睡眠: self-reported sleep quality (e.g. sleep latency, duration, efficiency, disturbance; Pittsburgh Sleep Quality Index); environmental and occupational items, use of mobile phones (questionnaire-based physicians' interview); health-related quality of life
Neither GSM frequency nor daily duration of mobile phone use was found to be associated with quality of sleep. Reduced quality of sleep was correlated with a higher number of unexplained somatic complaints as well as with subjective stress. Therefore, this aspect should be taken into account when evaluating quality of sleep in environmental studies.