[1] Nanjing Med Univ, Sch Publ Hlth, Dept Epidemiol & Biostat, Nanjing 210029, Peoples R China
[2] Chinese Acad Med Sci, Inst Canc, Dept Etiol & Carcinogenesis, Beijing 100037, Peoples R China
[3] Peking Union Med Coll, Beijing, Peoples R China
[4] Univ Texas, MD Anderson Canc Ctr, Dept Epidemiol, Houston, TX 77030 USA