mohammad eshagh afkari department of education and promotion, school of public health, tehran university of medical sciences, tehran, ir iran afsaneh ghasemi department of education and promotion, school of public health, tehran university of medical sciences, tehran, ir iran davoud shojaeizadeh department of education and promotion, school of public health, tehran university of medical sciences, tehran, ir iran azar tol department of education and promotion, school of public health, tehran university of medical sciences, tehran, ir iran abass rahimi foroshani department of epidemiology and biostatistics, school of public health, tehran university of medical sciences, tehran, ir iran mohammad hossein taghdisi department of education and promotion, school of public health, tehran university of medical sciences, tehran, ir iran; 4th floor, school of public health, tehran, ir iran. tel: +98-2188989128, fax: +98-2188989129

J. Jiang, P. Wang, T. Pang, T. Ri, Y. Wang,