1. Directorate of Research, Studies and Documentation, National Public Health Organization, 3-5 Agrafon Street, Marousi, 15123 Athens, Greece
2. Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, 87 Santa Sofia Street, 95124 Catania, Italy
3. Pathophysiology Department, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias Street, Goudi, 11527 Athens, Greece