Setting
This is a descriptive study and this study was conducted in Kermanshah, Kermanshah is located in the west of Iran. Kermanshah is one of the largest cities in Iran and one of the first places in the field of tobacco smoking. This study was conducted from January to August 2019..
Study population and sampling method
Participants in this study were 1302 high school female students aged 12–18. the inclusion criteria to this study for students over the age of 16 was a willingness to participate in the study and possession of informed consent, and written consent from parents was necessary for under the age of 16 years. sampling was a multi-stage randomized systematic approach. at first, a list of schools in three districts of Kermanshah was prepared and 12 schools were selected by systematic random sampling (4 Schools from each district ). at the school level, sampling units will be randomly selected based on the number of students from grades 7 to 12 and the proportion of the total sample size. The calculated P is determined based on study (17) .using 95% confidence interval and applying clustering coefficient 2.
Data collection instruments
The data collection instruments was questionnaire. The questionnaire included two parts. The first part included demographic questions, including age, education level, parents occupation, parents' education level, family size and living conditions. The second part included shisha smoking related factors : such as having smoking experience, the first place to smoke shisha, the first person who provide shisha for the students, having a parent who smokes shisha, having a friend who smokes shisha, encourage to smoke shisha by friends .
Pilot testing of questionnaire
The questionnaire was distributed among 15 students and asked them to express their own opinions about the appearance of the questionnaires, the clarity of the used terms, the font size and any confusion the required reforms were done.
Questionnaire reliability:
Internal reliability (internal consistency) and external reliability (test and retest) will be used to determine the reliability of the questionnaires. For this purpose, the questionnaire was distributed among 30 students at two time intervals over a 2-week period. The internal and external consistency coefficients of the questions were measured and the Cronbach's alpha value was more than 0.8.
Study Participants
This cross-sectional study was performed among 1302 high school female students recruited multistage random sampling method in Kermanshah city,west of Iran in 2019. There are three educational sectors in the city. which each region 4 schools randomly selected.
Ethics approval and consent to participate
Written informed consent was obtained from 16-year-old students and older students. Written informed consent was also obtained from parents of students under the age of 16. The names of the participants were not recorded in the questionnaire and other information was kept confidential and was used only in this study. The Ethical Committee of Hamadan University of Medical Sciences approved this study (reference number: IR.UMSHA.REC.1397.696).
Data collection
The person who was responsible for collecting data and distributing a questionnaire was native to the region and the questionnaire was coded without registration and surname, and this increased the confidence of the students. On the other hand, the subject of shisha was attractive to students, and all students tended to fill out questionnaires.
Statistical analysis
The data were entered into IBM SPSS 22 software after collection. Logistic regression was used to investigate and predict factors affecting shisha. Chi-square and logistic regression were performed to identify statistical diffrences and analyze factors associated with shisha .