Thomas A Boyle Daniel Z Uslan Jordan M Prutkin Arnold J Greenspon Larry M Baddour Stephan B Danik Jose M Tolosana Katherine Le Jose M Miro James Peacock Muhammad R Sohail Holenarasipur R Vikram Roger G Carrillo

maryam karkhane gastroenterology and liver diseases research center, research institute for gastroenterology and liver diseases, shahid beheshti university of medical sciences, tehran, ir iran mohamad amin pourhoseingholi gastroenterology and liver diseases research center, research institute for gastroenterology and liver diseases, shahid beheshti university of medical sciences, tehran, ir iran; basic and molecular epidemiology of gastrointestinal disorders research center, research institute for gastroenterology and liver diseases, shahid beheshti university of medical sciences, tehran, ir iran; gastroenterology and liver diseases research center, basic and molecular epidemiology of gastrointestinal disorders research center, research institute for gastroenterology and liver diseases, shahid beheshti university of medical sciences, tehran, ir iran. tel: +98-2122432514, fax: +98-2122432527 zahra kimiia gastroenterology and liver diseases research center, research institute for gastroenterology and liver diseases, shahid beheshti university of medical sciences, tehran, ir iran seyed mehdi mortazavi nursing faculty, baqiyatallah university of medical sciences, tehran, ir iran mohammad reza akbariyan torkabad nursing faculty, baqiyatallah university of medical sciences, tehran, ir iran seyed karim hossieni aghdam nursing faculty, baqiyatallah university of medical sciences, tehran, ir iran