[1] Third Mil Med Univ, Coll Prevent Med, Dept Hlth Stat, POB 400038, Chongqing 400038, Peoples R China
[2] Third Mil Med Univ, Xinqiao Hosp, Dept Informat, Chongqing 400038, Peoples R China
[3] Third Mil Med Univ, Coll Prevent Med, Dept Epidemiol, Chongqing 400038, Peoples R China
[4] Univ Washington, Sch Publ Hlth & Community Med, Dept Biostat, Seattle, WA 98124 USA
[5] Third Mil Med Univ, Inst Trop Med, Dept Epidemiol, Chongqing 400038, Peoples R China
[6] Chongqing Univ Posts & Telecommun, Sch Software Engn, Chongqing 400065, Peoples R China