[1] Chinese Acad Med Sci, Peking Union Med Coll Hosp, Dept Neurol, Beijing 100730, Peoples R China
[2] Chinese Acad Med Sci, Peking Union Med Coll Hosp, Dept Clin Epidemiol, Beijing 100037, Peoples R China
[3] Univ Texas, Hlth Sci Ctr, Dept Med & Neurol, San Antonio, TX USA
[4] Fudan Univ, Huashan Hosp, Dept Neurol, Shanghai 200433, Peoples R China
[5] Xian Transportat Univ, First Hosp, Dept Neurol, Xian, Peoples R China
[6] Tongren Hosp, Dept Neurol, Beijing, Peoples R China
[7] Beijing Sixth Hosp, Dept Neurol, Beijing, Peoples R China
[8] Natl Res Inst Family Planning, Dept Stat, Beijing, Peoples R China