Department of Biostatistics, Public Health College, Harbin Medical University, affiliation not provided to SSRN, Department of Biostatistics, Harbin Medical University, Department of Biostatistics, Harbin Medical University, Department of Biostatistics, Harbin Medical University, Department of Biostatistics, Harbin Medical University, Department of Biostatistics, Harbin Medical University, Harbin Medical University - Department of Biostatistics and Harbin Medical University - Department of Biostatistics