Parkinson's disease is considered the second most common degenerative brain disorder after Alzheimer's disease. Hepatitis C is a liver infection caused by a virus.
"Many factors clearly play a role in the development of Parkinson's disease, including environmental factors," said study author Chia-Hung Kao from China Medical University in Taichung, Taiwan.
"This nation-wide study, using the National Health Insurance Research Database of Taiwan, suggests that hepatitis caused specifically by the hepatitis C virus may increase the risk of developing the disease," said Kao.
The virus is transmitted through sharing needles, needle stick injuries in health care providers and passed on at birth from infected mothers.
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In Taiwan during the time of the study, blood transfusions were the most common cause of the virus. In the US, all donated blood has been screened for the virus since 1992.
The study involved 49,967 people with hepatitis and 199,868 people without hepatitis. Participants with hepatitis were placed into three groups: those infected with the hepatitis B virus (71 per cent), those with hepatitis C (21 per cent), and those who had both viruses (8 per cent).
Among those who did not have hepatitis, 1,060 developed Parkinson's disease.
Once researchers controlled for factors such as age, sex, diabetes and cirrhosis, they found that people with hepatitis C were nearly 30 per cent more likely to develop Parkinson's disease than the people who did not have hepatitis.
People with hepatitis B and those with both viruses were not more or less likely to develop Parkinson's than those who did not have hepatitis.