Urinary 6-sulfatoxymelatonin excretion in humans during domestic exposure to 50 hertz electromagnetic fields

Exposure to extremely low frequency electromagnetic fields (ELF-EMF) has been suggested to suppress melatonin secretion, which might result in higher cancer risks because of its missing oncostatic action. We investigated the effects of residential exposure to ELF-EMF on the excretion of urinary 6-sulfatoxymelatonin (6-OHMS), the major melatonin metabolite, as an indicator of nocturnal melatonin secretion. 6-OHMS was measured in two spot urine samples, collected at 22.00 h and 08.00 h, in 29 men and 22 women. Spot ELF-EMF measurements were conducted at the centre and the four angles of the living room, the bedroom, and the kitchen of study subjects at low current configuration (all lights and appliances turned off), and they were repeated immediately at high current configuration (all lights and appliances turned on). Risk of a reduced 6-OMHS nocturnal secretion was elevated for daily alcohol intake (OR = 6.4; 95%C.I. 1.4,33.1), and body mass index (BMI) above the median (OR = 2.2; 95%C.I. 0.5,9.6). Risk of disrupted rhythm of 6-OHMS excretion was moderately elevated for domestic ELF-EMF exposure above the upper tertile at low current configuration (OR = 2.6; 95%C.I. 0.4,15.7). Alcohol consumption, BMI, and gender seem to affect nocturnal melatonin secretion, while an effect of residential exposure to ELF-EMF is uncertain. Future studies should properly account for the effect of such variables, when addressing the hypothesis of disturbances in melatonin secretion as a plausible explanation for the reported excess risk of several tumoral diseases associated with low level ELF-EMF exposure.