Medical/biological study (observational study)

Relationship between amyloid beta protein and melatonin metabolite in a study of electric utility workers med./bio.

By: Noonan CW, Reif JS, Burch JB, Ichinose TY, Yost MG, Magnusson K

Published in: J Occup Environ Med 2002; 44 (8): 769-775

Aim of study (acc. to author)

To assess the relationship between occupational magnetic field exposure, the urinary melatonin metabolite 6-hydroxymelatoninsulfate and concentrations of amyloid beta protein, a protein (40-42 amino acids) associated with the lesions of Alzheimer's disease.

Background/further details

60 male employees from three electric utilities participated.

Endpoint

molecular biosynthesis: concentration of amyloid beta protein
endocrine changes: concentration of melatonin metabolite 6-hydroxymelatoninsulfate

Exposure

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: during the first 3 days of the week	magnetic flux density: 0.12 µT (distribution and generation workers) magnetic flux density: 0.06 µT (administration and maintenance workers) magnetic flux density: 0.3 µT mean (arithmetic mean for all workers) magnetic flux density: 0.11 µT mean (geometric mean for all workers)

General information

Measurement of magnetic field due to occupation exposure of employees working at electrical distribution, generation, administration and maintenance utilities.

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	during the first 3 days of the week

Exposure setup

Additional info	Male employees from electric power distribution and generation utilities served as high exposure groups while employees from administration and maintenance served as low exposure group.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.12 µT	-	measured	-	distribution and generation workers
magnetic flux density	0.06 µT	-	measured	-	administration and maintenance workers
magnetic flux density	0.3 µT	mean	measured	-	arithmetic mean for all workers
magnetic flux density	0.11 µT	mean	measured	-	geometric mean for all workers

Measurement and calculation details

The participants wore an EMDEX 2 meter in a pouch around the waist, both at work and at home.

Exposed system:

human
whole body

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: urinary concentration of amyloid beta protein (2 lengths of the protein (amino acids 1-40 and 1-42); ELISA)
endocrine changes: plasma concentration of 6-hydroxymelatoninsulfate (radioimmunoassay)
questionnaire about work activities, current medical conditions, family histories of neurodegenerative conditions, exposure to aluminium etc.

Investigated system:

isolated bio./chem. substance
blood and urine samples

Investigated organ system:

endocrine system

Time of investigation:

during exposure

Main outcome of study (acc. to author)

Average amyloid beta protein levels were positively associated with categories of magnetic field exposure, but this relationship was weak and not statistically significant. The melatonin metabolite was inversely correlated with amyloid beta protein (amino acids 1-42) and the ratio of "amyloid beta protein (amino acids 1-42) to amyloid beta protein (amino acids 1-40)".

Study character:

medical/biological study
observational study
full/main study
cohort study
blind study

Study funded by

National Institute of Environmental Health Sciences (NIEHS), North Carolina, USA
National Institutes of Health (NIH), Maryland, USA
Platte River Power Authority (PRPA), USA

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