Hepatitis C virus (HCV) infection is a significant risk factor for the development of Parkinson’s disease, data from a large study indicate.
Previous research has shown that HCV may induce dopaminergic neuron death, however Parkinson’s is rarely cited as a comorbidity in patients with HCV.
In the current study, Hsin-His Tsai, MD, of the National Taiwan University Hospital in Taipei, and colleagues analyzed data from a cohort of 249 835 people from the Taiwan National Health Insurance database to examine the association between HCV infection and Parkinson’s.
Patients newly diagnosed with hepatitis B virus (HBV) (n=35 619), HCV (n=10 286), or both (n=4062) from 2000 to 2010 were included (n=49 967, 43.5% women, mean age 46.4 years), with those under age 20 or those with Parkinson’s or parkinsonism history prior to infection excluded. Compared to controls (n=199 868), patients with the virus had more comorbidities, including (19.3% vs 14.4%, P<0.0001), hypertension (25.6% vs 21.4%, P<0.0001), ischemic heart disease (12.5% vs 9.73%, P<0.0001), epilepsy (0.75% vs 0.62%, P=0.002), diabetes (8.64% vs 7.93%, P<0.0001), liver cirrhosis (6.8% vs 0.77%, P< 0.0001), and head injury (10.1% vs 8.37%, P< 0.0001).
The overall incidence of developing Parkinson’s during follow-up in people with hepatitis infection and controls was not significant (91.16 vs 85.55 per 10,000 person-years; HR 1.06, 95% CI 5 0.93–1.22). Among those with HBV infection, the hazard ratio for having Parkinson’s was 0.66 (95% CI=0.55-0.80), 2.50 for those with HCV (95% CI=2.07-3.02), and 1.28 for those with coinfection (95% CI=0.88-1.85). After adjusting for demographics and comorbidities, the association between HCV and Parkinson’s remained statistically significant (adjusted HR= 1.29, 95% CI=1.06-1.56). A positive association between HCV and Parkinson’s was maintained in patients younger than 65, males, or those with any combination of comorbidities. Age remained a universal risk factor for Parkinson’s in all infection cohorts and controls.
In those with HCV infection, ischemic heart disease and head injury were associated with a statistically significant risk of Parkinson’s.
Previous evidence suggesting that HCV infection compromises the blood-brain barrier supports the findings of the study.
“…the significant association between HCV and PD in the young age group indicates the possibility of HCV as a potential individual risk factor in patients aged younger than 65 years. 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.
Additionally, the findings of the study suggest that HCV infection is a possible candidate to elicit an inflammatory response in Parkinson’s, however further studies are required to confirm the association between HCV, neuroinflammation, and Parkinson’s.