1. ¹Public Health Institute, 555 12th St, Oakland, CA 94607, USA
2. ²Center for Epidemiology and Biostatistics, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
3. ³Electric Power Research Institute (EPRI), 3412 Hillview Avenue, Palo Alto, CA 94304, USA
4. ⁴Enertech Consultants, 300 Orchard City Drive, Suite 132, Campbell, CA 95008, USA
5. ⁵Exponent Health Sciences Group, 1800 Diagonal Road, Suite 300, Alexandria, VA 22314, USA
6. ⁶Department of Epidemiology, School of Public Health, University of California, Los Angeles, 650 Charles E Young Drive South, Los Angeles, CA 90095, USA
7. ⁷Department of Pediatrics, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA

Correspondence: Dr DE Foliart, 3470 Buskirk Ave, Pleasant Hill, CA 94523, USA. E-mail: dfoliart@hospicecc.org

Received 1 September 2005; Revised 18 October 2005; Accepted 18 November 2005; Published online 10 January 2006.

Abstract

We examined the association between magnetic field (MF) exposure and survival among children with acute lymphoblastic leukaemia (ALL) treated at 51 Pediatric Oncology Group centres between 1996 and 2001. Of 1672 potentially eligible children under treatment, 482 (29%) participated and personal 24-h MF measurements were obtained from 412 participants. A total of 386 children with ALL and 361 with B-precursor ALL were included in the analysis of event-free survival (time from diagnosis to first treatment failure, relapse, secondary malignancy, or death) and overall survival. After adjustment for risk group and socioeconomic status, the event-free survival hazard ratio (HR) for children with measurements 0.3 T was 1.9 (95% confidence interval (CI) 0.8, 4.9), compared to <0.1 T. For survival, elevated HRs were found for children exposed to 0.3 T (multivariate HR=4.5, 95% CI 1.5–13.8) but based on only four deaths among 19 children. While risk was increased among children with exposures above 0.3 T, the small numbers limited inferences for this finding.