Incidence of hepatocellular carcinoma in New Zealand, 1974-78: ethnic, sex and geographical differences.

The incidence of hepatocellular carcinoma in New Zealand is examined for the period 1974-78. There was a significant north-south gradient for both Maori and non-Maori incidence rates, with the rates in the northern half of the North Island being approximately double those in the South Island. Within each region, Maori rates were approximately three times those of non-Maoris and incidence rates of males were approximately three times those of females. Incidence was particularly high in the Bay of Plenty, Waiapu and Otago hospital board districts. These patterns are generally consistent with available information concerning the distribution of hepatitis B surface antigen (HBsAg) carriage in New Zealand and suggest that HBsAg carriage is likely to be a major risk factor for hepatocellular carcinoma in New Zealand, as it is in other countries.