Epidemiology of childhood leukemia.

Leukemia is the most common malignancy among children under the age of 15. It has recently been shown that the incidence rate of acute lymphoblastic leukemia, the predominant type of childhood leukemia in the United States and many European countries, is increasing among young children. Several recent etiologic studies focusing on the investigation of leukemia risk among young children have suggested that maternal exposures during pregnancy, such as low-dose radiation from the Chernobyl accident, parental alcohol consumption, and dietary habits, may be related to the risk of leukemia in infants. Paternal preconception smoking has also been reported to be associated with an increased risk of childhood leukemia, particularly among young children. Other etiologic hypotheses investigated recently include the association of childhood leukemia with infection and with birth weight. This paper briefly surveys the progress of epidemiologic research on childhood leukemia in 1996.