Geomagnetic disturbances are associated with reduced nocturnal excretion of a melatonin metabolite in humans

• Published in: Neuroscience letters Vol. 266; no. 3; pp. 209 - 212
• Main Authors: Burch, J.B, Reif, J.S, Yost, M.G
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 14.05.1999; Elsevier
• Subjects: 6-Hydroxymelatonin sulfate; Biological and medical sciences; Circadian Rhythm - physiology; Electromagnetic Fields - adverse effects; Fundamental and applied biological sciences. Psychology; Hormones and neuropeptides. Regulation; Humans; Hypothalamus. Hypophysis. Epiphysis. Urophysis; K index; Magnetic fields; Male; Melatonin - analogs & derivatives; Melatonin - urine; Occupational Exposure; Photic Stimulation; Pineal; Vertebrates: endocrinology; 6-Hydroxymelatonin sulfate; K index; Magnetic fields; Pineal; Human; Excretion; Melatonin; Metabolite; Magnetic field; Geomagnetic disturbance; Pineal hormone
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(99)00308-0

The effects of geomagnetic disturbances on urinary excretion of the melatonin metabolite, 6-hydroxymelatonin sulfate (6-OHMS), were studied in conjunction with 60 Hz magnetic field (MF) and ambient light exposure in 132 electric utility workers. Geomagnetic activity was assessed using a local (equivalent amplitude or A K, Boulder, CO) and global (average antipodal or aa) index. Personal exposures to 60 Hz MFs and light were obtained using data-logging meters. The relationship between geomagnetic activity and 6-OHMS was assessed with adjustment for age, light exposure, and month of participation. Mean overnight 6-OHMS excretion was lower on days when the 36-h A K or aa values exceeded 30 nT. A greater reduction in 6-OHMS excretion was observed when increased geomagnetic activity was combined with elevated 60 Hz MF or reduced ambient light exposures.