The study, published online March 29 in Neurology, is the second in the past year to link hepatitis to Parkinson’s.
Specifically, the new study found that people who’d been infected with hepatitis B or C were 51 percent to 76 percent more likely to develop Parkinson’s, compared to people who’d never had hepatitis.
The researchers don’t know why the connection exists. And the study cannot prove a cause-and-effect link.
But the association between Parkinson’s disease and hepatitis appears to be “strong,” according to Dr. Michael Okun, national medical director of the Parkinson’s Foundation.
Last year, a study in Taiwan found that people with hepatitis C faced an increased risk of Parkinson’s. Now the new findings, based on millions of British adults, implicate hepatitis B as well.
“It’s a remarkable finding,” said Okun, who wasn’t involved in the research. “There’s a strong association between hepatitis and Parkinson’s, and the association is with hepatitis B, too — which would make it an even bigger problem.”
Hepatitis B and C are viral infections of the liver. In the United States, hepatitis B is most often spread through sex, while hepatitis C is usually transmitted by sharing injection-drug needles, according to the U.S. Centers for Disease Control and Prevention (CDC).
Parkinson’s disease, meanwhile, is a movement disorder that causes tremors, stiff limbs, and balance and coordination problems. There is no cure, and the symptoms gradually worsen over time.
What does that have to do with hepatitis?
It’s not clear. But, Okun pointed out, liver cirrhosis — a serious scarring of the liver — is known to sometimes cause movement problems similar to Parkinson’s.