国家自然科学基金资助项目81100684;首都卫生发展科研专项2011-5007-02;总参军事医学和老年病科研基金项目ZCWS14C19;北京市自然科学基金资助项目No.7173269National Natural Science Foundation of China81100684;Beijing Health Development Research Foundation,China2011-5007-02;Military Medicine and Geriatrics of the Headquarters of the General StaffZCWS14C19;Beijing Natural Science Foundation7173269