Hepatitis B, C Associated with Greater Risk of Parkinson's Disease

Patients with hepatitis B or C may be at an increased risk for Parkinson’s disease, according to researchers in the United Kingdom.

It’s challenging to determine how many people in the United States have hepatitis B and C since testing rates are not where they need to be. Even so, the US Centers for Disease Control and Prevention (CDC) estimate that the number of people with hepatitis B and C in the US range between 850,000 to 2.2 million and 2.7 to 3.9 million, respectively.

So how does hepatitis infection tie into Parkinson’s disease risk?

“The development of Parkinson’s disease is complex, with both genetic and environmental factors,” study author, Julia Pakpoor, BM, BCh, of the University of Oxford in the United Kingdom, said in a news 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.”

The team looked at hospital records from a UK database and identified patients with a first case of hepatitis B, hepatitis C, HIV, autoimmune hepatitis, and chronic active hepatitis. From 1999 to 2011, there were 22,000 people with hepatitis B, 48,000 with hepatitis C, almost 20,000 with HIV, 6,000 with autoimmune hepatitis, 4,000 with chronic active hepatitis. Health outcomes of these patients were compared with 6 million people diagnosed with minor conditions, including bunions, knee replacement surgery, and cataract surgery.

HIV, autoimmune hepatitis, and chronic active hepatitis were not associated with Parkinson’s disease. However, compared with those with minor conditions, people with hepatitis B were 76% more likely and people with hepatitis C were 51% more likely to develop Parkinson’s disease.

In the general population, it would be expected that there would be 25 cases of Parkinson’s, but in the hepatitis B cohort, 44 people developed the central nervous system disorder. In the patients with hepatitis C population, 73 people developed Parkinson’s, compared to the 49 expected in the general population.

The Parkinson’s risk was calculated into standardized rate ratio (RR). That risk was 1.76 (95% confidence interval (CI), 1.28-2.37; P < 0.001) for hepatitis B and 1.51 (05% CI, 1.18-1.9; P < 0.001) for hepatitis C.

“When including only those episodes for Parkinson’s disease that occurred first at least 1 year following each exposure condition, the RR for hepatitis B and hepatitis C were 1.82 (1.29-2.5) and 1.43 (1.09-1.84), respectively,” the authors wrote in the journal Neurology.

The researchers noted that they couldn’t control the study for lifestyle factors such as smoking and alcohol use, which could impact the risk of Parkinson’s. Regardless, they said that the findings provide strong evidence that hepatitis B and C are linked to higher rates of subsequent Parkinson’s.

“We hope that identifying this relationship may help us to better understand how Parkinson’s disease develops,” Pakpoor concluded.

The study, “Viral hepatitis and Parkinson disease,” was published in Neurology. The news release was provided by the American Academy of Neurology.

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