[1] Tianjin Med Univ, Sch Publ Hlth, Observ Rd, Tianjin 300070, Peoples R China
[2] Tianjin Med Univ, Sch Nursing, Observ Rd, Tianjin 300070, Peoples R China
[3] Tianjin Med Univ, Gen Hosp, Anshan Rd, Tianjin 300052, Peoples R China
[4] Jilin Med Coll, Sch Nursing, Jilin St, Jilin 132013, Peoples R China