[1] Umea Univ Hosp, Dept Radiat Sci, S-90185 Umea, Sweden
[2] Karolinska Inst, Inst Environm Med, S-10401 Stockholm, Sweden
[3] Karolinska Inst, Dept Med Epidemiol & Biostat, S-10401 Stockholm, Sweden
[4] Ohio State Univ, Sch Publ Hlth, Div Epidemiol & Biometr, Buckeye, OH USA
[5] Univ Tampere, Tampere Sch Publ Hlth, Dept Epidemiol, FIN-33101 Tampere, Finland
[6] Danish Canc Soc, Inst Canc Epidemiol, Copenhagen, Denmark
[7] STUK Radiat & Nucl Safety Author, Dept Res & Environm Surveillance, Helsinki, Finland
[8] Inst Canc Res, Epidemiol Sect, Surrey, England