Study type: Epidemiological study (observational study)

Occupational Exposure to Electromagnetic Field and Breast Cancer Risk in a Large, Population-Based, Case-Control Study in the United States. epidem.

Published in: J Occup Environ Med 2007; 49 (3): 266-274

Aim of study (acc. to author)

A population-based case-control study was conducted in the USA to investigate occupational exposure to electromagnetic fields and breast cancer risk.

Further details

Exposure was assessed according to the job exposure scheme of Coogan et al. (publication 1912) which is based on strength of potential magnetic field source, proximity of workstation to the source and how frequently a worker is at the workstation proximate to the source.

Endpoint/type of risk estimation

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



Exposure groups

Group Description
Reference group 1 exposure: background
Group 2 exposure: low
Group 3 exposure: medium
Group 4 exposure: high
Group 5 premenopausal women, exposure: background
Group 6 premenopausal women, exposure: low
Group 7 premenopausal women, exposure: medium
Group 8 premenopausal women, exposure: high
Group 9 postmenopausal women, exposure: background
Group 10 postmenopausal women, exposure: low
Group 11 postmenopausal women, exposure: medium
Group 12 postmenopausal women, exposure: high
Group 13 high potential for exposure: computer programmer
Group 14 high potential for exposure: assembler, electrical accessories
Group 15 medium potential for exposure: bookkeeper
Group 16 medium potential for exposure: data entry clerk
Group 17 medium potential for exposure: accounting clerk
Group 18 medium potential for exposure: telephone operator
Group 19 medium potential for exposure: accountant
Group 20 medium potential for exposure: payroll clerk


Case group

Control group

Study size

Cases Controls
Eligible 8,066 10,161
Participants 6,429 7,683
Participation rate 80 % 76 %
Evaluable 6,213 7,390
Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

A statistically not significant, slighly increased risk for breast cancer was observed for low, medium and high occupational exposure compared with the reference group. A statistically significant increased risk was found for data entry clerks.
The authors concluded that their findings, taken together with previous studies (publications 1912, 6826, 10719, 10081, 1048, 1060, and 10438), suggest that occupational exposure to electromagnetic fields might be associated with a slight elevation in breast cancer risk.

Limitations (acc. to author)

It is difficult to derive accurate exposure assessment from occupational data.

Study funded by

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