Vitamin D and diabetes

Vitamin D and its analogs in immune system regulation

Vitamin D was discovered as the cure for nutritional rickets, a disease of bone growth arising from inadequate intestinal calcium absorption, and for much of the 20th century, it was studied for its critical role in calcium homeostasis. However, we now recognize that the vitamin D receptor and vitamin D metabolic enzymes are expressed in numerous tissues unrelated to calcium homeostasis. Notably, vitamin D signaling can induce cellular differentiation and cell cycle arrest. Moreover, the vitamin D receptor and the enzyme CYP27B1, which produces the hormonal form of vitamin D, 1,25-dihydroxyvitamin D (1,25D), are expressed throughout the immune system. In addition, CYP27B1 expression in immune cells is regulated by physiological inputs independent of those controlling its expression in calcium homeostatic tissues. These observations have driven the development of 1,25D-like secosteroidal analogs and nonsecosteroidal analogs to separate the effects of vitamin D on cell differentiation and function from its calcemic activities. Notably, some of these analogs have had considerable success in the clinic in the treatment of inflammatory and immune-related disorders. In this review, we described in detail the mechanisms of vitamin D signaling and the physiological signals controlling 1,25D synthesis and catabolism, with a focus on the immune system. We also surveyed the effects of 1,25D and its analogs on the regulation of immune system function and their implications for human immune-related disorders. Finally, we described the potential of vitamin D analogs as anticancer therapeutics, in particular, their use as adjuncts to cancer immunotherapy. SIGNIFICANCE STATEMENT: Vitamin D signaling is active in both the innate and adaptive arms of the immune system. Numerous vitamin D analogs, developed primarily to minimize the dose-limiting hypercalcemia of the active form of vitamin D, have been used widely in preclinical and clinical studies of immune system regulation. This review presents a description of the mechanisms of action of vitamin D signaling, an overview of analog development, and an in-depth discussion of the immunoregulatory roles of vitamin D analogs.

Nutritional intake of micronutrient and macronutrient and type 2 diabetes: machine learning schemes

BACKGROUND

Diabetes mellitus, an endocrine system disease, is a common disease involving many patients worldwide. Many studies are performed to evaluate the correlation between micronutrients/macronutrients on diabetes but few of them have a high statistical population and a long follow-up period. We aimed to investigate the relationship between intake of macro/micronutrients and the incidence of type 2 diabetes (T2D) using logistic regression (LR) and a decision tree (DT) algorithm for machine learning.

METHOD

Our research explores supervised machine learning models to identify T2D patients using the Mashhad Cohort Study dataset. The study population comprised 9704 individuals aged 35-65 years were enrolled regarding their T2D status, and those with T2D history. 15% of individuals are diabetic and 85% of them are non-diabetic. For ten years (until 2020), the participants in the study were monitored to determine the incidence of T2D. LR is a statistical model applied in dichotomous response variable modeling. All data were analyzed by SPSS (Version 22) and SAS JMP software.

RESULT

Nutritional intake in the T2D group showed that potassium, calcium, magnesium, zinc, iodine, carotene, vitamin D, tryptophan, and vitamin B12 had an inverse correlation with the incidence of diabetes (p < 0.05). While phosphate, iron, and chloride had a positive relationship with the risk of T2D (p < 0.05). Also, the T2D group significantly had higher carbohydrate and protein intake (p-value < 0.05).

CONCLUSION

Machine learning models can identify T2D risk using questionnaires and blood samples. These have implications for electronic health records that can be explored further.

Redosing with Intralymphatic GAD-Alum in the Treatment of Type 1 Diabetes: The DIAGNODE-B Pilot Trial

Immunotherapies aimed at preserving residual beta cell function in type 1 diabetes have been successful, although the effect has been limited, or raised safety concerns. Transient effects often observed may necessitate redosing to prolong the effect, although this is not always feasible or safe. Treatment with intralymphatic GAD-alum has been shown to be tolerable and safe in persons with type 1 diabetes and has shown significant efficacy to preserve C-peptide with associated clinical benefit in individuals with the human leukocyte antigen DR3DQ2 haplotype. To further explore the feasibility and advantages of redosing with intralymphatic GAD-alum, six participants who had previously received active treatment with intralymphatic GAD-alum and carried HLA DR3-DQ2 received one additional intralymphatic dose of 4 μg GAD-alum in the pilot trial DIAGNODE-B. The participants also received 2000 U/day vitamin D (Calciferol) supplementation for two months, starting one month prior to the GAD-alum injection. During the 12-month follow-up, residual beta cell function was estimated with Mixed-Meal Tolerance Tests, and clinical and immune responses were observed. C-peptide decreased minimally, and most patients showed stable HbA1c and IDAA1c. The mean % TIR increased while the mean daily insulin dose decreased at month 12 compared to the baseline. Redosing with GAD-alum seems to be safe and tolerable, and may prolong the disease modification elicited by the original GAD-alum treatment.

Impact of complementary feeding on infant gut microbiome, metabolites and early development

Introducing complementary foods is critical for promoting infant health and development. During the weaning period, the dietary patterns provide essential nutrients and facilitate the development of a diverse gut microbiome, which plays significant roles in the regulation of immune, metabolic, and neurological functions. This study enrolled 200 families to assess the impact of complementary feeding on infant growth and health outcomes. Data included detailed records of feeding practices, infant growth measurements, health assessments, and fecal samples and breast milk collected between weeks 12 and 32 postpartum. The gut microbiome was analyzed using 16S rRNA sequencing, while metabolites such as human milk oligosaccharides (HMOs), monosaccharides, and short-chain fatty acids (SCFAs) were measured using chromatography-mass spectrometry. Results revealed a high prevalence of breastfeeding, with complementary food introduced at around 16 weeks. Significant alterations in the infant gut microbiome were observed, particularly in the genera Lactobacillus, Akkermansia, and Staphylococcus. Additionally, the levels of HMOs, monosaccharides, and SCFAs were found to be influenced by the introduction of complementary foods. Significant correlations emerged between complementary feeding practices, gut microbiome diversity, specific bacterial genera (e.g., Streptococcus, Lactobacillus, Bifidobacterium, and Clostridioides), and key metabolites (such as lacto-N-tetraose, lacto-N-neotetraose, mannose, and butyric acid). This study offers valuable insights into the complex interactions between complementary feeding, gut microbiome development, and metabolite profiles during early infant growth. Future research with larger cohorts and targeted dietary interventions is recommended to further elucidate the underlying mechanisms.

Eldecalcitol ameliorates diabetic osteoporosis and glucolipid metabolic disorder by promoting Treg cell differentiation through SOCE

Active vitamin D, known for its role in promoting osteoporosis, has immunomodulatory effects according to the latest evidence. Eldecalcitol (ED-71) is a representative of the third-generation novel active vitamin D analogs, and its specific immunological mechanisms in ameliorating diabetic osteoporosis remain unclear. We herein evaluated the therapeutic effects of ED-71 in the context of type 2 diabetes mellitus (T2DM), delving into its underlying mechanisms. In a T2DM mouse model, ED-71 attenuated bone loss and marrow adiposity. Simultaneously, it rectified imbalanced glucose homeostasis and dyslipidemia, ameliorated pancreatic β-cell damage and hepatic glycolipid metabolism disorder. Subsequently, in mice injected with the Treg cell-depleting agent CD25, we observed that the beneficial effects of ED-71 mentioned earlier were partially contingent on the Treg subsets ratio. Mechanistically, ED-71 promoted the differentiation of CD4+ T cells into Treg subsets, facilitating Ca2+ influx and the expression of ORAI1 and STIM1, pivotal proteins in store-operated Ca2+ entry (SOCE). The SOCE inhibitor, 2-APB, partially attenuated the positive effects of ED-71 observed in the above results. Overall, ED-71 regulates SOCE-mediated Treg cell differentiation, accomplishing the dual purpose of simultaneously ameliorating diabetic osteoporosis and glucolipid metabolic disorders, showcasing its potential in osteoimmunity therapy and interventions for diseases involving SOCE.

Vitamin D efficacy in type 1 and type 2 diabetes

It is well known that vitamin D has a profound effect on calcium and bone metabolism, but its influence on other organs (extraskeletal effect) has been proposed. Consistently, vitamin D deficiency is associated with an increased incidence of various diseases, including type 1 and type 2 diabetes, as reported by many observational studies. However, there has been no consensus on whether vitamin D deficiency is a causative factor in the incidence of diabetes mellitus. There have been no randomized controlled trials (RCTs) aimed at preventing the onset of type 1 diabetes with vitamin D intake. In addition, the results of RCTs evaluating the preventive effect of vitamin D supplementation on type 2 diabetes development have been inconsistent. The recent observational studies, randomized controlled trials, and meta-analyses are confirming that vitamin D or active vitamin D administration is effective in preventing the incident of type 1 and type 2 diabetes.

Forgetting the Frail: National Trends in Vitamin D Prescription After Fragility Fracture-A Large Insurance Claims Database Study

INTRODUCTION

Vitamin D plays a critical role in bone health, affecting bone mineral density and fracture healing. Insufficient serum vitamin D levels are associated with increased fracture rates. Despite guidelines advocating vitamin D supplementation, little is known about the prescription rates after fragility fractures. This study aims to characterize vitamin D prescription rates after three common fragility fractures in patients older than 50 years and explore potential factors influencing prescription rates.

METHODS

The study used the PearlDiver Database, identifying patients older than 50 years with hip fractures, spinal compression fractures, or distal radius fractures between 2010 and 2020. Patient demographics, comorbidities, and vitamin D prescription rates were analyzed. Statistical methods included chi-square analysis and univariate and multivariable analyses.

RESULTS

A total of 3,214,294 patients with fragility fractures were included. Vitamin D prescriptions increased from 2.50% to nearly 6% for all fracture types from 2010 to 2020. Regional variations existed, with the Midwest having the highest prescription rate (4.25%) and the West the lowest (3.31%). Patients with comorbidities such as diabetes, tobacco use, obesity, female sex, age older than 60 years, and osteoporosis were more likely to receive vitamin D prescriptions.

DISCUSSION

Despite a notable increase in vitamin D prescriptions after fragility fractures, the absolute rates remain low. Patient comorbidities influenced prescription rates, perhaps indicating growing awareness of the link between vitamin D deficiency and these conditions. However, individuals older than 60 years, a high-risk group, were markedly less likely to receive prescriptions, possibly because of practice variations and concerns about polypharmacy. Educational initiatives and revised guidelines may have improved vitamin D prescription rates after fragility fractures. However, there is a need to raise awareness about the importance of vitamin D for bone health, particularly in older adults, and additional study variations in prescription practices. These findings emphasize the importance of enhancing post-fracture care to reduce morbidity and mortality associated with fragility fractures.

LEVEL OF EVIDENCE

III.

Molecular effects of Vitamin-D and PUFAs metabolism in skeletal muscle combating Type-II diabetes mellitus

Multiple post-receptor intracellular alterations such as impaired glucose transfer, glucose phosphorylation, decreased glucose oxidation, and glycogen production contribute to insulin resistance (IR) in skeletal muscle, manifested by diminished insulin-stimulated glucose uptake. Type-2 diabetes mellites (T2DM) has caused by IR, which is also seen in obese patients and those with metabolic syndrome. The Vitamin-D receptor (VDR) and poly unsaturated fatty acids (PUFAs) roles in skeletal muscle growth, shapes, and function for combating type-2 diabetes have been clarified throughout this research. VDR and PUFAs appears to show a variety of effects on skeletal muscle, in addition it shows a promising role on bone and mineral homeostasis. Individuals having T2DM are reported to suffer from severe muscular weakness and alterations in shape of the muscle. Several studies have investigated the effect on VDR on muscular strength and mass, which leads to Vitamin-D deficiency (VDD) in individuals, in which most commonly seen in elderly. VDR has been shown to affect skeletal cellular proliferation, intracellular calcium handling, as well as genomic activity in a variety of different ways such as muscle metabolism, insulin sensitivity, which is the major characteristic pathogenesis for IR in combating T2DM. The identified VDR gene polymorphisms are ApaI, TaqI, FokI, and BsmI that are associated with T2DM. This review collates informations on the mechanisms by which VDR activation takes place in skeletal muscles. Despite the significant breakthroughs made in recent decades, various studies show that IR affects VDR and PUFAs metabolism in skeletal muscle. Therefore, this review collates the data to show the role of VDR and PUFAs in the skeletal muscles to combat T2DM.

Differences in Plasma 25-Hydroxyvitamin D Levels at Diagnosis of Celiac Disease and Type 1 Diabetes

AIM

The aim of this work is to assess the vitamin D levels, evaluated as plasma 25-hydroxyvitamin D of children with a new diagnosis of celiac disease (CD), of children with a new onset of type 1 diabetes (T1D) and in children with CD at diagnosis of T1D (T1D&CD).

METHODS

In this single-center observational study, we collected data for four groups of children and adolescents: T1D, CD, T1D&CD, and a control group (CG). The CG included schoolchildren who had negative results during a mass screening campaign for CD and were not diagnosed for T1D, according to RIDI Marche registry data, were considered for the purposes of this study. Plasma 25-hydroxyvitamin D, 25(OH)D2, and 25(OH)D3 were considered as the parameters for evaluating vitamin D nutritional status, and the date of measurement was recorded to analyze vitamin D level seasonality. Vitamin D nutritional status was categorized as follows: severe deficiency (<10 ng/mL), deficiency (<20 ng/mL), insufficiency (20-29 ng/mL), or sufficiency/adequacy (≥30 ng/mL). The Kruskal-Wallis test was used to compare the groups. The association of 25(OH)D levels with health conditions and seasonal differences of 25(OH)D levels was analyzed using a multiple linear regression model.

RESULTS

The number of children enrolled for the present study was 393: 131 in the CG, 131 CD, 109 T1D, and 22 T1D&CD. Significantly lower levels of vitamin D were displayed for children with CD, T1D, or both the diseases. Interestingly, severe vitamin D deficiency was detected in no children with CD, 1.5% of children in the CG, in 24.4% with T1D, and 31.8% with T1D&CD (p < 0.001). As expected, the CG children vitamin D levels were significantly influenced by seasonality. Contrarily, no seasonal differences were reported in children with CD, T1D, and T1D&CD. Multiple regression analysis showed that children with T1D and T1D&CD had lower 25(OH)D levels of 9.9 ng/mL (95% CI: 5.4; 14.5) and 14.4 ng/mL (95% CI: 6.2-22.7) compared to CG children (p < 0.001).

CONCLUSIONS

Our results showed low levels of vitamin D diagnosis of T1D, CD, and T1D&CD; however, severe deficiency was only reported in children with T1D and T1D&CD. More studies are needed to better understand the role of this deficiency in children newly diagnosed with CD and T1D.

Accurate Clinical Detection of Vitamin D by Mass Spectrometry: A Review

Vitamin D deficiency is thought to be associated with a wide range of diseases, including diabetes, cancer, depression, neurodegenerative diseases, and cardiovascular and cerebrovascular diseases. This vitamin D deficiency is a global epidemic affecting both developing and developed countries and therefore qualitative and quantitative analysis of vitamin D in a clinical context is essential. Mass spectrometry has played an increasingly important role in the clinical analysis of vitamin D because of its accuracy, sensitivity, specificity, and the ability to detect multiple substances at the same time. Despite their many advantages, mass spectrometry-based methods are not without analytical challenges. Front-end and back-end challenges such as protein precipitation, analyte extraction, derivatization, mass spectrometer functionality, must be carefully considered to provide accurate and robust analysis of vitamin D through a well-designed approach with continuous control by internal and external quality control. Therefore, the aim of this review is to provide a comprehensive overview of the development of mass spectrometry methods for vitamin D accurate analysis, including emphasis on status markers, deleterious effects of biological matrices, derivatization reactions, effects of ionization sources, contribution of epimers, standardization of assays between laboratories.

Is vitamin D deficiency associated with retinopathy in type 2 diabetes mellitus? A case-control study

BACKGROUND AND AIMS

This study aimed to determine the associations between vitamin D deficiency and diabetic retinopathy (DR) progression risk in type 2 diabetes mellitus (T2DM) patients.

METHODS

This is a case-control study that enrolled 201 diabetic retinopathy (DR) patients as case and 201 T2DM without DR as a control. Demographic variables were obtained during an interview using a questionnaire, furthermore, anthropometric measures were evaluated based on the standard protocol. In addition, biochemical indices including 25-hydroxyvitamin D, fasting blood glucose (FBG), insulin, Glycosylated hemoglobin (HbA1c), total cholesterol (TC), LDL-C, HDL-C, and triglyceride (TG) were assessed for all of the participants. Multivariate logistic regression was performed to estimate the relationship between vitamin D and retinopathy.

RESULTS

Based on the statistical analysis of age, sex, and BMI there was no significant difference between the two groups, while the mean concentration of 25-hydroxyvitamin D substantially was lower in case group in comparison with the control group (14.46 VS. 19.88). Furthermore, low levels of vitamin D are associated with DR and consequently proliferative diabetic retinopathy (PDR) in patients with T2DM.

CONCLUSION

Totally based on the results of the present study vitamin D deficiency increased the risk of RD in patients with T2DM, also in case of deficiency of this nutrient, retinopathy may develop into PDR type.

Association of a Combination of Sarcopenia and Type 2 Diabetes with Blood Parameters, Nutrient Intake, and Physical Activity: A Nationwide Population-Based Study

This study aimed to investigate the association of sarcopenia and type 2 diabetes (T2D) with blood parameters, nutrient intake, and physical activity in older Korean adults. We divided 2952 participants into four groups: sarcopenic diabetes (SD), sarcopenia alone (S), diabetes alone (D), and non-sarcopenia and non-diabetes (NSND). Sarcopenia was defined by the appendicular skeletal muscle mass index, and T2D by fasting glucose levels or ongoing treatment. Blood samples were collected after an 8-h fast. Nutrient intake was assessed using a 24-h recall; physical activity was evaluated using a questionnaire. Compared with those in the other groups, the men in the S and SD groups showed significantly lower hemoglobin and hematocrit levels; vitamin D levels in men and parathyroid hormone levels in women were significantly lower in the SD group. Total energy, protein, and carbohydrate intakes were significantly lower in the SD and S groups than those in the D and NSND groups. Physical inactivity was significantly more common in the SD group (men: odds ratio, 1.61; women: odds ratio, 2.37) than in the NSND group. A combination of sarcopenia and diabetes as well as sarcopenia alone was associated with low levels of blood parameters, poor nutrient intake, and low physical activity.

Factors Associated with Vitamin D Deficiency and Their Relative Importance among Indian Adolescents: An Application of Dominance Analysis

Vitamin D deficiency is a serious issue in developing nations, including India. This study investigates the determinants of vitamin D deficiency among Indian adolescents and assesses their relative importance using dominance analysis. Data from the Comprehensive National Nutrition Survey (CNNS) conducted between 2016 and 2018 were utilized in this study. Vitamin D levels were assessed based on serum 25-hydroxyvitamin D concentration, with a sample size encompassing 13,065 adolescents aged between 10 and 19 years. Backward stepwise multivariate logistic regression was used to identify the correlates of vitamin D deficiency, and the relative importance of these factors was assessed using dominance analysis. The study identified nine predictors that were significantly associated with vitamin D deficiency at a 1% level of significance (α = 0.001). Among these factors, sex was found to be the most significant predictor, with female adolescents being 2.66 (95% CI: 95% CI: 2.39-2.96) times more likely to be vitamin D deficient compared to male adolescents. Lifestyle and behavioral factors, such as "sex," "wealth index," and "place of residence," were more dominant in predicting vitamin D deficiency than biological indicators like "BMI" and "serum creatinine." This underscores the vital role of sunlight exposure in maintaining sufficient vitamin D levels. In summary, this study sheds light on the multifaceted factors contributing to vitamin D deficiency among Indian adolescents, emphasizing the significance of targeted interventions and public health awareness campaigns to mitigate this pressing issue.

25-Hydroxyvitamin D Is Associated with Islet Homeostasis in Type-2 Diabetic Patients with Abdominal Obesity

OBJECTIVE

Islet α cells input is essential for insulin secretion from β cells. The present study aims to investigate the association between 25-hydroxyvitamin D [25(OH)D] and islet function homeostasis in type-2 diabetes (T2D) patients.

METHODS

A total of 4670 T2D patients from seven communities in Shanghai, China were enrolled. The anthropometric indices, biochemical parameters, serum 25(OH)D, and islet function [including C-peptide (C-p) and glucagon] were measured.

RESULTS

The fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), glucagon, and C-p levels exhibited a significantly decreasing trend in T2D patients as the 25(OH)D levels increased. Next, the population was divided into two groups: abdominal obesity and non-abdominal obesity groups. After adjustment, the 25(OH)D level was found to be associated with HbA1c, glucagon, and homeostasis model assessment of β (HOMA-β) in the non-abdominal obesity group. There was a significant relationship between 25(OH)D and HbA1c, glucagon, HOMA-IR, baseline insulin or C-p in the abdominal obesity group. In the abdominal obesity group, the ordinary least squares (OLS) regression and quantile regression revealed that 25(OH) D was obviously associated with glucagon and fasting C-p levels. In the abdominal obesity group, the moderate analysis revealed a significant interaction effect of 25(OH)D and glucagon on C-p (P=0.0124). Furthermore, the conditional indirect effect of 25(OH)D on the glucagon/C-p ratio was significantly lower at 1 standard deviation (SD) below the mean (P=0.0002), and lower at the mean of the course of diabetes (P=0.0007).

CONCLUSION

25(OH)D was found to be negatively correlated to glucagon and C-p in T2D patients with abdominal obesity. The 25(OH)D influenced C-p in part by influencing glucagon. The effect of 25(OH)D on the glucagon/C-p ratio in T2D patients with abdominal obesity, in terms of islet homeostasis, is influenced by the course of diabetes.

The Possible Influence of Vitamin D Levels on the Development of Atrial Fibrillation-An Update

Atrial fibrillation (AF) is a severe and most common supraventricular arrhythmia in humans, which, if left untreated or treated ineffectively, can lead to ischemic stroke or heart failure. It has been suggested that serum vitamin D (VitD) deficiency may be one of the critical factors influencing the onset of AF, especially in the period after cardiac surgery, such as coronary artery bypass grafting. Several papers have indicated that VitD supplementation reduces the risk of AF, significantly reducing the proportion of patients between the control and study groups in both the pre- and postoperative periods. Factors that increase the risk of AF from VitD deficiency are also further indicated, and these are age, gender, weight, season or comorbidities. In addition, the cardiodepressive mechanism of VitD is not fully understood; however, it is suggested that it acts through at least two pathways. The first indicates a direct effect of VitD on atrial muscle degradation, while the second is related to the modulation of cardiovascular depression factors. Despite many reports showing correlations between no VitD concentrations on the development of AF, this topic is still widely debated and the results from these papers are still subject to doubt. Therefore, this review aims at describing in detail the problem of correlation between VitD deficiency and the development of AF associated mainly with the postoperative period, i.e., after cardiac surgery, especially pathogenesis, and results of this correlation, taking into account recent studies, limitations and future perspectives. Due to the fact that this is still a topical problem, we believe that the collection of the latest reports and a detailed description of the problem is most appropriate in this case.

Neuromodulatory effect of the combination of metformin and vitamin D3 triggered by purinergic signaling in type 1 diabetes induced-rats

Several studies have indicated the vitamin D deficiency in the development of macro- and microvascular complications of diabetes mellitus (DM) including DM-related cognitive dysfunction. The purinergic system plays an important role in the modulation of a variety of mechanisms, including neuroinflammation, plasticity, and cell-cell communication. In addition, purines, their receptors, and enzymes can regulate the purinergic axis at different levels in type 1 DM (T1DM). This study evaluated the effects of vitamin D₃ alone or in combination with metformin in the behavioral performance of streptozotocin-induced T1DM rats. The effects of this combination on the metabolism of ATP and ADP were also studied by NTPDase (CD39), AMP by 5'-nucleotidase (CD73), and adenosine by adenosine deaminase (E-ADA) in the brain and peripheral lymphocytes of type 1 diabetic STZ-induced rats. The results showed that anxiety and memory loss from the DM condition reverted after 30 days of vitamin D₃ treatment. Furthermore, the DM state affected systemic enzymes, with no effect on the central enzymes hydrolyzing extracellular nucleotides and nucleosides. Vitamin D₃ treatment positively regulated ectonucleotidase (NTPDase and 5'-nucleotidase) activity, E-ADA, and the purinergic receptors as a mechanism to prevent oxidative damage in the cerebral cortex of T1DM rats. A neuroprotector effect of vitamin D₃ through adenosine signaling was also observed, by regulating A1 and A_2A receptors proteins levels. The present findings suggest that purinergic signaling through vitamin D₃ modulation may be a novel alternative strategy for T1DM treatment, and may compensate for the negative changes in the central nervous system.

Serum 25-Hydroxyvitamin D concentrations are inversely associated with all-cause mortality among Koreans: a nationwide cohort study

Evidence on the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and all-cause and cause-specific mortality in Asians, especially Koreans, is limited. We hypothesized that high concentrations of 25(OH)D are associated with lower all-cause and cause-specific mortality in the general Korean population. This study included 27,846 adults participating in the Fourth and Fifth Korean National Health and Nutrition Examination Survey 2008-2012, followed up through December 31, 2019. Hazard ratios (HR) and 95% confidence intervals (CIs) for mortality from all causes, cardiovascular disease (CVD), and cancer were estimated using multivariable-adjusted Cox proportional hazards regression. The weighted mean serum 25(OH)D of study participants was 17.77 ng/mL; 66.5% had vitamin D deficiency (<20 ng/mL) and 94.2% had insufficient vitamin D (<30 ng/mL). During a median follow-up of 9.4 years (interquartile range, 8.1-10.6 years), 1680 deaths were documented, including 362 CVD deaths and 570 cancer deaths. Serum 25(OH)D levels ≥30 ng/mL were inversely associated with all-cause mortality (HR, 0.57; 95% CI, 0.43-0.75) compared with serum 25(OH)D levels <10 ng/mL. Based on the quartile cutoffs of serum 25(OH)D concentration, the highest quartile of serum 25(OH)D concentration (≥21.8 ng/mL) was associated with the lowest all-cause mortality (HR, 0.72; 95% CI, 0.60-0.85; P trend < .001), and CVD mortality (HR, 0.60; 95% CI, 0.42-0.85; P trend = .006). No association with cancer mortality outcome was found. In conclusion, higher serum 25(OH)D levels were associated with lower all-cause mortality in the general Korean population. An additional association was found between higher quartile of serum 25(OH)D and lower CVD mortality.

Allelic Discrimination of Vitamin D Receptor Polymorphisms and Risk of Type 2 Diabetes Mellitus: A Case-Controlled Study

(1) Background: Type 2 diabetes mellitus (T2DM) is one of the rapidly growing healthcare problems, and several vitamin D receptor (VDR) polymorphisms seem to modulate the risk of T2DM. Our research was designed to investigate the allelic discrimination of VDR polymorphisms and T2DM occurrence risk. (2) Methods: This case-control research included 156 patients with T2DM and 145 healthy control subjects. Most of the study population were males 56.6% vs. 62.8% in the case and control groups, respectively. Genotyping for VDR single nucleotide polymorphisms (SNPs), rs228570 (Fok1), rs7975232 (Apa1), and rs1544410 (Bsm1) was compared between both groups. (3) Results: There was a negative link between vitamin D levels and insulin sensitivity. A significant difference was noted in the allelic discrimination of VDR polymorphism rs228570 and rs1544410 between the study groups (p < 0.001). No difference was observed in the allelic discrimination of VDR polymorphism rs7975232 between the groups (p = 0.063). Moreover, T2DM patients had significantly higher levels of fasting blood sugar (FBS), glycated hemoglobin HbA1c, 2-h post-prandial blood sugar (PP), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic-pyruvic transaminase (SGPT), total cholesterol, and triglycerides (p < 0.001), while High-Density Lipoprotein (HDL) Cholesterol (HDL-C) was significantly decreased (p = 0.006). (4) Conclusions: VDR polymorphisms had a positive association with T2DM risk among the Egyptian population. Further large-scale research using deep sequencing of samples is strongly urged to investigate different vitamin D gene variants and interactions, as well as the influence of vitamin D on T2DM.

Longitudinal changes in vitamin D concentrations and the association with type 2 diabetes mellitus: the Tromsø Study

AIM

We aimed to investigate the relationship between pre- and post-diagnostic 25-hydroxyvitamin D (25(OH)D) concentrations and type 2 diabetes (T2DM) over a period of 30 years in individuals who developed T2DM compared to healthy controls.

METHODS

This case-control study included 254 participants with blood samples collected at five different time-points (T1-T5) between 1986 and 2016. Of the 254 participants, 116 were diagnosed with T2DM between T3 and T4, and were considered cases; the remaining 138 were controls. Linear mixed regression models were used to examine pre- and post-diagnostic changes in 25(OH)D concentrations, and logistic regression was used to examine associations between these concentrations and T2DM at each time-point.

RESULTS

25(OH)D concentrations at different time-points and the longitudinal change in concentrations differed between cases and controls, and by sex. For women, each 5-nmol/l increase in 25(OH)D concentrations was inversely associated with T2DM at T3 (odds-ratio, OR, 0.79), whereas for men, this same increase was positively associated with T2DM at T1 (OR 1.12). Cases experienced a significant decrease in pre-diagnostic 25(OH)D concentrations (p value < 0.01 for women, p value = 0.02 for men) and a significant increase in post-diagnostic 25(OH)D concentrations (p value < 0.01 for women, p value = 0.01 for men). As such, each 1-unit increase in month-specific z-score change between T1 and T3 was significantly inversely associated with T2DM (OR 0.51 for women, OR 0.52 for men), and each such increase between T3 and T5 was significantly positively associated with T2DM in women (OR 2.48).

CONCLUSIONS

25(OH)D concentrations seem to be affected by disease progression and type 2 diabetes diagnosis.

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.

Vitamin D: sources, physiological role, biokinetics, deficiency, therapeutic use, toxicity, and overview of analytical methods for detection of vitamin D and its metabolites

Vitamin D has a well-known role in the calcium homeostasis associated with the maintenance of healthy bones. It increases the efficiency of the intestinal absorption of dietary calcium, reduces calcium losses in urine, and mobilizes calcium stored in the skeleton. However, vitamin D receptors are present ubiquitously in the human body and indeed, vitamin D has a plethora of non-calcemic functions. In contrast to most vitamins, sufficient vitamin D can be synthesized in human skin. However, its production can be markedly decreased due to factors such as clothing, sunscreens, intentional avoidance of the direct sunlight, or the high latitude of the residence. Indeed, more than one billion people worldwide are vitamin D deficient, and the deficiency is frequently undiagnosed. The chronic deficiency is not only associated with rickets/osteomalacia/osteoporosis but it is also linked to a higher risk of hypertension, type 1 diabetes, multiple sclerosis, or cancer. Supplementation of vitamin D may be hence beneficial, but the intake of vitamin D should be under the supervision of health professionals because overdosing leads to intoxication with severe health consequences. For monitoring vitamin D, several analytical methods are employed, and their advantages and disadvantages are discussed in detail in this review.

Vitamin D regulates insulin and ameliorates apoptosis and oxidative stress in pancreatic tissues of rats with streptozotocin-induced diabetes

This study was designed to evaluate the potential therapeutic efficacy of vitamin D (Vit D) in averting the harmful effects of type 2 diabetes mellitus (T2D). Forty male Wistar rats were allotted into four groups: (1) the control, (2) Vit D, (3) streptozotocin (STZ), and (4) STZ + Vit D groups. Rats co-treated with Vit D had significantly (p < 0.05) decreased levels of cortisol; proinflammatory cytokines, including interleukin-6 (IL-6); and malondialdehyde (MDA). Meanwhile, the levels of insulin significantly (p < 0.05) increased, whereas the activity of the antioxidant system, including glutathione (GSH), superoxide dismutase (SOD), catalase, and total antioxidant capacity (TAC), significantly (p < 0.05) decreased. Histopathological examination revealed the destruction of beta cells in the islets of Langerhans in rats with diabetes. Meanwhile, immunoexpression revealed an increase in the immunoreactivity of caspase-3 and endothelial nitric oxide synthase and a reduction in the immunoreactivity of insulin in rats with diabetes. In conclusion, Vit D ameliorated the harmful biochemical impact of diabetes mellitus, probably by increasing insulin secretion and sensitivity, ameliorating β-cell function, and decreasing cortisol levels; also, the anti-inflammatory effect of Vit D reduces the number of proinflammatory cytokines (e.g., IL-6) and increases the activity of the antioxidant system, such as GSH, SOD, TAC, and catalase while reducing lipid peroxidation enzymes (e.g., MDA).

Association between serum 25-hydroxyvitamin-D and Triglycerides-Glucose index among Indian adolescents

Background

Vitamin D deficiency has been found to associated with numerous skeletal and non-skeletal diseases including Diabetes Mellitus. Insulin Resistance (IR) is considered as one of the primary reasons of Type-2 Diabetes Mellitus (T2DM). The association between vitamin D deficiency and IR has been extensively explore in previous studies, but none of them focused on Indian adolescents, and none of them used the TyG index as IR marker. Hence, this population-based cross-sectional study investigates the relationship between insulin resistance (IR) assessed using the Triglycerides Glucose Index (TyG index) and vitamin D measured by serum 25-hydroxyvitamin-D (25(OH)D).

Methods

For this study, we utilized data from the Comprehensive National Nutrition Survey (CNNS, 2016–18). The study is based on a sample size of 10,167 adolescents aged 10–19 years. The TyG index cut-off value of 4.65 was used to classify IR. We examined associations between the TyG index and serum 25(OH)D using multiple linear regression models adjusted for potential confounders. Odds of Insulin Resistance among vitamin D deficient/insufficient adolescents were assessed using multivariable logistic regression.

Results

A significant negative association was found between serum 25(OH)D and the TyG index, where a 10% increase in serum 25(OH)D was associated with 0.56 (95% CI = -0.67, -0.45) unit decrement in the TyG index. The odds of having IR were 90% higher among vitamin D deficient adolescents (OR: 1.90; 95% CI = 1.62—2.23) compared to adolescents with adequate levels of vitamin D. The association between vitamin D deficiency and IR was independent of sex; in other words, the association between vitamin D and IR was significant in both the sexes.

Conclusion

Independent of sex, this study found a significant inverse association between vitamin D and insulin resistance in Indian adolescents. The findings of this study highlight the utility of TyG index and the importance of vitamin D in lowering the risk of T2DM in future generations of the country.

Clinical, metabolic, and immunological characterisation of adult Ugandan patients with new-onset diabetes and low vitamin D status

BACKGROUND

Low vitamin D concentrations are associated with metabolic derangements, notably insulin resistance and pancreatic beta-cell dysfunction in Caucasian populations. Studies on its association with the clinical, metabolic, and immunologic characteristics in black African adult populations with new-onset diabetes are limited. This study aimed to describe the clinical, metabolic, and immunologic characteristics of a black Ugandan adult population with recently diagnosed diabetes and hypovitaminosis D.

METHODS

Serum vitamin D concentrations were measured in 327 participants with recently diagnosed diabetes. Vitamin D deficiency, vitamin D insufficiency, and normal vitamin D status were defined as serum 25 hydroxyvitamin D levels of < 20 ng/ml, 21-29 ng/ml, and ≥ 30 ng/ml, respectively.

RESULTS

The median (IQR) age, glycated haemoglobin, and serum vitamin D concentration of the participants were 48 years (39-58), 11% (8-13) or 96 mmol/mol (67-115), and 24 ng/ml (18-30), respectively. Vitamin D deficiency, vitamin D insufficiency, and normal vitamin D status were noted in 105 participants (32.1%), 140 participants (42.8%), and 82 participants (25.1%), respectively. Compared with those having normal serum vitamin D levels, participants with vitamin D deficiency and insufficiency had higher circulating concentrations of interleukin (IL) 6 (29 [16-45] pg/ml, 23 [14-40] pg/ml vs 18 [14-32] pg/ml, p = 0.01), and IL-8 (24 [86-655] pg/ml, 207 [81-853] pg/ml vs 98 [67-224], p = 0.03). No statistically significant differences were noted in the markers of body adiposity, insulin resistance, and pancreatic beta-cell function between both groups.

CONCLUSION

Vitamin D deficiency and insufficiency were highly prevalent in our study population and were associated with increased circulating concentrations of pro-inflammatory cytokines. The absence of an association between pancreatic beta-cell function, insulin resistance, and low vitamin D status may indicate that the latter does not play a significant role in the pathogenesis of type 2 diabetes in our adult Ugandan population.

Epidemiology of Type 1 Diabetes

PURPOSE OF REVIEW

Epidemiological research on type 1 diabetes (T1D) has traditionally focussed on the paediatric age group, but recent data in adults has confirmed it to be a disease of all ages with a wide clinical spectrum. We review the epidemiology and clinical features of T1D across the lifespan.

RECENT FINDINGS

While the peak incidence of T1D is still in early adolescence, T1D is now diagnosed more commonly in adulthood than childhood due to increasing recognition of adult-onset T1D and the length of the adult lifespan. It still follows the known geographic variations in incidence, being highest in Northern Europe and lowest in Asia. The onset of T1D in adulthood is usually less acute than in childhood and confers a lower, although still substantial, risk of complications and early mortality. Interventions to delay T1D onset are emerging and screening for those at risk at birth is increasingly available. Type 1 diabetes can develop at any age and may not present with ketosis or an immediate insulin requirement in adults. Macro- and microvascular complications are the greatest cause of excess morbidity and mortality in this population.

Glutamic acid decarboxylase immunotherapy for type 1 diabetes

PURPOSE OF REVIEW

To describe recent development of an autoantigen (GAD) treatment towards well tolerated and efficacious precision medicine in type 1 diabetes.

RECENT FINDINGS

Although subcutaneous GAD-alum treatment failed to reach primary endpoint in a phase III trial, metanalyses showed a 97% probability of efficacy, and clear efficacy in patients carrying Hyman Leucoycte Antigen (HLA) DR3DQ2. Efforts have been made to improve efficacy by trying combination therapies with vitamin D + Ibuprofen resp vitamin D + Etanercept (TNF-α inhibition), without any breakthrough until the administration of GAD-alum was changed from subcutaneous to intralymphatic. With a very small dose of GAD-alum (4 μg) given into an inguinal lymph three times with 1 month interval, the efficacy in patients with HLADR3DQ2 has been impressive, with significantly better beta cell preservation than patients who got placebo in a double-blind randomized trial, and clinical efficacy with more patients in partial remission (IDAA1c < 9) and larger proportion of patients with CGM-measured blood glucose Time In Range (TIR), significantly correlated to the C-peptide values. The treatment has been easy for patients and healthcare without treatment-related risk or adverse events.

SUMMARY

Intralymphatic GAD-alum treatment in type 1 diabetes patients carrying HLA DR3DQ2 seems to be an attractive immune intervention.

Effects of aerobic exercise on adiponectin levels potentially mediated by vitamin D in type 2 diabetic patients

Objective. The positive effects of exercise on adiponectin and vitamin D have independently been reported. Recent studies have suggested that vitamin D increases adiponectin synthesis through inhibition of the rennin-angiotensin system in adipose tissue. However, studies evaluating the effects of an aerobic exercise on adiponectin and vitamin D simultaneously investigating the potential mechanism of vitamin D-dependent adiponectin pathways in patients with type 2 diabetes mellitus (T2DM) are still limited. This study was undertaken to examine the effects of aerobic exercise on adiponectin and its association with vitamin D in patients with T2DM.

Methods. Total twenty-two patients with T2DM were randomly divided into intervention and control group. The intervention group underwent a moderate intensity of a walking mode treadmill aerobic exercise for four weeks. The exercise protocol was adapted from modified Bruce test with a periodic speed and inclination increase. In both groups, body mass index (BMI), vitamin D, and adiponectin levels, were measured before and after four weeks of the lasting program.

Results. The mean of the increased adiponectin and vitamin D levels after exercise was significantly higher in the intervened than the control group, but statistically significant difference was only found in the adiponectin effect (p=0.017). There was a significant association found between vitamin D and adiponectin in the intervention group after data adjustments to age and BMI (p=0.005).

Conclusion. Moderate intensity of treadmill exercise with increased speed and inclination periodically increased adiponectin level in patients with T2DM. The increased adiponectin might potentially be mediated by increased vitamin D, but the level of their association impact was dependent on the age and BMI.

Yeast as a biological platform for vitamin D production: A promising alternative to help reduce vitamin D deficiency in humans

Vitamin D is an important human hormone, known primarily to be involved in the intestinal absorption of calcium and phosphate, but it is also involved in various non-skeletal processes (molecular, cellular, immune, and neuronal). One of the main health problems nowadays is the vitamin D deficiency of the human population due to lack of sun exposure, with estimates of one billion people worldwide with vitamin D deficiency, and the consequent need for clinical intervention (i.e., prescription of pharmacological vitamin D supplements). An alternative to reduce vitamin D deficiency is to produce good dietary sources of it, a scenario in which the yeast Saccharomyces cerevisiae seems to be a promising alternative. This review focuses on the potential use of yeast as a biological platform to produce vitamin D, summarizing both the biology aspects of vitamin D (synthesis, ecology and evolution, metabolism, and bioequivalence) and the work done to produce it in yeast (both for vitamin D₂ and for vitamin D₃ ), highlighting existing challenges and potential solutions. This article is protected by copyright. All rights reserved.

Vitamin D Serum Levels in Type 2 Diabetic Patients: A Cross-Sectional Study

Background and objective

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by hyperglycemia. It is linked with an increase in morbidity (e.g., blindness, kidney failure, stroke, cardiovascular diseases, limb amputations), premature mortality, high healthcare costs, and is quickly becoming a global epidemic disorder. Several studies have shown that vitamin D supplements reduce insulin resistance in T2DM and improve insulin secretion and sensitivity. In this study, we aimed to determine the prevalence of vitamin D deficiency in T2DM patients in Saudi Arabia.

Methods

This was a retrospective cross-sectional study conducted at the King Faisal University Health Centre in Saudi Arabia. The study used patient data during the period from October 2014 to January 2021. After obtaining approval from the King Faisal University Polyclinic Administration, we collected patient data from the King Faisal University Health Centre. The Ethics and Research Committee at the College of Medicine of King Faisal University granted ethical approval with the approval number (2020-11-82). The relevant patient data were collected, including age, gender, nationality, and blood test findings (vitamin D and HbA1c levels).

Results

A total of 191 T2DM patients participated in this study. The mean age of the patients was 56.1 ± 11.4 years (range: 21-85 years); 107 (56%) patients were females, and 137 (71.7%) were Saudis. There were 134 (70.2%) patients with vitamin D deficiency, 53 (27.7%) with vitamin D insufficiency, and only four (2.1%) with normal vitamin D levels.

Conclusion

Based on our findings, the prevalence of vitamin D deficiency among T2DM patients is highly associated with poor diabetic control.

Changes in the macular choroidal thickness of children who have type-1 diabetes mellitus, with and without vitamin D deficiency

PURPOSE

To assess the peripapillary retinal nerve fiber layer (RNFL) and macular choroidal thickness (CT) of children who have Type 1 diabetes mellitus (DM), both with and without vitamin D deficiency (VDD).

METHODS

The prospective, case-control study herein comprised that included 46 children with DM and VDD (Group 1), 42 children with DM and normal vitamin D levels (Group 2), and 73 healthy children (Control group). The peripapillary RNFL thickness and macular CT were measured at three different points (subfoveal, 1500 μm nasal, and 1500 μm temporal from the fovea) and compared.

RESULTS

The subfoveal, 1500 μm nasal, and 1500 μm temporal CT values were determined to be lower in the patients in Group 1 and Group 2 when compared to those in the Control group (P < 0.001). The same parameters were determined to be lower in the patients in Group 1 when compared to those in Group 2, although this difference was not found to be statistically significant (P > 0.05). In all of the quadrants, the RNFL thickness was determined to be similar between the groups, with P > 0.05 for all of the groups, except for the nasal quadrant (P = 0.031). In the correlation analysis of the patients in Group 1, it was revealed that a positive correlation existed between the CT and the vitamin D levels (P < 0.05).

CONCLUSION

The choroids of pediatric diabetic children were thinner when compared to those of healthy children. The alterations in these parameters were more prominent in subjects who were determined to have lower levels of vitamin D.

The Immunologic Profile of Vitamin D and Its Role in Different Immune-Mediated Diseases: An Expert Opinion

Historically, vitamin D is recognized as an essential component for the maintenance of the musculoskeletal system. The immunomodulatory role of vitamin D in health and disease has gained much interest in recent years due to the many pathologies that share underlying immunological features where vitamin D has been shown to exert a potential role. Evidence from pre-clinical studies show that vitamin D elicits biological effects on both the innate and adaptive immune systems. Furthermore, in vivo studies have shown that administration of vitamin D can lead to changes in or the development of a range of immune-related diseases. This encourages the hypothesis that data derived from clinical and epidemiological studies connect vitamin D with the incidence and severity of many immune-mediated disorders such as rheumatoid arthritis, diabetes, and infectious diseases. Since some other immune-mediated diseases share similar features to that of viral infection such as COVID-19, in this review, we examined these other areas and the role of vitamin D in these diseases.

Vitamin D pathway gene variation rs3740165 is associated with serological uric acid levels in healthy Chinese women

AIM

To investigate the relationship between gene polymorphisms involved in the vitamin D metabolic pathway and serum uric acid (UA) levels in Chinese women.

METHODS

Fifteen key genes within the vitamin D metabolic pathway were screened using 96 single nucleotide polymorphisms in a group of 1,206 (37.96 ± 13.08 years) unrelated healthy Chinese women (aged 20-85 years). Blood and urine tests were performed at the same time. The Wilcoxon Mann-Whitney test was used to compare groups aged ≤50 years and >50 years. The mean serum UA values were computed within each group of homozygous referent, heterozygous, and homozygous variant genotypes for each single nucleotide polymorphism.

RESULTS

The exclusion process left 1,169 participants (38.16 ± 13.13 years) for analysis. One single nucleotide polymorphism in the CUBN gene (rs3740165) was identified as being significantly associated with serum UA levels in the group aged over 50 years. The wild type (C/C) population had higher serum UA levels in this group (P<0.001). In women aged over 50 years, allele C was associated with a higher risk of hyperuricemia than allele T (odds ratio 2.752, 95% confidence interval 1.458-5.192; P = 0.002). There was also a higher risk of hyperuricemia in genotype TC + CC compared with genotype TT (odds ratio 3.326, 95% confidence interval 1.513-7.313; P = 0.003) in women over 50 years of age.

CONCLUSION

The results suggest that the CUBN gene contributes to variability in serum UA levels in healthy Chinese Han women over 50 years of age.

Beneficial Role of Vitamin D on Endothelial Progenitor Cells (EPCs) in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death in the world. Endothelial progenitor cells (EPCs) are currently being explored in the context of CVD risk. EPCs are bone marrow derived progenitor cells involved in postnatal endothelial repair and neovascularization. A large body of evidence from clinical, animal, and in vitro studies have shown that EPC numbers in circulation and their functionality reflect endogenous vascular regenerative capacity. Traditionally vitamin D is known to be beneficial for bone health and calcium metabolism and in the last two decades, its role in influencing CVD and cancer risk has generated significant interest. Observational studies have shown that low vitamin D levels are associated with an adverse cardiovascular risk profile. Still, Mendelian randomization studies and randomized control trials (RCTs) have not shown significant effects of vitamin D on cardiovascular events. The criticism regarding the RCTs on vitamin D and CVD is that they were not designed to investigate cardiovascular outcomes in vitamin D-deficient individuals. Overall, the association between vitamin D and CVD remains inconclusive. Recent clinical and experimental studies have demonstrated the beneficial role of vitamin D in increasing the circulatory level of EPC as well as their functionality. In this review we present evidence supporting the beneficial role of vitamin D in CVD through its modulation of EPC homeostasis.

Prevalence of Vitamin D Deficiency and Its Association with Insulin Resistance in Obese Women with Normal Fasting Glucose

Results

A total of 264 obese and 133 normal BMI women (controls) of age range 20-50 years were selected. Obese women had significantly lower vitamin D compared to control women (P < 0.05). Among euglycemic (fasting glucose < 100 mg/dl) obese women (n = 221), 90 (40.7%) were vitamin D deficient. Serum PTH and calcium levels were negatively correlated, though nonsignificantly with vitamin D (r = −0.172, P = 0.090, and r = −0.051, P = 0.557, respectively). The mean age, BMI, waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), fasting glucose, fasting insulin, PTH, and calcium were not significantly different in vitamin D-deficient as compared to nondeficient obese women. IR was detected in 109 (49.3%) obese women. Mean HOMA-IR in vitamin D-deficient women was significantly higher than that in the nondeficient obese women (3.03 ± 1.64 vs. 2.40 ± 1.02; P = 0.041), but the percentage of women with IR was comparable in both groups (51.1% vs. 45.8%; P = 0.745). Univariate analysis revealed that HOMA-IR was negatively correlated with vitamin D and positively with BMI and PTH. A multivariate regression analysis, stepwise method revealed that BMI and PTH were independent determinants of HOMA-IR instead of vitamin D.

Conclusion

More than 40% of obese women were vitamin D deficient. Among euglycemic obese women, 49% were insulin resistant. Prevalence of insulin resistance, though negatively correlated with vitamin D, could be better explained by BMI and PTH levels.

Effects of vitamin D3 injection in close-up period on insulin resistance and energy balance in transition dairy cows

Background

Many studies in dairy cows are towards calcium homeostasis and there is a lack of knowledge about the effect of vitamin D in preventing insulin resistance and improving energy balance in the transition period of dairy cows.

Methods

The trial was conducted in a commercial dairy farm with about 1500 lactating cows in Tehran province, Iran. Twenty‐four Holstein cows had been randomly selected and divided into control and treatment groups. In the treatment group, 12 cows, received a single dose of 8,000,000 IU vitamin D3 intramuscularly and in the control group, 12 cows were injected placebo (distilled water) 2–8 days before the expected calving time. Blood samples were collected between 8 and 10 AM 2 h after feeding on 21 and 7 days before calving and 1,3,7,15 and 30 days after calving. 25(OH)vitamin D, insulin‐like growth factor 1 (IGF‐1), insulin, nonesterified fatty acid (NEFA), β‐hydroxybutyric acid (BHBA), albumin, total protein, glucose, urea, triglyceride, cholesterol and aspartate amino transferase (AST) were measured by commercially available kits. The insulin resistance index was calculated.

Results

Vitamin D3 injection significantly affected the amounts of 25(OH) vitamin D, urea, insulin and insulin resistance index (p ≤ 0.05). On the other hand, the amounts of glucose, NEFA, BHBA concentration and AST activity were higher in control group (p ≤ 0.05). Time had a significant effect on the amounts of most measured variables except IGF‐1 and insulin. There were no group and time interactions for measured variables.

Conclusion

It seems that injection of vitamin D3 in close up period influenced lipolysis potentially modifying energy metabolism and resulted in reducing insulin resistance.

Combined Etanercept, GAD-alum and vitamin D treatment: an open pilot trial to preserve beta cell function in recent onset type 1 diabetes

AIM

We aimed to study the feasibility and tolerability of a combination therapy consisting of glutamic acid decarboxylase (GAD-alum), Etanercept and vitamin D in children and adolescents with newly diagnosed with type 1 diabetes (T1D), and evaluate preservation of beta cell function.

MATERIAL AND METHODS

Etanercept Diamyd Combination Regimen is an open-labelled multi-centre study pilot trial which enrolled 20 GAD antibodies positive T1D patients (7 girls and 13 boys), aged (mean ±SD): 12.4 ± 2.3 (8.3-16.1) years, with a diabetes duration of 81.4 ± 22.1 days. Baseline fasting C-peptide was 0.24 ± 0.1 (0.10-0.35) nmol/l. The patients received Day 1-450 Vitamin D (Calciferol) 2000 U/d per os, Etanercept sc Day 1-90 0.8 mg/kg once a week and GAD-alum sc injections (20 μg, Diamyd™) Day 30 and 60. They were followed for 30 months.

RESULTS

No treatment related serious adverse events were observed. After 6 months 90-min stimulated C-peptide had improved in 8/20 patients and C-peptide area under the curve (AUC) after Mixed Meal Tolerance Test in 5 patients, but declined thereafter, while HbA1c and insulin requirement remained close to baseline. Administration of Etanercept did not reduce tumour necrosis factor (TNF) spontaneous secretion from peripheral blood mononuclear cells, but rather GAD65-induced TNF-α increased. Spontaneous interleukin-17a secretion increased after the administration of Etanercept, and GAD65-induced cytokines and chemokines were also enhanced following 1 month of Etanercept administration.

CONCLUSIONS

Combination therapy with parallel treatment with GAD-alum, Etanercept and vitamin D in children and adolescents with type 1 diabetes was feasible and tolerable but had no beneficial effects on the autoimmune process or beta cell function.

The Idiosyncratic Physiological Traits of the Naked Mole-Rat; a Resilient Animal Model of Aging, Longevity, and Healthspan

The subterranean-dwelling naked mole-rat (Heterocephalus glaber) is an extremophilic rodent, able to thrive in the harsh underground conditions of sub-Saharan Northeast Africa. This pelage-free mammal exhibits numerous unusual ecophysiological features including pronounced tolerance of thermolability, hypoxia, hypercapnia and noxious substances. As a mammal, the naked mole-rat provides a proof-of-concept that age-related changes in physiology are avoidable. At ages far beyond their expected lifespans given both their body size and/or the timing of early developmental milestones, naked mole-rats fail to exhibit meaningful changes in physiological health or demographic mortality. Lack of physiological deterioration with age is also evident in lean and fat mass, bone quality, and reproductive capacity. Rather, regardless of age, under basal conditions naked mole-rats appear to "idle on low" with their "shields up" as is manifested by low body temperature, metabolic rate, cardiac output and kidney concentrating ability, enabling better protection of organs and cellular function. When needed, they can nevertheless ramp up these functions, increasing cardiac output and metabolism 2-5 fold. Here we review many unusual aspects of their physiology and examine how these attributes facilitate both tolerance of the diverse suite of hostile conditions encountered in their natural milieu as well as contribute to their extraordinary longevity and resistance to common, age-related chronic diseases.

Sex-Dependent Association of Vitamin D With Insulin Resistance in Humans

BACKGROUND

Animal studies suggested that vitamin D might decrease insulin resistance. Estrogen increased insulin sensitivity and glucose tolerance in rodents. However, sex-specific association of vitamin D with insulin resistance in humans remains unclear.

OBJECTIVES

To investigate the sex-dependency of the association of insulin resistance and 25-hydroxyvitamin D [25(OH)D] in a large Caucasian population.

METHODS

Cross-sectional study from out-patients' blood samples with measurements of 25(OH)D and homeostatic model assessment of insulin resistance (HOMA-IR) drawn at exactly the same day (n = 1887). This cohort was divided into 3 groups: (1) group with vitamin D deficiency (n = 1190), (2) group with vitamin D sufficiency (n = 686), and (3) vitamin D excess groups (n = 11); the vitamin D excess group was excluded from further analysis due to the small size.

RESULTS

Analysis of the entire study population showed that serum 25(OH)D was inversely associated with HOMA-IR [Spearman correlation coefficient (rs) = -0.19, P < 0.0001]. When considering the vitamin D status, this association was only seen in the vitamin D deficiency group but not in the vitamin D sufficient group. The correlation was sex-dependent: HOMA-IR was inversely correlated with vitamin D in women with vitamin D deficiency (rs = -0.26, P < 0.0001) but not in men with vitamin D deficiency (rs = 0.01, P = 0.714). After multivariate linear regression analysis considering confounding factors, this relationship was again only seen in women.

CONCLUSION

Vitamin D was inversely and independently associated with insulin resistance only in women with vitamin D deficiency. Based on our data, we suggest that in particular vitamin D deficient women might benefit from vitamin D substitution by improving insulin resistance. This, however, needs to be proven in adequately designed double-blind placebo-controlled clinical studies.

Vitamin D Receptor gene polymorphisms and susceptibility to type 2 diabetes: evidence from a meta-regression and meta-analysis based on 47 studies

BACKGROUND

Evidence from various studies suggest that vitamin D receptor (VDR) gene polymorphisms are associated with type 2 diabetes (T2D); However, these results have been disputable. Here we conducted a meta-analysis to comprehensively evaluate the effect of VDR gene polymorphisms and susceptibility to T2D.

METHODS

All relevant studies reporting the association between VDR gene polymorphisms and susceptibility to T2D published up to August 2020 were identified by comprehensive systematic database search in web of science, Scopus, and Medline. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure strength of association. The methodological quality of each study was assessed according to the Newcastle-Ottawa Scale. Subgroup and meta-regression analysis were also performed.

RESULTS

A total of 47 case-control studies were included in this meta-analysis. The overall population results revealed a significant association between FokI, and BsmI (heterozygote model) polymorphisms and T2D in the overall analysis. However, no association was found with the TaqI and ApaI polymorphisms. Moreover, the pooled results of subgroup analysis by ethnicity suggested significant association between FokI, TaqI, and BsmI polymorphisms and T2D in some subgroups. Meta-regression analyses indicated that none of the publication year, ethnicity, and genotyping method were the source of heterogenicity in all four polymorphisms.

CONCLUSIONS

This meta-analysis suggested a significant association between VDR gene FokI, and BsmI (heterozygote model) polymorphisms and T2D susceptibility in overall population and ethnic-specific analysis.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40200-020-00704-z.

Diabetoporosis: Role of nitric oxide

Diabetoporosis, diabetic-related decreased bone quality and quantity, is one of the leading causes of osteoporotic fractures in subjects with type 2 diabetes (T2D). This is associated with lower trabecular and cortical bone quality, lower bone turnover rates, lower rates of bone healing, and abnormal posttranslational modifications of collagen. Decreased nitric oxide (NO) bioavailability has been reported within the bones of T2D patients and can be considered as one of the primary mechanisms by which diabetoporosis is manifested. NO donors increase trabecular and cortical bone quality, increase the rate of bone formation, accelerate the bone healing process, delay osteoporosis, and decrease osteoporotic fractures in T2D patients, suggesting the potential therapeutic implication of NO-based interventions. NO is produced in the osteoblast and osteoclast cells by three isoforms of NO synthase (NOS) enzymes. In this review, the roles of NO in bone remodeling in the normal and diabetic states are discussed. Also, the favorable effects of low physiological levels of NO produced by endothelial NOS (eNOS) versus detrimental effects of high pathological levels of NO produced by inducible NOS (iNOS) in diabetoporosis are summarized. Available data indicates decreased bone NO bioavailability in T2D and decreased expression of eNOS, and increased expression and activity of iNOS. NO donors can be considered novel therapeutic agents in diabetoporosis.

Wide-range direct detection of 25-hydroxyvitamin D3 using polyethylene-glycol-free gold nanorod based on LSPR aptasensor

Vitamin D is associated with various diseases such as obesity, digestive problems, osteoporosis, depression, and infections, which has emerged as an interest in public healthcare. Recently, vitamin D has received more attention because of the potential implication with coronavirus disease 2019. In this study, we developed a localized surface plasmon resonance (LSPR) aptasensor based on polyethylene-glycol(PEG)-free gold nanorods (AuNRs) for the wide-range and direct detection of 25-hydroxyvitamin D₃. The surfactant on AuNRs was removed by exchanging with polystyrene sulfonate (PSS) instead of PEG then the PSS was exchanged with citrate. By exchanging the stabilizer of AuNRs from PEG to PEG-free (i.e., citrate), the sensing efficiency of LSPR aptasensor was significantly improved. Additionally, LSPR aptasensor was functionalized with aptamer and blocking agent to enhance the sensing performance. The LSPR aptasensor achieved the direct, highly sensitive, and selective detection of 25-hydroxyvitamin D₃ over a wide concentration range (0.1-10⁵ ng/mL), with a limit of detection of 0.1 ng/mL. This detection range included the concentration of vitamin D from deficiency to excess. The PEG-free AuNR-based LSPR aptasensor affords a new avenue for the development of robust sensing technology for vitamins.

Non-Musculoskeletal Benefits of Vitamin D beyond the Musculoskeletal System

Vitamin D, a fat-soluble prohormone, is endogenously synthesized in response to sunlight or taken from dietary supplements. Since vitamin D receptors are present in most tissues and cells in the body, the mounting understanding of the role of vitamin D in humans indicates that it does not only play an important role in the musculoskeletal system, but has beneficial effects elsewhere as well. This review summarizes the metabolism of vitamin D, the research regarding the possible risk factors leading to vitamin D deficiency, and the relationships between vitamin D deficiency and numerous illnesses, including rickets, osteoporosis and osteomalacia, muscle weakness and falls, autoimmune disorders, infectious diseases, cardiovascular diseases (CVDs), cancers, and neurological disorders. The system-wide effects of vitamin D and the mechanisms of the diseases are also discussed. Although accumulating evidence supports associations of vitamin D deficiency with physical and mental disorders and beneficial effects of vitamin D with health maintenance and disease prevention, there continue to be controversies over the beneficial effects of vitamin D. Thus, more well-designed and statistically powered trials are required to enable the assessment of vitamin D’s role in optimizing health and preventing disease.

Vitamin D affects the neutrophil-to-lymphocyte ratio in patients with type 2 diabetes mellitus

AIMS/INTRODUCTION

Chronic inflammation is an underlying feature of type 2 diabetes mellitus. Hypovitaminosis D is associated with type 2 diabetes mellitus, but whether it contributes to chronic inflammation is unclear. We examined the effects of vitamin D on various immune markers to evaluate its contribution to systemic inflammation in type 2 diabetes mellitus.

MATERIALS AND METHODS

We retrospectively analyzed data from type 2 diabetes mellitus patients, people with prediabetes and control patients without diabetes (n = 9,746). Demographic and clinical variables were evaluated using descriptive statistics and generalized linear regression. A stratified analysis based on total serum vitamin D was also carried out.

RESULTS

Neutrophil count was a significant predictor of 1,5-anhydroglucitol and glycated hemoglobin (HbA1c) in patients with prediabetes (1,5-anhydroglucitol: β = -0.719, P < 0.001 and HbA1c: β = -0.006, P = 0.002) and patients with diabetes (1,5-anhydroglucitol: β = 0.207, P = 0.004 and HbA1c: β = -0.067, P = 0.010). Lymphocyte count was a significant predictor of HbA1c in patients without diabetes (β = 0.056, P < 0.001) and patients with prediabetes (β = 0.038, P < 0.001). The neutrophil-to-lymphocyte ratio (NLR) was a significant predictor of HbA1c in patients without diabetes (β = -0.001, P = 0.032). No immune markers differed significantly based on vitamin D level among patients without diabetes (P> 0.05 for all). Among patients with prediabetes, those who were vitamin D-deficient had the highest NLR (P = 0.040). Among patients with diabetes, those who were vitamin D-deficient had the highest neutrophil count (P = 0.001), lowest lymphocyte count (P = 0.016) and highest NLR (P < 0.001).

CONCLUSIONS

The NLR is strongly influenced by serum vitamin D level. Given the high prevalence of hypovitaminosis D and elevated NLR among chronic disease patients and the elderly, our results suggest that clinical interpretation of NLR as a predictive marker of type 2 diabetes mellitus-related inflammation should consider vitamin D level, age and pre-existing morbidity.

Experience in Nutrition Management of Diabetes-Affected COVID-19 Patients

When diabetic patients are ill, their bodies react by releasing hormones to combat the illness. These hormones can be triggered by some states, such as infections. Some illnesses that most likely have an influence on blood glucose levels include common cold or flu, COVID-19, bronchitis, or chest infections. So, it is important for diabetic patients affected by COVID-19 to eat a healthy balanced diet to maintain stable blood glucose levels and enhance their immune functions. The immune response has often been demonstrated to be attenuated by insufficient nutrition in many model systems as well as in human studies. We summarize and propose potential nutritional therapeutic options available for the treatment of this novel coronavirus in diabetic patients.

Association of Vitamin D Deficiency with Cardiovascular Disease Among Saudi Patients in Saudi Arabia

Background:

Vitamin D deficiency has a far-reaching impact on several metabolic functions including cardiovascular health. This study aimed to test the association of serum 25 [OH]-vitamin D3 levels among cardiovascular disease (i.e., hypertension and ischemic heart disease) patients.

Methods:

A cross-sectional study was conducted among 360 participants from the tertiary care hospital. The simple random technique was used to select the participants. Only Saudi nationals were included in the study. Sociodemographic information, nutritional status, biochemical parameter (lipid profile, blood glucose level), and questions relating to cardiovascular disease were collected from the hospital record through data collection sheet. Serum Vit D level was determined by serum 25 (OH) blood test. Statistical package for social science (SPSS) software version 24 was used for data analysis. Binary logistic regression model was fitted to indentify the associated factors of vitamin D deficiency among cardiovascular disease patients.

Results:

Approximately 40.6% and 27.8% of study participants had vitamin D deficiency and insufficiency, respectively. After adjustment of covariates, among cardiac patients, vitamin D deficiency was associated with ischemic heart disease (OR 2.24, 95% CI 1.11–4.52), and blood triglyceride level (OR 2.27, 95% CI 1.22–4.22).

Conclusions:

Vitamin D deficiency and insufficiency are associated with ischemic heart disease, hyperglycemia, and hypertriglyceridemia. There is a need for the screening of cardiovascular disease patients for vitamin D levels.

Glutamic Acid Decarboxylase Injection Into Lymph Nodes: Beta Cell Function and Immune Responses in Recent Onset Type 1 Diabetes Patients

In spite of intensive treatment Type 1 diabetes leads to serious complications. Preservation of residual beta cell function makes the disease milder, facilitates treatment, prevents complications and increase survival. So far immune interventions have had limited effect, and some serious adverse events and risks. In an open pilot trial we aimed to improve efficacy of GAD-alum treatment using lymph-node administration in combination with oral vitamin D. Here we report the clinical effect and focus on biomarkers for response to treatment. Patients (n = 12) aged 12 to 24 years with recent onset of Type 1 diabetes received 4 μg GAD-alum into lymph-node at day 30, 60, and 90, and oral Vitamin D 2000 U/d, days 1 to 120. Beta cell function was estimated by Mixed Meal Tolerance Tests. GADA, GADA subclasses, GAD₆₅-induced cytokines and proliferation, and T cells markers were analyzed. The treatment was tolerable with no adverse events. Fasting C-peptide and insulin requirement remained stable at 15 months, while HbA1c was lower than baseline. Stimulated C-peptide showed no change at 6 months but declined after 15 months (81% of baseline). Eleven patients remained in partial remission (IDAAC < 9). Patients (n = 9) with better clinical outcome had reduced proportion of IgG1 and increased IgG2, IgG3, and IgG4, increased IL-10 secretion, and reduction of proliferation and CD8⁺ T cells activation. Patients with poorer clinical response had higher baseline levels of GAD_65-induced cytokines and T-cell activation, and an increased ratio of effector/central memory T cells. Intra-lymphatic GAD treatment combined with Vitamin D might preserve beta cell function and improve clinical course in T1D. Patients with less benefit have a different quality of immune response both before and after treatment.