25-hydroxyvitamin-d-2 and Anemia--Iron-Deficiency

Vitamin D and iron deficiencies frequently co-exist. It is now appreciated that mechanistic interactions between iron and vitamin D metabolism may underlie these associations.. We examined interrelations between iron and vitamin D status and their regulatory hormones in pregnant adolescents, who are a group at risk of both suboptimal vitamin D and suboptimal iron status.. The trial was a prospective longitudinal study of 158 pregnant adolescents (aged ≤18 y). Maternal circulating biomarkers of vitamin D and iron were determined at midgestation (∼25 wk) and delivery (∼40 wk). Linear regression was used to assess associations between vitamin D and iron status indicators. Bivariate and multivariate logistic regressions were used to generate the OR of anemia as a function of vitamin D status. A mediation analysis was performed to examine direct and indirect relations between vitamin D status, hemoglobin, and erythropoietin in maternal serum.. Maternal 25-hydroxyvitamin D [25(OH)D] was positively associated with maternal hemoglobin at both midgestation and at delivery (P < 0.01 for both). After adjustment for age at enrollment and race, the odds of anemia at delivery was 8 times greater in adolescents with delivery 25(OH)D concentrations <50 nmol/L than in those with 25(OH)D concentrations ≥50 nmol/L (P <0.001). Maternal 25(OH)D was inversely associated with erythropoietin at both midgestation (P <0.05) and delivery (P <0.001). The significant relation observed between 25(OH)D and hemoglobin could be explained by a direct relation between 25(OH)D and hemoglobin and an indirect relation that was mediated by erythropoietin.. In this group of pregnant adolescents, suboptimal vitamin D status was associated with increased risk of iron insufficiency and vice versa. These findings emphasize the need for screening for multiple nutrient deficiencies during pregnancy and greater attention to overlapping metabolic pathways when selecting prenatal supplementation regimens.

Topics: 25-Hydroxyvitamin D 2; Adolescent; Anemia, Iron-Deficiency; Biomarkers; Calcifediol; Cohort Studies; Cross-Sectional Studies; Erythropoietin; Female; Hemoglobins; Humans; Linear Models; Longitudinal Studies; Maternal Nutritional Physiological Phenomena; New York; Nutritional Status; Pregnancy; Pregnancy Complications; Prospective Studies; Risk; Vitamin D Deficiency

Dietary phosphate intake and vitamin D receptor activator (VDRA) regulate fibroblast growth factor 23 (FGF23); iron may modulate FGF23 metabolism. We aimed to determine whether oral iron supplementation influences serum FGF23 concentration in hemodialysis (HD) patients, while excluding the effect of dietary phosphate intake.. This prospective study enrolled 27 maintenance HD patients with iron deficiency and hyperphosphatemia treated with sevelamer-HCl. The phosphate binder was changed from sevelamer-HCl to ferric citrate hydrate (FCH) to maintain constant phosphate levels. VDRA, other phosphate binders, and cinacalcet HCl were not changed. Serum intact FGF23, C-terminal FGF23 (C-term FGF23), intact parathyroid hormone (PTH), 1,25(OH)2D and other parameters were monitored for 12 weeks.. Serum phosphate levels (5.89 ± 1.45 mg/dl at baseline, 5.54 ± 1.35 mg/dl at 12 weeks) and 1,25(OH)2D levels were unchanged. Serum ferritin levels increased from 25.6 ± 24.3 ng/ml at baseline to 55.8 ± 33.5 ng/ml at 12 weeks with FCH administration. Serum intact FGF23 and C-term FGF23 levels significantly decreased at 12 weeks compared with baseline (2,000 (1,300.0-3,471.4) to 1,771.4 (1,142.9-2,342.9) pg/ml, p = 0.01, and 1,608.7 (634.8-2,308.7) to 1,165.2 (626.1-1,547.8) RU/ml, p = 0.007, respectively); serum intact PTH levels significantly increased (96 (65-125) to 173 (114-283) pg/ml, p < 0.001).. Oral FCH administration decreased serum intact FGF23 and C-term FGF23 levels and increased intact PTH levels; phosphate and 1,25(OH)2D levels were unchanged. Oral FCH administration to treat iron deficiency is a possible strategy for reducing serum FGF23 levels independent of phosphate and VDRA.

Topics: 25-Hydroxyvitamin D 2; Adult; Aged; Anemia, Iron-Deficiency; Bone Diseases; Chelating Agents; Female; Ferric Compounds; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Kidney Failure, Chronic; Male; Middle Aged; Parathyroid Hormone; Phosphates; Prospective Studies; Renal Dialysis; Sevelamer; Young Adult