Qom University of Medical Sciences Journal

Introduction
Each year many people die due to diseases caused by tobacco smoking, the highest percentage of which occurs in developing countries. Tobacco smoking can reduce the life expectancy of smokers compared to non-smokers. It is estimated that the deaths caused by smoking will increase from 4.8 million people in 2006 to 8.3 million people in 2030, 80% of whom are living in developing countries. Adolescent smoking is a complex behavior that is related to various environmental/social factors (culture, family, peers, etc.). It is essential to consider the effects of these factors on the initiation or continuation of smoking among young people in order to reduce the smoking rate as much as possible. Examining the situation is a prerequisite for planning and targeted intervention to promote health. This study aims to investigate the prevalence of cigarette smoking in young people in Tehran, Iran, based on the socio-demographic factors in order to help develop accurate and effective interventions to improve the health of Iranian young people.
Methods
This analytical cross-sectional study was conducted on 1556 young people aged 18-29 years in Tehran city (70% from urban areas and 30% from rural areas) covered by Shahid Beheshti University of Medical Sciences, who were selected using cluster and systematic sampling methods. The data were collected using a self-report questionnaire taken from the core questionnaires of the World Health Organization (WHO) and the Center for Disease Control and Prevention, which has been modified and localized by the Iranian Ministry of Health and Medical Education and has been used in other studies in Iran. After providing the necessary explanations and obtaining consent from the individuals, the questionnaires were completed. The questionnaire had 91 items and took 25-30 minutes to complete. Statistical analysis was done in SPSS software, version 16 and P<0.05 was considered as statistically significant. Descriptive statistics (frequency, percentage, Mean±SD) and analytical tests (chi-square test, logistic regression analysis, and Mann-Whitney U test) were used to analyze the research data.
Results
Among participants, 50.1% were female and 49.9% were male. The mean age of both male and female groups was 25.4±3.5 years. The percentage of single and married people was about 40% and 59%, respectively. About 97.4% of them lived in their own houses (with family). About 24% of people had a university education. The rest had no university education (high school diploma/lower than high school education). About 45.5% were employed people (15.5% students).
The prevalence of cigarette smoking in participants was 17.4%; 6.2% were daily smokers and 11.2% were non-daily smokers. The smoking rate in males was 78.44%, which was significantly higher than in females (21.56%). The major reasons for both smoking initiation and smoking continuation were fun, enjoyment and dealing (forgetting) with problems. The results of the chi-square test showed a statistically significant difference in cigarette smoking based on gender (P<0.001) and occupation (P=0.002). The results of rank-ordered logistic regression analysis showed that, among the causes of cigarette smoking, there was a statistically significant relationship between peer pressure and smoking (P=0.01). The likelihood of smoking initiation and smoking continuation in people who had peer pressure was 6.52 and 6.27 times higher than in people with no peer pressure, respectively.
Conclusion
The prevalence of cigarette smoking among young boys in Tehran is significantly higher than in young girls. Most of them start smoking non-daily for fun or enjoyment, but with the development of dependence on cigarettes, they continue smoking daily. Peer pressure plays a major role in the initiation and continuation of cigarette smoking in these young people. Considering these factors, scientific and practical planning for the prevention and control of cigarette smoking among young people seems necessary.
Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committee of Shahid Beheshti University of Medical Sciences, Tehran, Iran (Code: IR.SBMU.PHNS.REC.1398.186).
Funding
This article was extracted from master thesis of Leila Rajaei, approved by School of Public Health and Safety, Shahid Beheshti University of Medical Sciences and financially supported by Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Authors contributions
All authors equally contributed to preparing this article.
Conflicts of interest
The authors declared no conflict of interest.
Acknowledgements
The authors would like to thank the Deputy for Research of Shahid Beheshti University of Medical Sciences for their financial support and all the people who participated in this study for their cooperation.