Risk factors for hepatitis B transmission in South Brazil.

Background: Hepatitis B virus (HBV) infection is a major public health problem in Brazil. Several risk factors are involved in HBV infection and their identification by a rational and essential approach is required to prevent the transmission of this infection in Brazil.

Objectives: To evaluate risk factors associated with HBV infection in South Brazil.

Methods: A total of 260 patients with HBV and 260 controls from Caxias do Sul (state of Rio Grande do Sul, Brazil) participated in this study. All participants were given a standard questionnaire to yield the sociodemographic information and to identify HBV risk factors. HBV infection was detected by HBsAg test in all participants.

Findings: HBV infection in these cases was strongly associated with history of a family member HBV-infected, mainly mother [odds ratio (OR) = 4.86; 95% confidence intervals (CI): 1.69-13.91], father (OR = 5.28; 95% CI: 1.58-17.71), and/or siblings (OR = 22.16; 95% CI: 9.39-52.25); sharing personal objects (OR = 1.40; 95% CI: 1.37-2.38); and having history of blood transfusion (OR = 2.05; 95% CI: 1.10-2.84).

Conclusions: HBV infection was strongly associated with having a family member infected with hepatitis B, sharing personal objects, and having history of blood transfusion.