1. Department of Pneumonology, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece
2. Laboratory of Hygiene and Environmental Protection, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece
3. Second Department of Internal Medicine, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece
4. Sleep Unit, Department of Pneumonology, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece