Association Between Serum Ferritin, Vitamin D Levels, and Glycemic Control in Patients with Type 2 Diabetes Mellitus

Abstract

Background: Diabetes mellitus type 2 is a chronic metabolic disease defined by hyperglycaemia, insulin resistance and decreased insulin production. Changes in iron metabolic and vitamin D status can lead to metabolic dysfunction by oxidative stress, inflammatory mechanisms, and insulin signaling impairment.

Objective: To determine the association between serum ferritin, vitamin D levels, and glycemic control among patients with type 2 diabetes mellitus.

Materials and Methods: This hospital-based analytical cross-sectional study was designed for 140 patients with type 2 diabetes mellitus at DHQ Hospital Mandi Bahauddin, from November 2022 to May 2023. Demographic, clinical history, BMI, ferritin, serum 25-hydroxyvitamin D, fasting blood glucose, and glycated hemoglobin (HbA1c) were evaluated. Patients were classified as having good (HbA1c < 7%) or poor (HbA1c ≥ 7%) glycemic control. Data were to be analyzed statistically using SPSS version 26.0, appropriate group comparisons would be made, spearman correlation and multivariable logistic regression would be done and p-value<0.05 would be considered as statistically significant.

Results: The analysis included 140 patients with type 2 diabetes mellitus, with a mean age of 52.47 ± 8.77 years. Of these, 77 (55.0%) were male, and 95 (67.9%) had poor glycemic control (HbA1c ≥7%). The mean HbA1c was 7.77 ± 1.29%, while the median serum ferritin concentration was 139.00 ng/mL and the mean vitamin D level was 22.76 ± 7.74 ng/mL. Vitamin D deficiency was identified in 47 (33.6%) patients. Serum ferritin showed a significant positive correlation with HbA1c (r=0.450, p<0.001), whereas vitamin D demonstrated a significant negative correlation (r=−0.334, p<0.001). Patients with poor glycemic control had higher ferritin and lower vitamin D concentrations (both p<0.001). Multivariable logistic regression demonstrated significant associations of ferritin (aOR=1.150, 95% CI: 1.062–1.245; p=0.001) and vitamin D (aOR=0.177, 95% CI: 0.082–0.381; p<0.001) with poor glycemic control.

Conclusion: Evaluating serum ferritin and vitamin D alongside conventional glycemic indicators may improve understanding of metabolic abnormalities in type 2 diabetes mellitus. The clinical significance of these biomarkers requires interpretation in conjunction with established indicators of glycemic control and relevant confounding factors.

Keywords: Type 2 diabetes mellitus; serum ferritin; vitamin D; HbA1c; glycemic control; insulin resistance.