International Journal of Preventive Medicine (Int J Prev Med)2008-7802002016082017261726ENDepartment of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, TehranDepartment of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, TehranDepartment of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, TehranDepartment of Computer Engineering and Information Technology, Shahrood University of Technology, ShahroodDepartment of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran20160820<p><strong>Background:</strong> Cigarette smoking is one of the most important health‑related risk factors in terms of morbidity and mortality. In this study, we introduced a new method for deriving the transitional probabilities of smoking stages from a cross‑sectional study and simulated a long‑term smoking<br />behavior for adolescents.</p><p><strong>Methods:</strong> In this study in 2010, a total of 4853 high school students were randomly selected and were completed a self‑administered questionnaire about cigarette smoking. We used smoothed age‑ and sex‑specific prevalence of smoking stages in a probabilistic discrete event system for estimating of transitional probabilities. A nonhomogenous discrete time Markov chain analysis was used to model the progression of the smoking in 10 years ahead in the same population.<br />The mean age of the students was 15.69 &plusmn; 0.73 years (range: 14&ndash;19).</p><p><strong>Results:</strong> The smoothed prevalence proportion of current smoking varies between 3.58 and 26.14%. The age‑adjusted odds of initiation in boys is 8.9 (95% confidence interval [CI]: 7.9&ndash;10.0)<br />times of the odds of initiation of smoking in girls. Our study predicted that the prevalence proportion of current smokers increased from 7.55% in 2010 to 20.31% (95% CI: 19.44&ndash;21.37) for 2019.</p><p><strong>Conclusions:</strong> The present study showed a moderately but concerning prevalence of current smoking in Iranian adolescents and introduced a novel method for estimation of transitional probabilities from a cross‑sectional study. The increasing trend of cigarette use among adolescents<br />indicated the necessity of paying more attention to this group.</p><p><strong>Keywords:</strong> Adolescents, discrete event system, projection, smoking stages, transitional probability</p>http://ijpm.mui.ac.ir/index.php/ijpm/article/view/1726http://ijpm.mui.ac.ir/index.php/ijpm/article/download/1726/2016