Hepatitis C infection increases the risk of developing Parkinson’s disease, found a cohort study published in Neurology.
Hsin-Hsi Tsai, MD, of the National Taiwan University Hospital and College of Medicine in Taipei, and colleagues used a national Taiwanese health insurance database to analyze data between 2000 and 2010 from 49 967 patients with viral hepatitis and 199 868 patients without hepatitis. Among the hepatitis patients, with an average age of 46 years, 71% had hepatitis B, 21% had hepatitis C and 8% had both.
Patients with hepatitis C were 2.5 times more likely to develop Parkinson’s before confounder adjustments and 29% more likely to develop Parkinson’s after accounting for age, sex and other health conditions, including hyperlipidemia, hypertension, heart disease, epilepsy, diabetes, cirrhosis, stroke and head injury. These comorbidities were more common among the hepatitis patients than among the controls.
Before adjustments for confounders, patients with hepatitis B infections were 34% less likely to develop Parkinson’s disease, and those co-infected with hepatitis B and C were 28% more likely to develop Parkinson’s, though this latter finding didn’t reach statistical significance.
Age remained the universal risk factor for Parkinson’s across both groups, and most of the comorbidities among the controls were linked to a higher risk of Parkinson’s. Among hepatitis C patients, the only conditions found to be statistically significant additional risk factors were heart disease, which increased Parkinson’s risk 65%, and head injury, which doubled the risk.
Although hepatitis C’s influence on the nervous system is controversial, “a previous study revealed that dopaminergic neurotransmission is altered in patients with hepatitis C virus infection,” the authors noted. “Hepatitis C virus was also reported to induce dopaminergic neuronal toxicity in the mid- brain cell culture in rats.” The possibility of neuroinflammation partly triggered by hepatitis C is another possibility.
Tsai H, Liou H, Muo C, Lee C, Yen R, Kao C. Hepatitis C virus infection as a risk factor for Parkinson disease: A nationwide cohort study. Neurology. 2015; doi:2016;86:1–7.