[1] Dept Epidemiol, Local Hlth Author Asl RmE, Rome, Italy
[2] Univ Florence, Dept Stat, Florence, Italy
[3] Epidemiol Unit, Local Hlth Author, Milan, Italy
[4] Sch Phys, Dublin Inst Technol, Dublin, Ireland
[5] Univ Basel, Inst Social & Prevent Med, Basel, Switzerland