In patients with hepatitis B and hepatitis C virus infection, there is strong evidence of an increased risk for Parkinson disease (PD), according to research published in Neurology.1
Researchers from the Nuffield Department of Population Health at the University of Oxford in London, United Kingdom, conducted a retrospective cohort study using English National Hospital Episode Statistics and mortality data from 1999 to 2011.
Individuals were grouped into 5 different cohorts: hepatitis B (n=21,633), hepatitis C (n=48,428), autoimmune hepatitis (n=6225), chronic active hepatitis (n=4234), and HIV (19,870). These 5 cohorts were compared with a reference cohort of more than 6 million individuals with minor medical and surgical conditions.
After adjustments for demographic and socioeconomic factors, the standardized rate ratio (RR) for PD was 1.76 (95% CI 1.28-2.37, P <.001) after hepatitis B virus (HBV) diagnosis (44 patients in HBV cohort vs 25 in the reference cohort). The RR for PD was 1.51 (95% CI 1.18-1.9, P <.001) after hepatitis C virus (HCV) diagnosis (73 patients in HCV cohort vs 48.5 in the reference cohort). People in the autoimmune hepatitis, chronic active hepatitis, and HIV cohorts did not have an increased rate of PD.
In an effort to reduce surveillance bias and reverse causality, the researchers excluded data from the first year after PD diagnosis, and found similar RR results for HBV and HCV:
- HBV: 1.82 (95% CI 1.29-2.50, P <.001)
- HCV: 1.43 (95% CI 1.09-1.84, P =.008)
The findings from this study on the association between HCV and PD are in agreement with 2 previous Taiwanese studies.2,3 However, the risk associated with HBV and PD is new and needs further confirmation.
“It’s possible that the hepatitis virus itself or perhaps the treatment for the infection could play a role in triggering Parkinson disease or it’s possible that people who are susceptible to hepatitis infections are also more susceptible to Parkinson disease. We hope that identifying this relationship may help us to better understand how Parkinson disease develops,” concluded lead investigator Julia Pakpoor, BM, BCh, in a press release by the American Academy of Neurology.4
Study limitations included the inability to control for lifestyle factors such as smoking and alcohol use. Furthermore, this was a hospital-based study and thus patients included in this study may have represented patients at the more severe end of the disease spectrum.
- Pakpoor J, Noyce A, Goldacre R, et al. Viral hepatitis and Parkinson disease: A national record-linkage study [published online March 29, 2017]. Neurology. doi:10.1212/WNL.0000000000003848
- Tsai HH, Liou HH, Muo CH, Lee CZ, Yen RF, Kao CH. Hepatitis C virus infection as a risk factor for Parkinson disease: a nationwide cohort study. Neurology. 2016;86:840-846. doi:10.1212/WNL.0000000000002307
- Wu WY, Kang KH, Chen SL, et al. Hepatitis C virus infection: a risk factor for Parkinson’s disease. J Viral Hepat. 2015;22:784–791. doi:10.1111/jvh.12392
- Hepatitis B and C may be linked to increased risk of Parkinson’s disease [press release]. Minneapolis, MN: American Academy of Neurology; Published March 29, 2017. Accessed April 6, 2017.