Division of Biostatistics, Institute & Department of Public Health, National Yang-Ming University, Taipei 112, Taiwan.|Division of Biostatistics, Institute & Department of Public Health, National Yang-Ming University, Taipei 112, Taiwan.|Division of Biostatistics, Institute & Department of Public Health, National Yang-Ming University, Taipei 112, Taiwan.|Division of Biostatistics, Institute & Department of Public Health, National Yang-Ming University, Taipei 112, Taiwan.