Epidemiological study (observational study)

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

By: Turner MC, Benke G, Bowman JD, Figuerola J, Fleming S, Hours M, Kincl L, Krewski D, McLean D, Parent ME, Richardson L, Sadetzki S, Schlaefer K, Schlehofer B, Schüz J, Siemiatycki J, van Tongeren M, Cardis E

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

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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

brain tumor: glioma and meningioma

Type of risk estimation:

incidence

(odds ratio (OR))

Exposure

- 50/60 Hz
- magnetic field
- occupational

Assessment

questionnaire: lifetime occupational calendar for all jobs held for a minimum of 6 months, including job title, company name, company description, and start and stop year
job exposure matrix
calculation: cumulative exposure, average exposure, maximum exposure, and exposure duration were calculated for the lifetime and for time periods of 1-4, 5-9 and ≥ 10 years before diagnosis date based on the job exposure matrix

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

Group:
- men
- women
Age: 30–69 years
Observation period: 2000 - 2004
Study location: Australia, Canada, France, Germany, Israel, New Zealand, UK

Case group

Characteristics: patients with glioma or meningioma
Data source: INTEROCC study

Control group

Matching:
- sex
- age
- country

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:

conditional logistic regression

(adjustment:

age
sex
education
country

)

Results (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

3
AFSSET (L'Agence française de sécurité sanitaire de l'environnement et du travail) France
Association pour la Recherche sur le Cancer (ARC), France
Australian Research Council (ARC)
Bouygues Telecom, France
Canada Research Chairs (Chaires de Recherche du Canada), Ottawa, Ontario, Canada
Canadian Institutes of Health Research (CIHR)
Canadian Wireless Telecommunications Association (CWTA; Association canadienne des télécommunications sans fil (ACTS)), Canada
Cancer Council NSW, Australia
Cancer Council Victoria, Australia
Cancer Society of New Zealand
Department of Health, UK
Deutsches Mobilfunk Forschungsprogramm (DMF; German Mobile Phone Research Programme) at Federal Office for Radiation Protection (BfS)
Government of Canada
GSM Association, UK/Ireland
Guzzo Environment-Cancer Chair (University of Montréal) in partnership with Cancer Research Society (CRS) undertaken by the Environment-Cancer Fund, Canada
Hawkes Bay Medical Research Foundation (HBMR), New Zealand
Health and Safety Executive, UK
Health Research Council of New Zealand
International Union against Cancer (UICC; Union Internationale Contre le Cancer), Switzerland
Le Fonds de recherche du Québec – Santé (FRQS), Canada
MAIFOR Program (Mainzer Forschungsförderungsprogramm) of the University of Mainz, Germany
Ministerium für Klimaschutz, Umwelt, Landwirtschaft, Natur- und Verbraucherschutz Nordrhein-Westfalen (Ministry for Climate Protection, Environment, Agriculture, Conservation and Consumer Protection of the state of North Rhine-Westphalia), Germany
Ministerium für Umwelt, Klima und Energiewirtschaft, Baden-Württemberg (Ministry of the Environment, Climate Protection and the Energy Sector of the state of Baden-Württemberg), Germany
Mobile Manufacturers Forum (MMF), Belgium
Mobile Telecommunications and Health Research (MTHR), UK
National Institutes of Health (NIH), Maryland, USA
Natural Sciences and Engineering Research Council (NSERC) of Canada
O2
Orange
Quality of Life and Management of Living Resources program of European Union
Scottish Executive/Scottish Ministers, UK
SFR, France
T-Mobile
University of Sydney, Australia
Vodafone
Wellington Medical Research Foundation (WMRF), New Zealand

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