Background The prevalence of tobacco use, especially e-cigarette use, among 15-24 year-olds in China is on the rise, but few studies have focused on the use of e-cigarettes and the dual use of e-cigarettes and cigarettes by college students.

Objective This study investigates the prevalence of cigarettes and e-cigarettes and analyze their influencing factors among college students in Shanghai.

Methods A self-administered questionnaire survey was conducted among a total of 3 492 students from 6 universities and 6 colleges in Shanghai from September to December in 2017, who were selected by stratified cluster sampling. Their demographic information and the use of tobaccoincluding the use of cigarettes (currently smoking and smoking attempt), the use of e-cigarettes, and the dual use of them were asked in the questionnaire. Proportion and rate were used to describe their demographic characteristics and smoking prevalence. Chi-square test was used to compare the difference in smoking prevalence of the college students with selected characteristics. Multinomial logistic regression was used to analyze the influencing factors of tobacco use among the participants.

Results The smoking attempt rate, current smoking rate, e-cigarette using rate, and dual using rate of the college students in Shanghai were 15.72%, 8.79%, 7.65%, and 5.47%, respectively. More than half (71.53%) of the e-cigarette users were dual users. College students (9.34%, 6.27%), male students (12.28%, 9.13%), and students with allowance ≥ 1 500 yuan per month (10.76%, 8.21%) showed higher e-cigarette using rates and dual using rates than undergraduates (4.33%, 3.90%), female students (2.67%, 1.54%), and students with allowance < 1 500 yuan per month (5.44%, 3.53%), respectively (P < 0.05). The e-cigarette using rate in students of science and engineering majors (8.69%) was also higher than that in students of other majors (6.45%) (P < 0.05). Male students, students with allowance ≥ 1 500 yuan per month, college students, and sophomores and above were risk factors for e-cigarette use and the dual use of cigarettes and e-cigarettes. Their e-cigarette using related ORs (95% CI) were 5.28 (3.74-7.44), 2.53 (1.94-3.30), 2.55 (1.84-3.54), and 1.42 (1.09-1.85), and their dual using related ORs (95% CI) were 6.92 (4.48-10.70), 2.82 (2.06-3.86), 1.80 (1.26-2.57), and 1.41 (1.04-1.92), respectively.

Conclusion High e-cigarette using rate and dual using rate of college students are found in Shanghai. There are significant differences in all smoking rates between students of different genders, school types, and allowance levels. Gender, school type, allowance level, and grade are influencing factors for e-cigarette use and dual use.