the impact of education on smoking refrain based on the theory of planned behavior on shiraz high school students’ attitudes

background: smoking is one of the preventable causes of diseases as well as early deaths all around the world. in addition, conducting educational interventions plays a major role in preventing adolescents from smoking. therefore, the present study aimed to investigate the effect of educational intervention based on the theory of planned behavior on preventing shirazi students from smoking. methods: in the present quasi-experimental study, 154 male students of the 2nd grade of high school from shiraz were selected through multi-stage cluster sampling and randomly assigned to a control and an experimental group. the study data were collected through a questionnaire including the demographic information, questions on knowledge, and questions based on the components of the theory of planned behavior. after the pre-test, the intervention group underwent the educational intervention and after 2 months, both groups took part in the post-test. then, the data were entered into the spss statistical software (v.11.5) and analyzed through the non-parametric tests of mann-whitney, fisher, and chi- square as well as linear multiple logistic regression. results: no significant difference was observed between the two groups’ mean scores before the intervention. after the intervention, the intervention group’s scores of knowledge, attitude, intention, subjective norms, and perceived behavioral control significantly increased. conclusion: according to the findings of the present study, educational intervention based on the theory of planned behavior was highly effective in reducing shirazi high school students’ intention to smoke.