Medical/biological study (observational study)

No association between occupational exposure to ELF magnetic field and urinary 6-sulfatoximelatonin in workers. med./bio.

By: Gobba F, Bravo G, Scaringi M, Roccatto L

Published in: Bioelectromagnetics 2006; 27 (8): 667-673

Aim of study (acc. to author)

To study the effect of occupational extremely low frequency magnetic field exposure on urinary 6-sulphatoxy melatonin (6-OHMS) content in different workers (from clothing production, local utilities company, primary school, engineering industry and other companies).

Background/further details

Urinary 6-OHMS in morning samples is an indicator of night-time melatonin production. Urine was collected twice on friday and the following monday (interruption of occupational exposure).
Exposure was monitored for three complete work shifts in 59 workers using personal exposure meters. Workers were classified as "low exposed" (< or = 0.2 µT) or "higher exposed" (> 0.2 µT).

Endpoint

endocrine changes: melatonin secretion

Exposure

- magnetic field
- low frequency

Exposure	Parameters
Exposure 1: LF (< 10 MHz) Exposure duration: continuous for 3 complete work shifts	magnetic flux density: 0.54 µT mean (occupational exposure group) magnetic flux density: 0.04 µT mean (non-occupational exposure group)

Exposure 1

Main characteristics

Frequency	LF (< 10 MHz)
Type	magnetic field
Waveform	unspecified
Exposure duration	continuous for 3 complete work shifts
Additional info	Occupational exposure

Exposure setup

Setup	The meters were worn on the hip in a belted pouch. During the sleep, subjects were instructed to leave the meter beside the bed, close to the body, but not near electrical and electronic devices.
Additional info	59 workers, 26 men and 33 women, engaged in different occupations were included in the study: 26 in clothing production, 14 in local utility company, 6 primary school teachers, 5 in engineering industry and a further 8 in other occupations. Morning urine samples were collected twice: 1) on Friday after 4 days of occupational exposure or 2) on Monday after 2 days of no occupational exposure.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.54 µT	mean	measured	-	occupational exposure group
magnetic flux density	0.04 µT	mean	measured	-	non-occupational exposure group

Measurement and calculation details

MF was measured in all subjects using a personal exposure meters EMDEX Lite. The meter measures magnetic field induction in space along three orthogonal directions and calculates the values as the quadratic sum of all three directions.

Exposed system:

human
whole body

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: see "endocrine changes"
endocrine changes: melatonin secretion; creatinine content

Investigated system:

isolated bio./chem. substance
urine samples

Investigated organ system:

endocrine system

Time of investigation:

during exposure

Main outcome of study (acc. to author)

The data do not support the hypothesis that occupational exposure to extremely low frequency magnetic field may affect melatonin secretion.

Study character:

medical/biological study
observational study
full/main study

Study funded by

Ministero del Lavoro e delle Politiche Sociali (Ministry of Labour and Social Policies), Italy

Tiwari R et al. (2013): The Potential Bioeffects of Extremely Low Frequency Electromagnetic Fields on Melatonin Levels & Related Oxidative Stress in Electric Utility Workers Exposed to 132 kV Substation.
Burch JB et al. (2008): Geomagnetic activity and human melatonin metabolite excretion.
Davis S et al. (2006): Effects of 60-Hz magnetic field exposure on nocturnal 6-sulfatoxymelatonin, estrogens, luteinizing hormone, and follicle-stimulating hormone in healthy reproductive-age women: results of a crossover trial.
Touitou Y et al. (2003): Magnetic fields and the melatonin hypothesis: a study of workers chronically exposed to 50-Hz magnetic fields.
Hankin NN (2003): Comment on: Non-ionizing radiation, Part 1: Static and extremely low-frequency electric and magnetic fields, International Agency for Research on Cancer (IARC) Monograph (Vol. 80), 2002.
Youngstedt SD et al. (2002): No association of 6-sulfatoxymelatonin with in-bed 60-Hz magnetic field exposure or illumination level among older adults.
Bakos J et al. (2002): One week of exposure to 50 Hz, vertical magnetic field does not reduce urinary 6-sulphatoxymelatonin excretion of male wistar rats.
Lerchl A (2002): [The Melatonin Hypothesis – An Introduction].
Noonan CW et al. (2002): Relationship between amyloid beta protein and melatonin metabolite in a study of electric utility workers.
Karasek M et al. (2002): Melatonin and magnetic fields.
de Bruyn L et al. (2001): The influence of long-term exposure of mice to randomly varied power frequency magnetic fields on their nocturnal melatonin secretion patterns.
Bowman JD et al. (2000): Hazard surveillance for industrial magnetic fields: II. Field characteristics from waveform measurements.
Bakos J et al. (1999): Urinary 6-Sulphatoxymelatonin Excretion of Rats is not Changed by 24 Hours of Exposure to A Horizontal 50-Hz, 100-μT Magnetic Field.
Loscher W et al. (1998): Exposure of female rats to a 100-microT 50 Hz magnetic field does not induce consistent changes in nocturnal levels of melatonin.
Truong H et al. (1997): Effect of various acute 60 Hz magnetic field exposures on the nocturnal melatonin rise in the adult Djungarian hamster.
Bakos J et al. (1997): Urinary 6-sulphatoxymelatonin excretion is increased in rats after 24 hours of exposure to vertical 50 Hz, 100 microT magnetic field.
Mevissen M et al. (1996): Exposure of DMBA-treated female rats in a 50-Hz, 50 microTesla magnetic field: effects on mammary tumor growth, melatonin levels, and T lymphocyte activation.
Selmaoui B et al. (1996): Magnetic fields and pineal function in humans: evaluation of nocturnal acute exposure to extremely low frequency magnetic fields on serum melatonin and urinary 6-sulfatoxymelatonin circadian rhythms.
Floderus B et al. (1996): Magnetic-field Exposures in the Workplace: Reference Distribution and Exposures in Occupational Groups.
Stevens RG et al. (1996): The melatonin hypothesis: electric power and breast cancer.
Yellon SM (1996): 60-Hz magnetic field exposure effects on the melatonin rhythm and photoperiod control of reproduction.
Pfluger DH et al. (1996): Effects of exposure to 16.7 Hz magnetic fields on urinary 6-hydroxymelatonin sulfate excretion of Swiss railway workers.
Bakos J et al. (1995): Sinusoidal 50 Hz, 500 microT magnetic field has no acute effect on urinary 6-sulphatoxymelatonin in Wistar rats.
Rogers WR et al. (1995): Regularly scheduled, day-time, slow-onset 60 Hz electric and magnetic field exposure does not depress serum melatonin concentration in nonhuman primates.
Rogers WR et al. (1995): Rapid-onset/offset, variably scheduled 60 Hz electric and magnetic field exposure reduces nocturnal serum melatonin concentration in nonhuman primates.
Reiter RJ (1994): Melatonin suppression by static and extremely low frequency electromagnetic fields: relationship to the reported increased incidence of cancer.
Kato M et al. (1994): Horizontal or vertical 50-Hz, 1-microT magnetic fields have no effect on pineal gland or plasma melatonin concentration of albino rats.
Loscher W et al. (1994): Effects of weak alternating magnetic fields on nocturnal melatonin production and mammary carcinogenesis in rats.
Reiter RJ et al. (1988): Reduction of the nocturnal rise in pineal melatonin levels in rats exposed to 60-Hz electric fields in utero and for 23 days after birth.