[1] Capital Med Univ, Beijing Tiantan Hosp, Dept Neurol, 119 South 4th Ring West Rd, Beijing 100070, Peoples R China
[2] Capital Med Univ, Beijing Tiantan Hosp, China Natl Clin Res Ctr Neurol Dis, Beijing, Peoples R China
[3] Capital Med Univ, Sch Publ Hlth, Dept Epidemiol & Hlth Stat, Beijing, Peoples R China
[4] Beijing Municipal Key Lab Clin Epidemiol, Beijing, Peoples R China
[5] Capital Med Univ, Dept Clin Epidemiol & Clin Trial, Beijing, Peoples R China