Magnetic fields exposure and childhood leukemia risk: a meta-analysis based on 11,699 cases and 13,194 controls.

OBJECTIVE: To observe the association between childhood leukemia and magnetic field exposure.

METHODS: The literature was searched by PubMed, ProQuest, Web of Science (SCI) and Medline databases during 1997-2013. Heterogeneity in several studies was weighted by I-squared value. Publication bias was tested by funnel plot and Egger's test. Odds ratio (OR) and 95% CI were used to evaluate the association strength. The statistical analyses in present study were carried out by STATA software package (version 12.0, College Station, TX).

RESULTS: A total of 11,699 cases and 13,194 controls in 9 studies were stratified by different exposure cut-off points. On condition of the reference <0.1 μT, statistical association between magnetic field intensity ≥0.4 μT and childhood leukemia was exhibited (for total leukemia: OR = 1.57, 95% CI = 1.03-2.40; for acute lymphocytic leukemia: OR=2.43, 95% CI = 1.30-4.55). On condition of the reference level of <0.2 μT, the positive association between magnetic field intensity ≥0.2 μT and childhood leukemia was found (OR = 1.31, 95% CI = 1.06-1.61).

CONCLUSIONS: The result in this meta-analysis indicated that magnetic field exposure level may be associated with childhood leukemia.