[1] CHU Vaudois, Canc Epidemiol Unit, CH-1011 Lausanne, Switzerland
[2] CHU Vaudois, Canc Registry Vaud, Inst Univ Med Social & Prevent, CH-1011 Lausanne, Switzerland
[3] Mario Negri Inst Pharmacol Res, Lab Epidemiol, I-20157 Milan, Italy
[4] Univ Milan, Ist Stat Med & Biometria, I-20133 Milan, Italy