1. Department of Community Medicine, Faculty of Medicine, Ramathibodi Hospital, Rama VI Rd., Ratchathewi, Bangkok, Thailand
2. Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
3. Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
4. Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
5. College of Public Health Sciences, Chulalongkorn University, Bangkok, Thailand
6. Ramathibodi School of Nursing, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand