Nighttime screen use and sleep among medical students: an international cohort study

Abstract Background Screen use in the evening and at night is associated with poor sleep and may emerge as a significant public health concern, with smartphones being a central element. Medical students are a vulnerable group for harmful health behaviour and play a key role in future health promotion. The aim of the study was to examine the prevalence of nighttime screen use among medical students and explore its relationship with sleep and smartphone use. Methods The Medical Student Health Survey 2024, an international cross-sectional online survey, was conducted in universities across four study sites: Dresden (GER), Linz (AU) Pécs (HU) and Matsumoto (JA). Nighttime screen use was assessed using self-developed items, sleep behaviour via PSQI and problematic smartphone use (PSU) via SAS-SV. Descriptive statistics, correlation coefficients and hierarchical cluster analysis were calculated. Results Data from n = 1262 medical students were analysed. The study population was about M = 23 years old and mostly female (up to 73%). About 97% used a digital device within one hour of bedtime. Median duration of pre-bedtime screen use was 30 minutes and end of use was between 5-10 minutes before bedtime. The prevalence of smartphone addiction was up to 28% and the prevalence of poor sleep quality was up to 41%. Prolonged pre-bedtime screen use was associated with increased sleep latency (τ = 0.106, p < 0.001). Screen use after waking up at night was associated with a poorer outcome in 5 of 7 PSQI-subscales (each τ > 0.1, p < 0.001). The disturbance of sleep by a device was associated with a poorer outcome in 3 of 7 PSQI-subscales (each τ > 0.1, p < 0.001). PSU in connection with poor sleep quality and nighttime screen use was almost independent of socio-demographics. Conclusions Nighttime screen use associated with PSU and bad sleep quality is prevalent among medical students. The findings highlight the need for targeted interventions to raise awareness and encourage health-conscious screen use. Key messages • Nighttime screen use associated with PSU and bad sleep quality is prevalent among medical students. • The findings highlight the need for targeted interventions to raise awareness and encourage health-conscious screen use.