CASE-CONTROL STUDY OF LEUKEMIA AND DIAGNOSTIC RADIATION EXPOSURE

A case-control study of leukemia and diagnostic X-ray exposure was con ducted by a multi-institution co-operative study group. The subjects w ere 134 patients with acute myelogenous leukemia, 57 with chronic myel ogenous leukemia, 56 with acute lymphocytic leukemia and 50 with myelo dysplasia syndrome, who were between 15 and 79 years old, and diagnose d at one of 27 hospitals between September 1993 and August 1995. The c ontrols were 479 first-visit patients seen at eight of these 27 hospit als. History of diagnostic X-ray tests between 1982 and 1991 was deter mined by an anonymous self-administered questionnaire. The total relat ive dose of radiation exposure was calculated by summing the products of given weights and frequencies of each test. The relative risk was 0 .83 (95% confidence interval (C.I.), 0.58-1.19) for relative dose of 1 0-30 (equivalent to 4-11 times of UGI series), 0.76 (0.48-1.20) for re lative dose of 30 or more (more than 12 times of UGI series), when com pared with relative dose of 0-10 (0-3 times of UGI series). Analysis a ccording to type of leukemia revealed that only acute myelogenous leuk emia had an estimated relative risk above unity (1.08, 95% C.I. 0.69-1 .69, for relative dose 10-30). This study did not support the hypothes is that diagnostic X-ray tests increases leukemia risk. (C) 1997 Elsev ier Science Ireland Ltd.