A new study reported that both hepatitis B and hepatitis C viral infections may be associated with an increased risk of developing Parkinson’s disease.
The study was published in the journal Neurology, the medical journal of the American Academy of Neurology, and titled “Viral hepatitis and Parkinson disease; A national record-linkage study.”
The retrospective study was conducted by analyzing English National Hospital Episode Statistics and mortality data linked with cohorts of individuals infected with a first case of hepatitis B, hepatitis C, autoimmune hepatitis, chronic active hepatitis, or HIV from 1999 to 2011.
Data was cross-referenced to rates of subsequent Parkinson’s disease development, and compared with a reference control cohort of individuals who had been hospitalized with relatively minor conditions, such as cataract surgery, bunions, or knee replacements.
Researchers found that people infected with the hepatitis B virus (HBV) were 76% more likely to develop Parkinson’s disease than those in the control group. In total, 44 patients with hepatitis B developed Parkinson’s disease, compared to 25 cases in the control population.
People infected with the hepatitis C virus (HCV) were also more likely, by 51%, to develop Parkinson’s. In total, 73 patients with hepatitis C developed Parkinson’s disease compared to 49 cases in the control population.
However, an increased Parkinsons’s disease risk was not linked to people who became ill with autoimmune hepatitis, chronic active hepatitis, or HIV.
The investigators concluded that the data provides strong evidence indicating a higher risk of Parkinson’s disease development in patients with hepatitis B and hepatitis C, but caution that additional research is needed to confirm an association and to investigate pathophysiological pathways.
“The development of Parkinson’s disease is complex, with both genetic and environmental factors,” Julia Pakpoor, BM, BCh, the study’s first author, said in a press release. “It’s possible that the hepatitis virus itself or perhaps the treatment for the infection could play a role in triggering Parkinson’s disease, or it’s possible that people who are susceptible to hepatitis infections are also more susceptible to Parkinson’s disease. We hope that identifying this relationship may help us to better understand how Parkinson’s disease develops.”
Researchers emphasized that this study has some limitations, including not taking into account lifestyle factors that could contribute to Parkinson’s disease risk (like smoking and alcohol use), and the fact that the results were based solely on subjects who were evaluated in hospitals.
According to the U.S. Centers for Disease Control and Prevention (CDC), hepatitis B is caused by HBV and is transmitted via contact with blood, semen, or other body fluids from an infected person, such as can happen through sexual contact, needle and syringe sharing, or from mother to baby at birth. Chronic hepatitis B can lead to life-threatening health issues, like cirrhosis or cancer of the liver. A vaccine is available.
Hepatitis C is caused by the HCV and is spread most commonly by sharing needles or other drug injection equipment. For a minority of those who become infected, hepatitis C is a short-term illness, but in 70% to 85% of cases it becomes a dangerous, chronic infection that can result in long-term health problems and complications, including death. There is no hepatitis C vaccine.
The Parkinson Foundation defines Parkinson’s disease as a neurodegenerative brain disorder that progresses slowly in most cases, in which the affected person’s brain slowly stops producing a neurotransmitter called dopamine. As dopamine levels diminish, the person will have less and less ability to regulate body movements and emotions.