[Epidemiology of leukemias in children]

Leukemias account for about 32% of all cancer diagnosed in children. At this age, approximately 75% of leukemias are classified as acute lymphocytic leukemia and 15% as acute myelocytic leukemia. There is a significant variation in the incidence of acute leukemia world-wide, the rates ranging from 9 to 50 per million. The incidence rates are high in Costa Rica, among whites in the USA, New Zealand, Australia. The incidence is low among US blacks and in developing countries of Asia and Africa. Acute leukemia incidence rates in Russia were in 1995 34.0 and 31.0 per million population for boys and girls, respectively. The epidemiological studies have shown that the risk of acute leukemia in infants and young children is related with parental occupational exposures to pesticides and other mutagenic and carcinogenic substances as well as with maternal smoking and alcohol consumption, maternal history of miscarriages. Etiology of acute leukemia in children is also related with prenatal and postnatal exposures to ionizing radiation and possibly to electromagnetic fields.