title: Exposure to magnetic fields and childhood acute lymphocytic leukemia in São Paulo, Brazil.
abstract: BACKGROUND
  Epidemiological studies have identified increased risks of leukemia in children living near power lines and exposed to relatively high levels of magnetic fields. Results have been remarkably consistent, but there is still no explanation for this increase. In this study we evaluated the effect of 60 Hz magnetic fields on acute lymphocytic leukemia (ALL) in the State of São Paulo, Brazil.
  
  
  METHODS
  This case-control study included ALL cases (n=162) recruited from eight hospitals between January 2003 and February 2009. Controls (n=565) matched on gender, age, and city of birth were selected from the São Paulo Birth Registry. Exposure to extremely low frequency magnetic fields (ELF MF) was based on measurements inside home and distance to power lines.
  
  
  RESULTS
  For 24h measurements in children rooms, levels of ELF MF equal to or greater than 0.3microtesla (μT), compared to children exposed to levels below 0.1 μT showed no increased risk of ALL (odds ratio [OR] 1.09; 95% confidence interval [95% CI] 0.33-3.61). When only nighttime measurements were considered, a risk (OR 1.52; 95% CI 0.46-5.01) was observed. Children living within 200 m of power lines presented an increased risk of ALL (OR 1.67; 95% CI 0.49-5.75), compared to children living at 600 m or more of power lines. For those living within 50 m of power lines the OR was 3.57 (95% CI 0.41-31.44).
  
  
  CONCLUSIONS
  Even though our results are consistent with the small risks reported in other studies on ELF MF and leukemia in children, overall our results do not provide support for an association between magnetic fields and childhood leukemia, but small numbers and likely biases weaken the strength of this conclusion.
authors.affiliation: Faculdade de Saúde Pública, Universidade de São Paulo, Brazil. wunsch@usp.br
authors.forename: Victor
authors.initials: V
authors.lastname: Wünsch-Filho
authors.forename: Daniele M
authors.initials: DM
authors.lastname: Pelissari
authors.forename: Flávio E
authors.initials: FE
authors.lastname: Barbieri
authors.forename: Leonel
authors.initials: L
authors.lastname: Sant'Anna
authors.forename: Claúdia T
authors.initials: CT
authors.lastname: de Oliveira
authors.forename: Juliana F
authors.initials: JF
authors.lastname: de Mata
authors.forename: Luiz G
authors.initials: LG
authors.lastname: Tone
authors.forename: Maria Lúcia de M
authors.initials: ML
authors.lastname: Lee
authors.forename: Maria Lydia M
authors.initials: ML
authors.lastname: de Andréa
authors.forename: Paula
authors.initials: P
authors.lastname: Bruniera
authors.forename: Sidnei
authors.initials: S
authors.lastname: Epelman
authors.forename: Vicente Odone
authors.initials: VO
authors.lastname: Filho
authors.forename: Leeka
authors.initials: L
authors.lastname: Kheifets
mesh_terms: D001938:Brazil; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004574:Electromagnetic Fields / Q000009:adverse effects*; D005260:Female; D006798:Housing; D006801:Humans; D007223:Infant; D008297:Male; D016017:Odds Ratio; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology* / Q000209:etiology*