The Correlation Between Vitamin D Deficiency and Anemia: A Systematic Review.

Vitamin D deficiency (VDD) and anemia are common public health problems around the world. Recent data points to a biological connection between these disorders, especially in relation to vitamin D's function in controlling iron and hepcidin metabolism. The study aims to do a comprehensive review of the literature on the relationship between adult populations' anemia and VDD. PubMed, Web of Science, Scopus, and Embase were all thoroughly searched. Included were observational studies evaluating the connection between adult anemia and vitamin D levels. Six studies were included, with a total of 10,953 participants, and 2690 (24.6%) of them were men. The range of VDD prevalence was 18.8% to 87.1%, with a total prevalence of 5479 (50%). Among the participants with VDD, 2041 (37.2%) had anemia. Anemia was shown to be more common in those with VDD in every study. Mean hemoglobin, ferritin, and red blood cell counts were consistently lower in VDD groups. In the majority of studies, the connection persisted even after controlling for covariates. There is strong evidence supporting an association between VDD and increased risk of anemia. These results support more interventional research to evaluate the potential benefits of including vitamin D screening in anemia workups and the benefits of vitamin D supplementation in anemic persons.