Association of Paternal Diagnostic X-Ray Exposure with Risk of Infant Leukemia’

Whether low level radiation exposure before conception increases the risk of leukemia in offspring has been much debated. No study has specifically evaluated the effed of parental preconception diagnostic X-ray exposure in the development of leukemia among infants. Mothers of 302 infant leukemia cases (diagnosed at 1 8 months of age) and 558 individually matched regional controls, and fathers of 250 cases and 361 controls, were independently interviewed to obtain information on X-ray exposures. Paternal preconception X-ray exposure was associated with an increased risk of infant leukemia, higher risks being linked to exposures closer to conception. X-ray related leukemia risk varied with exposure site and histopathological type, the highest risk being for acute lymphocytic leukemia related to two or more X-rays of the lower gastrointestinal (GI) trad and lower abdomen (odds ratio, 3.78; 95% confidence interval, 1 .49-9.64). A positive association was observed between acute lymphocytic leukemia and number of paternal X-rays of the lower GI and lower abdomen (trend test, P < 0.01 ), upper GI (P = 0.04), and chest (P = 0.08). Exposures of head and neck and limbs were unrelated to risk. The risk of acute myelogenous leukemia was unrelated to paternal X-ray exposure, except for a marginally significant association (trend test, P = 0.07) for upper Gl X-rays. No consistent association between maternal X-ray exposure and infant leukemia was observed. The results of this study suggest that paternal low level radiation exposure before conception is associated with an increased risk of infant Received 6/28/94; revised 9/12/94; accepted 9/12/94. 1 Supported by National Cancer Institute Grant CA4279, the University of Minnesota Children’s Cancer Research Fund, and the United States Department of Health and Human Services. 2 To whom requests for reprints should be addressed, at Childrens Cancer Group, P.O. Box 60012, Arcadia, CA 91 066-601 2. 3 Contributing Childrens Cancer Group investigators, institutions, and grant numbers are given in the Appendix. leukemia, although the nature of this as3ociation needs to be further evaluated.