Association of Low Vitamin D Status With Adiponectin and Fibroblast Growth Factor-21 in Newly Diagnosed Type 2 Diabetes Mellitus Patients.

Introduction: Adiponectin and fibroblast growth factor-21 (FGF-21) have important roles in metabolic regulation and insulin sensitivity. Vitamin D is linked to metabolic dysregulation, inflammation, and oxidative stress in chronic type 2 diabetes mellitus (T2DM). The present study aimed to assess the relationship of vitamin D levels with adiponectin and FGF-21 in newly diagnosed T2DM.

Methods: A descriptive study was conducted on 47 patients with newly diagnosed T2DM recruited based on the American Diabetes Association criteria. Fasting plasma glucose and insulin were measured, and the homeostatic model assessment for insulin resistance was calculated. The serum levels of metabolic regulators such as vitamin D, adiponectin, and FGF-21; inflammatory markers such as interleukin-6 (IL-6), tumor necrosis factor-α, and high-sensitivity C-reactive protein; and oxidative stress markers such as malondialdehyde (MDA) and total antioxidant status were measured.

Results: The mean serum vitamin D concentration was 17.49±7.10 ng/ml, and all patients had low vitamin D levels (<30 ng/ml). Vitamin D was positively correlated with adiponectin (r=0.331, p=0.023), and it was negatively correlated with FGF-21 (r=-0.356, p=0.014), IL-6 (r=-0.411, p=0.004), and MDA (r=-0.515, p<0.001).

Conclusion: There was a reduction in vitamin D concentration in all subjects. Vitamin D showed a positive association with adiponectin and a negative association with FGF-21 and inflammatory and oxidative stress markers. Vitamin D deficiency might increase the risk of progression of T2DM in these subjects.