Vitamin D deficiency is common among Polish children with newly diagnosed type 1 diabetes mellitus

Abstract

Introduction: In recent years, the prevalence of T1DM (type 1 diabetes mellitus) and other autoimmune diseases in the paediatric population has been increasing. The aim of this study was to evaluate vitamin D levels among children with newly diagnosed T1DM, taking into account the most common coexisting autoimmune conditions. Material and methods: The database included 361 patients diagnosed with T1DM between 2020 and 2021, with a mean age of 9.27 ± 4.1 years, 189 boys. Auxological data and biochemical results of routinely performed tests were retrospectively analysed: blood pH and bicarbonate (HCO3–) on gasometry on admission, glycated haemoglobin (HbA1c), levels of antibodies against glutamic acid decarboxylase (GAD), antibodies against tyrosine phosphatase (IA2), antibodies against zinc transporters (ZnT8), 25-hydroxy vitamin D (25(OH)D), anti-IgA tissue transglutaminase antibodies (TTG-IgA), total IgA, levels of antibodies against thyroperoxidase (TPOAb), and antibodies against thyroglobulin (TgAb). Results: 35.5% of children (n = 128) with T1D presented 25(OH)D deficiency (< 20 ng/mL), 37% (n = 134) had suboptimal levels (20–30 ng/mL), and 25% (n = 90) had optimal vitamin D levels (30–50 ng/mL). 25(OH)D values were inversely proportional to the severity of diabetic ketoacidosis (p < 0.01) and negatively correlated with HbA1c values (p < 0.05). 25(OH)D levels were also found to be negatively correlated with children’s age at diagnosis (p < 0.001). Statistical analysis showed no association between 25(OH)D value and body mass index (BMI) Z-score or type of antibodies typical of T1D. There was also no statistically significant difference in vitamin D levels among patients with additional autoimmune processes (antibodies to thyroperoxidase and/or thyroglobulin and antibodies to tissue transglutaminase). Conclusions: More than one-third of Polish children with newly diagnosed T1D have 25(OH)D deficiency, especially in patients with diabetic ketoacidosis (DKA) at the diagnosis of diabetes. Determination of vitamin D levels should be a routine procedure in children with newly diagnosed T1DM.