Trends in the incidence of leukemia in Denmark, 1943-77: an epidemiologic study of 14,000 patients.

An epidemiologic study of the total population of patients with leukemia in Denmark during 1943-77 was performed with special emphasis on time trends. The material stemmed from the national Danish Cancer Registry and was believed to be virtually complete. Of the 13,813 patients, 40% had acute leukemia; 40%, chronic lymphocytic leukemia; patients, 40% had acute leukemia; 40%, chronic lymphocytic leukemia; and 20%, chronic myeloid leukemia. Over the 35-year period, the incidence of acute leukemia increased threefold in the age groups 0-9 and 50-70+ years; whereas the increase in the age group 0-9 years climaxed in the 5-year period 1968-72, and the increase in the age group 50-70+ years was sustained. The incidence of chronic lymphocytic and chronic myeloid leukemia remained unchanged. No geographic pattern was discernible.