Prevalence of Vitamin D Deficiency in Iran: A Systematic Review and Meta-Analysis

Introduction: Vitamin D deficiency (VDD) affects more than one billion individuals globally. We aimed to review all the published papers on vitamin D deficiency in in the country. Method: PubMed, Google Scholar, Web of Science, Scopus, Science direct and scientific information databases were searched for papers related to the prevalence of vitamin D insufficiency for all age groups in Iran from 2000 to 2018. The Joanna Briggs Institute prevalence critical appraisal tool was applied for the assessment of the methodological quality of these studies. The Meta-analysis is based on the random effect model using Comprehensive Meta-analysis data analysis. Results: Eighty-seven original articles reported on participants with vitamin D insufficiency in Iran. According to the meta-analysis of the prevalence of moderately deficient of vitamin D in men and women as well as younger and older individuals ( 18 years) using a cut-off point of 25(OH) D3 20 ng/mL was 39% and 51%, respectively. Vitamin D concentrations 30 ng/mL among Iranian populations in the cities of Tehran, Shiraz, Mashhad, and Zahedan were reported to be higher than 90%. The prevalence of vitamin D insufficiency in Iranian women was higher than in men in various age groups. The highest prevalence of vitamin D insufficiency in neonates, children, adults and pregnant women was observed in the Middle East. Most countries had a high prevalence of VDD in elderly people. Conclusion: Vitamin D insufficiency is common in the Iranian population and is an important public health problem that should be considered seriously.