1. Department of Pneumonology, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece
2. MSc Program in Sleep Medicine, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece
3. Department of Dentoalveolar Surgery, Implantology and Oral Radiology, School of Dentistry, Aristotle University of Thessaloniki, 56403 Thessaloniki, Greece
4. Laboratory of Hygiene and Environmental Protection, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece