Fat-Soluble Vitamin Deficiencies Drive Oxidative Stress, Dyslipidaemia, and Insulin Resistance in Paediatric Type 1 Diabetes: Evidence From a North African Cohort

Objectives Children with type 1 diabetes mellitus (T1DM) are prone to oxidative stress, dyslipidaemia, and insulin resistance, yet the contribution of fat-soluble vitamin deficiencies remains unclear. This study aimed to evaluate the levels of vitamins A, D, and E in paediatric T1DM patients and their association with oxidative stress markers, lipid profile, and insulin resistance indices. Material and Methods Ninety children with T1DM were enrolled in this cross-sectional study. Serum levels of vitamins A, D, and E were measured using high-performance liquid chromatography. Oxidative stress markers, including malondialdehyde (MDA), superoxide dismutase (SOD), and total antioxidant capacity (TAC), were assessed spectrophotometrically. Lipid profile parameters (LDL, HDL, triglycerides) and insulin resistance indices (HOMA-IR, QUICKI) were calculated. Subgroup, burden, and interaction analyses were performed, and multivariate regression models were applied to identify independent predictors. Results All three vitamins were significantly reduced in T1DM patients compared to reference values. Vitamin levels correlated inversely with LDL, TG/HDL ratio, and MDA, and positively with SOD, TAC, and QUICKI. Poor glycaemic control (HbA1c ≥9%) was associated with lower vitamin concentrations, higher MDA levels, and worse HOMA-IR scores. Children with multiple deficiencies (≥2 vitamins low) exhibited the most adverse oxidative and metabolic profiles. Interaction analysis revealed that vitamin D’s protective effect on insulin sensitivity was stronger in children with elevated TG/HDL ratios. Multivariate regression confirmed vitamins D and E as independent predictors of HOMA-IR. Conclusion Combined deficiencies of fat-soluble vitamins exacerbate oxidative imbalance and insulin resistance in paediatric T1DM, highlighting the critical need for routine micronutrient monitoring and potential supplementation in this vulnerable population.