Study type: Epidemiological study

Parental occupational exposure to low-frequency magnetic fields and risk of leukaemia in the offspring: findings from the Childhood Leukaemia International Consortium (CLIC). epidem.

Published in: Occup Environ Med 2019; 76 (10): 746-753

Aim of study (acc. to author)

The association between parental occupational exposure to extremely low frequency magnetic fields and the risk of leukemia in their offspring was studied in a pooled analysis of the Childhood Leukemia International Consortium (CLIC).

Further details

Two analytical approaches were used. First, a pooled analysis was performed including 11 case-control studies from 8 countries. Second, a meta-analysis was conducted based on individual risk estimates of the 11 case-control studies and further case-control studies (Smulevich et al. (1999), Feychting et al. (2000), Pearce et al. (2003) und Reid et al. (2011)).

Endpoint/type of risk estimation

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

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 paternal occupational exposure: ≤ 0.2 µT
Group 2 paternal occupational exposure: > 0.2 µT
Reference group 3 paternal occupational exposure: < 0.1 µT
Group 4 paternal occupational exposure: 0.1 - ≤ 0.2 µT
Group 5 paternal occupational exposure: > 0.2 - ≤ 1 µT
Group 6 paternal occupational exposure: > 1 µT
Reference group 7 maternal occupational exposure: ≤ 0.2 µT
Group 8 maternal occupational exposure: > 0.2 µT
Reference group 9 maternal occupational exposure: ≤ 0.1 µT
Group 10 maternal occupational exposure: > 0.1 - ≤ 0.2 µT
Group 11 maternal occupational exposure: > 0.2 µT

Population

Study size

Type Value
Total 26,822
Other:

overall 9,723 children with leukemia and 17,099 controls; analyzed: 8,420 children with ALL and 16,453 controls, 926 children with AML and 12,246 controls

Statistical analysis method: ( adjustment: )

Conclusion (acc. to author)

No statistically significant association between paternal or maternal occupational exposure to extremely low frequency magnetic fields and the risk for leukemia in their offspring was found. Similar results were observed for ALL or AML or in the highest exposure category.
The meta-analysis showed an increased overall risk of leukemia with borderline significance for paternal exposure (OR 1.11, CI 1.00-1.22) but not for maternal exposure (OR 1.04, CI 0.92-1.17).
The authors concluded that they did not find any associations between parental occupational exposure to extremely low frequency magnetic fields and childhood leukemia in the large international dataset.

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