Centre for Molecular Epidemiology, Department of Epidemiology and Public Health, National University of Singapore, Singapore.|Centre for Molecular Epidemiology, Department of Epidemiology and Public Health, National University of Singapore, Singapore.|Centre for Molecular Epidemiology, Department of Epidemiology and Public Health, National University of Singapore, Singapore.|Centre for Molecular Epidemiology, Department of Epidemiology and Public Health, National University of Singapore, Singapore.|Centre for Molecular Epidemiology, Department of Epidemiology and Public Health, National University of Singapore, Singapore.|Centre for Molecular Epidemiology, Department of Epidemiology and Public Health, National University of Singapore, Singapore.|Centre for Molecular Epidemiology, Department of Epidemiology and Public Health, National University of Singapore, Singapore.