Abstract
Sleep quality is a critical component of student well-being and academic performance. This study aimed to examine the association between demographic characteristics, health and mental behaviors, smartphone usage, and sleep quality among undergraduate students at Jazan University in Saudi Arabia. A cross-sectional web-based survey was conducted between April and June 2023. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). The questionnaire included demographic data, health behaviors (exercise, diet, stimulant intake, smoking, qat use), anxiety levels, and smartphone usage patterns. Data were analyzed using descriptive statistics, t-tests, ANOVA, and multivariable linear regression. A total of 1564 students participated. Demographic variables were not significantly associated with sleep quality. However, poor sleep quality was significantly associated with several factors. Students who exercised less (mean PSQI = 8.19 vs 7.67; P = .003) or followed an unhealthy diet (8.10 vs 7.33; P = .001) reported worse sleep. High intake of stimulants, such as coffee (>3 times/day: β = 1.08, P = .021), tea, and soft drinks, was also linked to poorer sleep. Anxiety showed a clear dose-response effect, with mild, moderate, and severe anxiety associated with PSQI increases of 0.89, 2.27, and 3.43 points, respectively (all P < .001). Evening (β = .52, P = .016) and bedtime (β = .42, P = .029) smartphone use further predicted worse sleep quality, independent of total usage time. Sleep quality among undergraduate students is primarily influenced by modifiable lifestyle and psychological factors. Interventions promoting healthier routines, reducing stimulant intake, managing anxiety, and improving digital habits are essential to support student well-being.