Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, 35294-0022, USA.|Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.|Department of Biostatistics, School of Public Health, Medical College of Soochow University, Suzhou, 215123, China.|Department of Biostatistics, School of Public Health, Medical College of Soochow University, Suzhou, 215123, China.|Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, 35294-0022, USA.|Department of Food Science and Technology and Core for Applied Genomics and Ecology, University of Nebraska, Lincoln, NE, 68583, USA.|Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, 35294-0022, USA. nyi@uab.edu.