Study type: Epidemiological study

Pooled analysis of recent studies of magnetic fields and childhood leukemia epidem.

Published in: Environ Res 2022; 204 Pt A: 111993

Aim of study (acc. to author)

The association between the exposure to extremely low-frequency magnetic fields and the risk for childhood leukemia was investigated in a pooled analysis.

Further details

The following four studies conducted after the most recent pooled analysis by Kheifets et al. (2010) were included: Kheifets et al. (2017), Pedersen et al. (2015), Salvan et al. (2015) and Bunch et al. (2016).

Endpoint/type of risk estimation

Type of risk estimation: (odds ratio (OR))

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 magnetic flux density: < 0.1 µT
Group 2 magnetic flux density: 0.1 - < 0.4 µT
Group 3 magnetic flux density: ≥ 0.4 µT
Reference group 4 magnetic flux density: < 0.1 µT
Group 5 magnetic flux density: 0.1 - < 0.2 µT
Group 6 magnetic flux density: 0.2 - < 0.4 µT
Group 7 magnetic flux density: ≥ 0.4 µT

Population

Study size

Type Value
Total 55,673
Evaluable 49,715
Other:

analyzed: 22,128 cases and 27,587 controls

Statistical analysis method: ( adjustment: )

Results (acc. to author)

A total of 60 out of 49,715 children were exposed to magnetic field strengths of ≥ 0.4 μT.
Unlike previous pooled analyses, no increased risk of leukemia among children exposed to ≥ 0.4 μT was observed in comparison to children exposed to < 0.1 μT (OR 1.01; CI 0.61-1.66). Similarly, no association was observed in the subset of acute lymphoblastic leukemia and other subgroup analyses (e.g., time periods). In these studies, there is a decline in risk over time, also evident when the three pooled analyses (Ahlbom et al. (2000), Kheifets et al. (2010) and the present analysis) were compared. A meta-analysis of these three pooled analyses overall presents a statistically non-significant increased risk for childhood leukemia for children exposed to ≥ 0.4 μT in comparison to children exposed to < 0.1 µT (OR 1.45; Cl 0.95-2.20).
The authors conclude that the results are not in line with previous pooled analysis and show a decrease in effect to no association between exposure to magnetic fields and childhood leukemia. This could be due to methodological issues, chance, or a true finding of disappearing effect.

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