Prevalence of Hepatitis B Virus (HBV) surface antigen and HBVassociated hepatocellular carcinoma in Kenyans of various ages

As a follow-up of an earlier study in Kenya that reported a 5:1 association between chronic liver disease and/or liver cancer with hepatitis B virus surface antigens (HBsAg), we investigated the prevalence of hepatitis B virus surface antigen in an asymptomatic rural normadic population, and among hepatocellular carcinoma patients in a major urban centre. In a rural population of 579 individuals, there was an overall HBsAg prevalence of 8.8%, with the largest number (34%) of those positive being between 5 and 10 years of age. The number of HBsAg positives decreased with advance in age, suggesting either mother to child transmission or early childhood exposure to hepatitis B virus (HBV). In a small group (N = 51) of rural patients seeking medical attention because of clinical symptoms of hepatomegaly and/or splenomegaly, 52% were HBsAg positive. Of the 88 liver cancer biopsies examined from an urban population, 78 (86.6%) were hepatocellular carcinoma (HCC) cases occurring mostly among 41 – 60 year old people, with the remaining being cholangiosarcomas (9%) and hepatoblastomas (2%). More importantly 75% of the HCC cases were HBsAg positive. Among the urban liver cancer cases, there was a male: female ratio of 5:2, which was also reflected by the high number of HBsAgpositive rural cases of patients with hepatomegaly. Taken together, these results indicate a greater than 5:2 association between HCC and HBV infection, and a higher prevalence of HBV exposure in males than females.