Study type: Epidemiological study (observational study)

Occupational exposure to extremely low frequency magnetic fields and brain tumour risks in the INTEROCC study. epidem.

Published in: Cancer Epidemiol Biomarkers Prev 2014; 23 (9): 1863-1872

Aim of study (acc. to author)

The association between occupational exposure to extremely low frequency magnetic fields and brain tumor risks was investigated in an international case-control study (INTEROCC study).

Further details

Seven of the overall 13 countries participating in the INTERPHONE study conducted the INTEROCC study to address potential occupational risk factors for glioma and meningioma.

Endpoint/type of risk estimation

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

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 cumulative exposure: < 2.11 µT-years
Group 2 cumulative exposure: 2.11 - < 3.40 µT-years
Group 3 cumulative exposure: 3.40 - < 5.00 µT-years
Group 4 cumulative exposure: 5.00 - < 7.50 µT-years
Group 5 cumulative exposure: ≥ 7.50 µT-years
Reference group 6 average exposure: < 0.11 µT
Group 7 average exposure: 0.11 - < 0.13 µT
Group 8 average exposure: 0.13 - < 0.17 µT
Group 9 average exposure: 0.17 - 0.24 µT
Group 10 average exposure: ≥ 0.24 µT
Reference group 11 maximum exposed job: < 0.13 µT
Group 12 maximum exposed job: 0.13 - < 0.17 µT
Group 13 maximum exposed job: 0.17 - < 0.23 µT
Group 14 maximum exposed job: 0.23 - < 0.62 µT
Group 15 maximum exposed job: ≥ 0.62 µT
Reference group 16 exposure duration: < 5 years
Group 17 exposure duration: 5 - < 15 years
Group 18 exposure duration: 15 - < 25 years
Group 19 exposure duration: ≥ 25 years

Population

Case group

Control group

Study size

Cases Controls
Eligible 5,399 11,112
Participants 3,978 5,601
Evaluable 3,761 5,404
Other:

1939 patients with glioma and 1822 patients with meningioma

Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

No association between lifetime cumulative exposure to extremely low frequency magnetic fields and glioma or meningioma risk was observed. However, an association between cumulative exposure to extremely low frequency magnetic fields in the time period 1 to 4 years before the diagnosis date and glioma was observed (OR ≥ 90th percentile vs. < 25th percentile: 1.67, CI 1.36-2.07), and a statistically non-significant association with meningioma (OR 1.23, CI 0.97-1.57) was found.
The authors concluded that the results showed an association between occupational exposure to extremely low frequency magnetic fields in the recent past and glioma. Occupational exposure to extremely low frequency magnetic fields may play a role in the later stages (promotion and progression) of brain tumorigenesis.

Study funded by

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