1. Institute of Dermatology, Department of Medical Services, Ministry of Public Health, Bangkok, Thailand
2. Dermatologic Surgery Division, Southern Regional Hospital of Tropical Dermatology – Trang Province, Department of Medical Services, Ministry of Public Health, Trang, Thailand
3. Center for Clinical Epidemiology and Clinical Statistics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
4. Department of Family Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand