Relationship between 25 Hydroxyvitamin D, Overweight/Obesity Status, Pro-Inflammatory and Oxidative Stress Markers in Patients with Type 2 Diabetes: A Simplified Empirical Path Model

MiRNA-200a and miRNA-200b expression, and vitamin-D level: Prognostic significance in obese non-diabetic and obese type 2 diabetes mellitus individuals

BACKGROUND

Obesity and type 2 diabetes mellitus (T2DM) are frequent co-occurring disorders that affect regular metabolic functions. Obesity has also been linked to an increased risk of developing diabetes. Obesity and diabetes are on the rise, increasing healthcare costs and raising mortality rates. Research has revealed that the expression profile of microRNAs (miRNAs) changes as diabetes progresses. Furthermore, vitamin D may have an anti-obesity effect and inverse association with body weight and body mass index (BMI). Low vitamin D levels do not solely cause obesity, which could be a factor in the etiology of T2DM.

AIM

To evaluate miRNA-200a and miRNA-200b expression, and vitamin-D levels in obese and obese T2DM individuals.

METHODS

This study included 210 participants, of which, 82 were obese (BMI > 30 kg/m²) without T2DM, 28 were obese with T2DM, and 100 were healthy controls. BMI was evaluated and both fasting and postprandial blood glucose were used to confirm T2DM. Exosomal miRNA-200a and miRNA-200b expression were analyzed using real-time PCR using Taqman probes, and vitamin-D levels were evaluated using an electrochemiluminescence-based immunoassay technique. All data analyses were performed using SPSS 20.0 and GraphPad Prism 5 software.

RESULTS

Overall, a 2.20- and 4.40-fold increase in miRNA-200a and miRNA-200b expression was observed among participants compared to healthy controls. MiRNA-200a and miRNA-200b expression among obese participants increased 2.40-fold and 3.93-fold, respectively, while in obese T2DM participants these values were 2.67-fold, and 5.78-fold, respectively, and these differences were found to be statistically significant (P = 0.02) (P < 0.0001). Obese participants showed a vitamin D level of 34.27 ng/mL, while in obese-T2DM participants vitamin D level was 22.21 ng/mL (P < 0.0001). Vitamin D was negatively correlated with miRNA-200a (r = -0.22, P = 0.01) and miRNA-200b (r = -0.19, P = 0.04). MiRNA-200a sensitivity was 75%, and specificity was 57%, with a cutoff value of 2.07-fold. MiRNA-200b sensitivity was 75%, and specificity was 71% with a cutoff value of 4.12-fold, suggesting that miRNA-200a and miRNA-200b with an increased expression of 2.07- and 4.12-fold could be predictive indicators for the risk of diabetes in obese participants.

CONCLUSION

MiRNA-200a and miRNA-200b were higher in diabetic obese participants vs non-diabetic obese participants, and insufficient vitamin D levels in obese T2DM participants may be involved in poor clinical outcome.

Serum vitamin D and obesity among US adolescents, NHANES 2011-2018

Background and objectives

Childhood obesity is highly prevalent worldwide. We aimed to assess whether serum 25-hydroxyvitamin D was associated with general/central obesity among US adolescents, and further to explore the mediatory impact of homeostasis model assessment of insulin resistance (HOMA-IR) on this association.

Methods

This study is cross-sectional in design. Study adolescents were enrolled from the National Health and Nutrition Examination Survey (NHANES), 2011-2018. Serum 25-hydroxyvitamin D categories associated with general (indexed by body mass index) and central (indexed by waist circumference to height ratio) obesity were regressed. The possible mediatory effect of HOMA-IR on this association was explored. The nonlinear and dose-response association was examined by restricted cubic spline (RCS) test.

Results

Total 2,696 adolescents were eligible for inclusion, and the mean age of all adolescents was 15.4 years. Overall, the percentage of general and central obesity was 38.0% and 38.6%, respectively. Compared with adolescents with sufficient vitamin D, adolescent with deficient and insufficient vitamin D intake were associated with general obesity and central obesity; fully-adjusted OR for general obesity was 1.602 (95% CI: 1.161-2.211) and 1.659 (1.385-1.986), and fully-adjusted OR for central obesity was 2.025 (1.445-2.837) and 1.557 (1.287-1.884), respectively, while there was no observable significance in adolescents with possibly harmful vitamin D. The proportion mediated by HOMA-IR was estimated to be 31.7% for global obesity and 50.3% for central obesity (both P < 0.05). More stratified analyses were presented, and identified that the association with general obesity was particularly present among Mexican American, while with central obesity among Non-Hispanic Black adolescents.

Conclusions

Our findings indicate that deficient or insufficient 25-hydroxyvitamin D concentrations were associated with the significant risk of general and central obesity among US adolescents, and approximately 30% and 50%, respectively, of these associations were mediated by HOMA-IR.

From the Sun to the Cell: Examining Obesity through the Lens of Vitamin D and Inflammation

Obesity affects more than one billion people worldwide and often leads to cardiometabolic chronic comorbidities. It induces senescence-related alterations in adipose tissue, and senescence is closely linked to obesity. Fully elucidating the pathways through which vitamin D exerts anti-inflammatory effects may improve our understanding of local adipose tissue inflammation and the pathogenesis of metabolic disorders. In this narrative review, we compiled and analyzed the literature from diverse academic sources, focusing on recent developments to provide a comprehensive overview of the effect of vitamin D on inflammation associated with obesity and senescence. The article reveals that the activation of the NF-κB (nuclear factor kappa B subunit 1) and NLRP3 inflammasome (nucleotide-binding domain, leucine-rich-containing, pyrin domain-containing-3) pathways through the toll-like receptors, which increases oxidative stress and cytokine release, is a common mechanism underlying inflammation associated with obesity and senescence, and it discusses the potential beneficial effect of vitamin D in alleviating the development of subclinical inflammation. Investigating the main target cells and pathways of vitamin D action in adipose tissue could help uncover complex mechanisms of obesity and cellular senescence. This review summarizes significant findings related to opportunities for improving metabolic health.

Serum and supplemental vitamin D levels and insulin resistance in T2DM populations: a meta-analysis and systematic review

Observational studies have shown a negative correlation between Vitamin D level and the likelihood of developing insulin resistance (IR) and/or diabetes over time, yet evidence remains inconsistent. In this meta-analysis and systematic review, we strive to define the potential association between serum or supplemental Vitamin D Levels and insulin resistance respectively, as well as the contribution of Vitamin D to type 2 diabetes, and to summarize the biologic plausibility of Vitamin D. Four databases (PubMed, Embase, Cochrane Library, and Web of Science) were searched for this Systematic Literature Review (SLR) to find appropriate observational studies and clinical trials published in English through to July 2022. EndNote (version X9) is used to manage the literature search results. We calculated Standard Mean Differences (SMDs) and Risk Ratios (RRs) with their 95% Confidence Intervals (CIs), separately, for continuous and dichotomous outcomes. The correlation coefficients were normalized to z values through Fisher's z-transformation to calculate the relevant statistics. Meta-analyses were carried out for all comparisons, based on a random-effects pooling model. Data analysis was performed using RevMan (version 5.3) and STATA (version 15.1). All statistical tests were two-sided, with P < 0.05 were regarded as significant. In our current meta-analysis, there are 18 RCTs and 20 observational studies including 1243 and 11,063 participants respectively. In the overall analysis, the diabetic with Vitamin D supplement treatment group showed significantly improve serum insulin (SMD =  - 0.265, 95% CI - 0.394 to - 0.136, P < 0.05), glucose (SMD =  - 0.17, 95% CI - 0.301to - 0.039, P < 0.05) and HOMA-IR (SMD =  - 0.441, 95% CI - 0.582 to - 0.3, P < 0.05) compared with the routine treatment group. Correlation analysis results showed that all three outcomes were significantly correlated in a negative manner with raised Vitamin D (insulin: r =  - 0.08 95% =  - 0.12 to - 0.04; glucose: r =  - 0.06 95% =  - 0.11 to - 0.01; HOMA-IR: r =  - 0.08 95% =  - 0.09 to - 0.06). Results of overall analysis proved that vitamin D has shown significant effect on regulates insulin resistance, and there is a significant inverse association between serum Vitamin D level and IR. Vitamin D supplementation is expected to be integrated into conventional medical approaches to prevent type 2 diabetes and to mitigate the burden of diabetes for individuals and society.PROSPERO registration number: CRD42022348295.

The Impact of Vitamin D Deficiency and Insufficiency on the Outcome of Type 2 Diabetes Mellitus Patients: A Systematic Review

Vitamin D deficiency and insufficiency are public health concerns that have contributed to multiple negative health outcomes. Recent studies have revealed that vitamin D deficiency and insufficiency influence glycaemic control and the development of diabetes complications. The goal of this systematic review is to summarise the latest evidence on the impact of vitamin D deficiency and insufficiency on the outcome of Type 2 Diabetes Mellitus (T2DM) patients. In this PRISMA-guided systematic review, articles were sourced from three databases, namely, PubMed, Scopus, and Web of Science. The review only included literature published from 2012 until 2022, and 33 eligible studies met the inclusion criteria for this review. The included articles were critically appraised using the Mixed Method Appraisal Tool (MMAT). According to our findings, vitamin D deficiency or insufficiency is associated with mental health status, macrovascular and microvascular complications of T2DM, metabolic syndrome, increased risk of obesity, increased blood pressure, dyslipidaemia, glycaemic control, nerve-related disease, musculoskeletal-related complications, and reduced quality of life. Due to the diverse implications of vitamin D deficiency and insufficiency, screening for vitamin D levels in T2DM patients may be beneficial.

Vitamin D Determinants, Status, and Antioxidant/Anti-inflammatory-Related Effects in Cardiovascular Risk and Disease: Not the Last Word in the Controversy

Beyond its key role in calcium homeostasis, vitamin D has been found to significantly affect the cardiovascular (CV) system. In fact, low vitamin D levels have been associated with increased CV risk, as well as increased CV morbidity and mortality. The majority of effects of this molecule are related directly or indirectly to its antioxidative and anti-inflammatory properties. Generally, vitamin D insufficiency is considered for 25-hydroxyvitamin D (25(OH)D) levels between 21-29 ng/mL (corresponding to 52.5-72.5 nmol/L), deficiency as 25(OH)D levels less than 20 ng/mL (<50 nmol/L), and extreme deficiency as 25(OH)D less than 10 ng/mL (<25 nmol/L). However, the definition of an optimal vitamin D status, as defined by 25(OH)D, remains controversial for many extra-bone conditions, including CV disease. In this review, confounding factors affecting the 25(OH)D measurement and status will be discussed. In particular, available evidence on the mechanism and role of vitamin D in relation to CV risk and disease through its antioxidant effect will be reported, also facing the aspect regarding the debate on the minimum blood 25(OH)D level required to ensure optimal CV health.

Independent Association of 25[OH]D Level on Reduced Glutathione and TNF-α in Patients ‎with Diabetes and/or Hypertension

Purpose

Oxidative and inflammatory pathways play a significant role in the pathophysiology of a wide variety of non-communicable diseases such as type 2 diabetes mellitus (T2DM) and hypertension. However, the effect of serum 25-hydroxyvitamin D ‎‎(25[OH]D) on these pathways is still controversial. To evaluate the association of 25[OH]D on ‎antioxidant and pro-inflammatory biomarkers, reduced glutathione (GSH) and tumor ‎necrosis factor (TNF)-α, in T2DM and hypertensive patients.

Patients and Methods

This is a cross-sectional study of a consecutive sample of patients attending the the Family Medicine clinic at King Abdullah bin Abdulaziz University Hospital (KAAUH). Participants were screened for eligibility according to the following ‎criteria: aged above 18 years and diagnosed with T2DM and/or hypertension for at least one ‎year. Patients receiving any kind of vitamin D or calcium supplements within the last three ‎months were excluded, as were those with a history of ‎renal failure, cancer, liver, thyroid, or any other chronic inflammatory diseases.

Results

In total 424 T2DM and/or ‎hypertensive patients (mean age 55±12 years) were recruited. In addition to routine ‎physical and laboratory examinations, levels of serum 25[OH]D, GSH and TNF-α were ‎measured. The prevalence of 25[OH]D deficiency (<50 nmol/L) was 35.1%, which was ‎independent from GSH and TNF-α levels. In T2DM, hypertensive and patients having ‎both diseases, GSH levels were 349.3±19, 355.4±19 and 428.8±20 μmol/L, ‎respectively. Uncontrolled T2DM and hypertension patients showed significantly higher ‎GSH compared with the controlled group. ‎Males showed slightly higher level ‎of TNF-α compared with females and uncontrolled hypertensive patients had relatively ‎higher TNF-α level when evaluated against controlled hypertensive patients. ‎

Conclusion

25[OH]D level is independent of oxidative stress and inflammation, ‎assessed by levels of GSH and TNF-α, respectively, in T2DM and hypertensive Saudi ‎patients. ‎

Association between serum 25-hydroxyvitamin d and myeloperoxidase: A cross-sectional study of a general population in China

Background

Several studies have found a strong association between cardiovascular diseases and myeloperoxidase (MPO) as a marker of oxidative stress. Although the anti-inflammatory effects of vitamin D in adults have been validated, evidence about the relationship between MPO and 25(OH)D is lacking. This study aimed to investigate the relationship between MPO and 25(OH)D in the general Chinese population.

Methods

From November 2018 to August 2019, a total of 6414 subjects were enrolled in a tertiary referral hospital in China, which included 3,122 women and 3,292 men. The dependent and independent variables were MPO and 25(OH)D, respectively. The confounders included age, sex, body mass index, waist-hip ratio, smoking status, alcohol drinking status, calcium, and parathyroid hormone concentration.

Results

In the fully adjusted model, we found that MPO decreased by 0.12 (95% CI −0.16, −0.08), ng/mL for each unit (1 nmol/L) increase in 25(OH)D. When 25(OH) D was divided into quartiles, compared with Q1 (< 41.4 nmol/L), the adjusted beta coefficients (β) of MPO in Q2–Q4 were −2.29 (95% CI, −4.31 to −0.27), −4.76 (95% CI, −6.83 to −2.69), and −6.07 (95% CI, −8.23 to −3.92), respectively (P for the trend < 0.0001). When 25(OH) D was divided according to clinical severity, compared with the severely deficient (< 30 nmol/L) s≥ 30, < 50 nmol/L) and sufficient groups (≥ 50 nmol/L) were −2.59 (95% CI, −5.87 to 0.69) and −5.87 (95% CI, −9.17 to −2.57), respectively (P for the trend < 0.0001).

Conclusion

After adjusting for age, sex, BMI, waist-hip ratio, smoking status, alcohol status, calcium, and PTH, circulating 25(OH)D was negatively associated with MPO.

Predictive Ability of Machine-Learning Methods for Vitamin D Deficiency Prediction by Anthropometric Parameters

Background: Vitamin D deficiency affects the general population and is very common among elderly Europeans. This study compared different supervised learning algorithms in a cohort of Spanish individuals aged 35–75 years to predict which anthropometric parameter was most strongly associated with vitamin D deficiency. Methods: A total of 501 participants were recruited by simple random sampling with replacement (reference population: 43,946). The analyzed anthropometric parameters were waist circumference (WC), body mass index (BMI), waist-to-height ratio (WHtR), body roundness index (BRI), visceral adiposity index (VAI), and the Clinical University of Navarra body adiposity estimator (CUN-BAE) for body fat percentage. Results: All the anthropometric indices were associated, in males, with vitamin D deficiency (p < 0.01 for the entire sample) after controlling for possible confounding factors, except for CUN-BAE, which was the only parameter that showed a correlation in females. Conclusions: The capacity of anthropometric parameters to predict vitamin D deficiency differed according to sex; thus, WC, BMI, WHtR, VAI, and BRI were most useful for prediction in males, while CUN-BAE was more useful in females. The naïve Bayes approach for machine learning showed the best area under the curve with WC, BMI, WHtR, and BRI, while the logistic regression model did so in VAI and CUN-BAE.

The Action of Vitamin D in Adipose Tissue: Is There the Link between Vitamin D Deficiency and Adipose Tissue-Related Metabolic Disorders?

Adipose tissue plays an important role in systemic metabolism via the secretion of adipocytokines and storing and releasing energy. In obesity, adipose tissue becomes dysfunctional and characterized by hypertrophied adipocytes, increased inflammation, hypoxia, and decreased angiogenesis. Although adipose tissue is one of the major stores of vitamin D, its deficiency is detective in obese subjects. In the presented review, we show how vitamin D regulates numerous processes in adipose tissue and how their dysregulation leads to metabolic disorders. The molecular response to vitamin D in adipose tissue affects not only energy metabolism and adipokine and anti-inflammatory cytokine production via the regulation of gene expression but also genes participating in antioxidant defense, adipocytes differentiation, and apoptosis. Thus, its deficiency disturbs adipocytokines secretion, metabolism, lipid storage, adipogenesis, thermogenesis, the regulation of inflammation, and oxidative stress balance. Restoring the proper functionality of adipose tissue in overweight or obese subjects is of particular importance in order to reduce the risk of developing obesity-related complications, such as cardiovascular diseases and diabetes. Taking into account the results of experimental studies, it seemed that vitamin D may be a remedy for adipose tissue dysfunction, but the results of the clinical trials are not consistent, as some of them show improvement and others no effect of this vitamin on metabolic and insulin resistance parameters. Therefore, further studies are required to evaluate the beneficial effects of vitamin D, especially in overweight and obese subjects, due to the presence of a volumetric dilution of this vitamin among them.