Medical/biological study (observational study)

Neurovegetative disturbances in workers exposed to 50 Hz electromagnetic fields med./bio.

By: Bortkiewicz A, Gadzicka E, Zmyslony M, Szymczak W

Published in: Int J Occup Med Environ Health 2006; 19 (1): 53-60

Aim of study (acc. to author)

To study the cardiovascular function in workers occupationally exposed to 50 Hz electromagnetic fields.

Background/further details

The study group comprised 63 workers of switchyard substations and the control group 42 workers with comparable workplaces with no electromagnetic field exposure.

Endpoint

effects on the cardiovascular system: heart rate variability

Exposure

- electrical substation
- occupational

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: duration of employment 1 to 41 years	magnetic flux density: 37.3 µT maximum (to 26.1 µT) electric field strength: 6.7 kV/m maximum (to 4.3 kV/m)

Exposure 1

Main characteristics

Frequency	50 Hz
Type	electric field magnetic field
Waveform	sinusoidal
Exposure duration	duration of employment 1 to 41 years
Additional info	Occupational exposure.

Exposure setup

Exposure source	switch yard substation operated at high and extra high voltage (110-400 kV)
Additional info	The exposed group comprised of 63 male technical service workers, aged 22-67 years, at four substations. The control group consisted of of 42 male technical service workers, aged 20-68 years, at four radio link stations.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	37.3 µT	maximum	measured	-	to 26.1 µT
electric field strength	6.7 kV/m	maximum	measured	-	to 4.3 kV/m

Measurement and calculation details

EF was measured with a broadband MEH-1a meter and AE-43 probe. MF was measured with MNP89 meter and a directional probe.

Exposed system:

human
whole body

Methods Endpoint/measurement parameters/methodology

effects on the cardiovascular system: heart rate variability (time- and frequency-domain heart rate variability parameters; power spectrum); ECG; blood pressure
general medical examinations combined with an interview

Investigated system:

investigation on living organism

Investigated organ system:

cardiovascular system

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The relative risk of decreased heart rate variability was significantly higher in the exposed group than in controls. The very low frequency power spectrum was significantly higher in the exposed group and correlated with the exposure level. The percentage of subjects with dominant sympathetic function was significantly higher in the study group than in controls (65% vs. 47%).
It was concluded that occupational exposure to 50 Hz electromagentic fields could influence the neurovegetative regulation of the cardiovascular system.

Study character:

medical/biological study
observational study
full/main study

Study funded by

National Committee for Scientific Research (KBN), Poland

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