Potential Link Between Parkinson's Disease and Viral Hepatitis

Hepatitis B virus (HBV) and hepatitis C virus (HCV) may be linked to an increased risk of developing Parkinson’s disease.

For a study published in Neurology, investigators used hospital records from a large British database to identify patients with a first case of HBV, HCV, autoimmune hepatitis, chronic active hepatitis, and HIV, from 1999 to 2011. The patients were compared with hospital records from individuals with relatively minor conditions, such as bunions, cataract surgery, and knee replacement surgery.

The records of all the participants were examined to identify who later developed Parkinson’s disease, according to the study.

Nearly 22,000 patients with HBV, 48,000 with HCV, and 6000 with autoimmune hepatitis, 4000 with chronic active hepatitis, and nearly 20,000 with HIV were included in the analysis. The patients were compared with more than 6 million individuals with minor conditions.

The results of the study showed that patients with HBV were 76% more likely to develop Parkinson’s disease compared with patients in the comparison group. Patients with HCV were 51% more likely to develop Parkinson’s disease.

In total, 44 patients with HBV developed Parkinson’s disease, compared with 25 cases that would be expected in the general population. Seventy-three individuals with HCV developed Parkinson’s disease, whereas, approximately 49 cases would have been expected in the general population.

There was no increased rate of Parkinson’s disease observed in patients with autoimmune hepatitis, chronic active hepatitis, and HIV.

Although a prior study showed a relationship between HCV and Parkinson’s disease, it did not show a relationship with HBV.

Limitations to the study were that investigators were unable to adjust for lifestyle factors, such as alcohol use and smoking, which could affect the risk of Parkinson’s disease. Furthermore, the study was based solely on patients who were evaluated at a hospital.

In the United States, the CDC estimates that anywhere from 850,000 to 2.2 million individuals have chronic HBV, and 2.7 to 3.9 million have chronic HCV.

“The development of Parkinson’s disease is complex, with both genetic and environmental factors,” said author Julia Pakpoor, BM, BCh. “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.”