Parkinson's Disease Patients' Relatives Have Raised Risk Of Developing Cognitive Impairment Or Dementia

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Main Category: Parkinson's Disease
Also Included In: Alzheimer's / Dementia;  Neurology / Neuroscience;  Genetics
Article Date: 09 Oct 2007 - 10:00 PDT

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A relative of a patient who has Parkinson's disease has a higher risk of developing dementia or cognitive impairment, compared to somebody who has no relative with the disease, says an article in Archives of Neurology (JAMA/Archives), October issue.

A Parkinson's disease patient typically experiences a decline in the functions of the CNS (central nervous system) - his/her motor and speech skills deteriorate. The authors explain that several previous studies had demonstrated a dementia risk for first-degree relative of patients with Parkinson's disease. However, other studies did not confirm this link.

The authors wrote "The co-occurrence of Alzheimer's disease and Parkinson's disease in families and in individuals may be due to the sharing of susceptibility genetic variants."

Walter A. Rocca, M.D., M.P.H, Mayo Clinic College of Medicine, Rochester, Minn., and team looked at 1,019 first-degree relatives of 162 patients with Parkinson's disease; they also studied 858 relatives of 147 healthy people whose sex and ages were the same as the Parkinson's disease patients, as well as another 2,716 relatives of 411 Parkinson's disease patients who had been referred to the Mayo Clinic. They determined levels of dementia and cognitive impairment by analyzing responses to a telephone questionnaire or a cognitive test - they also reviewed the medical records of the participants.

The writers explained "This study provides evidence that relatives of patients with Parkinson's 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 Parkinson's disease, but the risk does not vary across relatives of patients with different clinical characteristics of Parkinson's disease."

The risk for a relative was especially marked if the Parkinson's disease patient had developed the disease at the age of 66 or less.

The authors concluded "The observed associations suggest the action of shared familial susceptibility factors, genetic or nongenetic."

Risk of Cognitive Impairment or Dementia in Relatives of Patients With Parkinson Disease
Walter A. Rocca, MD, MPH; James H. Bower, MD; J. Eric Ahlskog, PhD, MD; Alexis Elbaz, MD, PhD; Brandon R. Grossardt, MS; Shannon K. McDonnell, MS; Daniel J. Schaid, PhD; Demetrius M. Maraganore, MD
Arch Neurol. 2007;64:1458-1464.
-- Click here to view abstract online

Written by: Christian Nordqvist
Copyright: Medical News Today
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