[1] Cleveland Clin Fdn, Dept Gynecol, Cleveland, OH 44195 USA
[2] Chinese Acad Med Sci, Canc Inst Hosp, Dept Epidemiol, Beijing 100021, Peoples R China
[3] Xinjiang Med Univ, Peoples Hosp Xinjiang Uygur Automatous Reg, Dept Gynecol, Urumqi, Peoples R China
[4] Univ N Carolina, Dept Epidemiol, Chapel Hill, NC USA
[5] So Calif Permanente Med Grp Fontana, Dept Obstet & Gynecol, Fontana, CA 92335 USA
[6] Merck Inc, West Point, PA USA
[7] So Calif Permanente Med Grp, Dept Res & Evaluat, Los Robles, CA USA