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Parkinson's disease is more common among whites and Hispanics than among blacks and Asians, according to the first nationwide study of Medicare records related to Parkinson's disease. The study also found that incidence was higher in urban areas than rural areas, and greatest in the northeast and midwest. The authors examined records from all Medicare beneficiaries from 2000 to 2005 (n=29.5 million in 2003), extracting PD cases using ICD-9 diagnosis codes to determine disease status, zip codes to determine residence, and self- declaration for ethnic category. Enrollees in some large HMOs were excluded because reimbursement practice at these organizations limits the detail of information passed on to Medicare. Mean incidence per 100,000 population rose with age, from 124 for age 65-69 to 970 for age 85 and over. The corresponding prevalence figures were 553 and 3,169. "Parkinson disease prevalence and annual incidence appear to continue to increase into very old age without any plateau," the authors conclude. The number of PD cases in the country is at least 480,000. By ethnic group, mean incidence/prevalence figures were 452/1672 for whites, 362/1036 for blacks, 476/1544 for Hispanics, and 339/1139 for Asians. The black/white incidence ratio was 0.74, while the prevalence ratio was 0.58, "suggest[ing] differential survival of blacks with Parkinson disease." PD incidence/prevalence was 413/1372 in "completely rural" areas, those not adjacent to an urban area and with county population of less than 2500. In urban areas with population over 1 million, incidence/prevalence was 477/1706. Figures were intermediate for areas with populations intermediate between these extremes, although the pattern was not entirely monotonic. PD was highest in the northeast and midwest portions of the country, leading the authors to dub this a "Parkinson disease belt." "This non-random disease distribution argues strongly for an environmental influence on the pathogenesis of Parkinson disease," they conclude. Geographic and ethnic variation in Parkinson disease: A population-based study of US Medicare beneficiaries AW Wright, BA Evanoff, M Lian, SR Criswell, BA Racette Neuroepidemiology 2010;34:143-151 ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn