Epidemiological study (observational study)

A cross-sectional study on oxidative stress in workers exposed to extremely low frequency electromagnetic fields epidem.

By: Li L, Xiong DF, Liu JW, Li ZX, Zeng GC, Li HL

Published in: Int J Radiat Biol 2015; 91 (5): 420-425

A cross-sectional study was conducted in China to investigate whether exposure to extremely low frequency magnetic fields could induce oxidative stress in workers regularly performing inspection tours close to voltage transformers and distribution power lines.

Type of risk estimation:

questionnaire: main activities during work and non-working periods
measurement: spot measurements of the magnetic flux density in the 500 kV and 220 kV transformer stations started 2 m from the authorized entrance of the areas and dotted at the outdoor routes of tour-inspections at 5 m apart and 1.5 m high from the ground; indoor spots dotted in rooms where the inspection staff took rest and in rooms of the administrative staff
calculation: 8 h time-weighted average magnetic flux density based on individual record of activities during work

Group	Description
Reference group 1	administrative staff: no exposure
Group 2	duration of magnetic field exposure: < 5 years
Group 3	duration of magnetic field exposure: ≥ 5 years
Reference group 4	8 h time-weighted average magnetic field strength: < 1.56 µT
Group 5	8 h time-weighted average magnetic field strength: 1.56 - 7.3 µT
Group 6	8 h time-weighted average magnetic field strength: > 7.3 µT

Group:
- men
- women
Age: ≥ 18 years
Characteristics: employees of power supply company
Observation period: not stated
Study location: China (Guangzhou)
Exclusion criteria: history of present illness, past illness, family heredopathia of mental and cardiovascular diseases

Type	Value
Total	700
Evaluable	560

Statistical analysis method:

In the 500 kV and 220 kV areas, the magnetic flux density at the spots ranged from 0.62-30.19 µT (median 18.7 µT) and from 0.51-60.11 µT (median 17.7 µT), respectively. In comparison, the magnetic flux density ranged from 0.07 to 0.72 µT with a median of 0.21 µT in the environment of the administrative staff. The 8 h time-weighted average magnetic flux density of the workers was 7.3 µT (1.56-26.3 µT).
No significant changes of the investigated oxidative stress parameters were found between workers that regularly perform inspection tours close to voltage transformers and distribution power lines and administrative staff.
The authors conclude that continual exposure to extremely low frequency electromagnetic fields might not induce oxidative stress in workers from a power supply company.

Bagheri Hosseinabadi M et al. (2021): Oxidative stress associated with long term occupational exposure to extremely low frequency electric and magnetic fields
Bagheri Hosseinabadi M et al. (2020): Investigating the effects of exposure to extremely low frequency electromagnetic fields on job burnout syndrome and the severity of depression; the role of oxidative stress
Zhang Y et al. (2016): Effects of dietary green tea polyphenol supplementation on the health of workers exposed to high-voltage power lines
Tiwari R et al. (2015): Epinephrine, DNA integrity and oxidative stress in workers exposed to extremely low-frequency electromagnetic fields (ELF-EMFs) at 132 kV substations
Villarini M et al. (2015): Primary DNA damage in welders occupationally exposed to extremely-low-frequency magnetic fields (ELF-MF)