Patterns and Factors Associated with E-Cigarette Initiation and Transition Among University Students in Al-Madinah City, Saudi Arabia: A Cross-Sectional Study

<b>Background/Objectives</b>: Electronic cigarettes (e-cigarettes) have gained popularity among young adults globally, but only limited research exists on usage patterns in Saudi Arabia. This study investigated the prevalence, patterns, and factors associated with e-cigarette use initiation and transition to cigarette smoking among university students in Saudi Arabia. <b>Methods</b>: A cross-sectional survey was conducted among 537 university students in Al-Madinah city during the 2024-2025 academic year. Data were collected using a self-administered online questionnaire assessing e-cigarette use patterns, motivations, susceptibility to future cigarette smoking, and demographic characteristics. Multivariable logistic regression analysis was used to identify factors associated with e-cigarette use. <b>Results</b>: E-cigarette prevalence was substantial: 11.7% of participants were current users, 5.4% were former users, and 27.9% were ever-users, compared with 5.8% current cigarette smokers. Males had significantly higher use rates than females (20.9% vs. 4.6%; <i>p</i> < 0.001). Senior students showed the highest current use (21.1%). Among ever-users, the primary motivations were enjoyment (29.3%), the possibility of use where smoking is banned (26.1%), and social acceptability (21.7%). Most users (73.0%) used high-nicotine liquids (≥20 mg/mL), and 55.4% vaped daily. Multivariable logistic regression revealed that e-cigarette use was independently associated with male gender (adjusted OR = 4.0), higher academic year (OR = 1.24), current smoking (adjusted OR = 3.45; 95 CI: 1.54-7.82), and lower harm perception (adjusted OR = 1.69; 95 CI: 1.16-2.51). Susceptibility to future cigarette smoking was 18.9% overall but much higher among current e-cigarette smokers (59.5%; <i>p</i> < 0.001). <b>Conclusions</b>: E-cigarette use was prevalent among Saudi university students, particularly males and senior students, with patterns suggestive of nicotine dependence. Strong associations with cigarette smoking and high-concentration nicotine use raise concerns about dual use and addiction potential.