Hepatitis B and C virus infection as a risk factor for Parkinson's disease in Israel-A nationwide cohort study.

OBJECTIVE:To study the association between hepatitis C and B viruses and Parkinson's disease (PD) in Israel. METHODS:A retrospective cohort study was performed by analyzing the computerized database of Clalit Healthcare Service in Israel. Cohorts of people with hepatitis C virus (HCV) infection, hepatitis B virus (HBV) infection and nonalcoholic steatohepatitis (NASH) were constructed and compared to a reference cohort for prevalence of PD. RESULTS:The prevalence of PD in Israel was found to be 0.5% in the general population. The M-H (Mantel-Haenszel) odds ratio (OR) of PD for HBV-positive patients was 1.08 (95% CI: 1.00-1.16). The M-H OR of PD for HCV-positive patients was 1.18 (95% CI: 1.04-1.35). The M-H OR of PD for patients infected with both hepatitis C and B was 1.13 (95% CI: 0.87-1.47). The M-H OR of PD for patients diagnosed with nonalcoholic steatohepatitis (NASH) was 1.13 (95% CI: 1.08-1.19). CONCLUSIONS:We report evidence supporting a minor increased risk for PD in patients with HCV. Co infection of HCV and HBV was not associated with an increased risk for PD. The increased risk for PD in the group of patients with NASH, raises the possibility that liver disease per se is a risk factor for PD rather than viral infection. In addition, it cannot be ruled out that the association is, at least in part, the result of the occurrence of cirrhosis induced parkinsonism that was misclassified as PD.