Serum hepcidin concentrations in relation to iron status in children with type 1 diabetes

Chronic low-grade inflammation in type 1 diabetes (T1D) might increase hepcidin synthesis, possibly resulting in functional iron deficiency (FID). We hypothesized that in T1D children with FID, hepcidin concentrations are increased compared to those with normal iron status and those with absolute iron deficiency (AID). We evaluated hepcidin concentrations in T1D children in relation to iron status, and investigated whether hepcidin is useful in assessing FID. A cross-sectional study was conducted. FID was defined as elevated zinc protoporphyrin/heme ratio and/or red blood cell distribution width, and AID as low serum ferritin concentration. Post-hoc analyses with different definitions of FID were performed, using transferrin saturation and reticulocyte hemoglobin content. Serum hepcidin concentrations were measured using mass-spectrometry. The IRODIAB-study is registered at www.trialregister.nl (NTR4642). This study included 215 T1D children with a median age of 13.7 years (Q ₁–Q ₃: 10.1–16.3). The median (Q ₁–Q ₃) hepcidin concentration in patients with normal iron status was 1.8 nmol/l (0.9–3.3), in AID-patients, 0.4 nmol/l (0.4–0.4) and in FID-patients, 1.6 nmol/l (0.7–3.5). Hepcidin concentrations in FID-patients were significantly higher than in AID-patients (p < 0.001). Irrespective of FID-definition used, hepcidin concentrations did not differ between FID-patients and patients with normal iron status. This might be explained by the influence of various factors on hepcidin concentrations, and/or by differences in response of iron parameters over time. Single hepcidin measurements do not seem useful in assessing FID in T1D children. Multiple hepcidin measurements over time in future studies, however, might prove to be more useful in assessing FID in children with T1D.