Early life exposure to diagnostic radiation and ultrasound scans and risk of childhood cancer: case-control studyBMJ 2011; 342 doi: https://doi.org/10.1136/bmj.d472 (Published 10 February 2011) Cite this as: BMJ 2011;342:d472
- Preetha Rajaraman, investigator1,
- Jill Simpson, research fellow2,
- Gila Neta, post-doctoral fellow1,
- Amy Berrington de Gonzalez, investigator1,
- Pat Ansell, senior lecturer2,
- Martha S Linet, senior investigator1,
- Elaine Ron, senior investigator1,
- Eve Roman, professor of epidemiology2
- 1Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, 6120 Executive Blvd, Bethesda, MD 20892-7238, USA
- 2Epidemiology and Genetics Unit, Department of Health Sciences, University of York, York, UK
- Correspondence to: P Rajaraman
- Accepted 1 November 2010
Objective To examine childhood cancer risks associated with exposure to diagnostic radiation and ultrasound scans in utero and in early infancy (age 0-100 days).
Design Case-control study.
Setting England and Wales.
Participants 2690 childhood cancer cases and 4858 age, sex, and region matched controls from the United Kingdom Childhood Cancer Study (UKCCS), born 1976-96.
Main outcome measures Risk of all childhood cancer, leukaemia, lymphoma, and central nervous system tumours, measured by odds ratios.
Results Logistic regression models conditioned on matching factors, with adjustment for maternal age and child’s birth weight, showed no evidence of increased risk of childhood cancer with in utero exposure to ultrasound scans. Some indication existed of a slight increase in risk after in utero exposure to x rays for all cancers (odds ratio 1.l4, 95% confidence interval 0.90 to 1.45) and leukaemia (1.36, 0.91 to 2.02), but this was not statistically significant. Exposure to diagnostic x rays in early infancy (0-100 days) was associated with small, non-significant excess risks for all cancers and leukaemia, as well as increased risk of lymphoma (odds ratio 5.14, 1.27 to 20.78) on the basis of small numbers.
Conclusions Although the results for lymphoma need to be replicated, all of the findings indicate possible risks of cancer from radiation at doses lower than those associated with commonly used procedures such as computed tomography scans, suggesting the need for cautious use of diagnostic radiation imaging procedures to the abdomen/pelvis of the mother during pregnancy and in children at very young ages.
We thank Emily Steplowski of Information Management Systems for help with statistical programming. We especially thank the families of children included in the study, without whom this investigation would not have been possible.
Contributors: All authors contributed to the design and conduct of the study, critically reviewed manuscript drafts, and approved the final version. PR and ERoman are the guarantors.
Funding: This research was supported in part by intramural funds from the National Cancer Institute, National Institutes of Health, Department of Health and Human Services, USA. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organisations imply endorsement by the US government. The United Kingdom Childhood Cancer Study (UKCCS) is sponsored and administered by Leukaemia and Lymphoma Research. The UKCCS was conducted by 12 teams of investigators (10 clinical and epidemiological and two biological) based in university departments, research institutes, and the National Health Service in Scotland. Its work is coordinated by a management committee. The researchers are independent from the funders.
Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare no relationships with companies that might have an interest in the submitted work in the previous three years and no non-financial interests that may be relevant to the submitted work.
Ethical approval: Initial approval for the study was obtained individually from all local ethics committees in Great Britain. Updated approval was obtained in 2005 from the Northern and Yorkshire Multi-Centre Research Ethics Committees (REC reference number 05/MRE03/22).
Data sharing: No additional data available.
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