Relatives of patients with Parkinsonís disease may have an increased risk of developing dementia or cognitive impairment, according to a report in the October issue of Archives of Neurology, one of the JAMA/Archives journals.
Parkinsonís disease is characterized by a decline in the functions of the central nervous system, such as motor skills and speech. Several studies have shown an increased risk of dementia in first-degree relatives of Parkinsonís disease patients, while other studies have not confirmed the association, according to background information in the article. ďThe co-occurrence of Alzheimerís disease and Parkinsonís disease in families and in individuals may be due to the sharing of susceptibility genetic variants,Ē the authors write.
Walter A. Rocca, M.D., M.P.H, of the Mayo Clinic College of Medicine, Rochester, Minn., and colleagues studied 1,019 first-degree relatives of 162 patients with Parkinsonís disease, 858 relatives of 147 people who were the same age and sex as someone in the Parkinsonís disease group but did not have the condition and 2,716 relatives of 411 patients with Parkinsonís disease who were referred to the Mayo Clinic. Dementia and cognitive impairment were determined by responses to a telephone questionnaire or cognitive test and a review of participantsí medical records.
ďThis study provides evidence that relatives of patients with Parkinsonís disease have an increased risk of cognitive impairment or dementia. This association is primarily driven by families of patients with younger age at onset of Parkinsonís disease, but the risk does not vary across relatives of patients with different clinical characteristics of Parkinsonís disease,Ē the authors write. Relatives of patients who experienced the onset of the disease at age 66 or younger had a particularly increased risk of developing dementia or cognitive impairment.
ďThe observed associations suggest the action of shared familial susceptibility factors, genetic or nongenetic,Ē they conclude.
(Arch Neurol. 2007;64(10):1458-1464. Available pre-embargo to the media at www.jamamedia.org.)
Editorís Note: This study was supported by a grant from the National Institutes of Health and was made possible by a Rochester Epidemiology Project grant, also from the National Institutes of Health. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
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