Incidence of childhood leukemia in Sweden 1975-1980.

During the six-year period 1975-1980, leukemia was diagnosed in 466 children in Sweden, giving an estimated incidence of 4.4/100 000 children per year (0-15 years at diagnosis). The incidence of acute lymphoblastic leukemia (ALL) was 3.7, of acute nonlymphocytic leukemia (ANLL) 0.6 and of chronic myelocytic leukemia (CML) 0.1/100 000 children per year. The over all incidence among boys was 4.5/100 000 per year and among girls 4.2. The male: female ratio was 1.13. This ratio was 1.22 in ALL and 0.71 in ANLL. Fifty per cent of the children were below 5 years of age at diagnosis, with a pronounced peak between 2-3 years, which was explained by the ALL distribution. In children with acute leukemia 13% had WBC values of greater than 100 X 10(9)/1, 4% had CNS leukemia and 10% had a mediastinal mass at diagnosis. The geographical distribution of leukemia in Sweden was analysed in a search for clusters of cases.