The relationship between smartphone usage and sleep quality among university students: a cross-sectional study

Excessive and poorly timed smartphone use has raised growing concerns about sleep health, particularly among university students. This study examines the relationship between smartphone usage behaviors and sleep quality among university students in Bangladesh, focusing on daily usage duration, bedtime smartphone use, and night-time notifications. A cross-sectional design was employed, with data collected from 402 students using a structured online questionnaire. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI), and smartphone usage was assessed through self-reports. Bedtime smartphone use was significantly associated with poorer sleep quality (β = 0.732, p = 0.001), while daily usage duration showed a weaker but statistically significant correlation with global PSQI scores (r = 0.2200, p < 0.001). Night-time notifications were not a significant predictor (β = 0.321, p = 0.068). Multivariate analyses confirmed that the timing of smartphone use, particularly before bedtime, is a stronger determinant of sleep disturbance than overall daily exposure. These findings highlight the need for digital health interventions targeting evening smartphone engagement to improve sleep outcomes among university students. Future research should employ longitudinal designs and objective measures to establish causal pathways between smartphone behaviors and sleep quality.