Most other epidemiological studies have looked at whether magnetic fields cause childhood leukaemia. This new study from 2006 looks instead at whether magnetic fields affect survival from childhood leukaemia. It does suggest that higher fields are associated with poorer survival, but because of small numbers and poor participation rates this can only be a suggestion. Another recent study from Germany has addressed the same issue.
Br J Cancer. 2006 Jan 16;94(1):161-4.
Magnetic field exposure and long-term survival among children with leukaemia.
Foliart DE, Pollock BH, Mezei G, Iriye R, Silva JM, Ebi KL, Kheifets L, Link MP, Kavet R. Public Health Institute, 555 12th St, Oakland, CA 94607, USA. email@example.com
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 muT was 1.9 (95% confidence interval (CI) 0.8, 4.9), compared to <0.1 muT. For survival, elevated HRs were found for children exposed to >/=0.3 muT (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 muT, the small numbers limited inferences for this finding.