Vitamin D levels, general health status, and work productivity among healthcare workers-a scoping review of published literature (2010-2025).

Introduction: The risk for Vitamin D deficiency has been reported to be elevated among healthcare workers (HCWs), a fact that raises concerns about their health, resilience, and work performance. The objective of the study is to review published literature on Vitamin D deficiency among HCWs, reported health implications as well as the association with productivity. Methods: A comprehensive search of two databases (2010-2025), PubMed and Scopus was conducted with Google Scholar used as a supplementary source following PRISMA-ScR guidelines. The inclusion criteria were full-text studies in English enrolling HCWs per WHO definition, measuring serum 25(OH)D, and reporting health or work-related outcomes. Results: Thirty-six studies met the criteria 30 cross-sectional, 2 prospective, 4 interventional studies, 2 of which were Randomized Controlled Trials (RCTs). Vitamin D deficiency was highly prevalent across studies with reported prevalence ranging from 30% to over 90% varying by geographic region, season, professional role, deficiency threshold and assay method, particularly among nurses and shift workers. Key determinants included indoor work, long shifts, night duties, limited sun exposure, female sex, younger age, higher Body Mass Index (BMI), veiling, and lack of supplementation. Seasonal variation was confirmed. Deficiency was linked to immune vulnerability (higher SARS-CoV-2 infection), musculoskeletal issues, and mixed evidence for mental health outcomes. Limited data suggest higher Vitamin D levels may reduce presenteeism. RCTs demonstrated that high-dose supplementation improved serum levels and reduced respiratory infections. Conclusion: Existing literature points that Vitamin D inadequacy among HCWs represents significant occupational health concern highlighting important evidence gaps and future research priorities.