Hepatitis C viral infection and the risk of dementia

Background and purpose Hepatitis C virus (HCV) infection may cause cognitive impairment, but no studies have focused specifically on cognitive impairment stemming from HCV. The purpose of this study was to investigate the potential increased risk for dementia in HCV‐infected patients. Methods A population‐based cohort study based on the Taiwan National Health Insurance Research Database was conducted. From all potential participants aged 50 years or more, a total of 58 570 matched (1:1) pairs of HCV‐infected patients and non‐HCV‐infected patients were included. Each subject was individually tracked from 1997 to 2009 to identify incident cases of dementia (onset in 1999 or later). Cox proportional hazards regressions were employed to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between HCV infection and dementia. Results There were 2989 dementia cases from the HCV‐infected cohort during the follow‐up period of 533 861.1 person‐years; the overall incidence rates of dementia differed from the non‐HCV cohort (56.0 vs. 47.7 cases per 10 000 person‐years, P