Jul 19 2012
By Andrew Czyzewski
Individuals aged 65 years and over who have carotid stenosis or electrocardiography (ECG) abnormalities face an elevated risk for subsequently being diagnosed with Parkinson's disease (PD), results of a 14-year longitudinal study show.
The findings add weight to the "conception of a premotor period of PD" in which cardiovascular physiology is affected, according to Samay Jain (University of Pittsburgh School of Medicine, Pennsylvania, USA).
The researchers analyzed data from the Cardiovascular Health Study (CHS) - a community-based cohort study of cardiovascular disease in adults aged 65 years and older who were followed longitudinally from 1989 to 2003.
They considered ECG abnormality, orthostasis (symptomatic or asymptomatic), heart rate variability (24-hour Holter monitoring), and any carotid stenosis by ultrasound, as primary predictors of incident PD diagnosis using multivariable logistic regression.
Incident PD cases were identified by at least one of the following: self-report, anti-parkinsonian medication use, and ICD-9 code during hospitalization.
Of 5888 participants, 154 developed PD over 14 years of follow up. At baseline, PD patients had a higher prevalence of carotid stenosis compared with non-PD cases (88.3 vs 77.4%), as well as major ECG abnormalities (38.3 vs 30.1%) and diabetes (23.3 vs 16.1%). However, they were more physically active (2109 vs 1700 kcal/day).
After adjusting models for confounders, patients with any ECG abnormality at baseline had an elevated risk for incident PD diagnosis (odds ratio [OR]=1.45) as did those with any carotid stenosis (OR=2.40). Neither orthostasis nor heart rate variability were significant predictors.
Discussing these findings, Jain et al suggest that the former two traits could be examples of early nonmotor features secondary to neurodegeneration during the premotor period of PD, or could be indicators of vascular disease and share common mechanisms of pathogenesis with PD.
Alternatively, they say the association could be down vascular parkinsonism being misclassified as PD.
To determine the true significance of these abnormalities will require "further investigation of premotor features in more diverse populations whose observation periods began when they were younger with more thorough ascertainment and validation of PD onset," Jain et al comment in the journal Movement Disorders.
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