1. Department of Social and Preventive Medicine, Centre for Epidemiology and Evidenced-Based Practice, Faculty of Medicine, Lembah Pantai, Kuala Lumpur, Malaysia
2. Batu 14 Health Clinic, Jalan Hulu Langat, Selangor, Malaysia
3. Hulu Langat District Health Office, Kajang, Selangor, Malaysia
4. Gastroenterology Service, Ministry of Health, Malaysia
5. Department of Internal Medicine, Hospital Sultanah Bahiyah, Kedah, Malaysia