[1] Vrije Univ Amsterdam Med Ctr, Dept Pathol, Amsterdam, Netherlands
[2] Sci Inst Publ Hlth, Canc Epidemiol Unit, Brussels, Belgium
[3] Univ British Columbia, British Columbia Ctr Dis Control, Vancouver, BC V5Z 1M9, Canada
[4] S Giovanni Univ Hosp, Piedmont Ctr Canc Prevent, Dept Oncol, Canc Epidemiol Unit, Turin, Italy
[5] Ist Ric Farmacol Mario Negri, Milan, Italy