Prevalence and Factors Associated with Hepatitis B Virus Infection Among Senior Citizens in a Southern Brazilian City

Background: Given the long term exposure to risk factors, it is likely that older adults exhibit the highest proportions of HBV serological markers. Nevertheless, there are few methodologically adequate studies in Brazil evaluating the prevalence and risk factors for HBV infection in individuals aged 60 years or more. Objectives: To estimate the prevalence and factors associated with HBV infection in elderly residents in the city of Tubarao/SC. Patients and Methods: This cross-sectional study included 820 individuals (>= 60 years) selected by simple random sampling. The variables were compared by chi-square test or Fisher's exact test and those with P < 0.200 were included in the regression model. Results: The mean age of patients was 68.6 +/- 7.0 years, 39% were men and 92% Caucasian. Five subjects (0.6%) presented with positive HBsAg and 124 (15.1%) were anti-HBc reactive. Bivariate analysis showed that the presence of anti-HBc was associated with age >= 67 years, <= 4 years of schooling, acupuncture therapy and lower proportion of subjects exposed to invasive procedures. In multivariate analysis, the following variables remained independently associated with HBV infection: male gender, marital status, <= 4 years of schooling and acupuncture. Conclusions: The prevalence of anti-HBc among the elderly in the city of Tubarao was higher than in previous studies evaluating blood donors in the same region. Despite the association of previous HBV infection and factors indirectly related to sexual risk behaviors, the results suggest the involvement of invasive therapeutic procedures in the HBV transmission chain.