Vitamin D status and the risk of diabetic nephropathy in pediatric patients: A comparative analysis of groups with different albumin excretion levels

Abstract

In press

Background. Type 1 Diabetes Mellitus (T1DM) in children is associated with a high risk of microvascular complications, with Diabetic Nephropathy (DN) being a leading cause of disability. The prevalence of DN necessitates the search for new modifiable risk factors. The role of vitamin D deficiency as a predictor of progression to albuminuria in children with a T1DM duration exceeding 5 years requires further investigation.

Aim. To evaluate the prognostic value of 25‑hydroxyvitamin D levels in the development of DN in children and adolescents with T1DM (disease duration >5 years) and to compare vitamin D status in patients with normo- and albuminuria.

Materials and Methods. A total of 50 patients aged 6–17 years with a T1DM duration of over 5 years were examined. The participants were divided into two groups: Group 1 (normoalbuminuria, n=26) and Group 2 (albuminuria, n=24). Serum 25‑hydroxyvitamin D (25(OH)D) levels were measured using the ELISA method. Renal function was assessed by the albumin-to-creatinine ratio and the estimated Glomerular Filtration Rate (eGFR) using the Schwartz formula (2009). Statistical analysis was performed using Statistica 13.3 (TIBCO Software Inc., USA) with the application of the Shapiro–Wilk test, Mann–Whitney U test, Spearman's rank correlation coefficient, and binary logistic regression. The study was conducted within the framework of a research project with state registration number 0123U101768.

Research Ethics. The study was conducted in accordance with the World Medical Association Declaration of Helsinki (1964–2024) and Order No.690 of September 23, 2009, of the Ministry of Health of Ukraine. Written informed consent was obtained from the parents of all participants.

Results. 25(OH)D levels in patients of Group 2 were significantly lower than in Group 1: 15.83 (12.22; 21.52) ng/mL vs. 22.03 (17.23; 24.04) ng/mL (p=0.009). Vitamin D deficiency was significantly more prevalent in Group 2 (75.0% vs. 42.3%, p=0.0223). Children with albuminuria and hypovitaminosis were more likely to exhibit hyperfiltration (29.2%) and a decrease in eGFR <90 mL/min/1.73 m² (41.6%). A decrease in vitamin D levels <20 ng/mL increases the odds of DN development by 3.49 times (OR=3.49; 95% CI [1.53–7.95]), independent of glycated hemoglobin levels and T1DM duration.

Conclusions. Vitamin D deficiency is an independent predictor of DN development in children with long-standing T1DM. Low 25(OH)D levels are associated with impaired renal filtration and the progression of albuminuria.

Keywords: pediatrics and neonatology, type 1 diabetes mellitus, vitamin D, albuminuria, children and adolescents.