The objective of the proposed study is to evaluate the pineal hormone, melatonin, as a potential biomarker of occupational exposure to magnetic fields. Although the epidemiologic data are inconsistent, occupational and residential exposure to magnetic fields appear to increase the risk for leukemia and brain cancer. However, the mechanism for induction of human health effects by EMF is unclear. Melatonin suppression is a biologically plausible mechanism which needs to be evaluated in human populations. Therefore, this study is designed to test the hypothesis that workers exposed to magnetic fields experience a decrease in melatonin production. The hypothesis will be tested by measuring magnetic field and light exposures in a group of electric utility workers with elevated EMF exposures and in a comparison group of workers. Magnetic fields will be measured on a 24 hour basis using individual data logging meters. Melatonin production will be evaluated by measuring urinary concentrations of its major metabolite, 6-hydroxymelatonin sulfate. If there is an association between EMF exposure and melatonin production in humans, urinary 6-hydroxymelatonin may be an important biomarker for evaluating the biological response of workers to EMF exposures.
The specific aims of the project are: 1) to assess 24 hours exposures of electric utility workers to magnetic fields and light; 2) to characterize the day and night time production of melatonin in the same population of workers by measuring 6-OHMS; 3) to replicate preliminary data indicating that magnetic field exposure is associated with a reduction in 6-OHMS excretion; 4) to evaluate the individual differences in 6-OHMS excretion in response to magnetic field exposure during work, non-work and sleep periods; 5) to determine which characteristics of magnetic field exposure are most strongly associated with reduced 6-OHMS excretion and 6) to determine the characteristics of melatonin suppression in response to magnetic field exposure over a one year period.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES008117-02
Application #
2459032
Study Section
Special Emphasis Panel (ZRG4-SOH (01))
Project Start
1996-08-20
Project End
1999-07-31
Budget Start
1997-08-01
Budget End
1999-07-31
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Colorado State University-Fort Collins
Department
Public Health & Prev Medicine
Type
Schools of Veterinary Medicine
DUNS #
112617480
City
Fort Collins
State
CO
Country
United States
Zip Code
80523
Burch, James B; Reif, John S; Yost, Michael G (2008) Geomagnetic activity and human melatonin metabolite excretion. Neurosci Lett 438:76-9
Clark, Maggie L; Burch, James B; Yost, Michael G et al. (2007) Biomonitoring of estrogen and melatonin metabolites among women residing near radio and television broadcasting transmitters. J Occup Environ Med 49:1149-56
Burch, James B; Clark, Maggie; Yost, Michael G et al. (2006) Radio frequency nonionizing radiation in a community exposed to radio and television broadcasting. Environ Health Perspect 114:248-53
Ichinose, Travers Y; Burch, James B; Noonan, Curtis W et al. (2004) Immune markers and ornithine decarboxylase activity among electric utility workers. J Occup Environ Med 46:104-12
Noonan, Curtis W; Reif, John S; Burch, James B et al. (2002) Relationship between amyloid beta protein and melatonin metabolite in a study of electric utility workers. J Occup Environ Med 44:769-75
Burch, J B; Reif, J S; Noonan, C W et al. (2002) Melatonin metabolite excretion among cellular telephone users. Int J Radiat Biol 78:1029-36
Burch, J B; Reif, J S; Noonan, C W et al. (2000) Melatonin metabolite levels in workers exposed to 60-Hz magnetic fields: work in substations and with 3-phase conductors. J Occup Environ Med 42:136-42
Burch, J B; Reif, J S; Yost, M G et al. (1999) Reduced excretion of a melatonin metabolite in workers exposed to 60 Hz magnetic fields. Am J Epidemiol 150:27-36
Burch, J B; Reif, J S; Yost, M G (1999) Geomagnetic disturbances are associated with reduced nocturnal excretion of a melatonin metabolite in humans. Neurosci Lett 266:209-12
Burch, J B; Reif, J S; Yost, M G et al. (1998) Nocturnal excretion of a urinary melatonin metabolite among electric utility workers. Scand J Work Environ Health 24:183-9