International Journal of Preventive Medicine (Int J Prev Med)2008-78022420110706158158ENMSc, Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran and Shiraz University of Medical Sciences, Shiraz, Iran.MD, PhD, Department of Epidemiology and Biostatistics, School of Public Health, and Knowledge Utilization Research Center (KURC), Tehran University of Medical Sciences, Tehran, Iran.PhD, Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.DVM, MSc, PhD, Professor, Center for Community Based Participatory Research (CBPR), and Department of Epidemiol- ogy and Biostatistics, School of Public Health, and Knowledge Utilization Re- search Center (KURC), Tehran niversity of Medical Sciences, Tehran, Iran.2011040820110629<p><strong>Objectives:</strong> Identifying the underlying factors contributing to smoking among teenagers is important in establishing smoking control programs. The present study was designed to identify and compare factors revealed in a preceding qualitative study conducted on 13-15 year-old boys living in two different socio-economic districts in the Northern and Southern parts of Tehran.</p><p class="abstract"><strong>Methods:</strong> Two completely similar case-control studies, each with 200 subjects, were conducted using a snowball sampling. The case and control subjects were matched based on the intimacy relations, i.e. six smokers were recruited in each of the Northern and Southern districts; they were then asked to introduce one of their smoker friends as a case and a non-smoker one as a control.</p><p class="abstract"><strong>Results:</strong> Multi-variable conditional logistic regression revealed that having a smoker father is the single effective factor in the two districts. As for boys living in the Northern (wealthier) part of the city, social capital (OR: 0.59, 95% CI: 0.43-0.81) played a protective role against smoking, whereas quitting home after a quarrel (OR: 15.07, 95% CI: 1.54-147.25), monthly allowance (OR: 2.22, 95% CI: 1.29-3.82) and hyperactivity (OR: 1.69, 95% CI: 2.64-240.45) were associated with a higher risk of becoming a smoker.</p><p class="abstract"><strong>Conclusions:</strong> The studied variables can be classified as personal, familial, and school-level factors. Familial intervention is effective for all the factors which revealed to be influential on the risk of becoming a smoker. It could be concluded that interventions on the family level should be used to prevent the cigarette use in Tehran.</p><p class="abstract"><strong>Keywords:</strong> Smoking, Teenagers, Male, Snowball sampling.</p>http://ijpm.mui.ac.ir/index.php/ijpm/article/view/158http://ijpm.mui.ac.ir/index.php/ijpm/article/download/158/351