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

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