In this cross-sectional analytical study, 1181 students were selected proportionally and randomly from 3 universities in city of Khorramabad (Lorestan University of Medical Sciences, Lorestan University, and Lorestan Islamic Azad University). They were assessed in January and February 2015. A self-administrated questionnaire, including questions about cigarette smoking, hookah use, drug abuse, alcohol consumption, as well as demographic information was distributed to the students. A total of 1131 students completed the study questionnaire, and response rate was 95.8%.
To enhance the validity of students’ self-reports, they were assured about the strict confidentiality of their responses and were further informed that they could not be recognized by their answers. They were also informed about the voluntary nature of their participation in the study and their right to refuse or skip any questions.
In this study, cigarette smoking was measured as never smoker, experimenter (less than100 cigarettes in lifetime), occasional user, regular smoker, and ex-smoker. The prevalence of cigarette smoking was calculated based on these answers. However, to consider the factors related to cigarette smoking, the respondents were classified into 2 categories of cigarette smoking: never smoker and ever smoker.
In this study, hookah smoking was measured using a multiple choice question including the following answers: never use, only tried, occasional use, at least once per month, and at least once per week. The prevalence of hookah smoking was calculated according to these answers. However, to consider the factors related to hookah smoking, the respondents were classified into 2 categories of hookah smoking: never smoker and ever smoker.
Alcohol use was defined as consuming alcohol in the past 30 days and ever or never alcohol use. Ever use of any illicit drugs, such as Ritalin, methamphetamine, ecstasy, cannabis, opium, and heroin, were regarded as drug abuse. In a pilot study, the questionnaire was completed by 37 students 2 times in a 3-week interval. The reliability of the questionnaire was approved with test retest correlation coefficient equal to 0.77. This study and the related questionnaire have been approved by the ethics committee of Lorestan University of Medical Sciences.
Logistic regression model, exact logistic regression model (due to the small number of cases in this study), chi square test, and t test were used for statistical analysis, which was performed using SPSS-22. Final logistic regression model was selected using likelihood ratio test. Also, the Shapiro-Wilk test was used to check the normality of quantitative data. Significance level was set at P < 0.05.