Trends in hepatitis B notifications 1976-87.

This paper considers trends in hepatitis B notifications in New Zealand during the period 1976 to 1987. It attempts also to demonstrate the fact that although notifications are never comprehensive, even incomplete statistics can give a reasonable and useful indication of trends. Since 1985 most districts have shown a gradual and persistent decline in notification rates. High notification rates are observed from Whangarei, Auckland, South Auckland, Rotorua, Gisborne and Hutt health districts. With a notification rate of 54 per 100,000 population in 1984 Whangarei health district gave the highest rate during this period. These observations are consistent with what is known from other studies about the geographical distribution of hepatitis B markers. Peak notification rates occur in the 15 to 25 age group with highest rates in groups of nonEuropean ethnicity. Notification rates within each district over the eleven year period are compared to the national rates. Further analyses by demographic factors based on information available for the year 1987 are presented. Again the highest rates are observed in groups of nonEuropean ethnicity with the Maori and Pacific Island populations showing rates of 27.2 and 23.0 per 100,000 population respectively. For the eleven year period notification rates for all types of infectious hepatitis are compared to identify secular trends. It is seen that hepatitis A notification rates have declined since the mid-1970s while rates for nonA nonB hepatitis and acute nonspecific hepatitis rose sharply in the early 1980s and have since declined slightly in 1986 and 1987.