Association between serum vitamin D levels and glycemic parameters in prediabetes and type 2 diabetes mellitus: a retrospective study
Zainaba Rafeena, Karthik Raj, Edelbert Anthonio Almeida, Sirigere MurugaAbstract
Background:
Beyond its well-established role in maintaining skeletal health, vitamin D has been implicated in glucose homeostasis through effects on pancreatic β-cell function, insulin secretion, and insulin sensitivity. Although observational studies frequently link vitamin D deficiency to impaired glucose metabolism, findings from interventional studies remain inconsistent. This study aimed to determine serum 25-hydroxy vitamin D [25(OH)D] levels in individuals with prediabetes and type 2 diabetes mellitus (T2DM) and to evaluate the association of these levels with glycemic parameters.
Materials and Methods:
This retrospective observational study included 243 participants: 66 with prediabetes and 177 with T2DM. We classified participants according to American Diabetes Association criteria. Fasting blood glucose (FBG) and postprandial blood glucose (PPBG) were measured by the glucose oxidase–peroxidase method; glycated hemoglobin (HbA1c) was estimated by high-performance liquid chromatography; and serum 25(OH)D levels were determined by an enhanced chemiluminescence immunoassay. We assessed associations between serum vitamin D concentrations and glycemic parameters using Spearman rank correlation.
Results:
The median serum 25(OH)D concentration was 30.9 ng/mL (interquartile range [IQR]: 25.3–38.4) in the prediabetes group and 29.45 ng/mL (IQR: 24.3–36.05) in the T2DM group, with no statistically significant difference between the groups (
Conclusion:
Serum 25(OH)D concentrations were not significantly associated with glycemic parameters among individuals with prediabetes or T2DM. These findings suggest that vitamin D status may not independently contribute to glycemic control in established dysglycemia. Further large-scale prospective and randomized interventional studies are warranted to clarify vitamin D’s role in glucose metabolism and in the pathogenesis of dysglycemic disorders.