1. Department of Epidemiology; Multidisciplinary Health International Research Training Program; Harvard School of Public Health; Boston MA USA
2. School of Nursing; Walailak University; Nakhon Si Thammarat Thailand
3. Department of Preventive and Social Medicine; Faculty of Medicine; Chulalongkorn University; Bangkok Thailand
4. College of Public Health Sciences; Chulalongkorn University; Bangkok Thailand
5. Department of Mathematics & Statistics; Georgetown University; Washington DC USA