Is Hepatitis C a Risk Factor for Parkinson's Disease

An article came out this morning on hepatitis C and risk of the development of Parkinson's Disease.  The full summary can be obtained at Journal Watch Neurology where Dr. Okun is an Associate Editor.  Here is a teaser.

Tsai and colleagues sought to investigate whether hepatitis C virus (HCV) infection was a risk factor for the later development of Parkinson disease (PD).  The authors used data from the Taiwan National Health Insurance Research Database.  The association between HCV and the later development of PD was the strongest , even after adjusting for age, sex, and comorbidities. The authors concluded that HCV infection increased the risk of the later development of PD. The idea that viruses such as HCV can cross the blood brain barrier and lead to nigral degeneration and Parkinson’s symptoms is not new, however this study is one of the few to offer well documented evidence of at least an association. The study is strengthened by the large sample size, however the results must be interpreted cautiously because of the lack of diagnostic certainty of PD, and because of the missing details; such as transfusion history, drug abuse, and other potentially important factors. Clinicians should be aware that a diagnosis of HCV may be a risk factor for the later development of PD.  The threshold for ordering a neurological consultation in HCV cases should be lower.