Decreasing incidence of acute appendicitis.

All cases of acute appendicitis operated upon with removal of the appendix in one hospital, and from a defined district in Norway almost exclusively served by this hospital, have been registered for the 30 year period 1943-72. While the population has decreased slightly over this period, the number of acute appendectomies has diminished to less than half. This holds true also in the age group below 20, and for different severity grades of appendicitis.