Effect of Vitamin D Replacement on Hemoglobin Concentration in Subjects with Concurrent Iron-Deficiency Anemia and Vitamin D Deficiency: A Randomized, Single-Blinded, Placebo-Controlled Trial

Abstract

Background: The effect of vitamin D replacement on hemoglobin (Hb) concentration in subjects with concurrent deficiencies of vitamin D and iron is not known. Methods: We report on an investigator-initiated, randomized, single-blinded, placebo-controlled, 12-week interventional trial. Thirty subjects with iron-deficiency anemia (serum ferritin <15 µg/l) were randomized to an intervention arm (cholecalciferol, i.e. vitamin D₃, 0.6 million units i.m. once) or placebo. In all subjects, iron deficiency was corrected with parental iron. Other causes of anemia were excluded with appropriate investigation. The primary end point was a rise in Hb concentration. Results: Baseline parameters of age, BMI, hemogram values and levels of serum ferritin, 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) were similar in the 2 arms. Twelve weeks after vitamin D replacement, there was a significant increase in 25 (OH)D levels (57.7 ± 20.5 vs. 14.1 ± 6.2 ng/ml, p < 0.0001) and a decrease in PTH levels (32.4 ± 16.4 vs. 52.9 ± 18.4 pg/ml, p = 0.003) in subjects in the intervention arm when compared to the placebo arm. However, the increments in serum ferritin and Hb concentration in the intervention and placebo arm did not differ. Conclusion: Vitamin D replacement in subjects with iron-deficiency anemia after iron correction does not improve Hb concentration further.