c-peptide and Hypercalcemia

This participant-blinded parallel-group randomized placebo-controlled study demonstrated that alfacalcidol (vitamin D analogue) preserves beta cell function in newly diagnosed type 1 diabetes (T1DM) in children.. Subjects from outpatient clinic were randomized to intervention and control groups. Inclusion: (1) age 8-15, (2) T1DM, (3) duration <8 weeks, (4) no chronic diseases, (5) stable diet. Exclusion: (1) vitamin D, calcium supplements or fortified foods, (2) hypercalcemia. Intervention group received alfacalcidol 0.25 μg twice daily, while control group received placebo. Insulin given physician-titrated to blood glucose. Safety monitored by serum calcium and phosphate. Beta cell function assessed at 0, 3, 6 months using fasting C-peptide (FCP) and daily insulin dosage per body weight (DID). Primary outcome measured using multivariate repeated measures GLM-ANOVA, with FCP and DID as primary measures and age, gender, sunlight exposure, 25-hydroxy vitamin D, and HbA1c as covariates.. Of 61 subjects, 7 dropped out. GLM-ANOVA showed that groups were different (p=0.019, Eta-squared=0.087), with no significant covariates. FCP was higher and DID lower in the intervention group, with males having stronger responses to alfacalcidol (p=0.001). No adverse effects were observed.. The study confirmed that alfacalcidol can safely preserve beta cell function in newly diagnosed T1DM in children, with a stronger effect in males.. IRCT201205159753N1.

Topics: Adolescent; Blood Glucose; Body Weight; C-Peptide; Calcium, Dietary; Child; Diabetes Mellitus, Type 1; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Humans; Hydroxycholecalciferols; Hypercalcemia; Insulin; Insulin-Secreting Cells; Linear Models; Male; Multivariate Analysis; Single-Blind Method

The effect of mild hypercalcaemia on the growth hormone (GH), C-peptide and glucose responses to arginine infusion in patients with insulin-dependent idiopathic diabetes mellitus (ID) was compared with that observed in patients whose diabetes was secondary to idiopathic haemochromatosis (IH) and chronic pancreatitis (CP). The summated GH responses to arginine infusion alone were similar in all three groups. Mild hypercalcaemia significantly diminished the GH response to arginine in patients with secondary diabetes, but not in those with ID. As the blood glucose and C-peptide responses were similar in the presence of a normal or raised serum calcium, the differences in GH response could not be ascribed to changes in blood glucose levels or to alterations in endogenous insulin release. For reasons as yet unknown, hypercalcaemia appears to have more of a stabilizing effect on the pituitary somatotrophic granules of those with secondary diabetes than in those with ID.

Topics: Adult; Arginine; C-Peptide; Chronic Disease; Diabetes Complications; Diabetes Mellitus; Female; Growth Hormone; Hemochromatosis; Humans; Hypercalcemia; Male; Middle Aged; Pancreatitis