Caffeine, Alcohol, and Tobacco Use in Shift-Working Healthcare Professionals: A Systematic Review

Background: Shift work is a central feature of modern healthcare systems, particularly in hospital and emergency settings. However, irregular schedules are associated with circadian disruption and sleep loss, which may lead to increased use of substances such as caffeine, alcohol, tobacco, and sleep aids among healthcare professionals. Understanding this association is essential for workforce well-being and patient safety. This systematic review examines the relationship between night or rotating shift work and substance use among physicians and nurses with attention to potential sleep disruption. Methods: Following PRISMA guidelines, we searched PubMed, Embase, Web of Science, PsycINFO, and CENTRAL. We included observational studies involving healthcare professionals exposed to night or rotating shifts and assessing substance use outcomes. Data were extracted on study design, population, exposure definitions, substances used, sleep factors, and risk of bias. Results: Ten observational studies (8 cross-sectional, 1 cohort, 1 case-control; n=327–3,917) were included. Caffeine was the most consistently associated substance, with seven to ten studies reporting higher intake among shift workers—up to 67% of surgeons and a significant increase among night-shift nurses. Alcohol and tobacco showed mixed associations: two studies found significantly higher use among shift workers, while others reported no difference after adjustment. Sleep aid and sedative use was elevated in several studies but rarely reached statistical significance. One Ethiopian study identified higher khat use among nurses with shift work sleep disorder, though significance was lost after adjustment. No study analyzed dose-response by shift intensity or duration. Overall, risk of bias was moderate and interpretation of these findings was limited by the predominance of cross-sectional designs, methodological heterogeneity, and reliance on self-reported measures. Conclusion: Caffeine consumption was a pervasive coping strategy among shift-working healthcare professionals, whereas associations with alcohol, tobacco, and sleep aids were inconsistent. Given the implications for fatigue, performance, and patient safety, institutional interventions, such as fair scheduling policies and preventive education on substance use, should be prioritized. Future longitudinal research is needed to clarify causal relationships and inform occupational health strategies.