Evaluation in humans of the effects of radiocellular telephones on the circadian patterns of melatonin secretion, a chronobiological rhythm marker

Abstract

A decrease in melatonin secretion has been observed in small mammals under exposure to extremely low frequency electromagnetic fields. As there is some concern about possible health effects of the increasing use of radiocellular telephones emitting radiofrequency electromagnetic fields, we examined whether such fields would alter melatonin levels in the human. Volunteers were two groups totalling 38 men, 20-32 yr old. Exposures were to commercially available cellular telephones of the GSM 900 type (Global System for Mobile communication at 900 MHz) or DCS 1800 type (Digital Communication System at 1800 MHz), for 2 hr/day, 5 days/wk, for 4 wk, at their maximum power. Attention of the volunteers was sustained by TV projection of movies. Blood samples were collected hourly during the night and every 3 hr in the daytime. Four sampling sessions were performed at 15-day intervals: before the beginning of the exposure period, at the middle and the end of the exposure period, and 15 days later to evaluate the persistence or late appearance of potential effects. Evaluated parameters were the maximum serum concentration, the time of this maximum, and the area under the curve of the hormone profile. Melatonin circadian profile was not disrupted in 37 young male volunteers submitted to a typical pattern of exposure to the electromagnetic fields generated by two common types of cell phones.

GSM modulated radiofrequency radiation does not affect 6‐sulfatoxymelatonin excretion of rats

“…So far there have been remarkably few researches carried out into the effects of RF GSM radiation on melatonin secretion. In human studies, no effects of GSM radiation were found either on salivary melatonin level [Radon et al, 2001] or on blood serum melatonin concentration [Mann et al, 1998;de Seze et al, 1999]. In laboratory animal studies, neither short [Vollrath et al, 1997] nor long term [Heikkinen et al, 1999] GSM RF exposure affected melatonin or 6SM production of rodents.…”

Effect of short-wave (6-22 MHz) magnetic fields on sleep quality and melatonin cycle in humans: the Schwarzenburg shut-down study

“…A melatonin suppressing or a rebound effect has not been detected so far in randomized crossover trials of mobile phone exposure (radiation in the high frequency range, 900-1800 MHz) de Seze et al, 1999;Radon et al, 2001;Bortkiewicz et al, 2002]. Three of those studies investigated melatonin in the night following or during the exposure only Radon et al, 2001;Bortkiewicz et al, 2002].…”

“…Two recent observational studies have found evidence of an association between decreased excretion of melatonin during night and increasing use of mobile phones [Burch et al, 2002;Jarupat et al, 2003]. However, four cross-over trials have found no association between exposure to mobile phone handset and melatonin excretion de Seze et al, 1999;Radon et al, 2001;Bortkiewicz et al, 2002].…”

Effects of electromagnetic radiation of mobile phones on the central nervous system

“…In primary pinealocyte cultures exposed in vitro to 60 Hz 0.05 mT vertical AC and 0.06 mT DC fields, melatonin production declined by almost 50% [Rosen et al, 1998], but in vivo studies of melatonin and other neurohormones revealed either increases [Lerchl et al, 1998;Zecca et al, 1998], decreases [Burch et al, 1999[Burch et al, , 2000Karasek et al, 1998;Reiter et al, 1998;Juutilainen et al, 2000], or no changes [Selmaoui et al, 1997;Truong and Yellon, 1997;Graham et al, 2000]. Pulsed microwave exposure at up to SAR 0.3 W/kg did not disrupt the normal circadian profile of melatonin or other hormones of the hypothalamo-pituitary-adrenal axis de Seze et al, 1998de Seze et al, , 1999, with the only exception of a commercial dairy herd kept in close proximity to a short wave (3-30 MHz) radio transmitter station. The animals in this herd, but not in another one, kept at a larger distance, exhibited a transient increase in salivary melatonin after the radio station was temporarily switched off [Stark et al, 1997].…”