Sleep Disturbances in the Vicinity of the Short-Wave Broadcast Transmitter Schwarzenburg Schlafstorungen in der Umgebung des Kurzwellensenders Schwarzenburg

Summary Objectives The studies reported here investigated the association between health complaints and the vicinity to the short wave transmitter Schwarzenburg, and looked for evidence for a relationship between magnetic field exposure and sleep disturbances. Subjects and Methods Between 1992 and 1998 two cross-sectional and two panel studies were performed in the area of Schwarzenburg. In each cross-sectional survey about 400 adults living in differently exposed areas were asked about somatic and psycho-vegetative symptoms including sleep disturbances as well as possible confounding factors. Exposure was estimated based on 2621 measurements of magnetic field strength made in 56 locations. In the panel studies, sleep quality and melatonin excretion was studied when the transmission was interrupted or definitively shut down, respectively. Results In both surveys, prevalence of difficulties of falling asleep and in particular, maintaining sleep, increased with increasing radio frequency electromagnetic field exposure (RF-EMF). Sleep quality improved after interruption of exposure. A chronic change of melatonin excretion following RF-EMF exposure could not be shown, but a parallel study of salivary samples in cows showed a temporary increase after a short latency period following interruption of exposure. Conclusions The series of studies gives strong evidence of a causal relationship between operation of a short-wave radio transmitter and sleep disturbances in the surrounding population, but there is insufficient evidence to distinguish clearly between a biological and a psychological effect.