1. Department of Marketing, Faculty of Business Administration and Accountancy, Khon Kaen University, Khon Kaen 40002, Thailand
2. Department of Epidemiology and Biostatistics, Faculty of Public Health, Khon Kaen University, Khon Kaen 40002, Thailand
3. Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand