1. Digestive Disease Research Institute; Tehran University of Medical Sciences; Tehran Iran
2. Qualitative Methods; Institute of Applied Health Research; University of Birmingham; Birmingham UK
3. Public Health & Primary Care; Institute of Applied Health Research; University of Birmingham; Birmingham UK
4. School of Nursing; The University of British Columbia; Vancouver BC Canada
5. School of Nursing and Midwifery; Nursing & Midwifery Care Research Center Tehran University of Medical Sciences; Tehran Iran
6. School of Public Health; Tehran University of Medical Sciences; Tehran Iran