of cognitive deficits seen among these patients using these and further cognitive tasks suggests that sub-groups of patients based on cognitive ability might be identifiable even in the early stages of disease, which may reflect regional differences in the underlying neuropathological processes.

Current status of Parkinson's disease treatment in Korea

The health insurance system in Korea has been under governmental control, and has covered whole population since 1989. About 97% of Korean people have benefits from this system, while 3% are covered by a Medical Aid system for poor people. According to the statistical yearbook of Health Insurance Review in Korea, the number of claims under Parkinson's Disease, in whole country increased steeply from 44619 in 1995 to 96229 in 2000. If each patient were to take medication for the full duration of their insurance coverage, the average number of visits per year would be 11 in 2000. Thus the number of PD patients calculated using these statistics is about 8600. The prevalence is 19/100000, which is much lower than that in Japan. Considering the significant increase in the number of claims in last few years, however, there are still many PD patients who do not receive an accurate diagnosis and appropriate treatment. The other factor influencing these statistics is the fact that patients were able to buy their medications in drug stores without prescription, i.e. without visiting a hospital (since 2001 this has no longer been allowed). Almost all PD medications are available in Korea. There are several forms of levodopa drugs. Dopamine agonists include bromocriptine, pergolide, dihydroergocriptine, ropinirol, and pramipexole. Other parkinsonian medications are amantadine, benztropin, trihexyphenydil, deprenyl, and entacapone. Recently multicentre clinical trials were performed using ropinirol and entacapone, which showed reliable results. Currently deep brain stimulation is available in a number of medical institutes.

Systematic review of incidence studies of Parkinson's disease

Incidence studies of Parkinson's disease (PD) are important for both health-care planning and epidemiological research. This report reviews the methods and results of previous incidence studies of PD and makes recommendations for future studies. Original articles that described the incidence of PD were located using several strategies. The methods were summarised, and the results of studies with similar methodologies were compared on a standardised population. Twenty-five incidence studies were included. Each used different methods to identify incident patients, although most screened both primary care and hospital records. Only eight studies were prospective, and only two of these had any follow-up. The diagnostic criteria for PD varied (11 studies used two or more cardinal motor features, four used the UK Brain Bank criteria), as did the exclusion criteria and the definition of an incident case. In 16 studies, attempts were made to confirm the diagnosis by examination of patients by a specialist as part of the study. None of the studies used identical methods, but five were sufficiently similar to merit comparison. Four of these gave a similar incidence (16-19/100000/year), but one from Italy had a much lower incidence (8.4/100000), the reason for which was unclear. Five studies found significantly greater incidence in men. This review highlights the difficulties in performing good quality incidence studies of PD. Further incidence studies using standardised methods are required. A set of minimal scientific criteria has been devised to improve the quality and consistency of future studies.

Estimation of incidence and prevalence of Parkinson's disease in the elderly using pharmacy records

PURPOSE

We determined the prevalence and incidence of Parkinson's disease among persons aged 55 years and older in pharmacy records.

METHODS

Data came from the PHARMO database which includes information on drug dispensing for all residents of six Dutch cities. We selected all persons aged 55 years and older who had used antiparkinsonian drugs, and calculated a chance for having Parkinson's disease with use of a previously validated logistic regression model. We used a cut-off of 0.5 (sensitivity 62%, positive predictive value 92%). Prevalence was estimated on the first Wednesday of October 1997, incidence on the first Wednesday of October 1993 until 1997. A patient was incident, if the first prescription for an anti-parkinsonian drug was dispensed at least 180 days after entry into PHARMO. Prevalence and incidence were standardized to the Netherlands population of 1 January 1998. The prevalence was adjusted for the sensitivity and positive predictive value of the model.

RESULTS

The unadjusted prevalence (per 100,000) for those aged 55-64 years was 111, 65-74 years 598, 75-84 years 1551 and for persons aged 85 years and older 1847. The adjusted and standardized prevalence was 970 per 100,000 (95% confidence interval 869 to 1071). The incidence (per 100,000 person years) for persons aged 55-64 years was 12, 65-74 years 108, 75-84 years 257 and for persons aged 85 years and older 247. The standardized incidence was 109 per 100,000 person years (96 to 121).

CONCLUSIONS

Prevalence and incidence were in range with the literature. Pharmacy records therefore seem to be a useful tool for continuous monitoring of incidence and prevalence of Parkinson's disease.

Influence of strict, intermediate, and broad diagnostic criteria on the age- and sex-specific incidence of Parkinson's disease

We studied the influence of three sets of diagnostic criteria on the age- and sex-specific incidence of Parkinson's disease (PD) among residents of Olmsted County, Minnesota, for the period 1976 to 1990. Incidence cases of parkinsonism were detected using the medical records-linkage system of the Rochester Epidemiology Project. PD was separated from other types of parkinsonism using strict, intermediate, and broad criteria. We found 154 incident cases of PD using the strict criteria, 215 using the intermediate criteria, and 266 using the broad criteria. The incidence rate was consistently higher for men across all ages with all three sets of criteria; however, sex differences were more striking at older ages when using the broad criteria. In men above age 79 years, the incidence rate of PD declined with strict criteria, remained stable with intermediate criteria, and increased with broad criteria. The impact of diagnostic criteria on the age-specific incidence curve was less striking for women. When using the broad criteria, the risk of PD increased constantly with age in both sexes, suggesting that PD is an aging-related disease. Our findings suggest that the diagnostic criteria used to separate PD from other types of parkinsonism influence the magnitude of PD incidence and its distribution by age and sex.

Prevalence of Parkinson's disease in lower Aragon, Spain

OBJECTIVE

We attempted to measure the prevalence of Parkinson's disease (PD) and to improve PD diagnosis in Lower Aragon (LA), a rural area located in northeast Spain with an elderly population numbering 60,724.

METHODS

Hospital records and a questionnaire targeted at general practitioners and retirement home personnel were used for case finding. Neurologic diagnoses were ascertained by a neurologist using a clinicoepidemiologic protocol and established diagnostic criteria after examining 84% of patients diagnosed with PD. Using stratified analysis, a comparison was run against reported PD prevalence from worldwide door-to-door surveys.

RESULTS

On the prevalence date, 134 individuals were found to be affected with PD. The prevalence per 100,000 population was 220.6 (crude) and 121.9 when age-adjusted using the European Standard Population. Prevalence increased with age, declining at 90 years and over. Questionnaires returned by general practitioners disclosed 20% of the prevalent PD cases. The prevalence of PD in pooled European populations was 2.56 times (95% confidence interval [CI]: 2.02-3.24) greater than that found in our study.

CONCLUSION

PD prevalence in Lower Aragon ranks at levels similar to those reported for white populations (European and non-European). One out of two individuals with PD was estimated to be undiagnosed before and three out of eight after the study.

Prevalence of Parkinson's disease in Northwestern Italy: comparison of tracer methodology and clinical ascertainment of cases

The prevalence of idiopathic Parkinson's disease (PD) in an area of Northwestern Italy (Socio-Sanitary District of Cossato, 61,830 inhabitants) was analyzed and the reliability of "drug tracer methodology" evaluated. The patients were identified by both conventional epidemiological methodology (general practitioners, consultant neurologist, computerized archives) and drug tracer methodology (registered levodopa prescriptions). The diagnosis of PD was clinically verified by examining all patients. Of 146 patients examined, 104 were affected by PD; the remaining by other types of parkinsonism. The crude point prevalence rate (October 20, 1991) was 168 per 100,000 population (95% confidence interval [95% CI] 138-204), with a progressive increase up to the 80-89 age group. Using "tracer" methodology, the estimated crude point prevalence rate was 196 (95% CI 163-235), with an overestimation of the prevalence in older patients and women and an underestimation in younger and less seriously affected cases. The uneven distribution of PD in Italy appears to be the result of, at least in part, methodological factors. "Tracer" methodology may cause biases in the evaluation of the epidemiological characteristics of PD, especially if the clinical diagnosis of cases identified by this method is not carefully verified. Nevertheless, it appears useful as an additional source of cases for descriptive surveys.

Clinical genetic analysis of Parkinson's disease in the Contursi kindred

We performed a clinical genetic analysis of a kindred originating in the town of Contursi in Salerno province, Italy, in which 60 individuals in 5 generations are known to have had Parkinson's disease (PD). Two previously reported autopsy cases showed typical PD with Lewy bodies. The inheritance pattern is apparently autosomally dominant with a segregation ratio of 40.1% for kindred members aged 50 years and older. The mean age at PD onset is 45.6 years (standard deviation, 13.48; range, 20-85) with a mean course to death of 9.2 years (standard deviation, 4.87; range, 2-20). Otherwise, clinical characteristics of PD in the kindred, including variance in onset age and incidence of tremor and levodopa responsiveness, are similar to those of PD in the community. The presence of tremor tended to be concordant in affected parent-child pairs, but there was no parent-child correlation for age at onset or intrasibship clustering of tremor or onset age. A suggestion of anticipation disappeared after adjustment for age-related ascertainment bias. The findings show that a presumably single mutation can produce a heterogeneous PD phenotype, even among siblings. This is consistent with the hypothesis that PD in the community may in fact be caused by such a mutation, but one producing a lower penetrance and older age at onset than those in this kindred.

Rural or urban living and Parkinson's disease

Although the precise etiology of Parkinson's disease (PD) is as yet unknown, it appears that certain environmental factors are involved. Prior living in a rural area has been implicated as a possible risk factor for PD, particularly in the early onset type. We evaluated the role of previous living conditions in the clinical correlates and outcome characteristics of 118 PD patients. All of them were seen from January 1987 to October 1992. The Rural Group (RG) comprised 71 patients (60.2%) who had lived in the rural area for at least 10 years (mainly in early phase of life) and the Urban Group (UG) consisted of 47 patients (39.8%) who had lived their entire life in an urban environment. The average age at the beginning of the symptoms was 58.8 in the RG and 54.1 in the UG. The mixed form of the disease (tremor, rigidity and akinesia) was the most frequent in both groups. A minimum 6-month follow-up period was undertaken with 63 patients (average 20 months) and no difference in response to treatment or in progression of the illness was detected between the two groups. Our data show that the previous living environment does not appear to be a determining factor in either the clinical or outcome characteristics of PD.

Estimate of parkinsonism prevalence through drug prescription histories in the Province of Rome, Italy

INTRODUCTION

The objective of the study was to estimate the prevalence of parkinsonism in the Province of Rome using antiparkinsonian prescription histories from 1986 to 1991.

METHODS

A subject was defined as a case of parkinsonism if he/she had received "specific" and "consistent" antiparkinsonian therapy in the study period.

RESULTS

In November 1990, 6,572 patients were defined as prevalent cases of parkinsonism. The crude prevalence ratio, for the total population of the Province of Rome, is 173.5 per 100,000 inhabitants (165.9 per 100,000 in men and 180.5 per 100,000 in women). The method was validated by record-linkage with clinical records of all patients visited during 1990 at the Department of Neurological Sciences of the University of Rome "La Sapienza". The sensitivity of the prevalence study was 83.6%.

CONCLUSIONS

The use of a computerized data base of all prescription data, routinely collected for administrative purposes, enabled us to obtain a prevalence estimate based on a very large population, with low costs and in a relatively short time.

Intracranial gliomas in Ferrara, Italy, 1976 to 1991

INTRODUCTION

We planned a descriptive study on the incidence of intracranial gliomas spanning a 16-year period (1976-1991) in the Local Health Service 31 of Ferrara, Northern Italy.

MATERIAL AND METHODS

We used a complete enumeration approach by reviewing all the possible sources of case collection available in the study area.

RESULTS

The mean annual incidence rate was 5.8 new cases per 100,000 population (6.96 for men and 4.78 for women; p < 0.05), resulting in 4.7 per 100,000 when directly adjusted to the Italian population. The age-specific incidences showed a small peak in childhood, an increase with age, reaching a maximum in the age group 60 to 64 and then a decline in the elderly. This pattern is similar for both sexes. The adjusted rates increased from 3.94 per 100,000 population in the first five-year period to 5.6 per 100,000 in the third (a nonsignificant difference). The distribution of cases within the study area was substantially uniform.

CONCLUSION

The incidence rates of Ferrara fell into the middle-high values so far reported and confirmed the male preponderance found in previous studies. The age-related pattern is similar to that observed, with few exceptions, in other surveys. Like other authors we did not find a significant temporal trend, although the incidence rates tended to increase with time. The data encourage further, wider epidemiological studies of a prospective nature.

Prevalence of Parkinson's disease in the elderly: a population study in Gironde, France

We investigated the prevalence of Parkinson's disease in a representative sample of the elderly population living in the Gironde département, France. Among 3149 people over age 65, the prevalence ratio for Parkinson's disease was 1.4%, without significant difference between men and women. We found that age-specific prevalence ratios increased with age from 0.5% in the age group 65 to 69 to 6.1% in individuals over age 90. This age pattern is consistent with that found in other population-based studies. Interestingly, the slope of age-specific prevalence ratios for Parkinson's disease was similar to that previously reported for Lewy bodies. Our study showed that a high proportion (42%) of Parkinson's disease cases in elderly subjects living in institutions were undiagnosed.

Prevalence of anti-parkinson drugs' use in Ferrara, northern Italy, 1988

INTRODUCTION

The period prevalence rate for anti-parkinson drugs (APD) use was reported in the Local Health Service of Ferrara (USL 31), Northern Italy, in 1988 (resident population: 177,000 inhabitants).

MATERIAL AND METHODS

The study was performed through the analysis of the complete list of APD prescriptions in the USL 31 area provided by the computerized archives of USL 31 and the identification code of the patients which is unique for each resident of USL 31. The patients treated with neuroleptics known to be potential parkinsonism-inducing drugs were excluded.

RESULTS

The period prevalence rate for APD users was 456.9 per 100,000 population. The prevalence rate for dopa derivatives users was 391.3 per 100,000. The prevalence did not varied between rural and urban zones of USL 31 both for APD and dopa derivatives users. A higher prevalence was obtained in a small rural commune of USL 31 both for APD users (758.5 per 100,000) and dopa derivatives users (718.6 per 100,000) than in the other 4 communes in which the study area is subdivided.

CONCLUSION

The reported prevalence could provide information on the occurrence of most parkinsonisms in the study area and some suggestion on the role of possible environmental factors.

Genetic factors in the etiology of idiopathic Parkinson's disease

Overshadowed by a vigorous search for an environmentally-derived toxin that would be possibly relevant for the pathogenesis of idiopathic Parkinson's disease (PD), genetic factors have largely been neglected for this condition during the last two decades. Recent descriptions of kindreds over three or more generations with several family members affected have renewed the interest in genetics of PD. Concurring with this, diagnostic concepts and pathologic criteria for PD and for idiopathic Lewy-body (LB) disease have been reevaluated such that LB-proven parkinsonism is sufficiently differentiated from familial parkinsonism without LB pathology. Surveys on genetic epidemiology in PD have confirmed the 19th century's notion that 10 to 15% of PD index cases report a further family member with PD. These figures were, however, substantiated on a statistical basis only in single surveys when comparisons were made with the numbers of PD relatives in control index cases. Twin studies did not reveal a higher rate of concordance within monozygotic pairs than in dizygotic pairs. Tests of striatal 18-F-Dopa uptake in clinically unaffected mono- and dizygotic co-twins did not alter the ratio between the concordance rates. Though not excluded by the twin studies, multifactorial (or polygenic) inheritance as well as mitochondrial inheritance are at present less likely to cover most of the inheritance pattern in familial LB parkinsonism. Instead, autosomal dominant inheritance with reduced penetrance is the most probable inheritance pattern for most of the reported pedigrees. Molecular genetic investigations have to consider the biochemical basis of the age- and region-specific pathology of PD. The first analyses of linkage and allelic associations gave inconclusive results in sporadic and familial PD. The hunt for metabolic factors that link geno- and phenotype expression in PD will continue.

Duration of amyotrophic lateral sclerosis is age dependent

Since 1985, we prospectively followed 246 patients with ALS. The relationship between the age of developing neurological impairment and disease duration was analyzed in 138 patients (86 men and 52 women) who died. Mean disease duration was 4.0 +/- 3.8 years for men and 3.2 +/- 2.5 years for women. There was an inverse, exponential, relationship between onset age and duration (goodness-of-fit P > 0.05). Mean duration at onset age < or = 40 years was 8.2 +/- 5.0 years compared with 2.6 +/- 1.4 years for patients aged 61 to 70 years (P > 0.001). The ratio of young (< or = 40 years) men to women was 3.6:1. When matched for age, disease duration was the same for patients with bulbar and nonbulbar onsets. We conclude that onset age, but not sex, is the most significant predictor determining disease duration in ALS. Longer survival in younger patients probably reflects their greater neuronal reserve.

Parkinson's disease mortality and the industrial use of heavy metals in Michigan

Parkinson's disease (PD) mortality rates in Michigan counties for 1986-1988 were calculated with respect to potential heavy metal exposure (iron, zinc, copper, mercury, magnesium, and manganese) from industry based on recent census data. Individuals were counted as a PD death if the diagnosis was listed as an "underlying" or "related" cause of death on the death certificate. Counties with an industry in the paper, chemical, iron, or copper related-industrial categories (ICs) had statistically significantly (p < 0.05) higher PD death rates than counties without these industries. Significant correlations of chemical (rs = 0.22; p = 0.05), paper (rs = 0.22; p = 0.05) and iron (rs = 0.29; p = 0.008) industry densities with PD death rates were also present. Counties were divided into high (> 15/100,000 individuals 45 years old and over) and low (< = 15/100,000) PD death rate counties by cluster analysis. Geographically, counties with high PD mortality were located mainly in the southern half of the lower peninsula and eastern half of the upper peninsula; low PD death rate counties formed two distinct clusters in the western edge of the upper peninsula and the north-central portion of the lower peninsula. Other possible risk factors that may explain the varied distribution of PD death rates in Michigan were examined. Those significantly correlated with PD mortality included population density (rs = 0.31; p = 0.005), farming density (rs = 0.25; p = 0.02), and well water use (rs = -0.24; p = 0.03). These ecologic findings suggest a geographic association between PD mortality and the industrial use of heavy metals.