Hepatitis C infection may increase the risk of Parkinson’s disease, according to a nationwide population-based study.
Researchers analyzed 10 years of data from the Taiwan National Health Insurance Research Database, which included 49,967 patients with viral hepatitis – 35,619 with hepatitis B infection, 10,286 with hepatitis C, and 4,062 with both – and 199,868 noninfected controls.
Courtesy US. Dept of Veterans Affairs
According to a paper published online Dec. 23 in Neurology, individuals with hepatitis C infection had a 29% greater incidence of Parkinson’s disease after adjustment for confounders such as sex, age, heart disease, stroke, and head injury (hazard ratio, 1.29; 95% confidence interval, 1.06-1.56).
There were no significant associations between hepatitis B or coinfection, and Parkinson’s disease risk (Neurology. 2016;86:1-7).
Age was the most common risk factor for Parkinson’s disease across all cohorts, and in the control group comorbidities such as hyperlipidemia, hypertension, ischemic heart disease, diabetes, and head injury all were associated with a significant increase in the risk of Parkinson’s disease.
Among individuals with hepatitis C infection, however, only ischemic heart disease and head injury remained significantly associated with Parkinson’s disease risk.
The possibility of an association between hepatitis C infection and Parkinson’s disease has emerged recently with evidence showing that the virus is neurotropic and can replicate in the central nervous system, reported Dr. Hsin-Hsi Tsai of the National Taiwan University Hospital, Taipei, and coauthors.
“Parkinsonism is rarely a described feature in patients with HCV. However, a recent study has discovered that HCV can induce dopaminergic neuron death, suggesting a possible association between HCV infection and” Parkinson’s disease, the authors wrote.
The study also showed that the association between hepatitis C infection and Parkinson’s disease was even more significant in individuals younger than 65 years old, who had a 61% greater risk of developing the neurodegenerative disease.
“Some of the risk factors for HCV infection, such as illicit drug use and associated behaviors, may be confounding factors in this age group,” the authors wrote, although they pointed out that, in Taiwan, use of intravenous drugs was not known to be a risk factor for infection. Commenting on a possible mechanism for the association between hepatitis C infection and Parkinson’s disease, Dr. Tsai and associates suggested the hepatitis C virus could be a possible viral candidate for triggering the neuroinflammation that is a characteristic feature of the disease.
“An earlier imaging study that involved using magnetic resonance spectroscopy to investigate the cerebral effect of HCV showed that chronic HCV infection was associated with elevated choline/creatinine ratios, a biomarker indicating inflammatory and infective conditions, in the basal ganglia and white matter,” they wrote.
The study was supported by the Taiwan Ministry of Health and Welfare Clinical Trial and Research Center of Excellence, China Medical University Hospital, Academia Sinica Taiwan Biobank, Stroke Biosignature Project, NRPB Stroke Clinical Trial Consortium, the Tseng-Lien Lin Foundation, the Taiwan Brain Disease Foundation, the Katsuzo and Kiyo Aoshima Memorial Funds, and CMU under the Aim for Top University Plan of the Ministry of Education. There were no conflicts of interest declared.