Background:
Smoking is increasing among adolescents and young adults. Adolescents’ smokingcan predict frequent smoking in early adulthood. The purpose of this study was to explore thepredictors of smoking among high school students using health belief model (HBM).Methods: In this cross-sectional study, ۴۴۴ boys were selected among high school students inBandar-Abbas city, South of Iran. They were selected through the stratified sampling design.Inclusion criteria were: male students studying in high school (sixth to twelfth grade) andwillingness to participate in the study. Exclusion criterion was: incomplete filling of thequestionnaire. Data were collected using a researcher-made questionnaire consisted of two mainsections: socio-demographic characteristics and HBM constructs. The HBM constructs were asfollowed: knowledge about the consequences of smoking (۱۰ questions), perceived susceptibility(۷ questions), perceived severity (۹ questions), perceived barriers (۵ questions), perceived benefits(۵ questions), cues to action (۴ questions) and self-efficacy in combating the temptation ofsmoking (۶ questions). The zero-inflated ordered probit (ZIOP) model was used for investigatingthe association between HBM constructs and smoking behavior. The ZIOP model is a twocomponentmixture model consisting of a binary probit regression at zero mixed with an orderedprobit regression. The part of binary probit regression is used to identify the smokers from thenon-smokers. The ordered probit regression is used to model the level of smoking count among thesmokers.Results: Mean age of the participants was ۱۶.۷±۰.۸۵ and ranged from ۱۵ to ۱۹ years. Resultsindicated that ۸۲% of participants never smoked cigarette at all. The results of ZIOP modelshowed that knowledge (P=۰.۰۲۶), susceptibility (P<۰.۰۰۱), severity (P=۰.۰۳۵), benefits(P=۰.۰۰۴) and cues to action (P=۰.۰۱۹) had significant effect on smoking cigarette after adjustingfor other covariates (i.e age, parents’ education, losing one of the parents). Moreover, having asmoker friend was an inflation factor (P<۰.۰۰۱). Those whose friends were smokers were about۴۴% less likely to be never-smokers than those whose friends did not smoke.Conclusion: Based on these findings, having a smoker friend, knowledge, susceptibility, severity,benefits and cues to action have a key role in predicting smoking and should be considered indesigning educational programs aiming at reducing smoking initiation among adolescents. It issuggested to design educational programs aiming at increasing students’ awareness of smokinglosses and promoting their self-efficacy as well as holding workshops to improve social skills suchas “saying no”. Planning alternative activities to fill students’ leisure time, increasing sports andrecreational centers, monitoring the production, purchase, and consumption of cigarettes, andincreasing counseling centers can be effective on the reduction of smoking.