1. Department of Hygiene and Epidemiology, Medical Faculty, School of Health Science, University of Thessaly, Medicine, Larissa, Greece
2. Post Graduate Program Primary Health Care, Medical Faculty, School of Health Science, University of Thessaly, Larissa, Greece
3. Clinic of Social and Family Medicine/Faculty of Medicine, University of Crete, Heraklion, Greece
4. Department of Hygiene and Epidemiology, Medical Faculty, School of Health Sciences, University of Thessaly, Larissa, Greece
5. Department of Nursing, School of Health Sciences University of Thessaly, Larissa, Greece
6. Department of Respiratory Medicine, Faculty of Medicine, University of Thessaly, Larissa, Greece
7. Saint Elizabeth’s Hospital and George Washington University School of Medicine, Washington, DC, USA