Vitamin D and diabetes

5. Lifestyle Management: Standards of Medical Care in Diabetes-2019

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

The Effects of Oral Magnesium Supplementation on Glycemic Response among Type 2 Diabetes Patients

Background: Magnesium (Mg) supplementation may help control glycemic response among type 2 diabetes (T2D) patients. Objective: This study means to determine whether Mg supplementation improves glycemic control indicators in patients with T2D. Methods: After one week of the dietary stabilization phase, 42 T2D patients were stratified according to sex, age, fasting blood sugar (FBS) and Mg levels and then randomly allocated into two groups. The intervention group was on 250 mg/day of elemental Mg for three months while the control group did not receive any type of supplements throughout the intervention period. Results: The daily administration of 250 mg of elemental Mg indicated a significant improvement in HbA1C (8.32 to 7.96%, p < 0.001), insulin levels (IL) (15.56 to 12.18 μIU/mL, p < 0.001), C-peptide (2.28 to 1.90 ng/mL, p = 0.001), HOMA.IR (6.16 to 4.44, p < 0.001) and HOMA.β% (59.99 to 52.37, p = 0.036) of the intervention group when compared with the control group after three months of intervention. Conclusion: The results of this study revealed that oral Mg supplementation reduces insulin resistance and improves the glycemic control indicators among T2D patients. Trial registration: current controlled trials PHRC/HC/32/15. Registered 5 October 2015.

The Relationship between Vitamin D Status and the Menstrual Cycle in Young Women: A Preliminary Study

Background: The aim of this study was to evaluate serum vitamin D levels and to compare these with the menstrual cycle in young women with different body weights. Methods: Eighty-four students were recruited into the study of which 77 remained at the study’s completion. Women were assigned to one of two subgroups, according to their 25-hydroxy vitamin D test level [25(OH)D] in which 60 women had low 25(OH)D levels (LD < 30 ng/mL) and 17 had normal levels (ND > 30 ng/mL ≤ 80 ng/mL). Results: In the LD group, 40% of participants reported having long cycles, 27% were classified as having oligomenorrhoea, and 13% as having amenorrhoea. In the ND group, only 12% reported menstrual cycle disorders, 6% had oligomenorrhoea, and 6% had amenorrhoea. Women who did not meet the recommended level of 30 ng/mL of 25(OH)D had almost five times the odds of having menstrual cycle disorders as women who were above the recommended vitamin D level. Conclusion: A relationship was demonstrated between the frequency of menstrual disorders and low levels of vitamin D. Supplementation is necessary in women with low levels of vitamin D in order to compensate for this deficiency and to assess its effect in regulating menstrual disorders.

Vitamin D Supplementation, Glycemic Control, and Insulin Resistance in Prediabetics: A Meta-Analysis

Diabetes prevention is a public health priority. Vitamin D supplementation may help prevent the development of diabetes in persons at increased risk. We performed a meta-analysis of controlled clinical trials that assessed glycemic outcome measures among adults at risk for type 2 diabetes, including prediabetes, overweight, or obesity. We searched PUBMED/ MEDLINE, CINAHL, and Google Scholar databases for trials published prior to April 2017. Placebo-controlled clinical trials with random allocation to vitamin D with or without calcium supplementation were selected. Data collection included country, study design, inclusion criteria, sample size, form, and dose of vitamin D, supplementation interval, control group, duration, participant characteristics, comorbidities, baseline and follow-up serum 25-hydroxyvitamin D [25(OH)D] concentration, and available outcome measures [glycosylated hemoglobin (HbA1c), fasting plasma glucose, plasma glucose after 2-hour oral glucose tolerance test, and homeostatic model assessment of insulin resistance (HOMA-IR)]. Data synthesis was conducted using random-effect models (PROSPERO registration no. CRD42017055326). Twenty-eight trials, representing 3848 participants, met the eligibility criteria. Compared with the control group, vitamin D supplementation significantly reduced HbA1c level by -0.48% (95% CI, -0.79 to -0.18), fasting plasma glucose level by -0.46 mmol/L (95% CI, -0.74 to -0.19), and HOMA-IR level by -0.39 (95% CI, -0.68 to -0.11). Subgroup analysis revealed that the effects of vitamin D supplementation on different glycemic measures were influenced by age, calcium coadministration, vitamin D deficiency, serum 25(OH)D level after supplementation, and duration of supplementation. Vitamin D supplementation and improved vitamin D status improved glycemic measures and insulin sensitivity and may be useful as part of a preventive strategy for type 2 diabetes.

Clinical diagnostic tools for vitamin D assessment

Vitamin D deficiency has been implicated in a plethora of diseases including rheumatoid arthritis, Parkinson's disease, Alzheimer's disease, and osteoporosis. Deficiency of this vitamin is a global epidemic affecting both developing and developed nations. Within a clinical context, the qualitative and quantitative analysis of vitamin D is therefore vital. The main metabolic markers for assessing vitamin D status in humans are the hydroxylated forms of vitamin D, 25OHD₃ and 25OHD₂ on account of their long half-lives within the body and excellent stability. An adequate level for healthy individuals of these hydroxylated forms is estimated to be around 20-40ng/ml of blood. There are three main analytical techniques for determining the levels of 25OHD₃ and 25OHD₂. The first technique is immunoassay-based and can be performed in a rapid, high throughput, automated manner, allowing as many as 240 tests per hour with the duration of each assay as little as 18min. Furthermore, it offers excellent sensitivity with a detection range of 3.4-156ng/ml. A major downside of immunoassays is that they are unable to distinguish between the various forms of vitamin D. While HPLC is a highthroughput low cost instrument it is not a very sensitive technique and cannot quantify the down stream metabolites of vitamin D. The third technique, namely liquid chromatography-mass spectrometry (LC-MS/), provides excellent sensitivity with a wide dynamic range from 0.068pg/ml to 100ng/ml. Additionally, it offers a high level of separation and permits identification of vitamin D-related metabolites. However, a huge limitation with LC/MS/MS is their poor throughput for sample analyses. As yet, there is no analytical technique which combines the fine detection capabilities of LC/MS/MS and the rapid, automated format of immunoassay, for vitamin D analyses. Future attention therefore needs to be given to this area if the current clinical diagnostic tools for vitamin D analysis are to be further improved.

Review on Potential Vitamin D Mechanism with Type 2 Diabetes Mellitus Pathophysiology in Malaysia

Evidences on vitamin D deficiency suggest there is increasing risk of diabetes. To date, some cohort, observation, cross-sectional studies on populations and randomized controlled trials in vitamin D supplements highlighting the potential of vitamin D are essentially in modifying Type 2 Diabetes Mellitus (T2DM) pathophysiology. Relevant literature sought in a various databases focus on the discovery of vitamin D studies in Malaysia, particularly in dietary, health status and disease study. However, recent data in Malaysia, the scope of the literature focuses on the deficient vitamin D mediated insulin impairment. The development of literary findings encompasses on the etiology of diabetes which highly correlates with decreased mechanism of action of vitamin D. It is important to understand diabetes etiology before explaining more about insulin resistance mechanisms which is strongly correlated with the involvement of c-Jun N-terminal kinase (JNK) pathways in insulin signalling. Furthermore, the vitamin D works synergistically with calcium homeostasis which is believed to have interaction with insulin. The purpose of this article is to illustrate the potential of vitamin D in modulating T2DM pathophysiology. Existing evidence showing the biochemical function of vitamin D is strongly involved in the pathogenesis of T2DM which requires considerable attention.

Vitamin D Supplementation in Patients With Type 2 Diabetes: The Vitamin D for Established Type 2 Diabetes (DDM2) Study

Context

Observational data support a role for vitamin D in type 2 diabetes, but evidence from trials is inconclusive.

Objective

To evaluate the effect of vitamin D supplementation on β-cell function and hemoglobin A1c (HbA1c) in patients with well-controlled type 2 diabetes.

Design

Double-blind, randomized, placebo-controlled clinical trial.

Setting

Tufts Medical Center, Boston, MA; VA Medical Center, Cincinnati, OH.

Participants

A total of 127 patients (mean age, 60 years) with stable (HbA1c ≤7.5%) diabetes managed with lifestyle only or lifestyle plus metformin.

Intervention

Subjects were given 4000 units of vitamin D₃ (cholecalciferol) daily or placebo for 48 weeks.

Main Outcome Measure

Insulin secretion rate (ISR) was estimated from peripheral plasma C-peptide levels after a 3-hour 75-g oral glucose tolerance test done at baseline and week 24. Changes in HbA1c were assessed at 16, 24, 36, and 48 weeks.

Results

Baseline mean plasma 25-hydroxyvitamin D [25(OH)D] concentration was 26.6 ng/mL, mean HbA1c was 6.6%, and 78% of patients were on metformin. At week 24, mean 25(OH)D changed by 20.5 and −1.6 ng/mL in the vitamin D and placebo groups, respectively (P < 0.001). The vitamin D and placebo groups did not differ in change in ISR or HbA1c. Among patients treated with lifestyle only (n = 28), vitamin D supplementation reduced HbA1c compared with placebo (−0.1% vs 0.3%, respectively; P = 0.034) at week 24. This result was not observed at the other time points and could be due to chance.

Conclusion

Vitamin D₃ at 4000 IU/d did not change ISR or HbA1c in patients with well-controlled type 2 diabetes on metformin not selected for vitamin D deficiency.

Vitamin D and pancreas: The role of sunshine vitamin in the pathogenesis of diabetes mellitus and pancreatic cancer

Increasing evidence suggests that vitamin D exerts multiple effects beyond bone and calcium metabolism. Vitamin D seems to play a role in pancreatic disease, including type 1 and type 2 diabetes mellitus as well as pancreatic cancer. Vitamin D's immune-modulatory action suggests that it could help prevent type 1 diabetes. In type 2 diabetes, vitamin D may influence β-cell function, insulin sensitivity, and systematic inflammation-all characteristic pathways of that disease. Data from observational studies correlated vitamin D deficiency with risk of type 1 and type 2 diabetes. Prospective and ecological studies of pancreatic cancer incidence generally support a beneficial effect of higher 25-hydroxyvitamin D concentration as well as inverse correlations between UVB dose or exposure and incidence and/or mortality rate of pancreatic cancer. This review discusses the literature regarding vitamin D's role in risk of diabetes and pancreatic cancer. The results to date generally satisfy Hill's criteria for causality regarding vitamin D and incidence of these pancreatic diseases. However, large randomized, blinded, prospective studies are required to more fully evaluate the potential therapeutic role of vitamin D in preventing pancreatic diseases.

Vitamin D Deficiency and Immune Disorders in Combined Endocrine Pathology

Introduction: Combined endocrine pathology is a serious healthcare problem in Ukraine. This prospective study assessed the blood levels of 25-hydroxyvitamin D [25(OH)D] and markers of immune function in response to vitamin D intervention in patients with type 1 and type 2 diabetes mellitus (T1DM and T2DM, respectively) and autoimmune thyroiditis (AIT). Objective: This study evaluated the relationship between the metabolic and immune status of DM + AIT patients with respect to their vitamin D status and changes after vitamin D₃ supplementation. Material and Methods: Patients with type 1 or type 2 DM in combination with AIT and decreased circulating levels of 25(OH)D were divided into two groups of 30 patients each. All patients with AIT were euthyroid and receiving hormonal replacement therapy. The levels of carbohydrate and fat metabolism markers, Immunologic markers, namely, Th1-type cytokines [interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-6, IL-12], Th2-type cytokines (IL-4, IL-5), IL-10, and IL-17 were measured before and after vitamin D₃ supplementation. The vitamin D status was assessed according to the level of 25(OH)D. Results: Patients with combined endocrine disorders (DM and AIT) with a decreased vitamin D status had significantly increased background concentrations of Th1-type cytokines and reduced concentrations of Th2-type cytokines (IL-4 and IL-5), IL-10, and IL-17. The results of our study showed that vitamin D₃ supplementation in patients with T1DM and T2DM reduced the concentrations of the inflammatory Th1-type cytokines and increased the levels of Th2-type cytokines. Conclusion: The presence of two endocrine diseases, aggravated by decreased circulating levels of 25(OH)D, leads to disorders wherein the immune status is markedly changed. These decreased levels of 25(OH)D contribute to an autoimmune inflammatory process and to the progression of complications in addition to the metabolic disorders. A vitamin D intervention resulted in significant changes in the blood levels of 25(OH)D that are related to parameters of autoimmunity and glucose metabolism. Vitamin D₃ supplementation should be considered for the prevention and treatment of combined endocrine pathology.

Lower vitamin D levels are associated with higher blood glucose levels in Asian Indian women with pre-diabetes: a population-based cross-sectional study in North India

BACKGROUND

Asian Indian women are predisposed to develop obesity, metabolic syndrome and vitamin D deficiency. Relationship of vitamin D deficiency with blood glucose levels has not been explored in Asian Indian women with pre-diabetes.

OBJECTIVE

We evaluated the associations of serum 25-hydroxy vitamin D (25(OH)D) concentrations among adult women with the pre-diabetes residing in North India (Delhi).

METHODS

This cross-sectional population-based study involved 797 women with pre-diabetes aged 20-60 years. Blood pressure, body mass index (BMI), fasting blood glucose (FBG), extent of sun exposure and serum 25(OH)D levels were assessed. For purpose of analysis, serum 25(OH)D levels (nmol/L) were categorized in quintiles as follows: 0-21.5 (first quintile), 21.51-35.60 (second quintile), 35.61-46.50 (third quintile), 46.51-62.30 (fourth quintile) and >62.31 (fifth quintile).

RESULT

The prevalence (%) of vitamin D deficiency, insufficiency and sufficiency was 68.6, 25.9 and 5.5, respectively. Mean age (p=0.004), systolic (p=0.05) and diastolic (p=0.04) blood pressure, weight (p=0.03), BMI (p=0.04) and FBG (p=0.02) were significantly higher in subjects with vitamin D deficiency as compared with those with vitamin D insufficiency and sufficiency. Unadjusted mean values of FBG were significantly decreased in fourth (p=0.02) and fifth quintiles (p=0.030) of 25(OH)D levels as compared with second quintile. Furthermore, after adjusting for age and family income FBG levels were significantly increased in first quintile (compared with fourth (p=0.012) and fifth (p=0.018) quintiles) and second quintile (compared with fourth (p=0.003) and fifth (p=0.004) quintiles) of 25(OH)D levels, respectively.

CONCLUSION

Lower vitamin D levels are associated with higher blood glucose values in Asian Indian women with pre-diabetes. These findings need confirmation in case-control and prospective studies.

4. Lifestyle Management: Standards of Medical Care in Diabetes-2018

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Association of Glycosylated Hemoglobin Levels With Vitamin D Status

Background

The discovery of vitamin D is one of medicine’s great achievements. Despite all the positive evidence emerging about the beneficial effect of vitamin D, we still find many are vitamin D deficient. The purposes of this study were to examine the association between serum 25-hydroxyvitamin D (25(OH)D) and glycosylated hemoglobin (HbA1c) levels, to test the hypothesis that lower 25(OH)D levels are associated with poorer glucose control in diabetes mellitus (DM) patients and to investigate the effect of vitamin D supplementation on HbA1c levels.

Methods

This was a prospective observational cohort study of all patients with type 1 and type 2 diabetes (above 12 years) who attended the outpatient clinics of a tertiary center in Riyadh. HbA1c and vitamin D levels were recorded prior to supplementation and after 9 months of supplementation with vitamin D. All patients were divided into four groups according to their vitamin D level and an association between 25(OH)D and HbA1c was tested.

Results

Results showed that 73.1% of the patients had 25(OH)D levels < 50 nmol/L. We observed lowering of HbA1c after vitamin D supplementation (from mean HbA1c of 10.55 to 7.70). We found HbA1c to be inversely related to serum vitamin D levels (r = -0.14 (P < 0.0000002) before supplementation and -0.16 (P < 0.000001) after supplementation with vitamin D).

Conclusions

Advising patients with higher HbA1c to test their vitamin D level and correct any deficiency will result in better blood glucose control and benefit the patient’s overall health.

Prevalence of vitamin D deficiency and its associated factors in three regions of Saudi Arabia

Objectives:

To measure prevalence of vitamin D deficiency in Saudi Arabia, unveil the life style, nutritional habits and status, as well as identify the potential risk factors.

Method:

A school-based survey targeting Saudi school students and employees was conducted during the period from 2013 to 2014 using multistage cluster random sample in Central, Western and Eastern regions. The prevalence of vitamin D deficiency and difference between various population subgroups were calculated. Logistic regression analysis was used to determine the predictors of potential risk factors.

Results:

Prevalence of vitamin D deficiency was 49.5% in students and 44% in employees. Life style was not adequate to protect against vitamin D depletion. Unhealthy nutritional habits were widespread, some manifested in childhood while others manifested later in life. Living in the Eastern region, females, 16-19 years of age, low economic class, obese and lack of omega 3 supplements were risk factors in students. Employees living in the Eastern region, females, middle-income class, carbonated soft drink consumers, and lack of multivitamin supplements were at higher risk.

Conclusion:

There is a need for a health awareness program using evidence-based recommendations. Screening for early detection and correction of the condition should be proposed to be part of the national health strategy. There is need for identifying the burden of vitamin D deficiency on other diseases to control and improve the prognosis of these conditions.

A Systematic Review: Vitamin D Status and Sleeve Gastrectomy

BACKGROUND

Bariatric patients regularly present with insufficient vitamin D status before and after surgery, which requires substantial supplementation to treat. This review aims to assess the effect of sleeve gastrectomy on vitamin D status and the effectiveness of vitamin D supplementation.

METHODS

This review was conducted in accordance with the Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies.

RESULTS

The current guidelines recommend initial vitamin D supplementation of at least 3000 IU/day post-operatively, with no need for follow-up testing after sleeve gastrectomy. Only one study has trialled a dose in line with the recommendations for this patient group. They found that it was effective in improving VitD status.

CONCLUSIONS

On-going monitoring of vitamin D status is necessary, as the recommended level is not often reached.

The Effects of Vitamin D Supplementation in Newly Diagnosed Type 1 Diabetes Patients: Systematic Review of Randomized Controlled Trials

AIM

The aim of this study was to examine the effects of vitamin D supplementation in patients newly diagnosed with type 1 diabetes (T1D) assessed by insulin needs and changes in glycemic indices, as evidenced by randomized controlled trials (RCTs).

METHODS

A total of 7 RCTs were retrieved from PubMed/Medline and EBSCO databases by MeSH term search, and were reviewed systematically. The RCTs included examined the effects of alphacalcidole (n = 2), cholecalciferol (n = 2), and calcitriol (n = 3) supplementation on changes in daily insulin dose (DID), fasting Cpeptide (FCP), stimulated C-peptide (SCP), and HbA1c. In total, 287 individuals, diagnosed with T1D within a period of 4 weeks to 1 year and aged between 5 to 38 years, were examined.

RESULTS

Significant positive effects on DID, FCP, and SCP levels were observed after supplementation with alphacalcidole and cholecalciferol, whereas supplementation with calcitriol showed no effect.

CONCLUSIONS

Vitamin D supplementation in the form of alphacalcidole and cholecalciferol appears to be beneficial in the treatment of T1D patients by attenuating the natural history of the disease.

Association of vitamin D and vitamin D binding protein (DBP) gene polymorphism with susceptibility of type 2 diabetes mellitus in Bangladesh

AIMS

Polymorphism in vitamin D binding protein gene may have an impact on serum vitamin D transport and thus may have relation with type 2 diabetes mellitus. In our study, we investigated the association of serum vitamin D level and vitamin D-binding protein gene polymorphism with the onset of type 2 diabetes mellitus.

MATERIALS AND METHODS

Blood samples were collected from 104 type 2 diabetic patients and 107 healthy volunteers. Serum vitamin D was measured by high-performance liquid chromatography. Genetic analysis of vitamin D-binging protein gene was carried out by polymerase chain reaction - restriction fragment length polymorphism method.

RESULTS

We found significantly (p<0.001) lower level of vitamin D in type 2 diabetic patients compared to control subjects. A significantly negative correlation (r=-0.25, p<0.05) between vitamin D level and fasting blood glucose level was found among type 2 diabetic subjects. The Glu/Glu at codon 416 (rs7041) (p<0.05) and Lys/Lys at codon 420 (rs4588) (p<0.01) variants of vitamin D binding protein gene was significantly higher in type 2 diabetic subjects than controls. The patients with Glu/Glu and Lys/Lys genotypes respectively at codon 416 (odds ratio=2.87; 95% confidence interval=1.19 to 6.95) and 420 (odds ratio=8.9; 95% confidence interval=1.89 to 41.99) were at high risk of developing type 2 diabetes.

CONCLUSIONS

Our present study strongly suggests that there might have an association of vitamin D, and vitamin D-binding protein gene (codon 416 & 420) polymorphisms with the occurrence of type 2 diabetes mellitus.

Circulating levels of miR-7, miR-152 and miR-192 respond to vitamin D supplementation in adults with prediabetes and correlate with improvements in glycemic control

Vitamin D may play an important role in modifying the risk of type 2 diabetes. Supplementation with cholecalciferol has been shown to improve β cell function and to attenuate the rise in glycated hemoglobin in people at high risk of diabetes. We examined whether circulating microRNAs (miRNAs) reflect disease progression and/or respond to vitamin D supplementation. We measured plasma levels of select miRNAs implicated in diabetes in people with prediabetes treated either with placebo (n=21) or 2000 U of cholecalciferol daily (n=21) for 4 months in the Calcium and Vitamin D for Diabetes Mellitus trial and compared the baseline-adjusted changes after correcting for age, body mass index, race, time of study entry (season) and baseline disposition index. Circulating levels of miR-7 (sixfold reduction, P=.01), miR-152 (1.5-fold increase, P=.03), and miR-192 (1.7-fold reduction, P=.026) displayed significant treatment-by-time interactions between the placebo- and the vitamin-D-treated groups. Plasma levels of miR-7 were reduced in the vitamin D and increased in the placebo group. The change in miR-152 positively correlated with the change in levels of the circulating metabolite 25-hydroxyvitamin D (r=0.33, P=.046) and negatively correlated with the change in glycated hemoglobin (r=-0.37, P=.024). The change in miR-192 positively correlated with the change in fasting glucose (r=0.41, P<.011). In conclusion, reduction of circulating miR-7 and miR-192, accompanied by elevation of miR-152, reflects a beneficial metabolic response to vitamin D treatment in people with prediabetes. These miRNAs may be useful biomarkers in diabetes prevention trials and other studies of vitamin D.

Vitamin D supplementation and glycemic control in type 2 diabetes patients: A systematic review and meta-analysis

INTRODUCTION

Low vitamin D status has been found to be associated with impaired glycemic control in patients who suffer from type 2 diabetes; however, whether vitamin D supplementation is associated with improved glycemic status remains controversial. The aim of this study was to summarize evidence from randomized controlled trials (RCTs) to assess the efficacy of vitamin D supplementation in reducing glycosylated haemoglobinA1c (HbA1c) and fasting blood glucose (FBG) levels.

MATERIALS/METHODS

We searched PubMed, Web of Science and the Cochrane Library for reports published up to March 2017. We selected parallel RCTs investigating the effect of vitamin D or vitamin D analogues on HbA1c or FBG levels in type 2 diabetes patients. Cohen's d was calculated to represent the standardized mean difference (SMD) for each study, and the SMDs with 95%confidence intervals (CIs) were pooled using a random effects model.

RESULTS

Twenty-four studies were included that evaluated HbA1c levels and 18 studies were included that evaluated FBG levels. Meta-analyses showed that vitamin D supplementation was associated with reduced HbA1c levels (standardized mean difference (SMD) -0.25 [-0.45 to -0.05]) but had no influence on FBG levels (SMD -0.14 [-0.31 to 0.03]). However, the subgroup analyses suggested that vitamin D supplementation was associated with reduced HbA1c levels (SMD -0.39 [-0.67 to -0.10]) and FBG (SMD -0.27 [-0.46 to -0.07]) among patients with 25-hydroxyvitamin D (25(OH) D) deficiency at baseline. Significantly reduced HbA1c levels were also observed in association with vitamin D supplementation in the subgroup including type 2 diabetes patients with a body mass index (BMI) <30kg m^-2 (SMD -0.30 [-0.54 to -0.07]).

CONCLUSIONS

Vitamin D supplementation could be effective at improving glycemic control in vitamin D deficient or non-obese type 2 diabetes patients.

Association of Directly Measured Plasma Free 25(OH)D With Insulin Sensitivity and Secretion: The IRAS Family Study

OBJECTIVES

We aimed to compare the associations of directly measured plasma free 25-hydroxyvitamin D [25(OH)D] and total 25(OH)D concentrations with insulin sensitivity (SI) and β-cell function in nondiabetic Hispanics and African Americans. We hypothesized that directly measured free 25(OH)D would be more strongly associated with these measures of glucose homeostasis and that associations would differ by race.

DESIGN

We studied 1189 nondiabetic participants in the Insulin Resistance Atherosclerosis Study Family Study using data from baseline examinations from 2000 to 2002. SI, acute insulin response, and disposition index (DI) were determined from frequently sampled intravenous glucose tolerance tests. Plasma free and total 25(OH)D concentrations were measured by enzyme-linked immunosorbent assay and radioimmunoassay, respectively.

RESULTS

The median concentrations of plasma free 25(OH)D were 3.46 pg/mL for Hispanics and 2.17 pg/mL for African Americans (P < 0.0001), whereas the median concentrations of plasma total 25(OH)D were 16 ng/mL for Hispanics and 10 ng/mL for African Americans (P < 0.0001). Plasma free and total 25(OH)D were both positively associated with SI and DI in generalized estimating equations adjusted for demographic and lifestyle factors. After further adjustment with body mass index, the associations were no longer statistically significant, except for a significant association between plasma free 25(OH)D and SI. There was no effect modification by ethnicity on any of the exposure-outcome associations.

CONCLUSIONS

Our data showed that plasma free 25(OH)D had a slightly stronger association with SI compared with plasma total 25(OH)D, although the difference was modest and there were no marked differences in the associations between Hispanics and African Americans.

Vitamin D, sub-inflammation and insulin resistance. A window on a potential role for the interaction between bone and glucose metabolism

Vitamin D is a key hormone involved in the regulation of calcium/phosphorous balance and recently it has been implicated in the pathogenesis of sub-inflammation, insulin resistance and obesity. The two main forms of vitamin D are cholecalciferol (Vitamin D3) and ergocalciferol (Vitamin D2): the active form (1,25-dihydroxyvitamin D) is the result of two hydroxylations that take place in liver, kidney, pancreas and immune cells. Vitamin D increases the production of some anti-inflammatory cytokines and reduces the release of some pro-inflammatory cytokines. Low levels of Vitamin D are also associated with an up-regulation of TLRs expression and a pro-inflammatory state. Regardless of the effect on inflammation, Vitamin D seems to directly increase insulin sensitivity and secretion, through different mechanisms. Considering the importance of low grade chronic inflammation in metabolic syndrome, obesity and diabetes, many authors hypothesized the involvement of this nutrient/hormone in the pathogenesis of these diseases. Vitamin D status could alter the balance between pro and anti-inflammatory cytokines and thus affect insulin action, lipid metabolism and adipose tissue function and structure. Numerous studies have shown that Vitamin D concentrations are inversely associated with pro-inflammatory markers, insulin resistance, glucose intolerance and obesity. Interestingly, some longitudinal trials suggested also an inverse association between vitamin D status and incident type 2 diabetes mellitus. However, vitamin D supplementation in humans showed controversial effects: with some studies demonstrating improvements in insulin sensitivity, glucose and lipid metabolism while others showing no beneficial effect on glycemic control and on inflammation. In conclusion, although the evidences of a significant role of Vitamin D on inflammation, insulin resistance and insulin secretion in the pathogenesis of obesity, metabolic syndrome and type 2 diabetes, its potential function in treatment and prevention of type 2 diabetes mellitus is unclear. Encouraging results have emerged from Vitamin D supplementation trials on patients at risk of developing diabetes and further studies are needed to fully explore and understand its clinical applications.

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

INTRODUCTION

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

PURPOSE AND METHODS

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

RESULTS AND CONCLUSIONS

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

A pilot interventional study to evaluate the impact of cholecalciferol treatment on HbA1c in type 1 diabetes (T1D)

BACKGROUND

Higher 25(OH)D3 levels are associated with lower HbA1c, but there are limited UK interventional trials assessing the effect of cholecalciferol on HbA1c.

AIMS

(1) To assess the baseline 25(OH)D3 status in a Manchester cohort of children with type 1 diabetes (T1D). (2) To determine the effect of cholecalciferol administration on HbA1c.

METHODS

Children with T1D attending routine clinic appointments over three months in late winter/early spring had blood samples taken with consent. Participants with a 25(OH)D3 level <50 nmol/L were treated with a one-off cholecalciferol dose of 100,000 (2-10 years) or 160,000 (>10 years) units. HbA1c levels before and after treatment were recorded.

RESULTS

Vitamin D levels were obtained from 51 children. 35 were Caucasian, 11 South Asian and 5 from other ethnic groups. 42 were vitamin D deficient, but 2 were excluded from the analysis. All South Asian children were vitamin D deficient, with mean 25(OH)D3 of 28 nmol/L. In Caucasians, there was a negative relationship between baseline 25(OH)D3 level and HbA1c (r = -0.484, P < 0.01). In treated participants, there was no significant difference in mean HbA1c at 3 months (t = 1.010, P = 0.328) or at 1 year (t = -1.173, P = 0.248) before and after treatment. One-way ANCOVA, controlling for age, gender, ethnicity, BMI and diabetes duration showed no difference in Δ HbA1c level.

CONCLUSION

We report important findings at baseline, but in children treated with a stat dose of cholecalciferol, there was no effect on HbA1c. Further studies with larger sample sizes and using maintenance therapy are required.

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.

Serum 25-Hydroxyvitamin D3 Levels Are Associated with Carotid Intima-Media Thickness and Carotid Atherosclerotic Plaque in Type 2 Diabetic Patients

Objective. To investigate the relationship between serum 25-hydroxyvitamin D3 [25(OH)D3] levels and carotid intima-media thickness (IMT) as well as carotid atherosclerotic plaque in patients with type 2 diabetes mellitus (T2DM). Methods. 314 patients with T2DM were enrolled in this study. The clinical data and laboratory examinations of subjects were recorded, such as serum 25(OH)D3, hemoglobin A1c (HbA1c), serum lipids, fasting blood glucose (FBG), and other biochemical parameters. Color Doppler ultrasound was used to measure carotid IMT and carotid atherosclerotic plaques. Patients were divided into four quartile groups according to the serum 25(OH)D3 levels from low to high: group Q1~group Q4. Results. From group Q1 to group Q4, carotid IMT and the incidence of plaque were gradually reduced. Serum 25(OH)D3 levels were lower in the plaque group compared with the nonplaque group (P < 0.01). Serum 25(OH)D3 levels were negatively correlated with the carotid IMT (r = -0.4, P < 0.01). Multiple linear stepwise regression analysis showed that serum 25(OH)D3 was independently associated with carotid IMT (β = -0.009, P < 0.01). Logistic regression analysis showed that serum 25(OH)D3 levels were independently associated with the presence of carotid plaque in T2DM (OR = 0.95; 95%CI: 0.92~0.98, P = 0.004). Conclusions. Low vitamin D status may contribute to the incidence of carotid atherosclerosis in type 2 diabetic patients.

Vitamin D: not just the bone. Evidence for beneficial pleiotropic extraskeletal effects

Vitamin D is a fat-soluble vitamin and a steroid hormone that plays a central role in maintaining calcium-phosphorus and bone homeostasis in close interaction with parathyroid hormone, acting on its classical target tissues, namely, bone, kidney, intestine, and parathyroid glands. However, vitamin D endocrine system regulates several genes (about 3 % of the human genome) involved in cell differentiation, cell-cycle control, and cell function and exerts noncalcemic/pleiotropic effects on extraskeletal target tissues, such as immune and cardiovascular system, pancreatic endocrine cells, muscle, and adipose tissue. Several studies have demonstrated the role of vitamin D supplementation in the prevention/treatment of various autoimmune diseases and improvement of glucose metabolism, muscle, and adipose tissue function. Hence, this review aims to elucidate the effects of vitamin D on extraskeletal target tissues and to investigate the potential therapeutic benefit of vitamin D supplementation among a broad group of pathological conditions, especially with regard to metabolic and autoimmune diseases. In addition, we focused on the best daily intakes and serum levels of vitamin D required for extraskeletal benefits which, even if still controversial, appear to be higher than those widely accepted for skeletal effects.

Role of Serum Adiponectin and Vitamin D in Prediabetes and Diabetes Mellitus

OBJECTIVES

The roles of deficient or deranged insulin, adiponectin and 25 hydroxy vitamin D (25[OH]D) levels regulating food intake, energy metabolism, glucose and lipid metabolism and body weight have been reported in the pathogenesis of prediabetes and type 2 diabetes mellitus. However, their congruity in the etiology of diabetes mellitus is unknown. Thus, the aim of the study was to investigate the roles of these parameters together and to establish their interrelationship in patients with prediabetes and diabetes.

METHODS

The preliminary cross-sectional study included 77 persons with type 2 diabetes who were matched for age, sex and body mass index (BMI); 73 persons with prediabetes; and 52 healthy control subjects. Fasting serum levels of adiponectin, insulin and 25(OH)D were measured by commercially available immune assay kits, and routine biochemical parameters were analyzed in all study groups.

RESULTS

The results show statistically significant lower levels of serum adiponectin and serum 25(OH)D and higher serum insulin levels in persons with prediabetes or type 2 diabetes with respect to controls. The changes in the serum adiponectin or serum 25(OH)D in persons with prediabetes and type 2 diabetes were found to be inversely correlated with the serum levels of insulin. Moreover, multiple linear regression analysis, with 25(OH)D, insulin and homeostatic model assessment-insulin resistance (HOMA-IR) as the variables, revealed that serum adiponectin levels might be an independent risk factor for the progression of prediabetes and type 2 diabetes in subjects.

CONCLUSIONS

The association of these hormones might act as a significant predictor of progression of prediabetes to type 2 diabetes. Decreased serum adiponectin levels might be an independent risk factor for progression to prediabetes and type 2 diabetes, which may help in developing experimental models of the disease or in identifying biomarkers or disease-modifying drugs.

Nutrition in Diabetes

Medical nutrition therapy (MNT) is a key component of diabetes management. The importance of balancing macronutrients, reducing carbohydrate load, lowering glycemic index, and implementing an overall healthy dietary pattern are emerging as better approaches for MNT in diabetes. Recent research points to improved glycemic control, reduction in body weight, and improvement in many cardiovascular risk factors when these approaches are provided by registered dietitians or health care providers. This review article discusses the current evidence about the role of sensible nutrition in diabetes management. Specific eating plans for weight reduction and for patients with type 1 diabetes are also discussed.

Lower Vitamin D Metabolites Levels Were Associated With Increased Coronary Artery Diseases in Type 2 Diabetes Patients in India

The purpose of the present study was to measure six vitamin D metabolites and to find the association between vitamin D deficiency and coronary artery diseases in diabetes (T2DM_CAD). Four groups [control (n = 50), type 2 diabetes (T2DM, n = 71), coronary artery diseases (CAD, n = 28), T2DM_CAD (n = 38)] of total 187 subjects were included in the study. Six vitamin D metabolites (D₂, D₃, 25(OH)D₂, 25(OH)D₃, 1,25(OH)₂D₂, 1,25(OH)₂D₃), total 25(OH)D and total 1,25(OH)₂D were measured by UPLC/APCI/HRMS method in these subjects. Although all the vitamin D metabolites were significantly decreased in T2DM_CAD as compared to both control and T2DM subjects (p < 0.05), only two metabolites i.e., 25(OH)D₃ and total 25(OH)D were significantly (p < 0.05) decreased in the T2DM subjects as compared with the control subjects (p < 0.05). Vitamin D₃, 1,25(OH)₂D₂, 25(OH)D, and 1,25(OH)₂D levels were significantly decreased in T2DM_CAD subjects as compared with CAD subjects (p < 0.05). Further, multiple logistic regression analysis revealed that total 25(OH)D and total 1,25(OH)₂D can be used to predict T2DM (OR 0.82.95% CI 0.68-0.99; p = 0.0208) and T2DM with CAD (OR 0.460, 95% CI 0.242-0.874; p = 0.0177), respectively. Our data concludes that lower concentration of 1,25(OH)₂D is associated with type 2 diabetes coexisting with coronary artery diseases in South Indian subjects.

Vitamin D-Cellular Ca2+ link to obesity and diabetes

The vitamin D hormone 1,25-Dihydroxyvitamin D₃ (1,25(OH)₂D₃)-induced cellular Ca²⁺ signals regulate apoptosis in adipocytes and insulin secretion from pancreatic β-cells, and low vitamin D status is considered a risk factor for obesity and type 2 diabetes. The anti-obesity effects of 1,25(OH)₂D₃ in mature adipocytes are determined by its activity to generate, via multiple Ca²⁺ signaling pathways, a sustained increase in intracellular Ca²⁺ followed by activation of the Ca²⁺-dependent initiators and effectors of apoptosis. In pancreatic β-cells, 1,25(OH)₂D₃ induces synchronous Ca²⁺ oscillations, which pattern pulsatile insulin secretion from these cells. An increased intake of vitamin D₃ in a high fat diet-induced obesity mouse model is associated with a decreased weight of white adipose tissue due to induction of apoptosis and the improved blood markers related to adiposity, diabetes, and vitamin D status (plasma concentrations of glucose, insulin, adiponectin, 25-hydroxyvitamin D, and 1,25(OH)₂D₃). High vitamin D₃ intake is also effective in increasing the mineral content of growing bone in obese mice via regulatory effects mediated by 1,25(OH)₂D₃-parathyroid hormone axis. The 1,25(OH)₂D₃-dependent cellular Ca²⁺ signaling can be important for maintaining the normal levels of apoptosis in adipose tissue and insulin secretion from pancreatic β-cells. An increased intake of vitamin D may contribute to the prevention of obesity, type 2 diabetes, and bone disorders associated with these diseases.

Serum calcium and incident type 2 diabetes: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Elevated serum calcium has been associated with a variety of metabolic abnormalities and may be associated with a greater risk of diabetes.

OBJECTIVE

The purpose of this study was to test the hypothesis that serum calcium concentration is positively and independently associated with the incidence of diabetes and to evaluate the association of calcium-sensing receptor (CaSR) gene single nucleotide polymorphism (SNP) rs1801725 with incident diabetes.

DESIGN

Atherosclerosis Risk in Communities study participants free of diabetes at baseline (n = 12,800; mean age: 53.9 y; 22.6% black) were studied for incident diabetes. Serum calcium was measured at baseline and corrected for serum albumin. Diabetes was defined by use of glucose concentrations, self-report, or medication use. Cox proportional hazards regression was used.

RESULTS

During a mean 8.8 y of follow-up, 1516 cases of diabetes were reported. Participants in the highest compared with lowest calcium quintile were at greater risk of incident diabetes after adjustment for demographic and lifestyle factors [HR (95% CI): 1.34 (1.14, 1.57); P-trend across quintiles <0.0001] and with further adjustment for waist circumference and body mass index [1.26 (1.07, 1.48); P-trend = 0.004]. Additional adjustment for biomarkers on the metabolic pathway (e.g., 25-hydroxyvitamin D, parathyroid hormone, phosphorus) had little impact. The calcium-diabetes association was statistically significant in blacks [1.48 (1.11, 1.98); P-trend = 0.002] but not whites [1.17 (0.96, 1.43); P-trend = 0.17] after adjustment for adiposity. In whites, CaSR gene SNP rs1801725 was associated with serum calcium but not with risk of diabetes.

CONCLUSIONS

Consistent with 3 previous cohort studies, elevated serum calcium was found to be associated with a greater risk of type 2 diabetes. Further research is needed to understand the role, if any, that calcium plays in the pathogenesis of diabetes.

Adequate vitamin D status is associated with the reduced odds of prevalent diabetic retinopathy in African Americans and Caucasians

BACKGROUND

Vitamin D status has been hypothesized to protect against development of diabetic retinopathy via its anti-inflammatory and anti-angiogenic properties. Additionally, in vitro and in vivo studies suggest vitamin D favorably influences blood pressure and blood glucose control, strong risk factors for diabetic retinopathy. We examined the association between vitamin D status and prevalent diabetic retinopathy in participants with diabetes from a population-based cohort.

METHODS

Among participants in the Atherosclerosis Risk in Communities (ARIC) study with diabetes at visit 3 (1993-1995), 1339 (906 Caucasians, 433 African Americans) had serum 25-hydroxyvitamin (25[OH]D) concentrations assessed at visit 2 (1989-1992) and nonmydriatic retinal photographs taken at visit 3. Dietary intake of vitamin D was assessed at visit 1 (1987-1989). Logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for diabetic retinopathy by categories of season-adjusted 25(OH)D (<30 [referent], 30-<50, 50-<75 and ≥75 nmol/L), by quartile of vitamin D intake (IU/day), and use of vitamin D or fish oil supplements (yes/no). P for trend was estimated using continuous 25(OH)D or vitamin D intake. ORs were adjusted for race, and duration of diabetes. We further adjusted for HBA1c and hypertension to examine if 25(OH)D influenced diabetic retinopathy via its effects on either glycemic control or blood pressure.

RESULTS

ORs (95 % CIs) for retinopathy, adjusted for race and duration, were 0.77 (0.45-1.32), 0.64 (0.37-1.10), and 0.39 (0.20-0.75), p for trend = 0.001, for participants with 25(OH)D of 30-<50, 50-<75, and ≥75 nmol/L, respectively. Further adjustment for hypertension minimally influenced results (data not show), but adjustment for HBA1c attenuated the OR among those with 25(OH)D ≥75 (0.47 [0.23-0.96], p for trend = 0.030). No statistically significant association was observed between vitamin D intake from foods or supplements and retinopathy.

CONCLUSIONS

25(OH)D concentrations ≥75 nmol/L were associated with lower odds of any retinopathy assessed 3 years later. We speculate this may be due in part to vitamin D's influence on blood glucose control.

Vitamin D Deficiency Is Associated with Severity of Acute Coronary Syndrome in Patients with Type 2 Diabetes and High Rates of Sun Exposure

BACKGROUND

Vitamin D deficiency has been associated with cardiovascular risk factors, including type 2 diabetes mellitus (T2DM). Evidence shows that patients with low serum 25-hydroxyvitamin D (25OHD) concentrations have a higher risk of developing coronary artery disease.

OBJECTIVE

The objective of this study was to assess vitamin D as a predictor of the severity in diabetics with acute coronary syndrome (ACS).

METHODS

A total of 166 patients were diagnosed with ACS. Serum 25OHD concentrations were analyzed, and risk factors for ACS were evaluated.

RESULTS

Patients diagnosed as having acute myocardial infarction with elevation of the ST segment had a higher rate of 25OHD, <20 ng/mL compared to ≥30 ng/mL (47.8% × 13.4%, P = 0.03). Diabetics with vitamin D deficiency had more multivessel lesions in the coronary angiography than non-diabetics (69% × 31.8%, P = 0.007). After adjustments for confounders, serum 25OHD remained associated with more severe disease.

CONCLUSION

Vitamin D deficiency is associated with more severe ACS and is a predictor of more extensive coronary lesions in patients with T2DM.

High levels of serum vitamin D are associated with a decreased risk of metabolic diseases in both men and women, but an increased risk for coronary artery calcification in Korean men

Background

There are conflicting results for relationships between serum vitamin D levels and metabolic diseases. The aim of this study was to investigate whether serum vitamin D levels were associated with various metabolic diseases including insulin resistance (IR), metabolic syndrome (MS), fatty liver (FL), and coronary artery calcification (CAC), along with assessing gender differences for these relationships in Korean adults.

Methods

A total of 180,918 subjects (98,412 men and 82,506 women) who participated in a comprehensive health examination in the 2012–2013 period at Kangbuk Samsung Hospital, College of Medicine, Sungkyunkwan University were included. Serum vitamin D and metabolic markers were analyzed and CAC was estimated. Subjects were divided according to quartile groups of serum vitamin D. To examine the relationships of serum vitamin D to metabolic diseases and metabolic factors, multivariate logistic analysis was conducted.

Results

High levels of serum vitamin D was associated with lower ORs for MS, IR and FL both in men and women (all p < 0.05). For men, ORs for CAC were significantly higher in third and the highest quartile groups for serum vitamin D in all the analyzed models (all p < 0.05). However, women showed no significant results between serum vitamin D and CAC.

Conclusions

High levels of serum vitamin D were associated with lower risk of MS, IR and FL in both Korean men and women, but were associated with higher risk of CAC only in men, and not in women.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0432-3) contains supplementary material, which is available to authorized users.

Baseline Regularization for Computational Drug Repositioning with Longitudinal Observational Data

Computational Drug Repositioning (CDR) is the knowledge discovery process of finding new indications for existing drugs leveraging heterogeneous drug-related data. Longitudinal observational data such as Electronic Health Records (EHRs) have become an emerging data source for CDR. To address the high-dimensional, irregular, subject and time-heterogeneous nature of EHRs, we propose Baseline Regularization (BR) and a variant that extend the one-way fixed effect model, which is a standard approach to analyze small-scale longitudinal data. For evaluation, we use the proposed methods to search for drugs that can lower Fasting Blood Glucose (FBG) level in the Marshfield Clinic EHR. Experimental results suggest that the proposed methods are capable of rediscovering drugs that can lower FBG level as well as identifying some potential blood sugar lowering drugs in the literature.

Vitamin D status in Moroccan pregnant women and newborns: reports of 102 cases

Introduction

Vitamin D insufficiency to pregnant women has been associated with a number of adverse consequences, and has been recognized as a public health concern. The aim of this study was to evaluate vitamin D status of Morrocan pregnant women and their newborns. Our study is being the first of its kind in Morocco, as it supports the program of systematic supplementation of pregnant women in the third quarter. Its results have established a new program for the fight against the deficit of various nutrients, thereby intake of vitamin D has become routine. So this work is a true example of action research.

Methods

It’s an observational and a cross sectional study. The data was collected prospectively from the 1st January to 31 December 2012 in the labor room of the Souissi maternity hospital, at the Ibn Sina university center of Rabat in Morocco. Women included were consented to participate in the study. Data on epidemiological, sociodemographic and clinical characteristics was recolted by interview, physical exam and biochemistry parameters. Hypovitaminosis D is defined as serum level of vitamin D ≤ 50 nmol/l (20 ng/ml).

Results

Our study included 102 cases of mother-newborn pairs. The average age of mothers was 28.3 +/- 6.7 years (range 17-43 years), 90.1% of women enrolled had a hypovitaminosis D, the average weight of newborns was 3377.9 +/- 509g (2270 - 4880g). Hypovitaminosis D is not correlated with the origin, season, body mass index, birth interval and birth weight. It was positively correlated with maternal serum calcium (p=0.000).

Conclusion

The maternal hypovitaminosis D is real public health problem. The prevention is necessary, by the systematic vitamin D supplementation for pregnant women.

Effect of Vitamin D3 Supplementation on Inflammatory Markers and Glycemic Measures among Overweight or Obese Adults: A Systematic Review of Randomized Controlled Trials

BACKGROUND

Obesity induced low-grade chronic inflammation disrupts proper immune and metabolic function. Vitamin D deficiency increases inflammation, which is associated with cardiometabolic risk. This systematic review examines the association between oral vitamin D (VD) supplementation and circulating inflammatory biomarkers and glycemic outcomes from randomized controlled trials (RCTs) of overweight and/or obese adults.

METHODS

MEDLINE OVID, EMBASE and the Cochrane Central Register of Controlled Trials were searched according to a predefined protocol. Eligible RCTs included adults randomized to receive either oral VD or placebo. Two reviewers independently assessed RCTs for inclusion. Bias was assessed using the Cochrane Collaboration risk of bias tool. Mean differences were calculated comparing end-of-study sample means between the independent VD and placebo groups.

RESULTS

Eleven unique RCTs met inclusion criteria from a total of 3,383 identified citations, including 79 screened articles and 14 full text data extractions. Inflammatory and glycemic measures were reported in 7 and 10 RCTs, respectively. Most trial findings were non-significant with considerable heterogeneity in design, participants and outcomes. All but one trial was rated as either high or unclear risk of bias. Two RCTs reported significant changes in inflammatory biomarkers; however, the mean difference between groups was not statistically significant: C-reactive protein 0.19 mg/L (p = 0.88); Tumor Necrosis Factor -0.54 pg/ml (p = 0.20). Two other trials found significant mean differences in fasting plasma glucose -0.32 mmol/L (p = 0.03), Hemoglobin A1c -0.13% (p = 0.04), and Homeostatic Model Assessment -0.86 (p = 0.02) following VD supplementation.

CONCLUSIONS

Overall, there is no clear established benefit of VD supplementation on inflammatory biomarkers among overweight/obese adults. Baseline serum VD possibly influences the effect of VD repletion on inflammatory markers. Risk of bias was present in most studies, thus supporting the need for higher quality studies in this area to more conclusively understand the role VD supplementation has on inflammatory pathways.

Vitamin D mitigates the adverse effects of obesity on breast cancer in mice

Obesity is an established risk factor for postmenopausal breast cancer (BCa), insulin resistance, and vitamin D deficiency, and all contribute to increased synthesis of mammary estrogens, the drivers of estrogen receptor-positive (ER+) BCa growth. As both dietary vitamin D and calcitriol treatments inhibit breast estrogen synthesis and signaling, we hypothesized that vitamin D would be especially beneficial in mitigating the adverse effects of obesity on ER+BCa. To assess whether obesity exerted adverse effects on BCa growth and whether vitamin D compounds could reduce these unfavorable effects, we employed a diet-induced obesity (DIO) model in ovariectomized C57BL/6 mice. Breast tumor cells originally from syngeneic Mmtv-Wnt1 transgenic mice were then implanted into the mammary fat pads of lean and obese mice. DIO accelerated the initiation and progression of the mammary tumors. Treatments with either calcitriol or dietary vitamin D reduced the adverse effects of obesity causing a delay in tumor appearance and inhibiting continued tumor growth. Beneficial actions of treatments with vitamin D or calcitriol on BCa and surrounding adipose tissue included repressed Esr1, aromatase, and Cox2 expression; decreased tumor-derived estrogen and PGE2; reduced expression of leptin receptors; and increased adiponectin receptors. We demonstrate that vitamin D treatments decreased insulin resistance, reduced leptin, and increased adiponectin signaling and also regulated the LKB1/AMPK pathway contributing to an overall decrease in local estrogen synthesis in the obese mice. We conclude that calcitriol and dietary vitamin D, acting by multiple interrelated pathways, mitigate obesity-enhanced BCa growth in a postmenopausal setting.

Effect of vitamin D supplementation on insulin resistance and glycaemic control in prediabetes: a systematic review and meta-analysis

AIMS

To evaluate the effect of vitamin D on insulin resistance and glycaemic control in prediabetes.

METHODS

A literature search was conducted of MEDLINE, the Cochrane Library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Scopus, Web of Science and www.clinicaltrials.gov, together with a historical search through the reference lists of relevant articles until end of June 2014. Studies were included if they were randomized controlled trials of vitamin D or vitamin D analogues in prediabetes and if they reported homeostatic model assessment of insulin resistance or 2-h plasma glucose after oral glucose tolerance test. Treatment effect was estimated according to mean difference in the changes from baseline of homeostatic model assessment of insulin resistance, 2-h oral glucose tolerance test plasma glucose, fasting plasma glucose and HbA1c between vitamin D and control groups. Meta-analysis of eligible studies was performed.

RESULTS

A total of 10 randomized controlled trials were included. Vitamin D did not significantly improve homeostatic model assessment of insulin resistance and 2-h oral glucose tolerance test plasma glucose: the mean differences were -0.06 (95% CI -0.36 to 0.24) and -0.23 mmol/l (95% CI -0.65 to 0.19), respectively. Subgroup analysis suggested that vitamin D improved homeostatic model assessment of insulin resistance in a subgroup with baseline 25-hydroxyvitamin D ≥ 50 nmol/l [mean difference -0.59 (95% CI -1.14 to -0.04); P = 0.03] and improved 2-h oral glucose tolerance test plasma glucose in the subgroup with baseline 25-hydroxyvitamin D < 50 nmol/l [mean difference -0.68 mmol/l (95% CI -1.35 to -0.01); P = 0.05]. Vitamin D significantly reduced fasting plasma glucose and HbA1c levels. The mean differences were -0.10 mmol/l (95% CI -0.18 to -0.03), P = 0.006 and -1 mmol/mol (95% CI -2 to 0), P = 0.008, respectively.

CONCLUSIONS

No beneficial effect of vitamin D in improving insulin resistance was identified.

Hypovitaminosis D: a novel risk factor for coronary heart disease in type 2 diabetes?

Vitamin D (25(OH)D) levels have been associated with cardiovascular disease. Thus, the aim of our study was to investigate the association of 25(OH)D levels with coronary heart disease (CHD) in 698 consecutive type 2 diabetic outpatients. 698 consecutive type 2 diabetic outpatients (25.2 % men, age 66 ± 9 years) and 100 (90 % men, age 65 ± 13 years) age-matched non-diabetic volunteers were enrolled. 25(OH)D assay and the main cardiovascular risk factors were explored. 25(OH)D concentration was 22 ± 10 ng/ml in control subjects and 18.23 ± 10 ng/ml in diabetic patients (p < 0.01). The prevalence of hypovitaminosis D was higher in diabetic patients than in control subjects (90 vs. 83 %, p < 0.01). Diabetic subjects with hypovitaminosis D had higher prevalence of high values of A1C (p < 0.01), BMI (p < 0.01), LDL cholesterol (p < 0.01), triglycerides (p < 0.01), and glycemia (p < 0.01) than their vitamin D-sufficient counterparts. 25(OH)D and HDL cholesterol were lower (p < 0.01), while BMI (p < 0.01), age (p < 0.01), systolic (p < 0.01) and diastolic blood pressure (p < 0.01), diabetes duration (p < 0.01), A1C (p < 0.01), glycemia (p < 0.01), fibrinogen (p < 0.01), triglycerides (p < 0.01), and total (p < 0.01) and LDL cholesterol (p < 0.01) were higher in diabetic subjects with CHD than diabetic subjects without CHD. At the logistic regression analysis, the association of vitamin D with CHD was lost, while sex (p = 0.026), diabetes duration (p = 0.023), and age (p = 0.024) were the most powerful predictors of CHD. The current study demonstrates that 25(OH)D does not have a direct effect on CHD but may have an indirect effect mediated by cardiovascular risk factors such as diabetes duration, age, and sex.

1,25-Dihydroxyvitamin D3 and type 2 diabetes: Ca2+-dependent molecular mechanisms and the role of vitamin D status

The hormone 1,25-dihydroxyvitamin D

Vitamin D metabolism-related genetic variants, dietary protein intake and improvement of insulin resistance in a 2 year weight-loss trial: POUNDS Lost

AIMS/HYPOTHESIS

Vitamin D and related genetic variants are associated with obesity and insulin resistance. We aimed to examine whether vitamin D metabolism-related variants affect changes in body weight and insulin resistance in response to weight-loss diets varying in macronutrient content.

METHODS

Three vitamin D metabolism-related variants, DHCR7 rs12785878, CYP2R1 rs10741657 and GC rs2282679, were genotyped in 732 overweight/obese participants from a 2 year weight-loss trial (POUNDS Lost). We assessed genotype effects on changes in body weight, fasting levels of glucose and insulin, and HOMA-IR at 6 months (up to 656 participants) and 2 years (up to 596 participants) in response to low-protein vs high-protein diets, and low-fat vs high-fat diets.

RESULTS

We found significant interactions between DHCR7 rs12785878 and diets varying in protein, but not in fat, on changes in insulin and HOMA-IR at both 6 months (p for interaction <0.001) and 2 years (p for interaction ≤ 0.03). The T allele (vitamin-D-increasing allele) of DHCR7 rs12785878 was associated with greater decreases in insulin and HOMA-IR (p < 0.002) in response to high-protein diets, while there was no significant genotype effect on changes in these traits in the low-protein diet group. Generalised estimating equation analyses indicated significant genotype effects on trajectory of changes in insulin resistance over the 2 year intervention in response to high-protein diets (p < 0.001). We did not observe significant interaction between the other two variants and dietary protein or fat on changes in these traits.

CONCLUSIONS/INTERPRETATION

Our data suggest that individuals carrying the T allele of DHCR7 rs12785878 might benefit more in improvement of insulin resistance than noncarriers by consuming high-protein weight-loss diets.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00072995.

Vitamin D Deficiency Adds an Element of Risk to Insulin Resistance in Colorectal Neoplasms

BACKGROUND

Both insulin resistance (IR) and vitamin D deficiency (VitDdef) have been suggested as risk factors for colorectal neoplasms (CRNs). However, the associations between the two with regard to CRNs are unclear.

AIMS

To determine whether IR is a risk factor for CRNs and whether VitDdef confers an additive risk of CRNs.

METHODS

Colonoscopy-naïve asymptomatic women undergoing a routine health screening program were analyzed. IR was defined as homeostatic model assessment of IR >3 and VitDdef set as <20 ng/mL. Multivariable logistic regression was performed between women with and without CRNs, matched for age and body mass index, to investigate associations with CRNs in IR, VitDdef, and VitDdef combined with IR.

RESULTS

We analyzed 216 women with CRNs and 216 without CRNs. A significant association was found between IR and CRNs (OR 1.838, 95 % CI 1.029-3.285, P = 0.040) but not with VitDdef. IR conferred a higher risk in advanced CRNs (OR 3.244, 95 % CI 1.588-6.631, P = 0.001) than CRNs. When VitDdef was combined with IR, risks of both CRNs and advanced CRNs increased (OR 2.131, 95 % CI 1.077-4.216, P = 0.030 and OR 4.438, 95 % CI 2.058-9.571, P < 0.001, respectively).

CONCLUSIONS

IR increases the risk of CRNs, and a combination of IR and VitDdef further increases this risk. As both VitDdef and IR are modifiable risk factors, such associations may have important clinical implications in the prevention of CRNs.

25-hydroxyvitamin D levels, vitamin D binding protein gene polymorphisms and incident coronary heart disease among whites and blacks: The ARIC study

BACKGROUND

In observational studies, low 25-hydroxyvitamin D (25(OH)D) has been associated with increased risk of coronary heart disease (CHD), and this association may vary by race. Racial differences in the frequency of vitamin D binding protein (DBP) single nucleotide polymorphisms (SNPs) might account for similar bioavailable vitamin D in blacks despite lower mean 25(OH)D. We hypothesized that the associations of low 25(OH)D with CHD risk would be stronger among whites and among persons with genotypes associated with higher DBP levels.

METHODS

We measured 25(OH)D by mass spectroscopy in 11,945 participants in the ARIC Study (baseline 1990-1992, mean age 57 years, 59% women, 24% black). Two DBP SNPs (rs7041; rs4588) were genotyped. We used adjusted Cox proportional hazards models to examine the association of 25(OH)D with adjudicated CHD events through December 2011.

RESULTS

Over a median of 20 years, there were 1230 incident CHD events. Whites in the lowest quintile of 25(OH)D (<17 ng/ml) compared to the upper 4 quintiles had an increased risk of incident CHD (HR 1.28, 95% CI 1.05-1.56), but blacks did not (1.03, 0.82-1.28), after adjustment for demographics and behavioral/socioeconomic factors (p-interaction with race = 0.22). Results among whites were no longer significant after further adjustment for potential mediators of this association (i.e. diabetes, hypertension). There was no statistically significant interaction of 25(OH)D with the DBP SNPs rs4588 (p = 0.92) or rs7041 (p = 0.87) in relation to CHD risk.

CONCLUSIONS

Low 25(OH)D was associated with incident CHD in whites, but no interactions of 25(OH)D with key DBP genotypes was found.