[1] Karolinska Hosp, Dept Canc Prevent, SE-17176 Stockholm, Sweden
[2] Karolinska Hosp, Dept Publ Hlth Sci, SE-17176 Stockholm, Sweden
[3] Karolinska Hosp, Dept Biostat & Epidemiol, SE-17176 Stockholm, Sweden
[4] Swedish Radiat Protect Inst, SE-17116 Stockholm, Sweden