Incidence of parkinsonism and Parkinson disease in a general population: the Rotterdam Study.

OBJECTIVE: To investigate the incidence of parkinsonism and Parkinson disease (PD) in the general population using in-person screening along with clinical data. METHODS: In the Rotterdam study, a prospective population-based cohort study of people aged > or =55 years, the authors assessed age- and sex-specific incidence rates of parkinsonism and PD among 6,839 participants who were free of parkinsonism at baseline. Case finding involved in-person screening at baseline and two follow-up visits, and additional information was obtained through continuous monitoring of the cohort by computer linkage to general practitioners' and pharmacy records. RESULTS: After a mean follow-up period of 5.8 years, 132 subjects with incident parkinsonism were identified, of whom 67 (51%) had PD. The incidence of parkinsonism and PD increased with age, with incidence rates for PD increasing from 0.3 per 1000 person-years in subjects aged 55 to 65 years, to 4.4 per 1000 person-years for those aged > or =85 years. The overall age-adjusted incidence rate of any parkinsonism was not different in men and women, but men seem to have a higher risk for PD (male-to-female ratio, 1.54; 95% CI, 0.95 to 2.51). CONCLUSION: Incidence rates for parkinsonism and Parkinson disease were higher than those reported by most previous studies, possibly because of the authors' intensive case-finding methods involving in-person screening.

Prevalence of Parkinson's disease in Europe: A collaborative study of population-based cohorts. Neurologic Diseases in the Elderly Research Group.

The results of seven population-based studies were examined separately and pooled to obtain age- and sex-specific estimates of the prevalence of PD. An in-person screening instrument and diagnostic clinical examination were used to detect potential PD cases. The overall prevalence (per 100 population) in persons 65 years of age and older was 1.8, with an increase from 0.6 for those age 65 to 69 years to 2.6 for those 85 to 89 years. There were no sex differences in prevalence of PD.

APOE and the risk of PD with or without dementia in a population-based study.

OBJECTIVE: To study the association between APOE genotype and PD with or without dementia. METHODS: The study formed part of the Rotterdam Study, a prospective, population-based cohort study on the frequency, etiology, and prognosis of chronic diseases. The cohort examined for PD consisted of 6,969 independently living or institutionalized inhabitants from a suburb of Rotterdam, the Netherlands, aged 55 years or older. All participants were screened at baseline (1990 to 1993) and at follow-up (1993 to 1994) for symptoms of parkinsonism by study physicians; screen positives received a diagnostic workup by a neurologist. RESULTS: APOE genotyping was available for 107 PD patients (26 with and 81 without dementia) and 4,805 non-PD control subjects. The presence of at least one epsilon2 allele significantly increased the risk of PD (OR = 1.7; 95% CI, 1.0 to 2.8). When we looked separately for demented and nondemented PD patients as compared with nonparkinsonian controls, APOE did not appear to be associated with PD without dementia, but both the epsilon2 and the epsilon4 allele increased the risk of PD with dementia (OR = 5.6; 95% CI, 2.0 to 15.2 and OR = 3.6; 95% CI, 1.3 to 9.9). The risk of dementia for epsilon4 allele carriers was not significantly different for persons with or without PD. However, the epsilon2 allele strongly increased the risk of dementia in patients with PD (interaction p < 0.007). CONCLUSIONS: In the elderly the APOE-epsilon2 allele increases the risk of PD and, in particular, the risk of PD with dementia.

Case ascertainment uncertainties in prevalence surveys of Parkinson's disease.

Using unpublished data from five completed prevalence surveys of Parkinson's disease (PD), we investigated case ascertainment uncertainties that potentially have a direct effect on prevalence. These uncertainties arise from the choice of diagnostic criteria, the choice of screening method, and the amount of information lost because of nonresponse. The surveys were conducted in Argentina, India, China, Italy, and the Netherlands. Our analyses consisted of simple comparisons of prevalence results, positive predictive values (a screening measure), and nonresponse percentages. We found that (a) prevalence comparisons between surveys have diminished value if the surveys used different diagnostic criteria for PD; (b) screening performance may be affected adversely if symptom questions are answered by one family member for the entire family living together rather than by each family member individually; and (c) nonresponse from refusal or unavailability does not necessarily lead to bias, but special caution may be appropriate with prevalence results pertaining to elderly women.

Dietary antioxidants and Parkinson disease. The Rotterdam Study.

OBJECTIVE: To investigate whether high dietary intake of antioxidants decreases the risk of Parkinson disease (PD). SETTING: The community-based Rotterdam Study, the Netherlands. DESIGN: The cross-sectional study formed part of a large community-based study in which all participants were individually screened for parkinsonism and were administered a semiquantitative food frequency questionnaire. The study population consisted of 5342 independently living individuals without dementia between 55 and 95 years of age, including 31 participants with PD (Hoehn-Yahr stages 1-3). RESULTS: The odds ratio for PD was 0.5 (95% confidence interval [CI], 0.2-0.9) per 10-mg daily dietary vitamin E intake, 0.6 (95% CI, 0.3-1.3) per 1-mg beta carotene intake, 0.9 (95% CI, 0.4-1.9) per 100-mg vitamin C intake, and 0.9 (95% CI, 0.7-1.2) per 10-mg flavonoids intake, all adjusted for age, sex, smoking habits, and energy intake. The association with vitamin E intake was dose dependent (P for trend = .03). To assess whether the association was different in participants with more advanced disease, we excluded those with PD who had a Hoehn-Yahr stage of 2.5 or 3. This did not fundamentally alter the results. CONCLUSION: Our data suggest that a high intake of dietary vitamin E may protect against the occurrence of PD.

A population perspective on diagnostic criteria for Parkinson's disease.

For Parkinson's disease (PD), little is known about how the choice of diagnostic criteria affects research results. Using data on PD from three community studies (from Argentina, the Netherlands, Italy), we compared the impact on prevalence of several sets of diagnostic criteria. Each set was based on cardinal signs--resting tremor, bradykinesia, rigidity, impaired postural reflexes--and required that other parkinsonism be excluded. Some sets had additional requirements related to duration of symptoms, asymmetry of signs, or response to medication. In terms of prevalence, much lower estimates were associated with the requirements of asymmetry of signs and response to medication. The assessment of these clinical features may not be practical in community studies. Impaired postural reflexes, as a cardinal sign, seemed superfluous. For community studies of PD, we recommend the following diagnostic criteria: at least two of resting tremor, bradykinesia, or rigidity, in the absence of other apparent causes of parkinsonism.

Prevalence of parkinsonism and Parkinson's disease in Europe: the EUROPARKINSON Collaborative Study. European Community Concerted Action on the Epidemiology of Parkinson's disease.

OBJECTIVES: To assess and compare the prevalence of parkinsonism and Parkinson's disease in five European populations that were surveyed with similar methodology and diagnostic criteria. METHODS: Joint analysis of five community surveys--Gironde (France), eight centres in Italy, Rotterdam (The Netherlands), Girona (Spain), and Pamplona (Spain)--in which subjects were screened in person for parkinsonism. Overall, these surveys comprised 14,636 participants aged 65 years or older. RESULTS: The overall prevalence (per 100 population), age adjusted to the 1991 European standard population, was 2.3 for parkinsonism and 1.6 for Parkinson's disease. The overall prevalence of parkinsonism for the age groups 65 to 69, 70 to 74, 75 to 79, 80 to 84, and 85 to 89 years was respectively, 0.9, 1.5, 3.7, 5.0, and 5.1. The corresponding age specific figures for Parkinson's disease were 0.6, 1.0, 2.7, 3.6, and 3.5. After adjusting for age and sex, the prevalence figures did not differ significantly across studies, except for the French study in which prevalence was lower. Prevalence was similar in men and women. Overall, 24% of the subjects with Parkinson's disease were newly detected through the surveys. CONCLUSIONS: Prevalence of both parkinsonism and Parkinson's disease increased with age, without significant differences between men and women. There was no convincing evidence for differences in prevalence across European countries. A substantial proportion of patients with Parkinson's disease went undetected in the general population.

Prevalence of Parkinson's disease in the elderly: the Rotterdam Study.

We assessed the prevalence of Parkinson's disease (PD) in a general elderly population in the Netherlands. The study formed part of the Rotterdam Study, a population-based door-to-door study, and included 6,969 persons 55 years of age or older living in a suburb of Rotterdam, the Netherlands. All participants were examined, and those who either had at least one possible cardinal sign of parkinsonism at the neurologic screening, reported that they had PD, or were taking antiparkinsonian drugs were invited for further evaluation. The prevalence of PD in this population was 1.4% (1.2% for men, 1.5% for women). Prevalence increased with age, and prevalence figures were 0.3% for those aged 55 to 64 years, 1.0% for those 65 to 74, 3.1% for those 75 to 84, and 4.3% for those 85 to 94. The corresponding age-specific figures for men were 0.4%, 1.2%, 2.7%, and 3.0%, and for women, 0.2%, 0.8%, 3.4%, and 4.8%. Among 95- to 99-year-old women the prevalence was 5.0%. Twelve percent of the subjects with PD were detected through the screening and had not been diagnosed previously.