Mashhad Razavi Hospital Razavi Journal of Medicine 3115-753X 14 3 2026 07 01 Association of all-cause and specific-cause mortality with diabetes mellitus in adults with vitamin D deficiency 36 46 118628 10.30483/rjm.2026.254709.1473 EN Sara Saffar Soflaei Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. International UNESCO Center for Health-Related Basic Sciences and Human Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran. Soheyla Jafarpour Department of Medical Genetics and Molecular Medicine, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Rasoul Alimi Department of Epidemiology and Biostatistics, School of Health, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran. Toktam Sahranavard International UNESCO Center for Health-Related Basic Sciences and Human Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran. Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. Emad Ghayour-Mobarhan Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran. Parsa Seyed Hosseini Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. Hossein Hatamzadeh Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Mahmoud Ebrahimi Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. Department of Cardiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Mohsen Moohebati Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. Department of Cardiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Gordon A Ferns Brighton and Sussex Medical School, Division of Medical Education, Brighton, UK. Habibollah Esmaily Department of Biostatistics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran. Social Determinants of Health Research center, Mashhad University of Medical Sciences, Mashhad, Iran. Majid Ghaour-mobarhan Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. International UNESCO Center for Health-Related Basic Sciences and Human Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran. Journal Article 2026 01 02 <strong>Background</strong>: There is increasing evidence indicating that vitamin D deficiency may contribute to the development of Type 2 Diabetes Mellitus (T2DM) by affecting insulin sensitivity, insulin secretion, and inflammation.<br><br><strong>Objectives</strong>: We have investigated the association between vitamin D deficiency, T2DM, and mortality outcomes.<br><br><strong>Methods</strong>: The study was conducted on a sample of 846 subjects, derived from the Mashhad stroke and heart atherosclerotic disorder (MASHAD) cohort study. Participants were considered as vitamin D deficient with vitamin D levels of less than 20 ng/ml. Over 10 years, participants were followed up every three years. The cause of death was identified using the death register of the Iranian Ministry of Health and Education and the death cause questionnaire. The study examined the relationship between T2DM and mortality using descriptive statistics, chi-square tests, and Cox proportional hazard regression analysis.<br><br><strong>Results</strong>: During the 10-year follow-up, 44 participants died from all causes, 15 from cancer, and 14 from cardiovascular causes. There was a significant association between diabetes and all-cause mortality, even after adjustment for age and sex yielding an HR of 2.07 (P=0.039). Vitamin D deficiency was associated with diabetes-related mortality (HR=3.16, P=0.038), but this link is not true for individuals who had vitamin D levels of more than 20 ng/ml. This association extends to mortality because of cancer (HR=3.64, P=0.025), but not cardiovascular mortality. <br><br><strong>Conclusion</strong>: Our findings underscore the potential role of vitamin D deficiency in the mortality risk of diabetics. Future research should further explore the mechanistic links between vitamin D deficiency, T2DM, and mortality outcomes to inform targeted interventions and improve clinical management strategies. https://journal.razavihospital.ir/article_118628_261209d3a391e1b25377435d6cb41382.pdf