Study type: Epidemiological study (observational study)

Occupational Exposure to Magnetic Fields and Breast Cancer Among Women Textile Workers in Shanghai, China epidem.

Published in: Am J Epidemiol 2013; 178 (7): 1038-1045

Aim of study (acc. to author)

A nested case-cohort study was conducted to investigate the association between occupational exposure to magnetic fields and the risk of breast cancer within a cohort of female textile workers in Shanghai, China.

Endpoint/type of risk estimation

Type of risk estimation: (harzard ratio)



Exposure groups

Group Description
Reference group 1 cumulative magnetic field exposure 1st quartil: > 0 - 2.70 µT-years
Group 2 cumulative magnetic field exposure 2nd quartil: > 2.70 - 4.13 µT-years
Group 3 cumulative magnetic field exposure 3rd quartil: > 4.13 - 6.24 µT-years
Group 4 cumulative magnetic field exposure 4th quartil: > 6.24 µT-years


Case group

Control group

Study size

Cases Controls
Eligible 1,763 4,780
Statistical analysis method: (adjustment: )

Results (acc. to author)

The average level of magnetic field exposure for all 102 positions studied was 0.25 µT, the range of arithmetic means for 102 positions was between 0.02 µT and 0.9 µT. The positions with highest MF exposure were spinning machine operators (0.9 µT) and sewing machine operators (0.81 µT).
No association was observed between cumulative exposure to magnetic fields and overall risk of breast cancer (hazard ratio for group 4: 1.03, CI 0.87, 1.21). Similar null findings were observed when exposures were lagged and stratified by age at breast cancer diagnosis.
The authors conclude that the findings do not support the hypothesis that magnetic field exposure increases the risk of breast cancer.

Study funded by

Comments on this article

Related articles