Hepatitis B virus infections in Melanesians and Polynesians in New Caledonia.

Hepatitis B virus infections were examined in two ethnically different Pacific Island groups, 532 Melanesians and 401 Polynesians, living under similar environmental circumstances on the island of Ouvea, New Caledonia. High hepatitis B virus infection rates (Melanesians, 89.3%, and Polynesians, 86.3%) and hepatitis B surface antigen (HBsAg) carrier rates (Melanesians, 11.7%, and Polynesians, 8.0%) were observed in both groups. The carrier rate for HBsAg was generally higher in men, particularly Melanesian men. Comparing the Ouvea Melanesians and Polynesians to 170 Melanesians living on the main island of New Caledonia, significantly lower rates for hepatitis B virus infection (47.1%) and HBsAg carrier state (0.6%) were found. The findings suggest that environmental factors may be more important than genetic factors in hepatitis B infections in these populations. Tattooing did not appear to influence the presence of hepatitis B virus infection.