[1] Univ Leuven, Ctr Human Genet, B-3000 Louvain, Belgium
[2] Univ Antwerp, B-2020 Antwerp, Belgium
[3] Univ Turin, Dept Biomed Sci & Human Oncol, Canc Epidemiol Unit, I-10124 Turin, Italy
[4] Finnish Inst Occupat Hlth, SF-11717 Helsinki, Finland
[5] Minist Educ, SF-11717 Helsinki, Finland