Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology
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Cancer Epidemiol. Biomarkers Prev. · Feb 2002
Diagnostic X-rays and ultrasound exposure and risk of childhood acute lymphoblastic leukemia by immunophenotype.
The objective of this study was to evaluate the association between in utero diagnostic X-rays and childhood acute lymphoblastic leukemia (ALL) and the less well-studied relationship of this malignancy to preconception and postnatal diagnostic X-rays or fetal ultrasound exposures. The Children's Cancer Group conducted a case-control study including interviews with parents of 1842 ALL cases diagnosed under the age of 15 years and 1986 individually matched controls. Associations of self-reported parental preconception, in utero, and postnatal X-ray exposure with risk of childhood ALL were examined using odds ratios (ORs) and corresponding 95% confidence intervals (CIs) obtained from logistic regression models among the overall group of ALL cases as well as immunophenotypic and age-specific subgroups. ⋯ We found little consistent evidence that in utero diagnostic ultrasound tests or X-rays were linked with an increased risk of childhood ALL. Small increases in total or pre-B ALL risks for children in selected age groups to very low ionizing radiation exposures from postnatal or preconception diagnostic X-ray exposures may represent chance findings or biases. Future studies of diagnostic X-rays and childhood leukemia in the United States will require extensive additional efforts and resources to quantify risk because of declining in utero exposures in the general population (thus necessitating large numbers of subjects, particularly cases) and the difficulty in validating reported exposures.