title: Residential magnetic field exposure and childhood brain cancer: a meta-analysis.
abstract: BACKGROUND
  We conducted a meta-analysis of studies on magnetic field exposure and childhood brain tumors to evaluate homogeneity in the results, to examine reasons for heterogeneity, and to derive a summary effect estimate. Comparison of results from studies of childhood brain cancer and childhood leukemia may also help to assess the potential for selection bias in childhood leukemia studies.
  
  
  METHODS
  We included results from 13 studies. Using an inverse variance-weighted method, summary effect estimates were calculated separately for distance, wire codes, and measured and calculated magnetic fields. Sensitivity analyses were conducted to assess the influence of individual studies, the potential for selection bias, and the possibility of publication bias.
  
  
  RESULTS
  With the exception of wire-code studies, results were compatible with homogeneity across studies. The summary odds ratios (95% confidence intervals) were 0.88 (0.57-1.37) for distance <50 m and 1.14 (0.78-1.67) for calculated or measured magnetic fields above 0.2 microT. For measured or calculated exposures above 0.3 or 0.4 microT, the summary odds ratio was 1.68 (0.83-3.43), with no differences by method of exposure assessment. No single study had a substantial effect on the summary estimates. There was no indication of publication bias.
  
  
  CONCLUSIONS
  With the exception of high cut-point analyses (0.3/0.4 microT), where the possibility of a moderate risk increase cannot be excluded, no increase in childhood brain cancer risk was evident for any of the exposure metrics.
authors: Environment Division, Electric Power Research Institute, Palo Alto, CA 94304, USA. gmezei@epri.com
authors: Gabor
authors: G
authors: Mezei
authors: May
authors: M
authors: Gadallah
authors: Leeka
authors: L
authors: Kheifets
mesh_terms: D001932:Brain Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D003627:Data Interpretation, Statistical; D004574:Electromagnetic Fields / Q000009:adverse effects*; D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D018570:Risk Assessment