1. University Department of Laboratory Medicine, Hospital of Desio, Milano, Italy
2. School of Medicine, University Milano-Bicocca, Milano, Italy
3. National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
4. Institute of Medical Statistics and Biometrics, University of Milano, Milano, Italy
5. Department for Preventive Medicine, Ministry of Health of Regione Lombardia, Milano, Italy