Relationship between serum 25-hydroxyvitamin D and red blood cell indices in German adolescents.

The link between serum 25(OH)D and several important hematological parameters may point to an inhibitory role of vitamin D in the regulation of erythropoiesis in adolescents. What is Known: • The physiological effects of vitamin D on calcium homeostasis and bone metabolism have been established. • However, much less is known about the impact of circulating vitamin D on erythropoiesis. What is New: • Data from the KiGGS study in German adolescents demonstrated significant associations between serum vitamin D concentrations and red blood cell indices. • Further studies should be conducted to decipher the underlying mechanisms of vitamin D on erythropoiesis.