Association of Screen Time with Physical and Mental Health in University Students: A Systematic Review and Meta-analysis (Preprint)

BACKGROUND Screen use has become nearly universal and numerous studies have highlighted both the benefits and the risks of this digital integration. However, evidence on the association between screen time (eg, television viewing, smartphone use, video gaming) and health outcomes among university students remains inconsistent. Substantial methodological variation across studies has limited the synthesis and interpretation of existing findings. OBJECTIVE This systematic review and meta-analysis aimed to quantify the association between screen time duration and physical and mental health outcomes among university students 17 years or older. METHODS A systematic search of PubMed, PsycINFO, CINAHL was searched using a combination of subject headings and free text for studies published up to December 31, 2024. Observational and experimental studies (using baseline data) were included if they assessed screen time duration and physical or mental health outcomes in university students, were published in English, and provided sufficient data to compute effect sizes. Screening was independently performed by 3 reviewers using Rayyan, resolving disagreements through consensus. Data extraction was conducted by one reviewer, including participant characteristics, measurement methods, study design, publication year, and study quality. Risk of bias was evaluated using the Agency for Healthcare Research and Quality (AHRQ) tools. Radom-effects meta-analyses were conducted to pool correlation coefficients. This review was conducted in accordance with PRISMA guidelines. RESULTS Of 18,349 nonduplicate records screened, 685 full-text studies were assessed for eligibility, and 51 studies met the inclusion criteria, comprising 55 independent samples and 110,331 participants (72,520/110,331, 65.5% female). Longer screen time duration was significantly associated with poorer physical health outcomes (30 samples; r=0.211, 95%CI 0.159-0.261) and mental health (25 samples; r=0.167,95%CI 0.081-0.251). Significant between-study heterogeneity was observed. Moderator analyses shows that geographic region significantly moderated associations with physical health with the strongest associations observed in South America. Meta-regression analyses indicated that study quality significantly moderated associations with physical health. The proportion of female participants significantly moderated associations with mental health. CONCLUSIONS This systematic review and meta-analysis found small to moderate significant correlations between screen time and poorer physical and mental health among university students. The review addressed a critical gap in the literature where prior research has largely focused on adolescents or examined outcomes in isolation. While many included studies were of high quality, heterogeneity in how screen time is measured, variability in health outcome instruments and operational definitions, as well as risk of bias, limits causal inference and the direct translation of findings into practice. The findings nonetheless reveal screen-related behaviors may represent an important and potentially modifiable correlate of student health. Future research should prioritize longitudinal designs and standardized measurement approaches to strengthen causal inference and inform evidence based digital health strategies within higher education settings. CLINICALTRIAL PROSPERO CRD42024539034; https://www.crd.york.ac.uk/PROSPERO/view/CRD42024539034