Age- and sex-specific incidence of childhood leukemia by immunophenotype in the Nordic countries

Background: Studies from various countries have found an increasing incidence of childhood leukemia in recent de-cades. To characterize time trends in the age- and sex-specific incidence of childhood acute leukemia during the last 20 years in the Nordic countries, we analyzed a large set of population-based data from the Nordic Society of Paedi-atric Haematology and Oncology (NOPHO) in their acute leukemia database covering a population of approximately 5 million children aged 0–14 years. Methods: Temporal trends in acute myeloid leukemia and acute lymphoblastic leukemia incidence rates overall and for acute lymphoblastic leukemia immunophenotypes and for specific age groups were ana-lyzed by Poisson regression adjusting for age, sex, and coun-try. All statistical tests were two-sided. Results: We identified 1595 girls and 1859 boys diagnosed with acute lymphoblasti