[1] Cent South Univ, Xiangya Hosp, Dept Orthoped, Changsha 410008, Hunan, Peoples R China
[2] Cent South Univ, Xiangya Sch Med, Changsha 410008, Hunan, Peoples R China
[3] Cent South Univ, Xiangya Hosp, Natl Clin Res Ctr Geriatr Disorders, Changsha 410008, Hunan, Peoples R China
[4] Natl Univ Mongolia, Sch Arts & Sci, Ulan Bator 14201, Mongolia
[5] Univ Liege, Dept Publ Hlth Epidemiol & Hlth Econ, CHU Sart Tilman B23, B-4000 Liege, Belgium