Graduate School, Qinghai University, Xining, 810016, Qinghai, People's Republic of China. Department of Community Health Education, Institute for Health Education of Qinghai Province, Xining, Qinghai, 810000, People's Republic of China. Department of Neurosurgery, Qinghai Provincial People's Hospital, No. 2 Gonghe Road, Xining, 810007, Qinghai, People's Republic of China. Department of Neurosurgery, Qinghai Provincial People's Hospital, No. 2 Gonghe Road, Xining, 810007, Qinghai, People's Republic of China. iloveyoucmu@163.com.