Paternal military service and risk for childhood leukemia in offspring.

To assess the association between paternal military service and risk for childhood leukemia, the authors analyzed data from three case-control studies conducted by the Children's Cancer Group from 1983 to 1993. A total of 605 acute myeloid leukemia (AML, age < or = 18 years) cases, 2,117 acute lymphoblastic leukemia (ALL, age < or = 14 years) cases, and 3,155 individually matched controls were included in these studies. Paternal military history and other exposure data were obtained in 2,343 matched case-control sets, including 1,805 ALL and 528 AML cases. Paternal general military service was not associated with the leukemia risk. A small, but significant, increase in the risk for AML was seen, however, among offspring of veterans who had served in Vietnam or Cambodia (odds ratio (OR) = 1.7; 95% confidence interval (CI): 1.0, 2.9), after adjustment for paternal education, race, income, smoking, X-ray exposure, and marijuana use. The risk was predominantly present in children diagnosed before the age of 2 (OR = 4.6; 95% CI: 1.3, 16.1), although there were inconsistencies in the risks associated with length of time served and interval between service and diagnosis of leukemia. Military service in Vietnam or Cambodia was unrelated to the risk for ALL. The etiologic importance, if any, of these observations has yet to be determined.