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Background: This population-based case-control study evaluated nutrient intake as a risk factor for Parkinson's disease (PD) among people aged > or =50 years in metropolitan Detroit.Methods: Cases (n = 126) were diagnosed between 1991 and 1995 and neurologist-confirmed. Controls (n = 432) were frequency-matched for sex, age (+/-5 years) and race. Using a standardized food frequency questionnaire, subjects reported the foods they ate within the past year.Results: Estimating the association between PD and risk of being in the highest versus the lowest intake quartile, there were elevated odds ratios for total fat (OR 1.94, 95% confidence interval [CI] : 1.05-3.58), cholesterol (OR 2.11, 95% CI: 1.14-3.90), lutein (OR 2.52, 95% CI: 1.32-4.84) and iron (OR 1.88, 95% CI: 1.05-3.38).Conclusions: These results suggest an association of PD with high intake of total fat, saturated fats, cholesterol, lutein and iron. [ABSTRACT FROM AUTHOR]

Background: Among the methods of retrospective occupational exposure assessment, expert review is considered the most accurate. Although expert review provides a more objective measure of exposure, depending on the exposure of interest it may still result in a significant degree of misclassification.Methods: To evaluate the reliability in occupational metal exposure assessment by expert review, we analysed job history data from a case-control study of a neurological disease. First, one industrial hygienist (IH) did an initial exposure assessment of the metals copper, iron and lead, blinded to case-control status, for 608 subjects who had 3033 total jobs. We then compared exposure assessments from the original review with a second blinded review of 60 job histories (306 jobs) by the same IH (intra-rater) and of 64 job histories (361 jobs) by a different IH (inter-rater).Results: The per cent agreements for the intra-IH comparisons were 89.6 for copper, 87.9 for iron and 94.6 for lead, whereas the inter-IH per cent agreements were 86.4 for copper, 81.1 for iron and 76.2 for lead. Based on the assumption that reliability is related to validity, we calculated an estimate of misclassification of metal exposure by one IH. Our exposure misclassification estimates show a sizable attenuation of the odds ratio, with the expected bias similar for copper and iron when using either intra- or inter-reliability results to estimate misclassification.Conclusion: Our results suggest that variation in the expert assessment of metal exposure is due mainly to the difficulties involved in transforming an occupational history into an estimate of exposure. [ABSTRACT FROM AUTHOR]

Background: The prevalence of probable dementia was determined in a rural, homogeneous community of Amish individuals in the Midwestern USA. The Amish are a genetically isolated group with a low level of formal education (< or = 8 years) and few exposures to modern life, who live in intergenerational setting and have strong social support networks.Methods: Using community directories, trained interviewers administered the Mini Mental State Examination (MMSE) and a medical history survey to all Amish over 64 years old in a four county area. Individuals with scores < 27 (out of a maximum of 30 points) were given additional neuropsychological tests. Results were reviewed by a neuropsychologist and subjects were classified with regard to probable cognitive impairment.Results: The MMSE scores were inversely related with age and directly with education. The Amish have higher MMSE scores than reported for the general US population. The overall prevalence of probable cognitive impairment for those over 64 years was 6.4%. The prevalence increased with age and lower education and was lowest among married individuals.Conclusions: The MMSE scores among the Amish were higher than the general population despite their low level of formal education. The lower level of cognitive impairment among the Amish could reflect a lack of inherited susceptibility to dementing diseases, or environmental factors characteristic of their traditional lifestyle. Even among this population with < or = 8 years of formal education, education may protect against cognitive impairment. [ABSTRACT FROM AUTHOR]