Study type: Epidemiological study (observational study)

Exposure to magnetic fields and the risk of poor sperm quality. epidem.

Published in: Reprod Toxicol 2010; 29 (1): 86-92

Aim of study (acc. to author)

A population-based case-control study was conducted in China to investigate whether exposure to high magnetic field levels reduces sperm quality.

Further details

Case or control status was determined by semen analyses of two specimens per participant according to the WHO criteria for poor semen quality. The magnetic field exposure was assessed by 24-h measurement on a typical day of the 3 months period representing the cycle length for spermatogenesis. The cutpoint 90th percentile was defined as the magnetic field level above which 10 % of all 24-h measurements had a higher value. The 90th percentile was 0.16 µT (1.6 mG) and corresponded to 2.4 h of the exposure period (10% of 24 h).

Endpoint/type of risk estimation

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



Exposure groups

Group Description
Reference group 1 magnetic field level at 90th percentile: < 0.16 µT
Group 2 magnetic field level at 90th percentile: ≥ 0.16 µT
Reference group 3 duration of magnetic field exposure ≥ 0.16 µT: < 1 h
Group 4 duration of magnetic field exposure ≥ 0.16 µT: 1 - 3 h
Group 5 duration of magnetic field exposure ≥ 0.16 µT: 3 - 6 h
Group 6 duration of magnetic field exposure ≥ 0.16 µT: > 6 h


Case group

Control group

Study size

Cases Controls
Eligible 127 95
Participants 76 72
Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

A two-fold increased risk of poor sperm quality was observed among participants with a daily exposure for a relative long duration (2,4 h/day) to magnetic fields ≥ 0.16 µT compared to less exposed participants. The association was further supported by a dose-response relationship (groups 3 - 6) and increased strength of the association after restricting to participants whose measurement day reflected their typical day of the previous three months (period of spermatogenesis). An inverse correlation was observed between magnetic field exposure and all semen parameters.
The author concluded that some evidence was found that magnetic fields might have an adverse effect on sperm quality.

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