Researchers from the University of Oxford studied the hospital records of thousands of people who had hepatitis B and hepatitis C infections.
They investigated if people with these infections were more likely to be diagnosed with Parkinson’s at a later date.
Hepatitis may increase risk of Parkinson's
They found that people with hepatitis B were 76% more likely to go on to develop Parkinson’s, and hepatitis C was linked to a 51% increase in risk.
The researchers concluded that the hepatitis virus, or treatment for hepatitis infection, could play a role in Parkinson’s.
But other viruses, including HIV, did not increase risk of Parkinson’s.
What is hepatitis?
Hepatitis B and hepatitis C are viruses that cause inflammation in the liver but often have no noticeable symptoms.
Hepatitis B is uncommon in the UK and is more common in Southeast Asia and sub-Saharan Africa.
Around 215,000 people in the UK have hepatitis C, which is usually spread through sharing needles used to inject drugs. These infections can be treated with antiviral medication.
A complex combination of factors
Beckie Port, Senior Research Communications Officer, comments:
"We still don’t fully understand the causes of Parkinson’s, but we know environment, lifestyle and genetic factors can all play a role. There is often a complex combination of factors and, in most cases, no single factor is to blame.
"Research has previously shown a potential link between hepatitis and Parkinson’s. This new study is the most comprehensive evidence that these two viruses may increase the risk of Parkinson’s.
"While there may be an increase in risk, the overall risk of a person with hepatitis going on to develop Parkinson’s is still low."