[1] Univ London Imperial Coll Sci Technol & Med, Natl Heart & Lung Inst, London, England
[2] Fdn IRCCS Ca Granda Osped Maggiore Policlin, Dept Prevent Med, Epidemiol Unit, Milan, Italy
[3] Univ Milan, Dept Clin Sci & Community Hlth, Milan, Italy
[4] NCI, Div Canc Epidemiol & Genet, NIH, Bethesda, MD 20892 USA
[5] Univ Utrecht, Environm Epidemiol Div, Inst Risk Assessment Sci, Utrecht, Netherlands
[6] Univ Western Australia, Western Australian Inst Med Res, Nedlands, WA 6009, Australia