Prevalence of 25-Hydroxyvitamin D Deficiency in Korean Patients with Anemia

Vitamin D deficiency is a very common health problem in Korea. Vitamin D has been suggested to have an important role on nonskeletal functions including cellular proliferation and differentiation, muscle function, immunity and erythropoiesis. Recent studies have been reported that vitamin D deficiency had associated with iron deficiency anemia, anemia of chronic kidney disease, and anemia of inflammation. In this study, we investigated the prevalence of vitamin D deficiency in Korean patients with anemia and also analyzed the association between vitamin D status and specific subtypes of anemia.

A total of 147 anemic patients (median age 66 years, range 19∼91 years) and 300 nonanemic controls (median age 60 years, range 29∼87 years) were included. Anemia was defined according to World Health Organization (WHO) criteria. Serum 25- hydroxyvitamin D [25(OH)D] was measured using electrochemiluminescence immunoassay. The deficiency of 25(OH)D was defined as <20 ng/mL and severe deficiency was defined as <10 ng/mL. We compared serum 25(OH)D levels based on the presence and subtypes of anemia.

The prevalence of 25(OH)D deficiency was 74% (109/147) and 70% (210/300) in anemic (median Hb 9. 6 g/dL) and nonanemic group (median Hb 14. 3 g/dL), respectively. The prevalence of severe 25(OH)D deficiency was significantly higher in anemic group than in nonanemic group [44. 8% (66/147) vs 11. 7% (35/300), P<0. 0001] Odds ratio for severe 25(OH)D deficiency in anemic patients was 6. 17 (95% CI 3. 820–9. 965, P<0. 0001). The prevalence of 25(OH)D deficiency was not different between iron deficiency anemia (IDA) group and anemia of chronic disease (ACD) group. However, the serum 25(OH)D levels of ACD patients were lower than those of IDA patients in male (median 25(OH)D 14. 34 ng/mL vs 23. 04 ng/mL, P=0. 04).

This study demonstrates that severe vitamin D deficiency is associated with anemia in Korea. Although vitamin D deficiency is also very common in nonanemic Korean population, anemia is related to much worse vitamin D deficient status. Multiple factors including poor nutritional status and potential roles of vitamin D on inflammation and erythropoiesis might be considered.

No relevant conflicts of interest to declare.