Vitamin D and diabetes

Effects of vitamin D supplementation on advanced glycation end products signaling pathway in T2DM patients: a randomized, placebo-controlled, double blind clinical trial

BACKGROUND

Several researches have recommended vitamin D possible health benefits on diabetic complications development, but a few number of studies have been accomplished on the molecular and cellular mechanisms. Certain cellular pathways modification and also some transcription factors activation may protect cells from hyperglycemia condition induced damages. This study purpose was to determine the vitamin D supplementation effect on some key factors [advanced glycation end products (AGEs) signaling pathway] that were involved in the diabetic complications occurrence and progression for type-2 diabetes participants.

METHODOLOGY

48 type-2 diabetic patients (T2DM) randomly divided into two groups (n = 24 per group), receiving: 100-µg vitamin D or placebo for 3 months. At this study beginning and the end, the receptor expression for advanced glycation end products (RAGE) and glyoxalase I (GLO1) enzyme from peripheral blood mononuclear cells (PBMCs) and AGEs and tumor necrosis factor-α (TNF-α) serum levels were measured by the use of real-time PCR and ELISA methods, respectively.

RESULTS

This study results demonstrated that vitamin D supplementation could down-regulate RAGE mRNA [fold change = 0.72 in vitamin D vs. 0.95 in placebo) P = 0.001)]. In addition, no significant changes were observed for GLO1 enzyme expression (P = 0.06). This study results also indicated that vitamin D serum level significantly increased in vitamin D group (P < 0.001). Moreover, AGES and TNF-α serum levels significantly reduced in vitamin D group, but they were remained unchanged in the placebo group.

CONCLUSION

In conclusion, vascular complications are more frequent in diabetic patients, and vitamin D treatment may prevent or delay the complications onset in these patients by AGEs serum level and RAGE gene expression reducing.Trial registration NCT03008057. Registered December 2016.

Vitamin D insufficiency: Definition, diagnosis and management

Severe vitamin D deficiency can be defined as the dose of vitamin D or serum 25OHD concentrations needed to prevent nutritional rickets or osteomalacia. There is large international consensus that these diseases can be prevented by 400 IU of vitamin D/d and 25OHD above 30 nmol/l (12 ng/ml). Vitamin D deficiency can also accelerate the risk of fractures and probably also of falls in elderly subjects but there is no consensus on the required daily doses or minimal 25OHD threshold for these endpoints. The majority of experts consider 800 IU/d and serum 25OHD above 50 nmol/l (20 ng/ml) as sufficient, with a minority opinion aiming for 75 nmol/l or even higher. For other extra-skeletal endpoints, no hard evidence is available to define whether or not this is causally related to vitamin D status. Therefore, for these endpoints no minimal dosage or 25OHD threshold can be defined.

Vitamin D levels are associated with metabolic syndrome in adolescents and young adults: The BCAMS study

BACKGROUND AND AIMS

The relationship between vitamin D deficiency and metabolic syndrome (MS) remains controversial with relatively sparse data among youth. Therefore, we attempted to explicate the association of 25-hydroxyvitamin D [25(OH)D] levels with MS in Chinese adolescents and young adults.

METHODS

A cohort of 559 subjects at elevated risk of MS were recruited at 14-28 years of age as a follow-up to the Beijing Child and Adolescent Metabolic Syndrome Study. Subjects underwent clinical assessment including a 2h-oral glucose tolerance test. The concentrations of 25(OH)D, glucose, insulin and lipids were determined. MS was defined using the 2009 harmonized definition.

RESULTS

The prevalence of vitamin D deficiency (< 20 ng/ml) was 78.3%. After adjusting for age, gender and season, 25(OH)D concentrations were negatively correlated with neck circumference, percent body fat, LDL cholesterol, fasting and 2h-glucose levels (all P < 0.05). 25(OH)D levels were significantly lower in participants with obesity, high triglycerides, type 2 diabetes, or MS, compared to their respective counterparts (all P < 0.05). After adjusting for potential confounders (e.g., body mass index), participants in the lowest 25(OH)D tertile were 2.5 times more likely to exhibit MS than were those in the highest tertile (Odds Ratio: 2.48; 95% CI: 1.13-5.45, P < 0.05).

CONCLUSIONS

Vitamin D deficiency was very common in this young Chinese population at risk for MS. Given this association between low vitamin D levels and MS, the role of vitamin D supplementation in Chinese youths needs further examination, particular in those at risk for MS.

Vitamin D Switches BAF Complexes to Protect β Cells

A primary cause of disease progression in type 2 diabetes (T2D) is β cell dysfunction due to inflammatory stress and insulin resistance. However, preventing β cell exhaustion under diabetic conditions is a major therapeutic challenge. Here, we identify the vitamin D receptor (VDR) as a key modulator of inflammation and β cell survival. Alternative recognition of an acetylated lysine in VDR by bromodomain proteins BRD7 and BRD9 directs association to PBAF and BAF chromatin remodeling complexes, respectively. Mechanistically, ligand promotes VDR association with PBAF to effect genome-wide changes in chromatin accessibility and enhancer landscape, resulting in an anti-inflammatory response. Importantly, pharmacological inhibition of BRD9 promotes PBAF-VDR association to restore β cell function and ameliorate hyperglycemia in murine T2D models. These studies reveal an unrecognized VDR-dependent transcriptional program underpinning β cell survival and identifies the VDR:PBAF/BAF association as a potential therapeutic target for T2D.

Calcium homeostasis in diabetes mellitus

Diabetes mellitus (DM) is becoming a lifestyle-related pandemic disease. Diabetic patients frequently develop electrolyte disorders, especially diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. Such patients show characteristic potassium, magnesium, phosphate, and calcium depletion. In this review, we discuss a homeostatic mechanism that links calcium and DM. We also provide a synthesis of the evidence in favor or against this linking mechanism by presenting recent clinical indications, mainly from veterinary research. There are consistent results supporting the use of calcium and vitamin D supplementation to reduce the risk of DM. Clinical trials support a marginal reduction in circulating lipids, and some meta-analyses support an increase in insulin sensitivity, following vitamin D supplementation. This review provides an overview of the calcium and vitamin D disturbances occurring in DM and describes the underlying mechanisms. Such elucidation will help indicate potential pathophysiology-based precautionary and therapeutic approaches and contribute to lowering the incidence of DM.

Vitamin D Deficiency and Supplementation in Cardiovascular Disorders

Cardiovascular disease (CVD) is the leading cause of death in developed countries. Similarly, the frequency of vitamin D deficiency is increasing, and a number of epidemiologic and clinical studies have suggested that there is an increased risk of CVD among people with depletion of this vitamin. This has raised much interest in the potential pathogenic and therapeutic role of vitamin D in CVD. However, randomized trials and meta-analyses have not shown a clear benefit of vitamin D supplementation with respect to cardiovascular events. Herein, we provide a comprehensive review of the most relevant evidence to date regarding vitamin D deficiency and supplementation, and their respective impact on CVD prevention and treatment.

Vitamin D and Incidence of Prediabetes or Type 2 Diabetes: A Four-Year Follow-Up Community-Based Study

Aim

To examine whether the baseline 25-hydroxyvitamin D [25(OH)D] level was predictive of the onset of prediabetes or type 2 diabetes (T2DM) in the Chinese population.

Methods

This was a 4-year follow-up study that was conducted in the Chengdu region of China as part of the China National Diabetes and Metabolic Disorders Study. The study included 490 participants that were free of prediabetes and type 2 diabetes mellitus (T2DM) at baseline and had complete data by follow-up examinations. Glucose, insulin, and 25(OH)D levels were measured at baseline and at 4 years later. Prediabetes and T2DM were defined by results obtained from an oral glucose tolerance test.

Results

Over a 4-year follow-up, 95 (48.5‰) developed prediabetes and 31 (15.8‰) individuals developed diabetes. Low 25(OH)D status was significantly associated with the risk of developing prediabetes [OR 3.01 (95% CI: 1.50–6.06), P = 0.002] and T2DM [OR 5.61 (95% CI: 1.73–18.27), P = 0.004] after adjustment for multiple potential confounders. In a multiple linear regression analysis, low baseline levels of 25(OH)D were an independent predictor of increased insulin resistance over a 4-year period (P < 0.05).

Conclusions

The current prospective study suggests that low 25(OH)D levels might have contributed to the incidence of prediabetes or T2DM in Chinese individuals. This trial is registered with TR-CCH-ChiCTR-OCS-09000361.

Current therapies in alleviating liver disorders and cancers with a special focus on the potential of vitamin D

Background

Liver dysfunction is a topic of global concern with many advancing therapies being researched. Though vitamin D takes a center place, other therapies especially nutritional are also gaining ground. Vitamin D has gone beyond its role in skeletal disorders by showcasing its associations in other metabolic dysfunctions too.

Result

Epidemiological evidences show a correlation between the status of vitamin D and different forms of cancer. Vitamin D receptors and alterations in gene expression appear decisive in the development of chronic liver disorders. Nutritional status therefore plays a significant role in avoiding the complications related to liver dysfunctions, making it mandatory in maintaining vitamin D sufficiency in the body. Therapies with omega-3 fatty acids, antioxidants, amino acids, steroids also render benefits which could be further explored. Recent research on the progression of certain forms of liver cancer using vitamin D analogs like Seocalcitol EB 1089 has shown good promise.

Conclusion

The anti-inflammatory and immuno- regulatory properties of vitamin D makes its analogs, suitable candidates of better choice for the prevention and treatment of liver disorders and cancer.

Associations of vitamin D with insulin resistance, obesity, type 2 diabetes, and metabolic syndrome

The aim of this study is to determine the relationships of vitamin D with diabetes, insulin resistance obesity, and metabolic syndrome. Intra cellular vitamin D receptors and the 1-α hydroxylase enzyme are distributed ubiquitously in all tissues suggesting a multitude of functions of vitamin D. It plays an indirect but an important role in carbohydrate and lipid metabolism as reflected by its association with type 2 diabetes (T2D), metabolic syndrome, insulin secretion, insulin resistance, polycystic ovarian syndrome, and obesity. Peer-reviewed papers, related to the topic were extracted using key words, from PubMed, Medline, and other research databases. Correlations of vitamin D with diabetes, insulin resistance and metabolic syndrome were examined for this evidence-based review. In addition to the well-studied musculoskeletal effects, vitamin D decreases the insulin resistance, severity of T2D, prediabetes, metabolic syndrome, inflammation, and autoimmunity. Vitamin D exerts autocrine and paracrine effects such as direct intra-cellular effects via its receptors and the local production of 1,25(OH)₂D₃, especially in muscle and pancreatic β-cells. It also regulates calcium homeostasis and calcium flux through cell membranes, and activation of a cascade of key enzymes and cofactors associated with metabolic pathways. Cross-sectional, observational, and ecological studies reported inverse correlations between vitamin D status with hyperglycemia and glycemic control in patients with T2D, decrease the rate of conversion of prediabetes to diabetes, and obesity. However, no firm conclusions can be drawn from current studies, because (A) studies were underpowered; (B) few were designed for glycemic outcomes, (C) the minimum (or median) serum 25(OH) D levels achieved are not measured or reported; (D) most did not report the use of diabetes medications; (E) some trials used too little (F) others used too large, unphysiological and infrequent doses of vitamin D; and (G) relative paucity of rigorous clinical data on the effects of vitamin D sufficiency on non-calcium endpoints. Although a large number of observational studies support improving T2D, insulin resistance, obesity, and metabolic syndrome with vitamin D adequacy, there is a lack of conclusive evidence from randomized control clinical trials that, these disorders are prevented following optimization of serum levels of 25(OH)D. However, none of the currently conducted clinical studies would resolve these issues. Thus, specifically designed, new clinical studies are needed to be conducted in well-defined populations, following normalizing the serum vitamin D levels in vitamin D deficient prediabetes subjects, to test the hypothesis that hypovitaminosis D worsens these disorders and correction would alleviate it.

Association of Vitamin D Deficiency and Degree of Coronary Artery Disease in Cardiac Patients with Type 2 Diabetes

Several modifiable factors may influence cardiac function in diabetic patients. The aim of the study was to evaluate the influence of vitamin D level on the stage of coronary atherosclerosis in cardiac patients diagnosed with type 2 diabetes. The study was performed in 337 consecutive patients undergoing coronarography. The stage of atherosclerosis was evaluated using Coronary Artery Surgery Study Score. The plasma 25(OH)D concentration was determined by an electrochemiluminescence method. Patients without significant lesions in coronary arteries presented the highest 25(OH)D level, significantly higher than patients with one-, two-, and three-vessel coronary artery disease (CAD) (p < 0.01). Significantly lower level of the 25(OH)D was observed in patients hospitalized due to acute coronary syndrome (ACS) in comparison to patients hospitalized due to stable CAD (p < 0.001). Lower 25(OH)D levels were observed in patients with the history of myocardial infarction (MI) in comparison to patients without previous MI (p < 0.001). In cardiac patients with diabetes, the higher number of stenotic coronary arteries is associated with lower values of the 25(OH)D. A group of male cardiac patients with diabetes with significant stenosis in three coronary arteries, hospitalized due to acute coronary syndrome, with a history of previous MI and hyperlipidemia presented the lowest vitamin D level.

The Relationship between Vitamin D and Type 2 Diabetes Is Intriguing: Glimpses from the Spect-China Study

OBJECTIVE

Vitamin D is a multifunctional vitamin for our body. Type 2 diabetes mellitus (T2DM) is a common metabolic disease. Whether T2DM affects the serum 25(OH)D level has not been reported. The objective of this study was to reveal the extent to which vitamin D is present in the population in East China and to explore the relationship between serum 25(OH)D and T2DM.

METHODS

The cohort was selected based on a large investigation named Survey on Prevalence in East China including 12,702 participants aged 21-92 years old. All the participants completed the questionnaire and went through a physical examination. Fasting blood samples were collected to test serum 25(OH)D and other metabolism-related indicators. AVONA was used to test the significance of differences among groups. Multinomial logistic regression was used to assess the association of T2DM with serum 25(OH)D level.

RESULTS

The overall percentage of vitamin D deficiency was 80.55% (male 74.1%, female 85.0%). Men with lower serum 25(OH)D level had high value in homeostasis model assessment of insulin resistance and HbA1c. The serum 25(OH)D level of those who were diagnosed with T2DM was higher than that in non-diabetics. The serum 25(OH)D level of pre-diabetes was the highest. T2DM patients trended to have higher serum 25(OH)D levels.

CONCLUSION

Vitamin D deficiency is common among the people in East-China. T2DM patients had higher levels of serum 25(OH)D. The relationship between vitamin D and T2DM is intriguing. It seemed that vitamin D was either irrelevant directly to T2DM or resisted in T2DM patients.

Vitamin D and type 2 diabetes

Vitamin D deficiency is associated with a decreased insulin release, insulin resistance and type 2 diabetes in experimental and epidemiological studies. Animal studies show that 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) stimulates the pancreatic β-cell to secrete insulin. The relationship between vitamin D deficiency and insulin resistance could develop through inflammation, as vitamin D deficiency is associated with increased inflammatory markers. In addition, genetic polymorphisms of vitamin D -related genes may predispose to impaired glycemic control and type 2 diabetes. Epidemiologic studies showed an association between low serum 25-hydroxyvitamin D₃ (25(OH)D₃) concentration and an increased risk for the metabolic syndrome and type 2 diabetes. This may be partly explained by an increased fat mass. A possible causal relationship between vitamin D deficiency and type 2 diabetes should be proven by randomized clinical trials showing that either type 2 diabetes can be prevented or insulin release and insulin sensitivity can be improved by vitamin D supplements. The results of randomized clinical trials on the effect of vitamin D versus placebo, sometimes combined with calcium, in patients with impaired glucose tolerance ("prediabetes") or type 2 diabetes are inconsistent. Some studies showed a slight decrease of fasting plasma glucose or improvement of insulin resistance, but often only in posthoc analyses. These effects are mainly visible in patients with vitamin D deficiency and impaired glucose tolerance at baseline. Meta-analyses of randomized clinical trials in general did not show significant effects of vitamin D supplementation on glycemic control. Currently, several large scale randomized clinical trials with vitamin D supplementation in doses of 1600-4000IU/d are ongoing with glycemic control or incidence of diabetes mellitus as outcome. Vitamin D deficiency needs to be prevented or cured, but until the results of these trials are published, high-dose vitamin D supplementation cannot be recommended for prevention or amelioration of type 2 diabetes.

Changes of vitamin D levels and bone turnover markers after CPAP therapy: a randomized sham-controlled trial

The aim was to investigate whether continuous positive airway pressure treatment could modulate serum vitamin D (25-hydroxyvitamin D) and bone turnover markers (collagen-type 1 cross-linked C-telopeptide, osteocalcin and N-terminal propeptide of type 1 collagen) in secondary analysis from a randomized controlled trial. Sixty-five continuous positive airway pressure-naïve male patients with obstructive sleep apnea (age = 49 ± 12 years, apnea-hypopnea index = 39.9 ± 17.7 events h^-1 , body mass index = 31.3 ± 5.2 kg m^-2 ) were randomized to receive either real (n = 34) or sham (n = 31) continuous positive airway pressure for 12 weeks. At 12 weeks, all participants received real continuous positive airway pressure for an additional 12 weeks. After 12 weeks of continuous positive airway pressure (real versus sham), there were no between-group differences for any of the main outcomes [Δ25-hydroxyvitamin D: -0.80 ± 5.28 ng mL^-1 (mean ± SE) versus 3.08 ± 3.66 ng mL^-1 , P = 0.42; Δcollagen-type 1 cross-linked C-telopeptide: 0.011 ± 0.014 ng mL^-1 versus -0.004 ± 0.009 ng mL^-1 , P = 0.48; Δosteocalcin: 1.13 ± 1.12 ng mL^-1 versus 0.46 ± 0.75 ng mL^-1 , P = 0.80; ΔN-terminal propeptide of type 1 collagen: 2.07 ± 3.05 μg L^-1 versus -1.05 ± 2.13 μg L^-1 , P = 0.48]. There were no further differences in subgroup analyses (continuous positive airway pressure-compliant patients, patients with severe obstructive sleep apnea or sleepy patients). However, after 24 weeks irrespective of initial randomization, vitamin D increased in patients with severe obstructive sleep apnea (9.56 ± 5.51 ng mL^-1 , P = 0.045) and in sleepy patients (14.0 ± 4.69 ng mL^-1 , P = 0.007). Also, there was a significant increase in osteocalcin at 24 weeks (3.27 ± 1.06 ng mL^-1 , P = 0.01) in compliant patients. We conclude that 12 weeks of continuous positive airway pressure did not modulate vitamin D or modulate any of the bone turnover markers compared with sham. However, it is plausible that continuous positive airway pressure may have late beneficial effects on vitamin D levels and bone turnover markers in selected groups of patients with obstructive sleep apnea.

Effect of Vitamin D deficiency treatment on thyroid function and autoimmunity markers in Hashimoto's thyroiditis: A double-blind randomized placebo-controlled clinical trial

Background:

The link between autoimmune thyroid diseases and Vitamin D deficiency has been reported. However, there are controversies in this regard. We conducted a double-blind randomized placebo-controlled clinical trial to investigate the effect of Vitamin D deficiency treatment on thyroid function and autoimmunity marker (thyroid peroxidase antibody [TPO-Ab]) in patients with Hashimoto's thyroiditis.

Materials and Methods:

Fifty-six patients with Hashimoto's thyroiditis and Vitamin D deficiency (25-hydroxyvitamin D level ≤20 ng/mL) were randomly allocated into two groups to receive Vitamin D (50000 IU/week, orally) or placebo for 12 weeks, as Vitamin D-treated (n = 30) and control (n = 26) groups, respectively. TPO-Ab, thyroid-stimulating hormone (TSH), parathormone, calcium, albumin, and creatinine concentrations were compared before and after trial between and within groups. The data were presented as mean (standard error [SE]) and analyzed by appropriate tests.

Results:

Mean (SE) of Vitamin D was increased in Vitamin D-treated group (45.5 [1.8] ng/mL vs. 12.7 [0.7] ng/mL, P = 0.01). Mean (SE) of TPO-Ab did not significantly change in both groups (734 [102.93] IU/mL vs. 820.25 [98.92] IU/mL, P = 0.14 in Vitamin D-treated and 750.03 [108.7] [IU/mL] vs. 838.07 [99.4] [IU/mL] in placebo-treated group, P = 0.15). Mean (SE) of TSH was not changed in both groups after trial, P = 0.4 and P = 0.15 for Vitamin D-treated and control groups, respectively. No significant difference was observed between two study groups in none studied variables (P > 0.05).

Conclusion:

Vitamin D treatment in Vitamin D deficient patients with Hashimoto's thyroiditis could not have significant effect on thyroid function and autoimmunity.

Vitamin D signaling in intestinal innate immunity and homeostasis

The lumen of the gut hosts a plethora of microorganisms that participate in food assimilation, inactivation of harmful particles and in vitamin synthesis. On the other hand, enteric flora, a number of food antigens, and toxins are capable of triggering immune responses causing inflammation, which, when unresolved, may lead to chronic conditions such as inflammatory bowel disease (IBD). It is important, therefore, to contain the gut bacteria within the lumen, control microbial load and composition, as well as ensure adequate innate and adaptive immune responses to pathogenic threats. There is growing evidence that vitamin D signaling has impacts on all these aspects of intestinal physiology, contributing to healthy enteric homeostasis. VD was first discovered as the curative agent for nutritional rickets, and its classical actions are associated with calcium absorption and bone health. However, vitamin D exhibits a number of extra-skeletal effects, particularly in innate immunity. Notably, it stimulates production of pattern recognition receptors, anti-microbial peptides, and cytokines, which are at the forefront of innate immune responses. They play a role in sensing the microbiota, in preventing excessive bacterial overgrowth, and complement the actions of vitamin D signaling in enhancing intestinal barrier function. Vitamin D also favours tolerogenic rather than inflammogenic T cell differentiation and function. Compromised innate immune function and overactive adaptive immunity, as well as defective intestinal barrier function, have been associated with IBD. Importantly, observational and intervention studies support a beneficial role of vitamin D supplementation in patients with Crohn's disease, a form of IBD. This review summarizes the effects of vitamin D signaling on barrier integrity and innate and adaptive immunity in the gut, as well as on microbial load and composition. Collectively, studies to date reveal that vitamin D signaling has widespread effects on gut homeostasis, and provide a mechanistic basis for potential therapeutic benefit of vitamin D supplementation in IBD.

Low serum vitamin D levels in type 2 diabetes patients are associated with decreased mycobacterial activity

Background

Concurrent diabetes mellitus and tuberculosis represent a significant health problem worldwide. Patients with diabetes mellitus have a high risk of tuberculosis, which may be mediated by an abnormal innate immune response due to hyperglycaemia or low vitamin D levels.

Methods

In the present study, we evaluated inactive vitamin D serum levels and the monocyte response to infection with M. tuberculosis, including phagocytosis of M. tuberculosis, antimycobacterial activity, LL-37, human β defensin-2 and IL-10 gene expression and nitric oxide production, between type 2 diabetes mellitus patients (n = 51) and healthy volunteers (n = 38).

Results

Twenty-seven type 2 diabetes mellitus patients had inadequate inactive vitamin D levels (<50 nM). The percentages of M. tuberculosis phagocytosis between monocytes were similar across groups according to microscopy. Intracellular mycobacterial growth was similar in infected monocytes from both groups. However, M. tuberculosis growth was significantly higher in monocytes obtained from type 2 diabetes mellitus patients and lower vitamin D levels after 1-h (D0) and 72-h (D3) post-infection (p ≤ 0.05). LL-37, human β defensin-2 and IL-10 mRNA expression were similar between monocytes across groups; vitamin D serum levels and LL-37, human β defensin-2 and IL-10 expression were not correlated. Nitric oxide production was significantly higher in healthy volunteers than in type 2 diabetes mellitus patients with low vitamin D serum levels at D3 post-infection (p ≤ 0.05).

Conclusions

Our results show that monocytes from type 2 diabetes mellitus patients and low vitamin D serum levels show an impaired ability to control the intracellular growth of M. tuberculosis, which is not associated with significant decrease of LL-37 or human β defensin-2 expression. Vitamin D could be the link between diabetes and tuberculosis susceptibility.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2705-1) contains supplementary material, which is available to authorized users.

The effect of Vitamin D supplementation on hormonal and glycaemic profile of patients with PCOS: A meta-analysis of randomised trials

BACKGROUND

Vitamin D deficiency is frequently manifested in women with polycystic ovarian syndrome (PCOS). To date, supplementation of deficient patients has not been correlated with the hormonal and metabolic status of these patients.

PURPOSE

We aimed to investigate the impact of vitamin D supplementation on the hormonal and metabolic profile of PCOS women.

MATERIALS AND METHODS

We searched Medline, Scopus, ClinicalTrials.gov and Cochrane Central Register databases for published randomised controlled trials. The meta-analysis was performed with the RevMan 5.3.5 software.

RESULTS

Nine studies were included in the present meta-analysis which investigated the impact of vitamin D supplementation in 647 patients. According to our meta-analysis neither serum testosterone (MD 0.04 ng/mL, 95% CI -0.09 to 0.17) nor serum LH (MD -0.48 IU/mL, 95% CI -1.97 to 1.00) were significantly affected by vitamin D supplementation in any of the subgroup comparisons. On the contrary, serum DHEAS was significantly affected by vitamin D (MD -32.24 μg/dL, 95% CI -32.24 to -14.01) an effect which was mainly affected by the vitamin D vs placebo comparison. Vitamin D supplementation did not have an impact on fasting glucose (MD 0.42 mg/dL, 95% CI -2.75 to 3.60) or fasting insulin (MD 1.27 μU/mL, 95% CI -1.42 to 3.97) levels. HOMA-IR was, however, increased among patients that received placebo compared to vitamin D (MD 0.52, 95% CI 0.39-0.65).

CONCLUSION

There is no evidence to support that vitamin D supplementation significantly benefits PCOS patients. However, given the relatively small number of enrolled patients further studies are needed to elucidate this field.

Role of Vitamin D in urogenital health of geriatric participants

INTRODUCTION

Role of Vitamin D is very well known for the functioning of many body organs. However, its role in the postmenopausal women in relation to various genitourinary disorders has been recognized recently. The main objective of this study was to evaluate role of Vitamin D in vaginal health, prolapse, bladder and bowel function, and bacterial vaginosis (BV).

MATERIALS AND METHODS

This was a randomized controlled study in which 200 geriatric female patients of 65-78 years of age divided into two groups comprising study and control group with 100 participants in each. Detailed obstetrical, gynecological, and clinical history was elicited. Detailed examination regarding the prolapse, urinary and bowel functions, and bacterial infections was done followed by follow-up of 3 and 6 months each. Chi-square and independent t-test used for data analysis.

RESULTS

Mean modified vaginal health index (MVHI) among patients with pelvic floor diseases was statistically significant with P = 0.0472. There was a visible increasing trend in Vitamin D deficiency with increase in time since menopause (P = 0.1193). Patients with pelvic floor disease had mean Vitamin D statistically significant with P = 0.0462. With increase in Vitamin D levels, MVHI was found to be better. The association of mean Vitamin D levels among patients with urinary incontinence as compared to controls was significant with P = 0.0460. Association of mean Vitamin D levels in patients with fecal incontinence and BV as compared to controls was not statistically significant with P = 0.6304 and 0.79, respectively. Low Vitamin D levels were associated with high mean parathyroid hormone (PTH) levels statistically significant with P = 0.034. MVHI was found to increase significantly with Vitamin D supplementation at 3 and 6 months' follow-up. There was increase in Vitamin D and calcium levels and fall in serum PTH levels at 3 and 6 months.

CONCLUSIONS

Vitamin D levels were associated with a decreased risk of pelvic floor disorders, improved MVHI in women in geriatric age group.

CYP3A4 is a crosslink between vitamin D and calcineurin inhibitors in solid organ transplant recipients: implications for bone health

The use of calcineurin inhibitors (CNIs) and vitamin D deficiency may contribute to the pathogenesis of post-transplant bone disease. CNIs and 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) are substrates of the drug-metabolizing enzyme CYP3A4. This review summarizes the indications for the use of activated vitamin D analogs in post-transplant care and the current knowledge on the impact of CNIs on bone. We searched for clinical evidence of the interaction between CNIs and 1,25(OH)₂D₃. We also provide an overview of the literature on the interplay between vitamin D metabolism and CYP3A4 in experimental and clinical settings and discuss its possible implications for solid organ transplant recipients. In conclusion, there is a body of evidence on the interplay between vitamin D and the drug-metabolizing enzyme CYP3A4, which may have therapeutic implications.

Vitamin D deficiency and diabetes

Vitamin D deficiency has been linked to the onset of diabetes. This review summarizes the role of Vitamin D in maintaining the normal release of insulin by the pancreatic beta cells (β-cells). Diabetes is initiated by the onset of insulin resistance. The β-cells can overcome this resistance by releasing more insulin, thus preventing hyperglycaemia. However, as this hyperactivity increases, the β-cells experience excessive Ca2+ and reactive oxygen species (ROS) signalling that results in cell death and the onset of diabetes. Vitamin D deficiency contributes to both the initial insulin resistance and the subsequent onset of diabetes caused by β-cell death. Vitamin D acts to reduce inflammation, which is a major process in inducing insulin resistance. Vitamin D maintains the normal resting levels of both Ca2+ and ROS that are elevated in the β-cells during diabetes. Vitamin D also has a very significant role in maintaining the epigenome. Epigenetic alterations are a feature of diabetes by which many diabetes-related genes are inactivated by hypermethylation. Vitamin D acts to prevent such hypermethylation by increasing the expression of the DNA demethylases that prevent hypermethylation of multiple gene promoter regions of many diabetes-related genes. What is remarkable is just how many cellular processes are maintained by Vitamin D. When Vitamin D is deficient, many of these processes begin to decline and this sets the stage for the onset of diseases such as diabetes.

Effect of a transcriptional inactive or absent vitamin D receptor on beta-cell function and glucose homeostasis in mice

Vitamin D deficiency is associated with beta-cell dysfunction and a higher risk of diabetes, but mice and humans with an absence of the vitamin D receptor (VDR) display normal glucose tolerance. Here, we investigated the direct effects of absence of VDR or absence of ligand activation of VDR on beta-cell function. For this purpose, we generated mice, with a mutation in the AF2 domain of Vdr (VDRΔAF2), preventing ligand-driven transcriptional activation of vitamin D responsive genes. VDRΔAF2 mice were compared to Vdr full knockout (VDR^-/-) and wild type (WT) mice. In order to avoid hypocalcemia, which has a direct effect on beta-cell function, mice were fed a high calcium, high lactose diet yielding comparable serum calcium in all mice. While VDR^-/- mice developed extensive alopecia by the age of 24 weeks, the fur of VDRΔAF2 remained normal. All VDRΔAF2 mice weighed significantly less than WT, while male but not female VDR^-/- mice had a lower body weight than WT mice. Dual-energy X-ray absorptiometry showed that both VDRΔAF2 (17.2% (females) and 16.6% (males)) and VDR^-/- (15.7% and 14.8%) mice have a lower percentage of body fat (vs 19.3% and 22.2% in WT). Serum 25(OH)D₃ concentrations were lower for both VDRΔAF2 (-4.55 fold, P<0.001) and VDR^-/- (-3.7 fold, P<0.001) as compared to 12 week old WT mice, while serum 1,25(OH)₂D₃ was increased for both strains 94.5 fold (P<0.01) and 92.8 fold (P<0.001) for VDRΔAF2 and VDR^-/- vs WT, respectively). In vivo glucose tolerance tests performed at 12 and 24 weeks of age, as well as ex vivo glucose stimulated insulin secretion on freshly isolated islets, revealed no major differences between the three strains. Microarray analysis on freshly isolated islets showed only 1 differentially expressed gene, phosphodiesterase 10a (Pde10a), which was 2.16 and 1.75 fold up-regulated in VDRΔAF2 and VDR^-/- islets as compared to WT islets, respectively (P≤0.001). We conclude that in the presence of normocalcemia, absence of VDR or its ligand-activated transcription of genes has no direct regulatory effect on murine glucose homeostasis or gene expression in islets of Langerhans.

Effects of vitamin D supplementation on glycated haemoglobin and fasting glucose levels in hypertensive patients: a randomized controlled trial

AIM

To investigate the efficacy of vitamin D supplementation on glycaemic control.

METHODS

The Styrian Vitamin D Hypertension Trial was a single-centre, double-blind, placebo-controlled study conducted between 2011 and 2014 at the Medical University of Graz, Austria. We enrolled 200 people with arterial hypertension and 25-hydroxyvitamin D [25(OH)D] concentrations <30 ng/mL. Study participants were randomized to receive either 2800 IU of vitamin D or placebo per day for 8 weeks. The present study was a post hoc analysis that incorporated an analysis of covariance (ancova) approach, while adjusting for baseline differences.

RESULTS

A total of 185 participants [mean ± standard deviation age, 60.1 ± 11.3 years; 47% women; mean 25(OH)D 21.2 ± 5.6 ng/mL, mean glycated haemoglobin (HbA1c) 44.8 ± 11.8 mmol/mol and mean body mass index 30.4 ± 5.4 kg/m(2) ] completed the trial. ancova showed a mean treatment effect [95% confidence interval (CI)] on HbA1c of -3.52 (-6.7 to -0.34) mmol/mol (p = .045). There was no difference in fasting glucose -4.7 mg/dL (95% CI -16.3 to 6.9; p = .426).

CONCLUSIONS

Vitamin D supplementation in obese hypertensive patients with low 25(OH)D reduces HbA1c levels. This finding warrants further investigation into potential vitamin D effects on glucose homeostasis.

Relationship between vitamin D receptor gene polymorphisms, cardiovascular risk factors and adiponectin in a healthy young population

AIM

To explore the association between VDR polymorphisms and several cardiovascular risk factors and adiponectin.

MATERIALS & METHODS

Three-hundred and sixty-nine healthy students were randomly selected. Five VDR polymorphisms were genotyped: BsmI rs1544410; Cdx2 rs11568820; ApaI rs7975232; TaqI rs731236 and FokI rs2228570. BMI, waist circumference (WC), blood pressure, lipid/glycemic profiles and adiponectin were assessed.

RESULTS

In men, BsmI, ApaI and TaqI were associated with BMI and WC (p < 0.05). FokI was associated with triglycerides and high-density lipoprotein levels (p = 0.0036; p = 0.005) whereas BsmI and Cdx2 were associated with adiponectin levels (p = 0.026; p = 0.048). Associations disappeared after BMI and WC adjustments. In women, ApaI was associated with systolic blood pressure (p = 0.02).

CONCLUSION

Our study demonstrated a gender-specific difference between VDR SNPs and various cardiovascular risk factors and adiponectin.

UVR protection influences fructosamine level after sun exposure of healthy adults

BACKGROUND

Seasonal variation in glycated hemoglobin levels has been observed, and sun exposure has been considered as one of the factors associated with this relationship. Fructosamine is a short-time marker of blood protein glycation.

AIM

We investigated the effect of seven days of sunbathing on blood fructosamine concentration in healthy volunteers using different ultraviolet radiation (UVR) protections.

MATERIALS AND METHODS

Participants were assigned to one of three groups: group A - used a UVA and UVB absorbing sunscreen (N = 15), group B - used a UVB absorbing sunscreen (N = 18), and group C - followed uncontrolled sun protection habits (N = 22).

RESULTS

Overall, the fructosamine concentration did not change after sun exposure (baseline 248.8 μmol/l, 25-75%: 238.5 to 258.8 μmol/l vs. after 247.3 μmol/l, 25-75%: 234.9 to 261.8 μmol/l, P = 0.6637). Median change of fructosamine differed significantly between groups (A: -1.90 μmol/l, 25-75%: -17.10 to 1.80 μmol/l vs. B: -3.80 μmol/l, 25-75%: -18.50 to 2.40 μmol/l vs. C: +4.05 μmol/l, 25-75%: -3.20 to 22.0 μmol/l; one-way ANOVAP = 0.0277). After age adjustment and combining groups A and B, the difference in change of fructosamine concentration was statistically significant between groups A + B (decrease) vs. group C (increase, P = 0.0193).

CONCLUSION

Appropriate sunscreen use during sunbathing resulted in decreased fructosamine concentrations, while inadequate UVR protection resulted in its increase.

Factors Affecting Hemoglobin A1C in the Diagnosis of Diabetes and Prediabetes in Youth

We sought to examine the correlation between variables and A1C levels to determine if prediction modeling could be used in the screening and diagnosis of diabetes and prediabetes in youth. We also sought to test relationships between A1C levels to insulin sensitivity indices and β-cell function indices.

DESIGN AND METHODS

We performed a retrospective review of 904 medical records from youth deemed at-risk for the disease. We performed Pearson correlation, multiple regression, and simple regression testing to determine the relationship between variables and A1C levels. In addition, we performed Pearson correlation testing on insulin sensitivity indices and β-cell function indices to determine the strength of correlation to A1C levels.

RESULTS

Statistical analysis did not show a strong relationship between the variables tested and the A1C. When racial and ethnic groups were tested together, the results from African American participants resulted in bias estimates, and as a result, a statistical model for the entire sample could not be performed. Results indicate that A1C is correlated with all β-cell function proxy measurements and correlated to the corrected insulin level at 30minutes, but not the fasting insulin or insulinogenic index.

DISCUSSION

The results from this study underline the multi-dimensional causes of diabetes and prediabetes and further stress the difficulties in predicting the diseases. The causes of diabetes and prediabetes are multifaceted, often individualized, and often difficult to ascertain.

PRACTICE IMPLICATIONS

Clinicians should continue to examine a variety of variables prior to determining the need for diabetes diagnostic testing.

Risk of Malnutrition, Trace Metal, and Vitamin Deficiency Post Roux-en-Y Gastric Bypass--a Prospective Study of 20 Patients with BMI < 35 kg/m²

BACKGROUND

Due to its reliable effects on type 2 diabetes mellitus (T2DM) remission, Roux-en-Y gastric bypass (RYGB) has recently been investigated as a treatment option for nonseverely obese patients with T2DM (body mass index (BMI) <35 kg/m(2)). The purpose of this study was to investigate whether RGYB induces malnutrition of macro- and micronutrients within 24 months in these patients.

METHODS

A prospective cohort of 20 patients with longstanding, insulin-dependent T2DM and a BMI of 25-35 kg/m(2) were treated with RYGB. The patients were supplemented with over-the-counter, multivitamin, and micronutrient supplements. Serum concentrations of albumin, vitamins, and trace elements, hemoglobin, and bone density were measured preoperatively and over a 24-month period (DRKS00004605).

RESULTS

RYGB did not result in underweight or protein malnutrition. No new onset of deficiencies of water- or fat-soluble vitamins developed over the study period. However, serum selenium, zinc, and ferritin decreased significantly (selenium, 1.17 ± 0.13 to 0.89 ± 0.11 μmol/l, p = 0.018; zinc, 13.9 ± 0.5 to 10.8 ± 0.5 μmol/l, p = 0.012; ferritin, 171.7 ± 26.9 to 31.8 ± 11.2 μg/l, p = 0.018). Hemoglobin remained stable. Vitamin D (13.7 ± 1.8 to 19.1 ± 1.1 ng/ml, p = 0.017) and osteocalcin (15.3 ± 1.7 to 25.4 ± 2.7 ng/ml, p = 0.025) rose significantly, whereas the parathyroid hormone remained stable. Despite increased bone formation, bone density decreased (T score hip, 0.15 ± 0.25 to -0.71 ± 0.34, p = 0.005) resulting in a significant increase in osteopenia rates (18 to 50 %, p = 0.046).

CONCLUSIONS

This is the first prospective cohort to investigate malnutrition after RYGB in nonseverely obese patients. These patients are at risk of developing iron, selenium, and zinc deficiencies within 24 months, as well as osteopenia despite an increase in bone formation.

Expression-Based Genome-Wide Association Study Links Vitamin D-Binding Protein With Autoantigenicity in Type 1 Diabetes

Type 1 diabetes (T1D) is caused by autoreactive T cells that recognize pancreatic islet antigens and destroy insulin-producing β-cells. This attack results from a breakdown in tolerance for self-antigens, which is controlled by ectopic antigen expression in the thymus and pancreatic lymph nodes (PLNs). The autoantigens known to be involved include a set of islet proteins, such as insulin, GAD65, IA-2, and ZnT8. In an attempt to identify additional antigenic proteins, we performed an expression-based genome-wide association study using microarray data from 118 arrays of the thymus and PLNs of T1D mice. We ranked all 16,089 protein-coding genes by the likelihood of finding repeated differential expression and the degree of tissue specificity for pancreatic islets. The top autoantigen candidate was vitamin D-binding protein (VDBP). T-cell proliferation assays showed stronger T-cell reactivity to VDBP compared with control stimulations. Higher levels and frequencies of serum anti-VDBP autoantibodies (VDBP-Abs) were identified in patients with T1D (n = 331) than in healthy control subjects (n = 77). Serum vitamin D levels were negatively correlated with VDBP-Ab levels in patients in whom T1D developed during the winter. Immunohistochemical localization revealed that VDBP was specifically expressed in α-cells of pancreatic islets. We propose that VDBP could be an autoantigen in T1D.

1,25-Dihydroxyvitamin D increases the gene expression of enzymes protecting from glucolipotoxicity in peripheral blood mononuclear cells and human primary endothelial cells

Besides its classical function as an orchestrator of calcium and phosphorus homeostasis, vitamin D also affects insulin secretion and tissue efficiency. A number of studies have consistently reported the inverse relationship between vitamin D deficiency and type 2 diabetes. Activation of certain metabolic pathways and down-stream transcription factors may protect from glucolipotoxicity and their targeted activation -e.g. by vitamin D - might explain the detrimental role of vitamin D deficiency in diabetes. The aim of the study was to quantify gene and protein expression of selected enzymes involved in the protection from glucolipotoxicity, specifically glyoxalase 1 (GLO1), and other enzymes with antioxidant activity - hemoxygenase (HMOX), thiamin pyrophosphokinase (TPK1) and transketolase (TKT), under normo- and hyperglycemic conditions and upon addition of vitamin D in peripheral blood mononuclear cells (PBMCs) and human umbilical vein endothelial cells (HUVEC). The results of our study indicate that the active form of vitamin D regulates gene expression of enzymes opposing the harmful effect of glucolipotoxicity whose activities appear to be suppressed by hyperglycemia. However, we were unable to confirm this effect on protein expression. While we cannot speculate on the effect of vitamin D on diabetes itself our results support its role in the protection against existing glucolipotoxicity therefore possibly translating into the prevention of development of diabetic complications.

Vitamin D deficiency in pregnancy is not associated with diabetes mellitus development in pregnant women at low risk for gestational diabetes

OBJECTIVE

We aimed to investigate the effect of vitamin D deficiency as a risk factor for the development of gestational diabetes mellitus (GDM) among pregnant women without known risk factors.

MATERIALS AND METHODS

The study was conducted on pregnant women who had been under regular follow-up and had low risk for GDM development. The patients were divided into two groups according to the presence of GDM; GDM and no GDM (control) group. Body mass index (BMI), sociodemographic data including level of education and nutritional habits were recorded. Serum 25 (OH) vitamin D3 levels, hemoglobin, hematocrit, and mean corpuscular volume (MCV) values were measured. An oral glucose tolerance test was performed, between 24 and 28 weeks of pregnancy.

RESULTS

GDM ratio was calculated as 4.6%. The false positive rate of 50 g oral glucose load screening test was found to be 16.5%. The BMI levels of women diagnosed as having GDM and those with no GDM group at the beginningof the pregnancy period were calculated as 24.3±2.6 and 22.8±1.6 kg/m2 respectively, exhibiting a statistically significant difference between the two groups (p=0.001). Hemoglobin, hematocrit, and MCV values did not show a statistically significant difference between the two groups (p>0.05). The levels of 25 (OH) vitamin D3 of the study groups were found comparable in both groups (p=0.13).

CONCLUSION

Plasma levels of vitamin D may not be a contributing factor for the development of GDM in women with a low risk for GDM.

Calcium and Vitamin D in Obesity and Related Chronic Disease

There is a pandemic of lifestyle-related diseases. In both developed and lesser developed countries of the world, an inadequacy of calcium intake and low vitamin D status is common. In this chapter, we explore a mechanistic framework that links calcium and vitamin D status to chronic conditions including obesity, systemic inflammation, endothelial dysfunction, dyslipidemia and cardiovascular disease, and type 2 diabetes mellitus. We also update the available clinical evidence, mainly from randomized controlled trials, to provide a synthesis of evidence in favor or against these hypotheses. There is consistent data to support calcium increasing whole body fat oxidation and increasing fecal fat excretion, while there is good cellular evidence for vitamin D reducing inflammation. Clinical trials support a marginal reduction in circulating lipids and some meta-analysis support an increase in insulin sensitivity following vitamin D. However, these mechanistic pathways and intermediate biomarkers of disease do not consistently transcribe into measurable health outcomes. Cementing the benefits of calcium and vitamin D for extraskeletal health needs a reexamination of the target 25(OH)D level to be achieved and the minimum duration of future trials.

Effects of vitamin D repletion on glycemic control and inflammatory cytokines in adolescents with type 1 diabetes

OBJECTIVE

Little is known about the relationship between vitamin D deficiency and adolescents with type 1 diabetes. On the basis of adult studies showing that vitamin D improves insulin sensitivity and decreases inflammatory cytokines linked to microvascular complications, we hypothesized that treating vitamin D deficiency in adolescents with type 1 diabetes would improve glycemia and reduce inflammatory markers.

RESEARCH DESIGN AND METHODS

This was a randomized, prospective, crossover study of 25 adolescents with type 1 diabetes for at least a year (aged: 13-21 yr; 62% female; 62% Hispanic) and vitamin D deficiency (25-OH vitamin D ≤30 ng/mL). Subjects received vitamin D3 (20 000 IU/week) for 6 months, either immediately or after 6 months of observation.

RESULTS

At baseline, 63% of subjects screened were vitamin D deficient and randomized. Interleukin-6 (IL-6) was significantly higher in the vitamin D deficient group compared with the sufficient group (medians: 0.36 vs. 0.18) (p = 0.026), whereas neither C-reactive protein (CRP) nor tumor necrosis factor-α (TNF-α) differed. Vitamin D treatment increased serum levels of 25-OH vitamin D from 22 ± 5.3 to 34.3 ± 12.1 ng/mL (p < 0.01). However, treatment did not affect glycated hemoglobin (HbA1c), insulin dosage, CRP, interleukin-6 (IL-6), or TNF-α.

CONCLUSIONS

Vitamin D deficiency is prevalent in the adolescent type 1 diabetes population, and could be associated with changes in inflammatory markers. However, vitamin D repletion over 6 months did not affect glycemia or markers of inflammation in our study, highlighting the need for additional research to validate these findings.

Relationship between vitamin D status, glycemic control and cardiovascular risk factors in Brazilians with type 2 diabetes mellitus

OBJECTIVES

Determine the prevalence and identify predictors of hypovitaminosis D in patients with type 2 diabetes mellitus (T2DM); 2) correlate vitamin D levels with variables indicative of glycemic control and cardiovascular risk.

RESEARCH DESIGN AND METHODS

We conducted a cross-sectional study with consecutive patients treated at a University Hospital's Endocrinology outpatient clinic located at 12°58'S latitude, between October 2012 and November 2013. Hypovitaminosis D was defined as 25-hydroxyvitamin D < 30 ng/mL (chemiluminescence).

RESULTS

We evaluated 108 patients with mean duration of T2DM of 14.34 ± 8.05 years and HbA1c of 9.2 ± 2.1%. Mean age was 58.29 ± 10.34 years. Most were women (72.2%), non-white (89.8%) and had hypertension (75.9%) and dyslipidemia (76.8%). Mean BMI was 28.01 ± 4.64 kg/m²; 75.9% were overweight. The prevalence of hypovitaminosis D was 62%. In multiple logistic regression, independent predictors of hypovitaminosis D were female gender (OR 3.10, p = 0.02), dyslipidemia (OR 6.50, p < 0.01) and obesity (OR 2.55, p = 0.07). In multiple linear regression, only total cholesterol (β = -0.36, p < 0.01) and BMI (β = -0.21, p = 0.04) remained associated with levels of 25-hydroxyvitamin D.

CONCLUSIONS

Using currently recommended cutoffs, the prevalence of hypovitaminosis D in Brazilians with T2DM was as high as that of non-tropical regions. Female gender, dyslipidemia and obesity were predictors of hypovitaminosis D. Low levels of 25-hydroxyvitamin D were correlated with high cholesterol and BMI values. Future studies are needed to evaluate whether vitamin D replacement would improve these parameters and reduce hard cardiovascular outcomes.

Factors associated with vitamin D status of low-income, hospitalized psychiatric patients: results of a retrospective study

BACKGROUND

Recent evidence has indicated a potential role of vitamin D3 in a range of neuropsychiatric outcomes, as well as on cognitive function, but conflicting data have left that role uncertain. Understanding potential associations of vitamin D status with psychiatric illness will allow clinicians to better assess therapeutic options. Few studies have examined vitamin D status among a racially diverse group of psychiatric patients who have been hospitalized, and none has done so in the southern US where socioeconomic inequality is high.

METHODS

In this retrospective study, medical records from 113 patients hospitalized for psychiatric illness were retrieved and analyzed. Vitamin D status in this population was estimated, along with any patterns of association between deficiency and risk factors.

RESULTS

The vast majority of patients hospitalized for psychiatric illness in this biracial, low-income sample had either insufficient or deficient vitamin D levels. African-American patients had lower levels of vitamin D than Caucasian patients.

DISCUSSION

Our findings demonstrate that hospitalized psychiatric patients are at increased risk for vitamin D deficiency and in particular low-income, African-American populations. These results suggest that vitamin D should be assessed and therapy considered at the initiation of psychiatric hospitalizations.

The vitamin D status and its effects on life quality among the elderly in Jinan, China

A challenge for researchers is that vitamin D has many functions in the body, and vitamin D status across the world is not optimistic. There was little data regarding insufficient vitamin D status and its adverse effect on health of elderly Chinese people. So we selected 686 subjects (310 men and 376 women) aged 60-89 years to explore the correlation between vitamin D status and their life quality in a community-based osteoporosis prevention study at Qianfoshan Hospital of Shandong University from 2009 to 2010. All subjects were divided into three groups: vitamin D adequacy [serum 25(OH)D ≧ 75 nmol/L], hypovitaminosis D (50-74.9 nmol/L), and vitamin D insufficiency (<50 nmol/L). Participants were requested to complete SF-36 health survey. The regression models were used to evaluate respectively the association between 25(OH)D levels and parameters of SF-36. As a result, serum 25(OH)D levels were 58.60 nmol/L in male [95% confidence interval (95% CI): 56.7-60.5 nmol/L] and 54.17 nmol/L in female (95% CI: 52.8-55.8 nmol/L). Vitamin D adequacy was in 19.4% of male and 14.4% of female. With aging, proportions of insufficient vitamin D increased significantly in male (P=0.004), and in female (P<0.001). The elderly with hypovitaminosis D got lower scores than that with vitamin D adequacy (almost P<0.01). Regression analysis showed that vitamin D appeared a positive association with parameters of SF-36 (almost P<0.001). In conclusion, vitamin D status in the elderly was severely inadequate, which decreased their life quality and cause adverse effect on their health.

Serum vitamin D levels are inversely related with non-alcoholic fatty liver disease independent of visceral obesity in Chinese postmenopausal women

The aim of the present study was to investigate the association between serum vitamin D levels and both visceral adipose and with non-alcoholic fatty liver disease (NAFLD) in Chinese postmenopausal women. Four hundred and fifty-one postmenopausal women between 45 and 74 years of age (mean (± SD) age 57.3 ± 4.6 years) were enrolled in the study. All subjects participated in the Shanghai Obesity Study between June and August 2011 and underwent abdominal magnetic resonance imaging and an abdominal ultrasonography. Patients with a visceral fat area (VFA) ≥ 80 cm(2) were classified as abdominally obese. Serum 25-hydroxyvitamin D3 (25(OH)D3 ) levels were measured with an electrochemiluminescence immunoassay. The prevalence of NAFLD in the study population was 34.8% (n = 157). Women with abdominal obesity had significantly lower serum 25(OH)D3 levels than those without abdominal obesity (median (interquartile range) 11.23 (8.64-14.12) vs 12.56 (9.41-15.98) ng/mL, respectively; P < 0.01). Regardless of abdominal obesity status, serum 25(OH)D3 levels in patients with NAFLD were lower than those without non-NAFLD (11.14 (8.63-13.81) vs 12.92 (9.48-16.37) ng/mL (P < 0.05) for those without abdominal obesity; 10.86 (8.61-13.56) vs 11.55 (8.82-16.38) ng/mL (P < 0.05) for those with abdominal obesity). Partial correlation analyses demonstrated a negative correlation between serum 25(OH)D3 levels and VFA (P < 0.05). Logistic regression analysis revealed that high serum 25(OH)D3 levels were a protective factor against NAFLD after adjusting for risk factors such as VFA. In conclusion, independent of visceral obesity, vitamin D is inversely correlated with NAFLD in Chinese postmenopausal women.

Knowledge, attitude, and practice of general practitioners in Dammam, Saudi Arabia towards Vitamin D supplementation to infants

Background:

With the report of high prevalence rate of Vitamin D deficiency in the literature since the 1980s, the condition can be considered an epidemic in Saudi Arabia. However, no specific steps have been taken by the Ministry of Health to tackle the problem. Moreover, little is known about general practitioners’ (GPs) knowledge, attitude, and practice (KAP) of Vitamin D supplementation for infants.

Objectives:

To measure the KAP of GPs, of Vitamin D supplementation for infants in Dammam, Saudi Arabia.

Materials and Methods:

This was a cross-sectional study of GPs practicing in primary healthcare centers in the Dammam area of Saudi Arabia. All the 110 GPs working in primary health centers (PHCs) in Dammam were invited to participate in the study. Data was collected with the help of a self-administered questionnaire. Data was analyzed using SPSS 20.0. Statistical analysis included descriptive analysis of all the variables, expressed as the mean (standard deviation [SD]) or the median if not normally distributed.

Results:

Ninety-three GPs working in the Dammam area participated in the study. Thirty percent had excellent knowledge of Vitamin D. Ninety two percent had a positive attitude toward Vitamin D supplementation and sixty percent regularly prescribed Vitamin D supplementation for infants.

Conclusion:

The majority of GPs had a positive attitude toward Vitamin D supplementation for infants. However, their knowledge and practice need improvement.

Vitamin D and atherosclerosis

PURPOSE OF REVIEW

To provide an overview of the association between vitamin D deficiency and atherosclerosis.

RECENT FINDINGS

Vitamin D exerts protective effects on atherosclerosis through multiple mechanisms. It has been shown to protect against endothelial dysfunction, vascular smooth muscle cell proliferation and migration, and modulation of the immune system, as well as the inflammatory response. In addition, vitamin D has been shown to have systemic effects on insulin resistance, dyslipidemia, and hypertension.

SUMMARY

Vitamin D deficiency is widely prevalent in the United States and worldwide. Although deficiency of this fat-soluble vitamin is usually associated with musculoskeletal disorder, it is associated with a wide range of disease processes that include multiple organ systems. Recently, there has been mounting evidence linking vitamin D deficiency to cardiovascular disease and atherosclerosis.

Clinical implications of vitamin D deficiency

Vitamin D deficiency is a common medical problem worldwide and its prevalence rises along with latitude, obesity, sedentary lifestyle, limited sunlight exposure and aging. A great body of evidence has shown that patients with vitamin D deficiency have increased cardiovascular risks and total mortality. Conversely, the presence of comorbidities progressive with age such as abdominal obesity, insulin resistance, type 2 diabetes and hypertension places the patients at an increased risk of vitamin D deficiency. The multidirectional effect of vitamin D deficiency is present in different phases of the aging process. Based on the literature review, the risk factors for vitamin D insufficiency most often found in post-menopausal women include limited sun exposure and time spent outdoors, inadequate dietary vitamin D intake, winter season and increased age. Vitamin D supplementation in this group might offer prevention of falls and fractures and may be beneficial for cardiovascular health, what may be especially important in osteoporotic and elderly populations. Prevention and treatment processes involve education regarding sunlight exposure and pharmacological cholecalciferol supplementation according to the recommendations for Central Europe. This manuscript reviews the role of vitamin D and its deficiency and considers their clinical implications, with particular regard to peri- and postmenopausal women.

Links between Vitamin D Deficiency and Cardiovascular Diseases

The aim of the present paper was to review the most important mechanisms explaining the possible association of vitamin D deficiency and cardiovascular diseases, focusing on recent experimental and clinical data. Low vitamin D levels favor atherosclerosis enabling vascular inflammation, endothelial dysfunction, formation of foam cells, and proliferation of smooth muscle cells. The antihypertensive properties of vitamin D include suppression of the renin-angiotensin-aldosterone system, renoprotective effects, direct effects on endothelial cells and calcium metabolism, inhibition of growth of vascular smooth muscle cells, prevention of secondary hyperparathyroidism, and beneficial effects on cardiovascular risk factors. Vitamin D is also involved in glycemic control, lipid metabolism, insulin secretion, and sensitivity, explaining the association between vitamin D deficiency and metabolic syndrome. Vitamin D deficit was associated in some studies with the number of affected coronary arteries, postinfarction complications, inflammatory cytokines and cardiac remodeling in patients with myocardial infarction, direct electromechanical effects and inflammation in atrial fibrillation, and neuroprotective effects in stroke. In peripheral arterial disease, vitamin D status was related to the decline of the functional performance, severity, atherosclerosis and inflammatory markers, arterial stiffness, vascular calcifications, and arterial aging. Vitamin D supplementation should further consider additional factors, such as phosphates, parathormone, renin, and fibroblast growth factor 23 levels.

Genome-based nutrition: An intervention strategy for the prevention and treatment of obesity and nonalcoholic steatohepatitis

Obesity and nonalcoholic steatohepatitis are increasing in westernized countries, regardless of their geographic location. In Latin America, most countries, including Mexico, have a heterogeneous admixture genome with Amerindian, European and African ancestries. However, certain high allelic frequencies of several nutrient-related polymorphisms may have been achieved by past gene-nutrient interactions. Such interactions may have promoted the positive selection of variants adapted to regional food sources. At present, the unbalanced diet composition of the Mexicans has led the country to a 70% prevalence rate of overweightness and obesity due to substantial changes in food habits, among other factors. International guidelines and intervention strategies may not be adequate for all populations worldwide because they do not consider disparities in genetic and environmental factors, and thus there is a need for differential prevention and management strategies. Here, we provide the rationale for an intervention strategy for the prevention and management of obesity-related diseases such as non-alcoholic steatohepatitis based on a regionalized genome-based diet. The components required to design such a diet should focus on the specific ancestry of each population around the world and the convenience of consuming traditional ethnic food.

Beneficial effects of calcitriol on hypertension, glucose intolerance, impairment of endothelium-dependent vascular relaxation, and visceral adiposity in fructose-fed hypertensive rats

Besides regulating calcium homeostasis, the effects of vitamin D on vascular tone and metabolic disturbances remain scarce in the literature despite an increase intake with high-fructose corn syrup worldwide. We investigated the effects of calcitriol, an active form of vitamin D, on vascular relaxation, glucose tolerance, and visceral fat pads in fructose-fed rats. Male Wistar-Kyoto rats were divided into 4 groups (n = 6 per group). Group Con: standard chow diet for 8 weeks; Group Fru: high-fructose diet (60% fructose) for 8 weeks; Group Fru-HVD: high-fructose diet as Group Fru, high-dose calcitriol treatment (20 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding; and Group Fru-LVD: high-fructose diet as Group Fru, low-dose calcitriol treatment (10 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding. Systolic blood pressure was measured twice a week by the tail-cuff method. Blood was examined for serum ionized calcium, phosphate, creatinine, glucose, triglycerides, and total cholesterol. Intra-peritoneal glucose intolerance test, aortic vascular reactivity, the weight of visceral fat pads, adipose size, and adipose angiotensin II levels were analyzed at the end of the study. The results showed that the fructose-fed rats significantly developed hypertension, impaired glucose tolerance, heavier weight and larger adipose size of visceral fat pads, and raised adipose angiotensin II expressions compared with the control rats. High- and low-dose calcitriol reduced modestly systolic blood pressure, increased endothelium-dependent aortic relaxation, ameliorated glucose intolerance, reduced the weight and adipose size of visceral fat pads, and lowered adipose angiotensin II expressions in the fructose-fed rats. However, high-dose calcitriol treatment mildly increased serum ionized calcium levels (1.44 ± 0.05 mmol/L). These results suggest a protective role of calcitriol treatment on endothelial function, glucose tolerance, and visceral adiposity in fructose-fed rats.