Study type: Medical/biological study (observational study)

Magnetic fields and the melatonin hypothesis: a study of workers chronically exposed to 50-Hz magnetic fields. med./bio.

Published in: Am J Physiol Regul Integr Comp Physiol 2003; 284 (6): R1529-R1535

Aim of study (acc. to author)

To investigate the potential effect of occupational and residential exposure to 50 Hz magnetic fields on the secretion of melatonin in men.

Background/further details

Thirty male subjects participated in the study. Out of these, 15 were exposed to 50 Hz magnetic fields during worktime (in electrical substation) and free-time (living near the substation). The other 15 subjects had non-technical jobs and were subjected only to the normal electric and magnetic fields of daily environment.
Occurring magnetic fields were measured for each subject for one week with a wearable measurement device during normal activities. To determine the melatonin level in blood, subjects stayed in a hospital for one night. A catheter was inserted to collect blood samples hourly without waking. Additionally urine was collected to determine the 6-sulphatoxy melatonin level.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 1 - 20 years
Exposure 2: 50 Hz
control subjects

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration 1 - 20 years
Additional info exposed subjects
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2.6 µT mean measured - -
magnetic flux density 0.1 µT mean measured - -
magnetic flux density 0.64 µT mean measured - arithmetic mean of daytime
magnetic flux density 0.82 µT mean measured - arithmetic mean of nighttime
magnetic flux density 0.72 µT mean measured - arithmetic mean

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Additional info control subjects
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.092 µT mean measured - -
magnetic flux density 0.004 µT mean measured - -
magnetic flux density 0.04 µT mean measured - arithmetic mean of daytime
magnetic flux density 0.04 µT mean measured - arithmetic mean of nighttime
magnetic flux density 0.04 µT mean measured - arithmetic mean

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated material:
Investigated organ system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

No significant differences in the melatonin level as well as in the 6-sulphatoxy melatonin level were found between exposed subjects and the control group.
The authors conclude that occupational and residential exposure to 50 Hz magnetic fields do not lead to alterations in the melatonin secretion.

Study character:

Study funded by

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