1. Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
2. Department of Child Psychiatry, School of Medicine, National and Kapodistrian University of Athens, “Aghia Sophia” Children’s Hospital, Athens, Greece
3. Institute of Preventive Medicine, Environmental & Occupational Health, Prolepsis, Athens, Greece
4. Department of Public and Community Health, Laboratory of Hygiene and Epidemiology, University of West Attica, Athens, Greece