宁夏回族自治区卫生厅科研基金资助项目项目编号2014NW072;宁夏医科大学校级科研基金资助项目项目编号2014-2015Fund ProjectsScientific Research Project of Public Health Department of Ningxia Hui Autonomous Region Project No?2014NW072;Scientific Research Project of Ningxia Medical University Project 2014-2015