[1] Chinese Acad Med Sci, Natl Canc Inst, Dept Epidemiol, Beijing 100021, Peoples R China
[2] Radcliffe Infirm, Nuffield Dept Clin Med, Clin Trial Serv Unit, Oxford OX2 6HE, England
[3] Radcliffe Infirm, Nuffield Dept Clin Med, Epidemiol Studies Unit, Oxford OX2 6HE, England
[4] Cornell Univ, Div Nutr Sci, Ithaca, NY 14853 USA
[5] Chinese Acad Prevent Med, Inst Nutr & Food Hyg, Beijing 100050, Peoples R China