Hepatitis infection may increase the risk for Parkinson’s disease, though the reasons for the link remain unknown.
British investigators used records of 100,390 patients hospitalized with various forms of hepatitis or H.I.V. from 1999 to 2011. They compared Parkinson’s incidence in these patients with incidence in more than six million people admitted for medical or surgical conditions like cataracts, knee replacement or varicose veins.