Comprehensive effects and dose–response relationship of screen exposure on university students' physical and mental health and academic performance in the digital age: a systematic review and meta-analysis

Abstract Objective This study aims to systematically review the impact of total screen time on university students' health outcomes and academic performance, and to explore its dose–response relationship. Methods The PubMed, Web of Science, Embase, Cochrane Library, and PsycINFO databases were systematically searched to collect studies related to university students' screen time, with the search period from inception to July 2025. After two researchers independently screened the literature, extracted data, and assessed quality, meta-analysis was performed using Stata 17.0 software. The pooled effect sizes were the reported odds ratios (OR) with 95% confidence intervals (CI). Additionally, dose–response analysis was performed using R 4.4.3 software, and restricted cubic splines were used to fit the non-linear dose–response curve at fixed knots of the exposure distribution. Results A total of 69 cross-sectional studies and 3 longitudinal studies were included, comprising 71,633 university students. Meta-analysis results showed that screen time was significantly associated with an increased risk of depression (OR = 1.93; 95%CI: 1.75–2.12) and digital eye strain (OR = 1.96; 95%CI: 1.67–2.31). Dose–response analysis further revealed that after daily screen time exceeded 2.5 h, the risks of depression and digital eye strain increased sharply, with the risks increasing by more than 15% for each additional hour of screen exposure. In addition, screen time was also significantly associated with anxiety, stress, physical pain, sleep quality deterioration, insufficient physical activity, and reduced academic performance, with OR values ranging from 1.12 to 1.79. However, no significant associations were found between screen time and sleep duration or body mass index (BMI). Conclusions Current evidence indicates that screen time exerts adverse effects on university students' mental health, physical pain, sleep quality, digital eye strain, physical activity, and academic performance, while no significant association is observed between screen time and sleep duration or BMI. Protocol registration The review protocol has been registered at the PROSPERO website since 26 May 2025 (CRD420251060967).