[1] Univ London Imperial Coll Sci Technol & Med, Dept Epidemiol & Publ Hlth, London W2 1PG, England
[2] Fed Environm Agcy, Dept Environm Hyg, Berlin, Germany
[3] Natl Inst Publ Hlth & Environm, NL-3720 BA Bilthoven, Netherlands
[4] Karolinska Inst, Inst Environm Med, S-10401 Stockholm, Sweden
[5] Univ Athens, Sch Med, Dept Hyg & Epidemiol, GR-11527 Athens, Greece
[6] Univ Athens, Lab Prevent, Sch Nursing, GR-11527 Athens, Greece
[7] Reg Agcy Environm Protect, Environm Epidemiol Unit, Grugliasco, Italy