Researchers have uncovered an association between hepatitis B and C viruses (HBV/HCV) and an increased risk of Parkinson’s disease, The New York Times reports.

Publishing their findings in the journal Neurology, researchers analyzed data on Parkinson’s rates among patient records in the English National Hospital Episode Statistics database, covering 1999 to 2011. They analyzed records of 22,000 people with hep B, 48,000 people with hep C, 6,000 people with autoimmune hepatitis, 4,000 people with chronic active hepatitis and close to 20,000 people with HIV. They compared these groups with a cohort of more than 6 million people with relatively innocuous conditions, including cataract surgery, bunions and knee replacement surgery.

The investigators found that compared with the group with the relatively minor health conditions, those with hep B and hep C were a respective 76 percent and 51 percent more likely to develop Parkinson’s. All told, 44 cohort members with hep B developed Parkinson’s, compared with the 25 cases that would be expected among the general population. For those with hep C, the corresponding number of cases were 73 and 49.

Those with autoimmune hepatitis, chronic active hepatitis and HIV did not have an increased risk of Parkinson’s compared with the cohort with the relatively minor health conditions.

The study is limited by the fact that the investigators could not adjust the data to take into account lifestyle factors that may affect the risk of Parkinson’s, such as smoking and alcohol use. Additionally, the study looked only at those who were evaluated at a hospital.

To read the New York Times article, click here.

To read the study abstract, click here.

To read a press release about the study, click here.