Association between Vitamin D Receptor Polymorphisms (BsmI and FokI) and Glycemic Control among Patients with Type 2 Diabetes

Vitamin D deficiency and VDR gene polymorphism FokI (rs2228570) are associated with diabetes mellitus in adults: COVID-inconfidentes study

BACKGROUND

Diabetes mellitus is a chronic and multifactorial condition, including environmental risk factors such as lifestyle habits and genetic conditions.

OBJECTIVE

We aimed to evaluate the association of VDR gene polymorphism (rs2228570) FokI and vitamin D levels with diabetes in adults.

METHODS

Cross-sectional population-based study in adults, conducted from October to December 2020 in two Brazilian cities. The outcome variable was diabetes, defined as glycated hemoglobin ≥ 6.5% or self-report medical diagnosis or use of oral hypoglycemic drugs. Vitamin D (25-hydroxyvitamin D) was measured by indirect electrochemiluminescence, and classified as deficiency when 25(OH)D < 20 ng/mL. All participants were genotyped for VDR FokI polymorphism by qPCR and classified as homozygous mutant (ff or GG), heterozygous (Ff or AG), or homozygous wild (FF or AA). A combined analysis between the FokI polymorphism and vitamin D levels with diabetes was also examined. A directed acyclic graph (DAG) was used to select minimal and sufficient adjustment for confounding variables by the backdoor criterion.

RESULTS

The prevalence of DM was 9.4% and vitamin D deficiency (VDD) was 19.9%. The genotype distribution of FokI polymorphism was 9.9% FF, 44.8% Ff, and 45.3% ff. It was possible to verify a positive association between vitamin D deficiency and DM (OR = 2.19; 95% CI: 1.06-4.50). Individuals with the altered allele (ff) had a 1.78 higher prevalence of DM (OR: 1.78; 95% CI; 1.10-2.87). Combined analyses, individuals with vitamin D deficiency and one or two copies of the altered FokI allele had a higher prevalence of DM (Ff + ff: OR: 1.67; 95% CI; 1.07-2.61; ff: OR: 3.60; 95% CI; 1.40-9.25).

CONCLUSION

Our data suggest that vitamin D deficiency and FokI polymorphism are associated with DM.

The role of interaction between vitamin D and VDR FokI gene polymorphism (rs2228570) in sleep quality of adults

To evaluate association of vitamin D with sleep quality in adults and the influence of VDR-gene polymorphism FokI (rs2228570;A > G). Cross-sectional population-based study in adults, conducted in Brazil. The outcome was sleep-quality, evaluated by the Pittsburgh Sleep Quality Index. Vitamin D was determined by indirect electrochemiluminescence and classified as deficiency (VDD), 25(OH)D < 20 ng/mL in a healthy population or 25(OH)D < 30 ng/mL for groups at risk for VDD. FokI polymorphism in the VDR-gene was genotyped by qPCR and classified as homozygous wild (FF or AA), heterozygous (Ff or AG), or homozygous mutant (ff or GG). Multivariate logistic analysis was used to estimate the association between vitamin D and FokI polymorphism with sleep-quality. In a total of 1674 individuals evaluated, 53.6% had poor-sleep-quality, 31.5% had VDD, and the genotype frequency of the FokI polymorphism was 9.9% FF, 44.6% Ff, and 45.5% ff. In multivariate analysis, individuals with VDD had 1.51 times the chance of poor-sleep-quality, and individuals with the ff genotype had 1.49 times the chance of poor-sleep-quality (OR:1.49;95%CI:1.05-2.12) when compared to individuals with the FF or Ff genotype. In the combined analysis, individuals with VDD and ff genotype had more chance of poor-sleep-quality than individuals with sufficient vitamin D and genotype Ff or FF (OR:2.19;95%CI:1.27-3.76). Our data suggest that VDD and VDR FokI gene polymorphism are associated with poor-sleep-quality, and combining the two factors increases the chance of poor-sleep-quality compared to separate groups.

Effects and potential mechanisms of exercise and physical activity on eye health and ocular diseases

In the field of eye health, the profound impact of exercise and physical activity on various ocular diseases has become a focal point of attention. This review summarizes and elucidates the positive effects of exercise and physical activities on common ocular diseases, including dry eye disease (DED), cataracts, myopia, glaucoma, diabetic retinopathy (DR), and age-related macular degeneration (AMD). It also catalogues and offers exercise recommendations based on the varying impacts that different types and intensities of physical activities may have on specific eye conditions. Beyond correlations, this review also compiles potential mechanisms through which exercise and physical activity beneficially affect eye health. From mitigating ocular oxidative stress and inflammatory responses, reducing intraocular pressure, enhancing mitochondrial function, to promoting ocular blood circulation and the release of protective factors, the complex biological effects triggered by exercise and physical activities reveal their substantial potential in preventing and even assisting in the treatment of ocular diseases. This review aims not only to foster awareness and appreciation for how exercise and physical activity can improve eye health but also to serve as a catalyst for further exploration into the specific mechanisms and key targets through which exercise impacts ocular health. Such inquiries are crucial for advancing innovative strategies for the treatment of eye diseases, thereby holding significant implications for the development of new therapeutic approaches.

The Relationship Between Non-HDL-C /HDL-C Ratio (NHHR) and Vitamin D in Type 2 Diabetes Mellitus

Purpose

The objective of this research was to examine the relationship between non-HDL cholesterol/HDL cholesterol ratio (NHHR) and vitamin D in type 2 diabetes mellitus (T2DM).

Patients and Methods

This study enrolled 617 T2DM participants. Participants were separated into two groups: no vitamin D deficiency and vitamin D deficiency. Participants were split into two categories: individuals who had a high NHHR and those with a low NHHR, with the median NHHR serving as the cut-off. Eventually, the study participants were classified into two groups by gender, which were further classified into vitamin D deficient and non-vitamin D deficient groups.

Results

NHHR values were substantially greater in vitamin D deficient group than in the non-deficient group in both male and female T2DM patients (P<0.05). The high NHHR group displayed substantially lower vitamin D levels than the low NHHR group [16.21 (12.55,21.35) vs 19.05 (14.59,24.07), P<0.001]. NHHR was discovered to be negatively and independently associated with vitamin D levels, and there was no sex difference.

Conclusion

For the first time, our research revealed a negative relationship between NHHR and vitamin D in patients with T2DM.

Impact of vitamin D receptor polymorphisms in selected metabolic disorders

PURPOSE OF REVIEW

Vitamin D (vitD) can regulate metabolic pathways in adipose tissue and pancreatic β cells by interacting with its vitamin D receptor (VDR). The aim of this study was to review original publications published in the last months and verify the relationship between genetic variants in the VDR gene and type 2 diabetes (T2D), metabolic syndrome (MetS), overweight, and obesity.

RECENT FINDINGS

The recent studies concern genetic variants located in the coding and noncoding regions of the VDR gene. Some of the described genetic variants may affect VDR expression or posttranslational processing altered functionality or vitD binding capacity of VDR. Nevertheless, the data collected in recent months on the assessment of the relationship between VDR genetic variants and the risk of T2D, MetS, overweight, and obesity still do not give a clear answer to whether they have a direct impact on these metabolic disorders.

SUMMARY

Analysis of the potential association between VDR genetic variants and parameters such as glycemia, body mass index, body fat, and lipid levels improves the current understanding of the pathogenesis of T2D, MetS, overweight, and obesity. A thorough understanding of this relationship may provide important information for individuals with pathogenic variants and enable the implementation of appropriate prevention against the development of these disorders.

Association of Vitamin D Receptor Gene Polymorphisms with Cardiometabolic Phenotypes in Hispanics: A Life Course Approach

The vitamin D receptor (VDR) is vital for maintaining calcium and phosphate balance and regulating bone metabolism. Recent research has suggested that VDR also plays an essential role in metabolic diseases. Previous studies on non-Hispanic whites have shown that VDR single nucleotide polymorphisms (SNP) are associated with cardiometabolic phenotypes. However, the association between VDR SNPs and cardiometabolic traits in Hispanics remains unclear. This study investigated the association between VDR SNPs and cardiometabolic phenotypic data in self-reported Hispanics (n = 1610) from the Arizona Insulin Resistance registry and Sangre Por Salud Biobank. The study population was predominantly female (66.4%) with a mean age of 40 ± 14 years (n = 121 <18 years) and an average body mass index (BMI) of 29.8 ± 6.3 kg/m2. We performed a genotyping association analysis of VDR SNPs (Taq1-rs731236, Fok1-rs2228570 and Apa1-rs7975232) with cardiometabolic traits using linear regression models. The results showed that Taq1 and Apa1 were strongly associated with systolic blood pressure (SBP) in children (<18 years), while Fok1 was associated with measures of adiposity, including fat mass, waist circumference, and BMI. In age-stratified adult (≥18 years) models, Taq1 was strongly associated with hemoglobin A1c, while Apa1 was associated with BMI and fasting glucose. Fok1 had no significant associations in the adult models. In conclusion, the VDR SNPs were associated with several cardiometabolic phenotypes in this Hispanic sample, but the type and strength of the associations varied by age group.

Association of vitamin D and magnesium with insulin sensitivity and their influence on glycemic control

Insulin resistance increases the risk of developing diabetes, and the degree of resistance influences the glycemic control of patients with diabetes. Numerous researchers have focused on improving insulin sensitivity in order to prevent diabetes-related complications and other chronic diseases. Several studies have also linked vitamin D levels to insulin secretion and resistance, given that both vitamin D and its receptor complex play important roles in regulating pancreatic β-cells. It has been suggested that vitamin D supplementation improves vitamin D levels, but further research is needed to confirm this as neither insulin function nor glycemic control improves when vitamin D levels increase. Magnesium is a cofactor for many enzymes. Although the role of magnesium in the management of diabetes has long been evaluated, it has not yet been determined whether magnesium supplements improve insulin function. However, several researchers have found that patients with good glycemic control have high magnesium levels. Magnesium is closely related to vitamin D and is necessary for the transport and activation of vitamin D in humans. Combined supplementation with vitamin D and magnesium improves glycemic control in patients with diabetes.

The relationship between vitamin D receptor gene polymorphisms and periodontitis in turkish individuals with type 2 diabetes mellitus

Background and Aim

Vitamin D receptor (VDR) gene polymorphisms have been implicated in the pathogenesis of many diseases, such as periodontitis and diabetes mellitus (DM). The present study aimed to evaluate the distributions of VDR polymorphisms in diabetic individuals with healthy periodontium (DMH), diabetic individuals with periodontitis (DMP), nondiabetic individuals with healthy periodontium (H), and nondiabetic individuals with periodontitis (P).

Material and Methods

A total of 200 individuals (DMH = 40, DMP = 60, H = 40, and P = 60) were recruited. All clinical periodontal parameters, demographical, and biochemical variables were recorded. Blood samples were collected, and genomic DNA was isolated by Purelink® Genomic DNA Mini Kit. Genotyping of VDR polymorphisms ApaI, BsmI, FokI, and TaqI were determined by real-time polymerase chain reaction (PCR) using allele-specific probes.

Results

The distribution of the BsmI variant showed differences between DMH and H groups (P = 0.034). In addition, carrying the GG genotype (OR = 0.317; 95% CI = 0.126-0.797; P = 0.013) and the G allele (OR = 2.373; 95% CI = 1.203-4.681; P = 0.012) increased the risk of type 2 DM. Moreover, it was determined that the frequency of CC genotype of FokI variant was higher in DMP compared to DMH (P = 0.046). It was determined that having the CC genotype (OR = 2.706; 95% CI = 1.185-6.176; P = 0.017) and the C allele (OR = 1.917; 95% CI = 0.995-3.694; P = 0.049) increased the risk of periodontitis among diabetic individuals. No differences were detected among groups in the genotype and allele distributions of ApaI and TaqI variants (P > 0.05).

Conclusions

The present study showed that the BsmI variant was a risk factor for DM among periodontally healthy individuals and the FokI variant for periodontitis among diabetic individuals.

The Prevalence of Insulin Resistance in Malaysia and Indonesia: An Updated Systematic Review and Meta-Analysis

Background and Objectives: Noncommunicable diseases such as diabetes are strongly associated with the insulin resistance (IR) status of an individual. However, the prevalence of insulin resistance in Southeast Asia is poorly reported. Hence, this study investigated the prevalence of IR in Southeast Asia from the year 2016 to 2021. Materials and Methods: This study was carried out according to PRISMA guidelines. The literature search was conducted utilizing the PubMed and SCOPUS databases from the year 2016 to 2021 using the keywords ‘(insulin AND resistance) OR (insulin AND sensitivity) OR (prevalence OR incidence) AND (Malaysia OR Thailand OR Singapore OR Brunei OR Cambodia OR Indonesia OR Laos OR Myanmar OR Philippines OR Timor leste OR Vietnam)’. Funnel plot and publication bias were assessed using Egger’s tests. Data were expressed as the prevalence rate. Results: A total of 12 studies with 2198 subjects were considered in the meta-analysis. Significant heterogeneity (I2 > 94% and p-value < 0.001) was observed in the meta-analysis. The overall prevalence of IR in Southeast Asia was 44.3%, with Malaysia having the highest prevalence rate at 50.4%, followed by Indonesia at 44.2%. Bias was detected in the meta-analysis. It may be that reports published before the year 2016 met the study selection criteria, but were excluded from the meta-analysis. Conclusions: The results from the meta-analysis indicate that the prevalence of IR in Southeast Asia is very high. This provided insights for healthcare policy makers and public health officials in designing IR screening programs.

The Relationship Between Triglyceride Glucose Index and Vitamin D in Type 2 Diabetes Mellitus

PURPOSE

The study aimed to investigate the relationship between 25-hydroxyvitamin D [25(OH) D] and triglyceride glucose index (TyG) levels in male and female patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

This cross-sectional study recruited 592 patients with type 2 diabetes. The subjects were divided into the non-vitamin D deficiency group [25(OH)D≥20ng/mL] and the vitamin D deficiency group [25(OH)D<20ng/mL]. The triglyceride glucose (TyG) index is calculated using the following formula, ln[fasting triglycerides (mg/dL)*fasting blood glucose (mg/dL)/2]. Participants were divided into high TyG group and low TyG group, with the median of TyG as the boundary. All participants were divided into male and female groups and normal Body mass index (BMI) and high BMI groups, and then divided into high TyG group and low TyG group.

RESULTS

We found that TyG levels are independently and negatively correlated with vitamin D levels in male patients with T2DM. In the female group, there was no significant correlation between TyG and vitamin D levels, regardless of an adjusted or unadjusted confounding factor. Subgroup analysis showed that the correlation between TyG and the risk of vitamin D deficiency in the normal BMI group was significantly stronger than that in the high BMI group.

CONCLUSION

This study indicates that vitamin D deficiency is related to high TyG level in patients with T2DM for males, and this relationship is not significant for female patients. The risk of vitamin D deficiency is significantly correlated with high TyG level in normal BMI group. However, there was no statistically significant difference between TyG level and the risk of vitamin D deficiency in the high BMI group. Difference between TyG level and the risk of vitamin D deficiency.