Association of vitamin D levels and polymorphisms in vitamin D receptor with type 2 diabetes mellitus

Investigating the association between FOK1 polymorphism in the vitamin D receptor (VDR) gene and type 2 diabetes prevalence: A comprehensive analysis

There is mounting evidence that suggests vitamin D insufficiency may have a role in the emergence of type 2 diabetes. Additionally, as VDR mediates the actions of vitamin D, variants in its sequence could have implications in this disease. One of these polymorphisms, Fok1 (rs2228570), has been demonstrated to generate changes in the receptor's structure, causing a shorter protein. The purpose of this research is to establish a potential association between the Fok1 polymorphism and DM2. To achieve such goal, a comprehensive study of this SNP was conducted using functional in-silico analysis and a systematic review with meta-analysis. Additionally, an examination of VDR gene expression in patients with diabetes compared to controls was performed in order to investigate possible differences in expression levels. Our expression analysis showed that VDR has no differential expression between these two groups. To study its functional consequences and stability, different tools were combined, without consistent results. Finally, our systematic review and meta-analysis showed that theFok1 variant was not significantly associated with the DM2 prevalence. This extensive analysis did not provide support for an association between the presence of Fok1 polymorphism and DM2. This result aligns with some previous studies but contrasts others that have reported both protective and risk factors.

Vitamin D Receptor TaqI Gene Polymorphism and Risk of Type 2 Diabetes Mellitus: A Case-Control Study Among Ethiopian Population

Background: Type 2 diabetes mellitus (T2DM) is a complex and diverse illness that is influenced by several vulnerable genes as well as environmental risk factors. The aim of this study was to ascertain the relationship between the vitamin D receptor TaqI gene polymorphisms and the risk of T2DM at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. Methods: An age- and sex-matched hospital-based case-control study involved 70 patients with T2DM and 70 nondiabetic healthy controls. Demographic information was assessed in order to identify the associated risk variables. To ascertain the TaqI genotypes, DNA was taken from blood samples and used in a polymerase chain reaction and agarose gel electrophoresis analysis. Results: The frequency of the homozygous TaqI-tt genotype [odds ratios (OR): 2.69; 95% confidence level (CL): 1.05-6.44; P = 0.38], and the t allele (OR: 1.90; 95% CL: 1.16-3.12; P = 0.0099) was significantly higher in patients with T2DM compared to nondiabetic controls. Conclusion: The results suggest that the TaqI gene polymorphism may be related to the onset of T2DM in the Ethiopian population under study.

Vitamin D Reduces the Activity of Adenosine Deaminase and Oxidative Stress in Patients with Type Two Diabetes Mellitus

SCOPE

Patients with Type 2 diabetes mellitus (T2DM) have lower levels of vitamin D. An elevation in uric acid (UA) contributes to T2DM via an increase in oxidative stress. Adenosine deaminase (ADA) is an enzyme of the purine degradation pathway. It is hypothesized that a reduction of ADA activity via vitamin D supplementation reduces UA and oxidative stress.

METHODS AND RESULTS

A total of 162 participants (81 with T2DM and 81 controls) are enrolled in a case-control study. A follow-up interventional study is performed on 30 patients with vitamin D deficiency. These patients receive 50 000 IU (international units) of vitamin D3 on a weekly basis for 12 weeks. This intervention is followed by the measurement of several markers. T2DM patients has higher ADA activity, UA, and lipid peroxidation but lower 25-hydroxy-vitamin D (25 (OH) vitamin D) and GSH/GSSG ratio (p < 0.05). Vitamin D supplementation results in a reduction of ADA activity and UA levels (p < 0.05) along with an increase in GSH/GSSG ratio (p < 0.05).

CONCLUSION

The results highlight the presence of an axis in T2DM patients between ADA, UA, and oxidative stress. Modulation of this axis can be achieved by clinically approved vitamin D supplementation protocols.

Serum 25-Hydroxyvitamin D Concentrations in Patients with Type 2 Diabetes Mellitus in Eastern Sudan: A Case-Control Study

Introduction

Diabetes mellitus (DM) is one of the world's major public health problems. There are few published data on 25-hydroxyvitamin D (25[OH]D) concentrations and DM, and these studies showed different results.

Objectives

The current study aimed to compare 25[OH]D concentrations between patients with type 2 DM (T2DM) and healthy controls in eastern Sudan.

Methods

A case-control study of two groups matched for age and gender (88 in each group) was conducted in eastern Sudan from March to May 2022. The cases were patients with T2DM, and the controls were healthy participants. Sociodemographic data were collected, and serum 25(OH)D levels were assessed. A univariate analysis was performed.

Results

Of the total 176, 82 (47%) were males, and 94 (53%) were females; the median (interquartile range [IQR]) of age, body mass index (BMI), and 25(OH)D concentration were 55 (50-61) years, 27 (23-31) kg/m2, and 13 (10-19) ng/mL, respectively. Of the 176, 137 (78%) were vitamin D deficiency cases. Compared with the controls, age, gender, educational level, marital status, or BMI were not different in the circumstances. Moreover, the median (IQR) for serum 25(OH)D concentrations showed no difference between patients with T2DM and the healthy controls (12 [10-18] ng/mL vs. 13 [10-20] ng/mL). The prevalence of vitamin D deficiency (25(OH)D level < 20 ng/mL) was not different between patients with T2DM and the healthy controls (66/88 [75%] vs. 71/88 [81%]). There was no association in the serum 25(OH)D levels between diabetic and nondiabetic participants (OR = 1.01, 95% CI 0.97-1.06) or in vitamin D deficiency between diabetic and nondiabetic participants (OR = 0.72, 95% CI 0.35-1.47).

Conclusion

There was no significant difference in 25(OH)D levels between diabetic and nondiabetic participants in this study. Further studies investigating the mechanisms of association between 25(OH)D levels and DM are needed.

Level of biochemical parameters in patients with type 2 diabetes mellitus depending on the genotype of the FokI polymorphism in the vitamin D3 receptor (VDR gene)

OBJECTIVES

Diabetes mellitus type 2 (T2DM) is a multifactorial and polygenic disorder characterised by chronic hyperglycaemia accompanied by impaired lipid, carbohydrate, and protein metabolism. The disease is associated with several genetic polymorphisms, including the FokI polymorphism in the vitamin D receptor (VDR) gene.

METHODS

We conducted a study of 327 probands (191 T2DM patients, 136 controls), with a mean age 65.06 (SD ± 10.88) years of patients with T2DM and 58.89 (SD ± 6.59) years in the healthy probands. We investigated the association between FokI polymorphism and biochemical parameters in T2DM patients in the Slovak population. Anthropometric measurements, biochemical, and genetic analysis were statistically evaluated by Statistica ver.13 software using t-tests.

RESULTS

Biochemical analysis confirmed significantly higher mean values of total cholesterol (TC), triglyceride (TG), glucose (GLU), and uric acid (UA) (p < 0.001) in T2DM probands and statistically significantly lower values of high-density lipoprotein (HDL), cholesterol and vitamin D (p < 0.001). Allele frequencies and genotype distributions of the FokI (rs2228570) polymorphism were not significantly different between T2DM patients and controls (p = 0.909). Patients with T2DM and TT genotype had the highest glucose level of 11.39 (SD ± 2.32) uU/ml (p < 0.001).

CONCLUSION

Our study did not provide evidence for an association of the investigated FokI polymorphism of the VDR gene with T2DM in the Slovak population. Further research is needed to evaluate the impact of single nucleotide polymorphisms (SNPs) in the VDR gene, focusing on related genetic analyses in a larger T2DM cohort.