Genetic Variations in the Vitamin D Receptor Predict Type 2 Diabetes and Myocardial Infarction in a Community-Based Population: The Tromsø Study

Effect of vitamin D supplementation on type 2 diabetes biomarkers: an umbrella of interventional meta-analyses

BACKGROUND

Vitamin D supplementation exerts several supporting effects on improving glycemic status, however, results are inconclusive. Thus, in the present study, we aimed to conduct an umbrella of meta-analysis regarding the impact of vitamin D on type 2 diabetes (T2DM) biomarkers.

METHODS

The Scopus, PubMed, Web of Science, Embase, and Google Scholar online databases were searched up to March 2022. All meta-analyses evaluating the impact of vitamin D supplementation on T2DM biomarkers were considered eligible. Overall, 37 meta-analyses were included in this umbrella meta-analysis.

RESULTS

Our findings indicated that vitamin D supplementation significantly decreased fasting blood sugar (FBS) (WMD =  - 3.08; 95% CI: - 3.97, - 2.19, p < 0.001, and SMD =  - 0.26; 95% CI: - 0.38, - 0.14, p < 0.001), hemoglobin A1c (HbA1c) (WMD =  - 0.05; 95% CI: - 0.10, - 0.01, p = 0.016, and SMD =  - 0.16; 95% CI: - 0.27, - 0.05, p = 0.004), insulin concentrations (WMD =  - 2.62; 95% CI: - 4.11, - 1.13; p < 0.001, and SMD =  - 0.33; 95% CI: - 0.56, - 0.11, p = 0.004), and homeostatic model assessment for insulin resistance (HOMA-IR) (WMD =  - 0.67; 95% CI: - 1.01, - 0.32, p < 0.001, and SMD =  - 0.31; 95% CI: - 0.46, - 0.16, p < 0.001).

CONCLUSION

This umbrella meta-analysis proposed that vitamin D supplementation may improve T2DM biomarkers.

Vitamin D and cardiovascular disease risk. A literature overview

BACKGROUND

Atherosclerosis and cerebro and cardiovascular disease associated represent the major cause of morbidity and mortality worldwide. Recently, vitamin D deficiency has been considered a new potential risk factor of these conditions.

METHODS AND RESULTS

In this reviw we briefly describe the biological role of vitamin D, analyze the pathophysiological associations between cardiovascular disease and vitamin D, summarize and synthesize the evidence from literature about the association between vitamin D and cardiovascular disease.

RESULTS

Vit D is an essential vitamin for bone metabolism and homeostasis. The maintenance of optimal blood levels contributes to the correct homeostasis by influencing different metabolic processes, including those underlying cardiovascular diseases. However, the evidence does not support vitamin D routine administration for the prevention and treatment of cardiovascular disease and intake to achieve specific cardiovascular effects. Evidence shows that maintaining optimal levels of vitamin D, ensures cardiovascular protection.

Effects of active vitamin D on insulin resistance and islet β-cell function in non-diabetic chronic kidney disease patients: a randomized controlled study

Purpose

The purpose of the study is to observe the effects of active vitamin D supplementation on insulin resistance and islet β-cell function (HOMA-β) in patients with non-diabetic chronic kidney disease (NDCKD).

Methods

A total of 134 patients with NDCKD who met the inclusion criteria were enrolled in the prospective controlled study and categorized as such: 60 patients in the non-dialysis (ND) group; 36, hemodialysis (HD) group; and 38, peritoneal dialysis (PD) group. Each group was divided into two equal-numbered subgroups for vitamin D supplementation. Those in the experimental subgroups received calcitriol 0.5 ug/day orally, and were followed-up for 6 months. A total of 117 patients were followed-up, including 57 patients in the ND group; 29, HD group; and 31, PD group. Changes in the insulin resistance index (HOMA-IR) and HOMA-β index were calculated and compared at the time of enrollment and after 1, 3, and 6 months of intervention.

Results

(1) Mean HOMA-IR value: In the ND group, mean HOMA-IR value of the experimental group significantly decreased compared with that of the control group after 3 months of intervention (P = 0.02). In the HD and PD groups, there was no statistical difference between the experimental and control groups (P > 0.05). (2) Mean HOMA-β index: In the ND group, mean HOMA-β index of the experimental group was higher than that of the control group after 1 month of active vitamin D treatment (P = 0.03), and, with an extended intervention time, the index gradually increased (P < 0.001). In the HD group, mean HOMA-β index of the experimental group was higher than that of the control group after 3 months of active vitamin D treatment (P = 0.01). Among PD patients, mean HOMA-β index of the patients in the experimental group was higher than that of the control group after 6 months of active vitamin D treatment (P = 0.02).

Conclusions

Active vitamin D supplementation improved insulin resistance and HOMA-β after 6 months in ND patients, but only improved HOMA-β in the dialysis patients, with no significant effect on insulin resistance.

Vitamin D pathway-related gene polymorphisms and their association with metabolic diseases: A literature review

PURPOSE

Given that the relationship between vitamin D status and metabolic diseases such as obesity and type 2 diabetes (T2D) remains unclear, this review will focus on the genetic associations, which are less prone to confounding, between vitamin D-related single nucleotide polymorphisms (SNPs) and metabolic diseases.

METHODS

A literature search of relevant articles was performed on PubMed up to December 2019. Those articles that had examined the association of vitamin D-related SNPs with obesity and/or T2D were included. Two reviewers independently evaluated the eligibility for the inclusion criteria and extracted the data. In total, 73 articles were included in this review.

RESULTS

There is a lack of research focusing on the association of vitamin D synthesis-related genes with obesity and T2D; however, the limited available research, although inconsistent, is suggestive of a protective effect on T2D risk. While there are several studies that investigated the vitamin D metabolism-related SNPs, the research focusing on vitamin D activation, catabolism and transport genes is limited. Studies on CYP27B1, CYP24A1 and GC genes demonstrated a lack of association with obesity and T2D in Europeans; however, significant associations with T2D were found in South Asians. VDR gene SNPs have been extensively researched; in particular, the focus has been mainly on BsmI (rs1544410), TaqI (rs731236), ApaI (rs7975232) and FokI (rs2228570) SNPs. Even though the association between VDR SNPs and metabolic diseases remain inconsistent, some positive associations showing potential effects on obesity and T2D in specific ethnic groups were identified.

CONCLUSIONS

Overall, this literature review suggests that ethnic-specific genetic associations are involved. Further research utilizing large studies is necessary to better understand these ethnic-specific genetic associations between vitamin D deficiency and metabolic diseases.

Overview of dietary supplements on patients with type 2 diabetes

BACKGROUND AND AIMS

The primary approach for managing type 2 diabetes mellitus (T2DM) involves lifestyle modification and diet therapy along with pharmacologic interventions. Many patients are interested to identify nutritional supplements that may provide benefit in prevention and management of diabetes. However, the efficacy and safety of nutritional supplements such as chromium, n-3 polyunsaturated fatty acids (PUFAs), vitamin D, zinc and magnesium in disease treatment is a worrying and controversial matter. In this narrative review, patients and health care providers are introduced to the effects of mentioned dietary supplements that may help in choosing or not choosing these supplements in treatment of diabetes.

METHODS

This review was carried out using comprehensive and systematic literature reports on the dietary supplements in the management of diabetes. Empirical searches were conducted using Google Scholar, Science Direct and PubMed databases. Searches were also undertaken using keywords, in English, such as "chromium" OR "vitamin D" OR "omega-3 fatty acids" OR "zinc" OR "magnesium" in combination with "type 2 diabetes".

RESULTS

The available evidence is insufficient to create a definite conclusion that nutritional supplements including chromium, n-3 PUFAs, vitamin D, zinc and magnesium might be beneficial for the prevention and treatment of T2DM and therefore, the general recommendation to use these supplements in the management of diabetes cannot be justified. The results of most studies lack uniformity across multiple aspects, including different dose and formation of supplements, duration, and subjects under intervention.

CONCLUSIONS

There is a need for well-designed, high quality, large and long-term studies to strengthen the available evidence and ensure the safety and efficacy of products.

Association of Vitamin D deficiency and Vitamin D Receptor Gene Polymorphisms with Type 2 diabetes mellitus Saudi patients

Background

Type 2 diabetes mellitus (T2DM) is a global problem. Association of multiple genes in T2DM becomes a hot point recently. This study was aimed to evaluate association of vitamin D receptor gene polymorphisms with susceptibility to T2DM.

Subjects and methods

One hundred T2DM Saudi male patients were included in this study and one hundred healthy Saudi men were used as control. For each individual, fasting blood glucose, cholesterol, HDL-C, LDL-C, HbA1c, insulin and 25-(OH) vitamin D were measured. In addition, Apal, BsmI and TaqI genotypes were performed for each subject. Data was analyzed by SPSS version 16, using Spearman's rho and ANOVA tests.

Results

There was significant inverse correlation between 25-(OH) vitamin D level and T2DM (p<0.01). HbA1c was inversely correlated with 25-(OH) vitamin D level (P<0.05). Genotype study showed that tt of TaqI genotype was higher in T2DM group compared with control group (p<0.05). Moreover, tt genotype has higher HbA1c than both TT and Tt genotypes (p<0.05).

Conclusion

An association was confirmed between TaqI genotypes and T2DM but there is no correlation between BsmI, ApaI and T2DM. In addition, HbA1c is positively correlated with tt genotype of TaqI.

The role of vitamin D in the pathogenesis and treatment of diabetes mellitus: a narrative review

Diabetes mellitus, a metabolic disorder associated with chronic complications, is traditionally classified into two main subtypes. Type 1 diabetes mellitus (T1DM) results from gradual pancreatic islet β cell autoimmune destruction, extending over months or years. Type 2 diabetes mellitus (T2DM) is a heterogeneous disorder, with both insulin resistance and impairment in insulin secretion contributing to its pathogenesis. Vitamin D is a fat-soluble vitamin with an established role in calcium metabolism. Recently, several studies have provided evidence suggesting a role for it in various non-skeletal metabolic conditions, including both types of diabetes mellitus. Preclinical studies of vitamin D action on insulin secretion, insulin action, inflammatory processes, and immune regulation, along with evidence of an increase of hypovitaminosis D worldwide, have prompted several epidemiological, observational, and supplementation clinical studies investigating a potential biological interaction between hypovitaminosis D and diabetes. This narrative review aims to summarize current knowledge on the effect of vitamin D on T1DM and T2DM pathogenesis, prevention, and treatment, as well as on micro- and macrovascular complications of the disease. Furthermore, on the basis of current existing evidence, we aim to highlight areas for potential future research.

Preoperative Vitamin D Deficiency Is Associated With Higher Postoperative Complication Rates in Total Knee Arthroplasty

The purpose of this study was to determine the relative incidence of postoperative complications in 25-hydroxyvitamin D (25D)-deficient and -sufficient patients undergoing total knee arthroplasty (TKA). Patients who were either serum 25D deficient (25D <20 ng/mL) or 25D sufficient (25D ≥20 ng/mL) 90 days prior to primary TKA from 2007 to 2016 were identified using the Humana administrative claims registry. The incidence of postoperative medical and surgical complications was determined by querying for relevant International Classification of Diseases, Ninth Revision and Current Procedural Terminology codes. Risk-adjusted odds ratios (ORs) were calculated using multivariate logistic regression with age, sex, and Charlson Comorbidity Index as covariates. In total, 868 of 6593 patients who underwent TKA from 2007 to 2016 were 25D deficient, corresponding to a 13.2% prevalence rate. On adjustment for age, sex, and Charlson Comorbidity Index, 25D-deficient patients had a higher incidence of postoperative stiffness requiring manipulation under anesthesia (OR, 1.69; 95% confidence interval [CI], 1.39-2.04; P<.001), surgical site infection requiring irrigation and debridement (OR, 1.76; 95% CI, 1.25-2.48; P=.001), and prosthesis explantation (OR, 2.97; 95% CI, 2.04-4.31; P<.001) at 1 year. Patients who were 25D deficient also had higher rates of postoperative deep venous thrombosis (OR, 1.80; 95% CI, 1.36-2.38; P<.001), myocardial infarction (OR, 2.11; 95% CI, 1.41-3.15; P<.001), and cerebrovascular accident (OR, 1.73; 95% CI, 1.17-2.57; P=.006). Thus, serum 25D levels below 20 ng/mL are associated with a higher incidence of postoperative complications and may be a perioperative modifiable risk factor in TKA. [Orthopedics. 2018; 41(4):e489-e495.].

Role of Vitamin D in Cardiovascular Diseases

Vitamin D is critical in mineral homeostasis and skeletal health and plays a regulatory role in nonskeletal tissues. Vitamin D deficiency is associated with chronic inflammatory diseases, including diabetes and obesity, both strong risk factors for cardiovascular diseases (CVDs). CVDs, including coronary artery disease, myocardial infarction, hypertrophy, cardiomyopathy, cardiac fibrosis, heart failure, aneurysm, peripheral arterial disease, hypertension, and atherosclerosis, are major causes of morbidity and mortality. The association of these diseases with vitamin D deficiency and improvement with vitamin D supplementation suggest its therapeutic benefit. The authors review the findings on the association of vitamin D deficiency and CVDs.

Vitamin D and diabetes mellitus: Causal or casual association?

The incidence of both type 2 and type 1 diabetes mellitus has been increasing worldwide. Vitamin D deficiency, or the awareness of its prevalence, has also been increasing. Vitamin D may have a role in the pathogenic mechanisms predisposing to type 2 diabetes by modulating insulin resistance and/or pancreatic β-cell function. Vitamin D status or elements involved in its activation or transport may also be involved in the development of type 1 diabetes mellitus through immunomodulatory role . Based on these observations a potential association between vitamin D and diabetes has been hypothesized. In this review we discuss up to date evidence linking vitamin D with the development of diabetes. Moreover, the role of vitamin D supplementation in the prevention of both types of diabetes is analysed together with its role in improving glycemic control in diabetic patients. We also address the potential role of vitamin D deficiency in the development of macro- and microvascular complications in diabetes. Finally, we provide recommendation for Vitamin D therapy in diabetes in view of current evidence and highlight areas for potential future research in this area.

Vitamin D supplementation in the prevention and management of major chronic diseases not related to mineral homeostasis in adults: research for evidence and a scientific statement from the European society for clinical and economic aspects of osteoporosis and osteoarthritis (ESCEO)

INTRODUCTION

Optimal vitamin D status promotes skeletal health and is recommended with specific treatment in individuals at high risk for fragility fractures. A growing body of literature has provided indirect and some direct evidence for possible extraskeletal vitamin D-related effects.

PURPOSE AND METHODS

Members of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis have reviewed the main evidence for possible proven benefits of vitamin D supplementation in adults at risk of or with overt chronic extra-skeletal diseases, providing recommendations and guidelines for future studies in this field.

RESULTS AND CONCLUSIONS

Robust mechanistic evidence is available from in vitro studies and in vivo animal studies, usually employing cholecalciferol, calcidiol or calcitriol in pharmacologic rather than physiologic doses. Although many cross-sectional and prospective association studies in humans have shown that low 25-hydroxyvitamin D levels (i.e., <50 nmol/L) are consistently associated with chronic diseases, further strengthened by a dose-response relationship, several meta-analyses of clinical trials have shown contradictory results. Overall, large randomized controlled trials with sufficient doses of vitamin D are missing, and available small to moderate-size trials often included people with baseline levels of serum 25-hydroxyvitamin D levels >50 nmol/L, did not simultaneously assess multiple outcomes, and did not report overall safety (e.g., falls). Thus, no recommendations can be made to date for the use of vitamin D supplementation in general, parental compounds, or non-hypercalcemic vitamin D analogs in the prevention and treatment of extra-skeletal chronic diseases. Moreover, attainment of serum 25-hydroxyvitamin D levels well above the threshold desired for bone health cannot be recommended based on current evidence, since safety has yet to be confirmed. Finally, the promising findings from mechanistic studies, large cohort studies, and small clinical trials obtained for autoimmune diseases (including type 1 diabetes, multiple sclerosis, and systemic lupus erythematosus), cardiovascular disorders, and overall reduction in mortality require further confirmation.