公益性行业科研专项201502006,201002007;国家自然科学基金81973126,82073633;北京大学流行病与卫生统计学顶尖学科建设项目201502006, 201002007;Special Fund for Health Scientific Research in the Public Welfare81973126, 82073633;National Natural Science Foundation of China;Peking University Outstanding Discipline Construction Project of Epidemiology and Biostatistics