A cohort study of hepatitis C virus (HCV) infection in an HCV epidemic area of Japan: age and sex-related seroprevalence of anti-HCV antibody, frequency of viremia, biochemical abnormality and histological changes

We studied the age-and sex-specific prevalence of hepatitis C virus (HCV) i nfection and aminotransferase abnormalities as well as histological changes in the liver associated with HCV infection. Of the eligible 3,707 inhabita nts aged 6 years and older in an HCV infection epidemic area 2,382 (63.3%) were examined. The anti-HCV positivity rate was 20.7% on average and increa sed according to age. Age was the most potential risk indicator for anti-HC V positivity by multiple stepwise regression analysis. The HCV RNA positivi ty rate in females with anti-HCV was significantly lower than that in males . However, as the age of females increased, the HCV RNA positivity rate bec ame higher. The proportion of subjects with aminotransferase abnormalities among HCV RNA-positive subjects was significantly lower in females than mal es. Aminotransferase abnormalities significantly increased with age in fema les. In subjects with abnormal aminotransferase levels, nearly half of the HCV RNA-positive females were aged 50 or older and also nearly half of the male subjects showed CAH2B or liver cirrhosis, while most of the HCV RNA-po sitive females younger than 50 exhibited histological findings consistent w ith CPH. In conclusion, age was the principal risk indicator for HCV infect ion in this area. Females, especially those younger than 50, both biochemic ally and histologically showed less severity of HCV infection than males. G ender and age might have effects on the outcome of HCV related liver diseas e.