Vitamin D and type 2 diabetes mellitus (D2)

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D supplementation during pregnancy may help improve maternal and neonatal health outcomes (such as fewer preterm birth and low birthweight babies) and reduce the risk of adverse pregnancy outcomes (such as severe postpartum haemorrhage).

OBJECTIVES

To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve certain maternal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Trials Register (which includes results of comprehensive searches of CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform, and relevant conference proceedings) (3 December 2022). We also searched the reference lists of retrieved studies.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of studies against the inclusion criteria, ii) assessed trustworthiness based on pre-defined criteria of scientific integrity, iii) extracted data from included studies, and iv) assessed the risk of bias of the included studies. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

The previous version of this review included 30 studies; in this update, we have removed 20 of these studies to 'awaiting classification' following assessments of trustworthiness, one study has been excluded, and one new study included. This current review has a total of 10 included studies, 117 excluded studies, 34 studies in awaiting assessment, and seven ongoing studies. We used the GRADE approach to assess the certainty of the evidence. This removal of the studies resulted in evidence that was downgraded to low-certainty or very low-certainty due to study design limitations, inconsistency between studies, and imprecision. Supplementation with vitamin D compared to no intervention or a placebo A total of eight studies involving 2313 pregnant women were included in this comparison. We assessed four studies as having a low risk of bias for most domains and four studies as having high risk or unclear risk of bias for most domains. The evidence is very uncertain about the effect of supplementation with vitamin D during pregnancy compared to placebo or no intervention on pre-eclampsia (risk ratio (RR) 0.53, 95% confidence interval (CI) 0.21 to 1.33; 1 study, 165 women), gestational diabetes (RR 0.53, 95% CI 0.03 to 8.28; 1 study, 165 women), preterm birth (< 37 weeks) (RR 0.76, 95% CI 0.25 to 2.33; 3 studies, 1368 women), nephritic syndrome (RR 0.17, 95% CI 0.01 to 4.06; 1 study, 135 women), or hypercalcaemia (1 study; no cases reported). Supplementation with vitamin D during pregnancy may reduce the risk of severe postpartum haemorrhage; however, only one study reported this outcome (RR 0.68, 95% CI 0.51 to 0.91; 1 study, 1134 women; low-certainty evidence) and may reduce the risk of low birthweight; however, the upper CI suggests that an increase in risk cannot be ruled out (RR 0.69, 95% CI 0.44 to 1.08; 3 studies, 371 infants; low-certainty evidence). Supplementation with vitamin D + calcium compared to no intervention or a placebo One study involving 84 pregnant women was included in this comparison. Overall, this study was at moderate to high risk of bias. Pre-eclampsia, gestational diabetes, and maternal adverse events were not reported. The evidence is very uncertain about the effect of supplementation with vitamin D and calcium on preterm birth (RR not estimable; very low-certainty evidence) or for low birthweight (RR 1.45, 95% CI 0.14 to 14.94; very low-certainty evidence) compared to women who received placebo or no intervention. Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D) One study involving 1298 pregnant women was included in this comparison. We assessed this study as having a low risk of bias in all domains. Pre-eclampsia was not reported. The evidence is very uncertain about the effect of supplementation with vitamin D, calcium, and other vitamins and minerals during pregnancy compared to no vitamin D on gestational diabetes (RR 0.42, 95% CI 0.10 to 1.73; very low-certainty evidence), maternal adverse events (hypercalcaemia no events and hypercalciuria RR 0.25, 95% CI 0.02 to 3.97; very low-certainty evidence), preterm birth (RR 1.04, 95% CI 0.68 to 1.59; low-certainty evidence), or low birthweight (RR 1.12, 95% CI 0.82 to 1.51; low-certainty evidence).

AUTHORS' CONCLUSIONS

This updated review using the trustworthy assessment tool removed 21 studies from the previous update and added one new study for a total of 10 included studies. In this setting, supplementation with vitamin D alone compared to no intervention or a placebo resulted in very uncertain evidence on pre-eclampsia, gestational diabetes, preterm birth, or nephritic syndrome. It may reduce the risk of severe postpartum haemorrhage; however, only one study reported this outcome. It may also reduce the risk of low birthweight; however, the upper CI suggests that an increase in risk cannot be ruled out. Supplementation with vitamin D and calcium versus placebo or no intervention resulted in very uncertain evidence on preterm birth and low birthweight. Pre-eclampsia, gestational diabetes, and maternal adverse events were not reported in the only study included in this comparison. Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D) resulted in very uncertain evidence on gestational diabetes and maternal adverse events (hypercalciuria) and uncertain evidence on preterm birth and low birthweight. Pre-eclampsia was not reported in the only study included in this comparison. All findings warrant further research. Additional rigorous, high-quality, and larger randomised trials are required to evaluate the effects of vitamin D supplementation in pregnancy, particularly in relation to the risk of maternal adverse events.

Body composition phase angle: A potential predictor of vitamin D status in early pregnancy

Phase angle and vitamin D can reflect the state of the body cells, and the two may interact with each other. Therefore, this study was conducted to find out the relationship between PA and vitamin D. Taking women in early pregnancy as our study subjects, we found that PA had a positive effect on vitamin D levels. Body composition phase angle, as a noninvasive, easy-to-operate, and easy-to-monitor indicator, can be used an early screening index for vitamin D nutrition levels in early pregnancy, and the cutoff value was 4.95°.

Serum 25-Hydroxyvitamin D Levels in Type 2 Diabetes Patients in North China: Seasonality and the Association between Vitamin D Status and Glycosylated Hemoglobin Levels

Background and Aims

Previous studies have reported a correlation between vitamin D levels and seasonality in healthy populations. However, there are few studies on the seasonal variation in vitamin D levels and its relationship with glycosylated hemoglobin (HbA1c) in patients with type 2 diabetes mellitus (T2DM). The objective of this study was to investigate seasonal changes in serum 25-hydroxyvitamin D [25(OH)D] levels and the associations between these vitamin D concentrations and HbA1c levels in T2DM patients in Hebei, China.

Methods

A cross-sectional study of 1,074 individuals with T2DM was conducted from May 2018 to September 2021. Levels of 25(OH)D in these patients were assessed based on both sex and season, and relevant clinical or laboratory variables that could impact vitamin D status were also considered.

Results

In the T2DM patient cohort, the mean blood 25(OH)D levels were 17.05 ng/mL. A total of 698 patients (65.0%) had insufficient serum 25(OH)D levels. The vitamin D deficiency rates were significantly higher in the winter and spring compared to the autumn (P < 0.05), indicating that seasonal fluctuations can have a significant impact on 25(OH)D levels. The levels of vitamin D inadequacy were highest in the winter (74%), and females were more likely than males to be deficient (73.4% vs. 59.5%, P < 0.001). In comparison to the winter and spring, both males and females showed higher 25(OH)D levels in the summer (P < 0.001). HbA1c levels were 8.9% higher in those with vitamin D deficiencies than in nondeficient patients (P < 0.001). HbA1c and vitamin D levels were negatively correlated (r = -0.119, P < 0.001).

Conclusion

Vitamin D deficiencies are particularly prevalent among T2DM patients in Hebei, China, with exceptionally high rates in the winter and spring. Female T2DM patients were at an elevated risk of vitamin D deficiency, and vitamin D levels were negatively correlated with HbA1c.

Effect of Intramuscular Injection of Vitamin D on 25-Hydroxyvitamin D Levels, Glycaemic Control, and Liver Enzymes in Libyan Patients with Type 2 Diabetes Mellitus

Background Vitamin D is a fat-soluble hormone that plays an important role in glycaemic control. In addition, it has a positive effect on improving liver enzyme function.

Aim This study was performed to examine the effect of intramuscular injection of vitamin D on serum 25-hydroxyvitamin D [25(OH)D] levels, glycemic control, and liver enzymes in Libyan patients suffering from type 2 diabetes mellitus (T2DM) with vitamin D deficiency.

Methods and Materials This cross-sectional study enrolled 100 T2DM (50 males and 50 females). Their serum 25(OH)D, fasting blood glucose (FBG), and liver enzymes were measured at the baseline and 12 weeks after treatment with vitamin D (200,000 IU) injection monthly for 3 months. Data analysis involved the estimation of mean ± standard error (SE) and comparison of means between pre and post-treatment values using paired t-test. Independent t-test was used to compare the means between males and females. The level of significance was set at p < 0.05.

Results Females had a lower 25(OH)D blood levels than males at baseline (7.03 ± 0.25 ng/mL versus 7.86 ± 0.26 ng/mL, respectively p < 0.02). 25(OH)D levels in both sexes was increased significantly from 7.45 ± 0.18 ng/mL to 26.69 ± 0.24 ng/mL after 12 weeks of vitamin D injections (p < 0.001), with no significant differences between male and females. FBG levels in both sexes was significantly decreased from 144.68 ± 1.84 mg/dL to 85.96 ± 0.34 mg/dL post treatment (p < 0.001). Alanine aminotransferase (ALT) was increased from 10.24 ± 0.17 U/L at baseline to 20.34 ± 1.15 U/L post treatment (p < 0.001). Similarly, aspartate aminotransferase (AST) was increased from 11.23 ± 0.21 to 20.57 ± 0.22 U/L (p < 0.001), and alkaline phosphatase (ALP) was decreased from 124.95 ± 1.15 U/L to 111.17 ± 1.27 U/L (p < 0.001). There were no significant differences between male and female liver enzymes either pre- or post-vitamin D injections

Conclusion Treatment with vitamin D injection showed a significant increase in 25(OH)D accompanied by decreased FBG and ALP levels and increased ALT and AST levels. Vitamin D levels should be monitored and adjusted in diabetic patients.

Comparison of the levels of 25(OH) vitamin D3 in women with gestational diabetes mellitus and normoglycemic pregnant women

INTRODUCTION

Gestational diabetes mellitus (GDM) is a public health problem that currently affects a large part of the female population and has short- and long-term consequences for the fetus and the mother. It has been reported that GDM affects 1%-14% of all pregnancies, and that its incidence has been steadily rising. In recent years while exploring the etiological factors responsible for the emergence of insulin resistance particularly that of transient nature, vitamin D has emerged as one of the possible factors. Although systematic review and metaanalysis of observational studies show that low blood vitamin D level during pregnancy is associated with 1.8 times higher odds of GDM as compared to those having normal blood vitamin D levels; however, individual observational studies about maternal vitamin D status and risk of GDM are conflicting, The aim of this study is to compare the levels of 25(OH) vitamin D in women with gestational diabetes mellitus and normoglycemic pregnant women to assess the pathogenic role of vitamin D in the causation of GDM.

MATERIALS AND METHODS

This study was conducted in the Department of Obstetrics and Gynecology, Era's Lucknow Medical College and Hospital (ELMCH), Lucknow from December 2018 to November 2020 The present study was an analytical case-control study, in which a total of 30 pregnant women in 24-28 weeks of gestation diagnosed as GDM using Diabetes in Pregnancy Study Group criteria were enrolled as cases while another 30 pregnant women in same gestational age range with normoglycemic profile were enrolled as controls. The 25(OH)D levels were assessed by the chemiluminecence immunoassay. The statistical analysis was performed using SPSS (Statistical Package for Social Sciences) Version 21.0.

RESULTS

On multivariate analysis, vegetarian diet and GDM were found to be significantly associated with vitamin D deficiency. The present study endorsed the relationship between vitamin D deficiency and GDM and showed a high prevalence of vitamin D deficiency, and that too at severe level could result in GDM. Appropriate awareness and intervention strategies are warranted on a larger sample.

Association between vitamin D and glycaemic parameters in a multi-ethnic cohort of postmenopausal women with type 2 diabetes in Saudi Arabia

BACKGROUND

The relationship between vitamin D (VitD) and insulin sensitivity and secretion in type 2 diabetes mellitus (T2D) has been shown to be different amongst different ethnic populations. In Saudi Arabia, where both T2D and VitD deficiency are highly prevalent health concerns, little is known about the relationship between VitD, insulin sensitivity, resistance and the relative importance of ethnicity. Our primary aim in this study was to investigate influence of ethnicity on VitD association with glycaemic profile and to measures of obesity as a secondary outcome, among multiethnic postmenopausal women with T2D in Saudi Arabia.

METHODS

A cross-sectional study was conducted at King Fahad Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia. Postmenopausal females (n = 173, age ≥ 50 years) with T2D were randomly selected in this study. Anthropometric measures and fasting blood samples were obtained for all study participants. Several biochemical parameters were measured including 25-hydroxyvitamin D (25(OH)D), glycosylated hemoglobin (HbA1c), insulin, glucose and c-peptide. Surrogate markers for insulin resistance were calculated using Homeostasis Model Assessment 2 for insulin resistance and beta cell activity (HOMA2-IR, HOMA2-β).

RESULTS

Overall, 25(OH)D was inversely associated with fasting glucose (r=-0.165, P = 0.037), insulin (r=-0.184, P = 0.02), C-peptide (r=-0.19, P = 0.015) and HOMA2- IR C-peptide (r=-0.23, P = 0.004). Additionally, serum 25 (OH)D showed a negative correlation with body weight (r=-0.173 P = 0.028), waist and hip circumferences (r=-0.167, P = 0.033; r=-0.22, P = 0.004 respectively) but not with body mass index (BMI) or waist hip ratio (WHR). In the white ethnic group but not in black or Asian population groups, 25(OH)D level was also associated with only serum fasting C-peptide and HOMA2-IR C-peptide and BMI (P < 0.05).

CONCLUSIONS

Insulin resistance and obesity were associated with VitD status in T2D in this cohort. Our findings also suggest that these VitD associations in women from white ethnic background are different than in those from black/Asian ethnic backgrounds. Whether VitD supplements are able to improve either obesity and/or insulin sensitivity should be further investigated in different ethnic population groups.

Synergistic Association of Carcinoembryonic Antigen and Carbohydrate Antigen 19-9 on the Risk of Abnormal Glucose Regulation

PURPOSE

Carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) are tumor-associated antigens. An increased serum level of CEA and CA19-9 separately has been reported in diabetes. In this study, we examined the composite effect of elevated serum levels of both CEA and CA19-9 on subjects with type 2 diabetes and prediabetes.

PATIENTS AND METHODS

A total of 3568 adults who attended a health examination were enrolled into this cross-sectional study. Subjects were grouped into four groups according to the median serum CEA and CA19-9 levels.

RESULTS

Subjects with high CEA and high CA19-9 levels had the highest proportions of diabetes (43.9%) and prediabetes (33.04%). There was a statistically significant trend in the proportion of diabetes across the four groups (P < 0.001). Multivariable logistic regression analysis revealed higher risks of type 2 diabetes in subjects with high CEA and low CA19-9 levels (odds ratio [OR] = 2.10, 95% confidence interval [CI]: 1.39-3.18, P < 0.001) and in those with high CA19-9 and low CEA levels (OR = 2.18, 95% CI: 1.42-3.34, P < 0.001) than in those with low CEA and low CA19-9 levels; among these four groups, the highest risk of type 2 diabetes was observed in subjects with high CEA and high CA19-9 levels (OR = 2.65, 95% CI: 1.81-3.88, P < 0.001). The risk of prediabetes was significantly higher only in subjects with high CEA and high CA19-9 levels compared to those with low CEA and low CA19-9 levels (OR = 1.32, 95% CI: 1.08-1.61, P = 0.006).

CONCLUSION

CEA and CA19-9 had a synergistic ability to increase the risk of type 2 diabetes and prediabetes.

The Relationship Between Vitamin D Deficiency and Glycated Hemoglobin Levels in Patients with Type 2 Diabetes Mellitus

PURPOSE

The aims of this study were to determine the relationship between 25-hydroxyvitamin D [25(OH) D] and glycated hemoglobin (HbA1c) levels in male and female patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

The participants were adults diagnosed with T2DM recruited from Hebei General Hospital. Patient information and information regarding blood indicators were collected. The subjects were divided into no vitamin D deficiency group [25(OH) D >20 ng/mL] and vitamin D deficiency group [25(OH) D <20 ng/mL], and these groups were then further subdivided into male-only or female-only subgroups. And then, the subjects were divided into male group and female group in different 25(OH) D levels.

RESULTS

HbA1c levels in the vitamin D deficiency group were significantly higher than those in the no vitamin D deficiency group for all subjects. The same was true for female patients but not for male patients. There was no difference in HbA1c levels between male and female patients with T2DM, regardless of 25(OH) D deficiency. A negative correlation existed between 25(OH) D and HbA1c in all subjects, as well as in the male-only and female-only subgroups. Vitamin D deficiency was associated with high HbA1c levels before and after adjusting for confounding factors in all participants and in the female-only subgroup, but not in the male-only subgroup.

CONCLUSION

This study confirmed that vitamin D deficiency was related with high HbA1c levels in patients with T2DM, and this relationship differs between female and male patients.

Vitamin D and Gestational Diabetes Mellitus: Is There a Link?

Gestational diabetes mellitus (GDM) is a very common condition among pregnant women worldwide with important metabolic implications on the mother and the offspring. Vitamin D status has been suggested to potentially play a role in GDM risk with no documented consequences for the offspring. The purpose of this article was to review currently available evidence on the relationship between vitamin D and GDM. Current evidence shows an association between vitamin D blood levels and risk of GDM, despite heterogeneity of results across studies limit the conclusions. Moreover, data from randomized controlled trials is scarce and resulting in null findings. Among the limitations to be noted, improving the standardization of dosages, the characteristics of individuals in the sample, and the appropriate outcome measurement could provide a more effective approach in understanding the relationship between vitamin D and GDM. In conclusions, despite observational studies may suggest that adequate vitamin D levels may decrease the risk of GDM compared to deficiency status, evidence from clinical trials is inadequate to draft any definitive conclusion regarding its supplementation. Future better designed randomized clinical trials taking into account a more integrated approach could provide clearer and definitive data on the outcomes of such a multifactorial condition.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D supplementation during pregnancy may be needed to protect against adverse pregnancy outcomes. This is an update of a review that was first published in 2012 and then in 2016.

OBJECTIVES

To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register (12 July 2018), contacted relevant organisations (15 May 2018), reference lists of retrieved trials and registries at clinicaltrials.gov and WHO International Clinical Trials Registry Platform (12 July 2018). Abstracts were included if they had enough information to extract the data.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of trials against the inclusion criteria, ii) extracted data from included trials, and iii) assessed the risk of bias of the included trials. The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included 30 trials (7033 women), excluded 60 trials, identified six as ongoing/unpublished trials and two trials are awaiting assessments.Supplementation with vitamin D alone versus placebo/no interventionA total of 22 trials involving 3725 pregnant women were included in this comparison; 19 trials were assessed as having low-to-moderate risk of bias for most domains and three trials were assessed as having high risk of bias for most domains. Supplementation with vitamin D alone during pregnancy probably reduces the risk of pre-eclampsia (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.30 to 0.79; 4 trials, 499 women, moderate-certainty evidence) and gestational diabetes (RR 0.51, 95% CI 0.27 to 0.97; 4 trials, 446 women, moderate-certainty evidence); and probably reduces the risk of having a baby with low birthweight (less than 2500 g) (RR 0.55, 95% CI 0.35 to 0.87; 5 trials, 697 women, moderate-certainty evidence) compared to women who received placebo or no intervention. Vitamin D supplementation may make little or no difference in the risk of having a preterm birth < 37 weeks compared to no intervention or placebo (RR 0.66, 95% CI 0.34 to 1.30; 7 trials, 1640 women, low-certainty evidence). In terms of maternal adverse events, vitamin D supplementation may reduce the risk of severe postpartum haemorrhage (RR 0.68, 95% CI 0.51 to 0.91; 1 trial, 1134 women, low-certainty evidence). There were no cases of hypercalcaemia (1 trial, 1134 women, low-certainty evidence), and we are very uncertain as to whether vitamin D increases or decreases the risk of nephritic syndrome (RR 0.17, 95% CI 0.01 to 4.06; 1 trial, 135 women, very low-certainty evidence). However, given the scarcity of data in general for maternal adverse events, no firm conclusions can be drawn.Supplementation with vitamin D and calcium versus placebo/no interventionNine trials involving 1916 pregnant women were included in this comparison; three trials were assessed as having low risk of bias for allocation and blinding, four trials were assessed as having high risk of bias and two had some components having a low risk, high risk, or unclear risk. Supplementation with vitamin D and calcium during pregnancy probably reduces the risk of pre-eclampsia (RR 0.50, 95% CI 0.32 to 0.78; 4 trials, 1174 women, moderate-certainty evidence). The effect of the intervention is uncertain on gestational diabetes (RR 0.33,% CI 0.01 to 7.84; 1 trial, 54 women, very low-certainty evidence); and low birthweight (less than 2500 g) (RR 0.68, 95% CI 0.10 to 4.55; 2 trials, 110 women, very low-certainty evidence) compared to women who received placebo or no intervention. Supplementation with vitamin D and calcium during pregnancy may increase the risk of preterm birth < 37 weeks in comparison to women who received placebo or no intervention (RR 1.52, 95% CI 1.01 to 2.28; 5 trials, 942 women, low-certainty evidence). No trial in this comparison reported on maternal adverse events.Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D)One trial in 1300 participants was included in this comparison; it was assessed as having low risk of bias. Pre-eclampsia was not assessed. Supplementation with vitamin D + other nutrients may make little or no difference in the risk of preterm birth < 37 weeks (RR 1.04, 95% CI 0.68 to 1.59; 1 trial, 1298 women, low-certainty evidence); or low birthweight (less than 2500 g) (RR 1.12, 95% CI 0.82 to 1.51; 1 trial, 1298 women, low-certainty evidence). It is unclear whether it makes any difference to the risk of gestational diabetes (RR 0.42, 95% CI 0.10 to 1.73) or maternal adverse events (hypercalcaemia no events; hypercalciuria RR 0.25, 95% CI 0.02 to 3.97; 1 trial, 1298 women,) because the certainty of the evidence for both outcomes was found to be very low.

AUTHORS' CONCLUSIONS

We included 30 trials (7033 women) across three separate comparisons. Our GRADE assessments ranged from moderate to very low, with downgrading decisions based on limitations in study design, imprecision and indirectness.Supplementing pregnant women with vitamin D alone probably reduces the risk of pre-eclampsia, gestational diabetes, low birthweight and may reduce the risk of severe postpartum haemorrhage. It may make little or no difference in the risk of having a preterm birth < 37 weeks' gestation. Supplementing pregnant women with vitamin D and calcium probably reduces the risk of pre-eclampsia but may increase the risk of preterm births < 37 weeks (these findings warrant further research). Supplementing pregnant women with vitamin D and other nutrients may make little or no difference in the risk of preterm birth < 37 weeks' gestation or low birthweight (less than 2500 g). Additional rigorous high quality and larger randomised trials are required to evaluate the effects of vitamin D supplementation in pregnancy, particularly in relation to the risk of maternal adverse events.

Efficacy of vitamin D supplementation in gestational diabetes mellitus: Systematic review and meta-analysis of randomized trials

BACKGROUND

Trials have examined on the benefits of vitamin D supplementation in pregnant women.

OBJECTIVE

This review aimed to evaluate whether oral vitamin D supplements, when given to pregnant women with gestational diabetes mellitus (GDM), would improve maternal and neonatal outcomes, compared with no treatment or placebo.

METHOD

We performed a systematic review following Cochrane methodology, and randomized trials were included where pregnant women with GDM received vitamin D supplementation versus placebo/no treatment or vitamin D and calcium versus placebo/no treatment. Primary outcomes were preeclampsia, preterm birth, cesarean delivery, gestational hypertension, and adverse events related to vitamin D supplementation. The search strategies were applied to the following databases: MEDLINE, Embase, LILACS, and CENTRAL. Similar outcomes in at least two trials were plotted using Review Manager 5.3 software. The quality of evidence was generated according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).

RESULTS

The total of 1224 references were identified, eleven trials were potentially eligible, and six were included in this review (totaling 456 women). The meta-analysis of frequency of cesarean deliveries did not show significant differences between groups, none of the trials evaluated the remaining primary outcomes. For secondary outcomes, our results suggest that vitamin D supplementation in pregnant women with GDM may reduce newborn complications such as hyperbilirubinemia, polyhydramnios (RR: 0.40, 95% CI: 0.23 to 0.68; RR: 0.17, 95% CI: 0.03 to 0.89; respectively), and the need for maternal or infant hospitalization (RR: 0.13; 95% CI: 0.02 to 0.98; RR: 0.40, 95% CI: 0.23 to 0.69). However, the evidence was of low or very low quality.

CONCLUSION

We did not find moderate or high quality evidence indicating that vitamin D supplementation, when compared with placebo, improves glucose metabolism, adverse maternal and neonatal outcomes related to GDM in pregnant women.

Serum Calcium Concentrations, Chronic Inflammation and Glucose Metabolism: A Cross-Sectional Analysis in the Andhra Pradesh Children and Parents Study (APCaPS)

BACKGROUND

Evidence suggests a role for elevated serum calcium in dysregulated glucose metabolism, linked through low-level chronic inflammation.

OBJECTIVES

We investigated the association of elevated serum calcium concentrations (corrected for albumin) with markers of dysregulated glucose metabolism and type II diabetes and tested if these associations were accounted for by chronic inflammation in a rural Indian population.

METHODS

A cross-sectional analysis of participants aged 40-84 y from the Andhra Pradesh Children and Parents Study (APCaPS; n = 2699, 52.2% women) was conducted. Comprehensive information on household, sociodemographic, and lifestyle factors; medical and family history; physical measurements; blood measurements including fasting plasma glucose (FPG), fasting insulin (FI), serum calcium, albumin, phosphorous, vitamin D (in a subset), and creatinine were analyzed. Additionally, in a random sample of healthy participants (n = 1000), inflammatory biomarkers (interleukins 6 and 18, soluble intercellular adhesion molecule 1, adiponectin, and high-sensitivity C-reactive protein) were measured and an inflammatory score (IScore) calculated.

RESULTS

After adjustments for sociodemographics, lifestyle factors, and anthropometry the highest calcium quartile (Q4 compared with Q1) was associated with FI (β = 1.4 µU/ml; 95% CI: 1.2, 1.5 µU/ml; P-trend < 0.001), the homeostasis model assessment for insulin resistance (HOMA-IR) (β = 1.4; 95% CI: 1.2, 1.5; P-trend < 0.001), and was modestly associated with FPG (β = 2.1 mg/dL; 95% CI: -0.9, 5.2 mg/dL; P-trend = 0.058) and prevalent type II diabetes (OR = 1.6; 95% CI: 1.0, 2.6; P-trend= 0.020). In the healthy subgroup, the association of the highest calcium quartile was similar for FI and HOMA-IR. Additional adjustment with IScore did not alter the associations. Further, in a subset, all these associations were independent of endogenous regulators of calcium metabolism (serum vitamin D, phosphorus, and creatinine). Independently, after accounting for potential confounders, the highest IScore quartile (Q4 compared with Q1) was positively associated with FPG, FI, HOMA-IR, and prevalent prediabetes, and also with serum calcium concentrations in men.

CONCLUSIONS

Elevated serum calcium was positively associated with markers of dysregulated glucose metabolism and prevalent type II diabetes in a rural Indian population. Chronic inflammation did not mediate this association but was independently associated with markers of dysregulated glucose metabolism. Inflammation might be responsible for elevated serum calcium concentrations in men.

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 association between the baseline bone resorption marker CTX and incident dysglycemia after 4 years

Bone is an endocrine organ involved in modulating glucose homeostasis. The role of the bone formation marker osteocalcin (OCN) in predicting diabetes was reported, but with conflicting results. No study has explored the association between baseline bone resorption activity and incident diabetes or prediabetes during follow-up. Our objective was to examine the relationship between the baseline bone resorption marker crosslinked C-telopeptide of type I collagen (CTX) and glycemic dysregulation after 4 years. This longitudinal study was conducted in a university teaching hospital. A total of 195 normal glucose tolerant (NGT) women at baseline were invited for follow-up. The incidence of diabetes and prediabetes (collectively defined as dysglycemia) was recorded. A total of 128 individuals completed the 4-year study. The overall conversion rate from NGT to dysglycemia was 31.3%. The incidence of dysglycemia was lowest in the middle tertile [16.3% (95% confidence interval (CI), 6.8%–30.7%)] compared with the lower [31.0% (95% CI, 17.2%–46.1%)] and upper [46.5% (95% CI, 31.2%–62.6%)] tertiles of CTX, with a significant difference seen between the middle and upper tertiles (P=0.002 5). After adjusting for multiple confounding variables, the upper tertile of baseline CTX was associated with an increased risk of incident dysglycemia, with an odds ratio of 7.09 (95% CI, 1.73–28.99) when the middle tertile was the reference. Osteoclasts actively regulate glucose homeostasis in a biphasic model that moderately enhanced bone resorption marker CTX at baseline provides protective effects against the deterioration of glucose metabolism, whereas an overactive osteoclastic function contributes to an increased risk of subsequent dysglycemia.

Effect of paricalcitol on pancreatic oxidative stress, inflammatory markers, and glycemic status in diabetic rats

OBJECTIVES

This study is designed to explore the effect of paricalcitol (vitamin D receptor agonist) on pancreatic oxidative stress, inflammatory markers, and adiponectin and glycemic status in diabetic rats.

MATERIALS AND METHODS

Forty Sprague-Dawley male rats aged 10-12 weeks (150-250 g) were used in this study. Type 2 diabetes was developed by providing 4 weeks of high-fat-diet feeding before one shot of streptozotocin injection (40 mg/kg i.p.). Four study groups were designed as normal control rats, diabetic control vehicle-treated, diabetic paricalcitol-treated (0.8 μg/kg), and diabetic glibenclamide-treated (0.6 mg/kg) groups with 10 animals in each. After treatment of diabetic rats for 3 months, pancreatic inflammatory and oxidative stress markers, plasma adiponectin, glycemic status parameters, and histopathological pancreatic islet changes were evaluated.

RESULTS

Paricalcitol and glibenclamide treatment significantly (P < 0.05) decreased plasma glucose, insulin resistance, and pancreatic malondialdehyde and tumor necrosis factor-α levels. Moreover, they significantly (P < 0.05) increased plasma fasting insulin, C-peptide, adiponectin, pancreatic IL-2, catalase, superoxide dismutase, glutathione peroxidase, and reduced glutathione when contrasted with diabetic control rats. Furthermore, they prevented extensive histopathological damage in the pancreas of diabetic rats.

CONCLUSIONS

Paricalcitol reduced pancreatic oxidative stress and inflammatory markers, and improved glycemic status in diabetic rats.

Vitamin D receptor gene FokI variant in diabetic foot ulcer and its relation with oxidative stress

PURPOSE

The patient's suffering and financial costs affiliated with Diabetic Foot Ulcer (DFU), as one of the most important complications of diabetes, are highly undesirable and this highlights the importance of preventive medicine about this disorder. Furthermore hyperglycemia causes generation of free radicals which leads to oxidative stress (OS). Hence, this study aims to examine the association between vitamin D receptor (VDR) gene FokI polymorphism and DFU in Iranian population and also its correlation with OS biomarkers.

MATERIALS AND METHODS

In a case-control study, a total of 212 patients with type 2 diabetes with and without diabetic foot ulcer were included. Genotyping was conducted by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. Samples were analyzed for thiobarbituric reactive substances (TBARS) and ferric reducing ability of plasma (FRAP) as markers of OS.

RESULTS

The results indicated a significant difference in genotype frequencies of VDR gene FokI polymorphism in patients with diabetic foot ulcer in comparison to those without diabetic foot ulcer (TT+TC vs. CC p=0.04; OR=1.76; 95% CI=1.02-3.05). Moreover, the patients carrying the T allele had a significantly higher level of TBARS (p=0.01).

CONCLUSIONS

We found a significant association between FokI functional variant of VDR gene and diabetic foot ulcer in an Iranian population. Increased levels of TBARS in patients carrying the T allele of FokI polymorphism indicate an association between this variant and OS in patients with diabetes.

Association between tuberculosis, diabetes and 25 hydroxyvitamin D in Tanzania: a longitudinal case control study

Background

Vitamin D level is inversely associated with tuberculosis (TB) and diabetes (DM). Vitamin D could be a mediator in the association between TB and DM. We examined the associations between vitamin D, TB and DM.

Methods

Consecutive adults with TB and sex- and age-matched volunteers were included in a case-control study in Dar es Salaam, Tanzania. Glycemia and total vitamin D (25(OH)D) were measured at enrolment and after TB treatment in cases. The association between low 25(OH)D (<75 nmol/l) and TB was evaluated by logistic regression adjusted for age, sex, body mass index, socioeconomic status, sunshine hours, HIV and an interaction between low 25(OH)D and hyperglycemia.

Results

The prevalence of low 25(OH)D was similar in TB patients and controls (25.8 % versus 31.0 %; p = 0.22). In the subgroup of patients with persistent hyperglycemia (i.e. likely true diabetic patients), the proportion of patients with low 25(OH)D tended to be greater in TB patients (50 % versus 29.7 %; p = 0.20). The effect modification by persistent hyperglycemia persisted in the multivariate analysis (p_interaction = 0.01).

Conclusions

Low 25(OH)D may increase TB risk in patients with underlying DM. Trials should examine if this association is causal and whether adjunct vitamin D therapy is beneficial in this population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1960-x) contains supplementary material, which is available to authorized users.

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.

Preschool diets in children from Piła, Poland, require urgent intervention as implied by high risk of nutrient inadequacies

BACKGROUND

Among the studies published after the year 2000 which focused on nutrition at preschool, only three aimed to assess children's intake of energy and selected nutrients at preschool. The purpose of this study was to assess dietary intake in children during their stay at preschool.

METHODS

The studied population comprised 128 4-6-year-old children who attended preschools in Piła, Poland. Intakes of energy and macronutrients were estimated from a 5-day weighed food record completed by the preschool staff. Weight and height were measured, and BMI was calculated. Statistical analysis was carried out using the IBM SPSS Statistics 21.0 computer programme. The data were analysed according to gender.

RESULTS

Energy intake was the lowest in children with underweight, 2004 kJ (478 kcal), and the highest in obese children, 3388 kJ (809 kcal). Energy intake from lactose was statistically significantly higher in boys than in girls, 3.0 vs 2.6 %. Statistically significantly higher percentage of boys in comparison to girls had intakes of vitamin C below 70 % of EAR, 56.9 vs 38.1 %. It is important to highlight the excessive intake of energy from saturated fatty acids and energy from sucrose, along with inadequate intake of energy from polyunsaturated fatty acids. We also found excessive intake of sodium and inadequate intakes of dietary fibre, water, vitamin D, vitamin E, folate, niacin, calcium and potassium.

CONCLUSIONS

Preschool diets need urgent improvement to prevent diet-related diseases in the studied preschoolers in the future. The inadequacies observed in these diets are in accordance with the previously reported inadequacies in menus planned for preschoolers. More research is needed to investigate dietary intake of children during their stay at preschool. Common regulations worked out for all preschools in the European Union would be a good way to provide adequate nutrition to preschool children.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D deficiency or insufficiency is thought to be common among pregnant women. Vitamin D supplementation during pregnancy has been suggested as an intervention to protect against adverse pregnancy outcomes.

OBJECTIVES

To examine whether oral supplements with vitamin D alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (23 February 2015), the International Clinical Trials Registry Platform (31 January 2015), the Networked Digital Library of Theses and Dissertations (28 January 2015) and also contacted relevant organisations (31 January 2015).

SELECTION CRITERIA

Randomised and quasi-randomised trials with randomisation at either individual or cluster level, evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of studies against the inclusion criteria ii) extracted data from included studies, and iii) assessed the risk of bias of the included studies. Data were checked for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

In this updated review we included 15 trials assessing a total of 2833 women, excluded 27 trials, and 23 trials are still ongoing or unpublished. Nine trials compared the effects of vitamin D alone versus no supplementation or a placebo and six trials compared the effects of vitamin D and calcium with no supplementation. Risk of bias in the majority of trials was unclear and many studies were at high risk of bias for blinding and attrition rates. Vitamin D alone versus no supplementation or a placebo Data from seven trials involving 868 women consistently show that women who received vitamin D supplements alone, particularly on a daily basis, had higher 25-hydroxyvitamin D than those receiving no intervention or placebo, but this response was highly heterogeneous. Also, data from two trials involving 219 women suggest that women who received vitamin D supplements may have a lower risk of pre-eclampsia than those receiving no intervention or placebo (8.9% versus 15.5%; risk ratio (RR) 0.52; 95% CI 0.25 to 1.05, low quality). Data from two trials involving 219 women suggest a similar risk of gestational diabetes among those taking vitamin D supplements or no intervention/placebo (RR 0.43; 95% CI 0.05, 3.45, very low quality). There were no clear differences in adverse effects, with only one reported case of nephritic syndrome in the control group in one study (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women, low quality). Given the scarcity of data for this outcome, no firm conclusions can be drawn. No other adverse effects were reported in any of the other studies.With respect to infant outcomes, data from three trials involving 477 women suggest that vitamin D supplementation during pregnancy reduces the risk preterm birth compared to no intervention or placebo (8.9% versus 15.5%; RR 0.36; 95% CI 0.14 to 0.93, moderate quality). Data from three trials involving 493 women also suggest that women who receive vitamin D supplements during pregnancy less frequently had a baby with a birthweight below 2500 g than those receiving no intervention or placebo (RR 0.40; 95% CI 0.24 to 0.67, moderate quality).In terms of other outcomes, there were no clear differences in caesarean section (RR 0.95; 95% CI 0.69 to 1.31; two trials; 312 women); stillbirths (RR 0.35 95% CI 0.06, 1.99; three trials, 540 women); or neonatal deaths (RR 0.27; 95% CI 0.04, 1.67; two trials, 282 women). There was some indication that vitamin D supplementation increases infant length (mean difference (MD) 0.70, 95% CI -0.02 to 1.43; four trials, 638 infants) and head circumference at birth (MD 0.43, 95% CI 0.03 to 0.83; four trials, 638 women). Vitamin D and calcium versus no supplementation or a placeboWomen who received vitamin D with calcium had a lower risk of pre-eclampsia than those not receiving any intervention (RR 0.51; 95% CI 0.32 to 0.80; three trials; 1114 women, moderate quality), but also an increased risk of preterm birth (RR 1.57; 95% CI 1.02 to 2.43, three studies, 798 women, moderate quality). Maternal vitamin D concentration at term, gestational diabetes, adverse effects and low birthweight were not reported in any trial or reported only by one study.

AUTHORS' CONCLUSIONS

New studies have provided more evidence on the effects of supplementing pregnant women with vitamin D alone or with calcium on pregnancy outcomes. Supplementing pregnant women with vitamin D in a single or continued dose increases serum 25-hydroxyvitamin D at term and may reduce the risk of pre-eclampsia, low birthweight and preterm birth. However, when vitamin D and calcium are combined, the risk of preterm birth is increased. The clinical significance of the increased serum 25-hydroxyvitamin D concentrations is still unclear. In light of this, these results need to be interpreted with caution. Data on adverse effects were lacking in all studies.The evidence on whether vitamin D supplementation should be given as a part of routine antenatal care to all women to improve maternal and infant outcomes remains unclear. While there is some indication that vitamin D supplementation could reduce the risk of pre-eclampsia and increase length and head circumference at birth, further rigorous randomised trials are required to confirm these effects.

Prevalence of and Risk Factors for Type 2 Diabetes Mellitus in Vietnam: A Systematic Review

This systematic review examined trends in the prevalence of type 2 diabetes mellitus (T2DM) and identified its risk factors among adults in Vietnam. PubMed, Web of Science, Wiley Online Library, and Scopus databases were searched to identify relevant literature. The search yielded 10 studies, including 2 national surveys and 8 regional investigations. National prevalence estimates of T2DM were 2.7% in 2002 and 5.4% in 2012. The estimates for the northern region were 1.4% in 1994 and 3.7% in 2012 and those for the southern region were 3.8% in 2004, 7.0% in 2008, and 12.4% in 2010. The major determinants of T2DM included older age, urban residence, high levels of body and abdominal fat, physical inactivity, sedentary lifestyle, genetic factors, and hypertension. The prevalence rate by gender was variable in both national and regional studies. There was insufficient information available on some potentially important risk factors such as smoking, dietary intake, income, and educational level. Our review signifies a rapidly growing prevalence of T2DM in Vietnam and suggests that extra effort is required to prevent and control this disease.

Vitamins and their derivatives in the prevention and treatment of metabolic syndrome diseases (diabetes),

A cluster of inter-related conditions such as central obesity, dyslipidemia, impaired glucose metabolism, and hypertension is referred to as Metabolic Syndrome, which is a risk factor for the development of type-2 diabetes. The micro- and macro-vascular complications of diabetes contribute to its morbidity and mortality. In addition to its calcitropic effect, vitamin D is a regulator of gene expression as well as cell proliferation and differentiation. Various cross-sectional and longitudinal cohort studies have indicated a beneficial effect from vitamin D supplementation on the development of type-2 diabetes. Binding of retinol-bound retinol-binding protein to a membrane-binding protein suppresses insulin signaling. All-trans retinoic acid, a derivative of vitamin A, reverses these effects, resulting in increased insulin sensitivity, suppression of the phosphoenolpyruvate carboxy kinase (PEPCK) gene, and the induction of the glucokinase gene. Glucokinase and PEPCK are also regulated in opposite directions by the vitamin biotin, acting at the transcriptional level. Biotin also regulates the synthesis of insulin by the islet of Langerhans cells of the pancreas. The increase in advanced glycation end products (AGEs) is implicated in the initiation and progression of diabetes-associated microvascular diseases. Benfotiamine, a derivative of thiamine, and pyridoxamine, a vitamer of vitamin B6, both have anti-AGE properties, making them valuable therapeutic adjuvants in the treatment of diabetic complications. Thus, various vitamins and their derivatives have profound therapeutic potential in the prevention and treatment of type-2 diabetes.

Effect of Vitamin D supplementation on glycemic parameters and progression of prediabetes to diabetes: A 1-year, open-label randomized study

BACKGROUND

Whether Vitamin D supplementation in prediabetes subjects prevents the development of diabetes is a matter of debate, and the results are inconsistent. This open-label, randomized study in subjects with prediabetes evaluated the effect of 12 months of Vitamin D supplementation on glycemic parameters and progression of prediabetes to diabetes in an ethnically homogeneous Kashmiri population.

MATERIALS AND METHODS

A total of 147 subjects were diagnosed as prediabetes out of which 137 subjects were randomized to receive in addition to standard lifestyle measures, either Vitamin D 60,000 IU weekly for 4 weeks and then 60,000 IU monthly (n = 69) or no Vitamin D (n = 68). Fasting plasma glucose (FPG), 2-h plasma glucose and A1C levels were estimated at 0, 6 and 12 months. Changes in FPG, 2-h plasma glucose, A1C level and the proportion of subjects developing diabetes were assessed among 129 subjects.

RESULTS

At 12 months, A1C levels were significantly lesser (5.7% ± 0.4%) in the Vitamin D supplemented group when compared with non-Vitamin D supplemented (6.0% ± 0.3%). Similarly, FPG (97 ± 7) and 2-h plasma glucose (132 ± 16) were significantly less in Vitamin D supplemented group as compared with non-Vitamin D supplemented group (FPG = 116 ± 6 and 2-h plasma glucose = 157 ± 25) at 12 months. Nine out of 65 in non-Vitamin D supplemented and seven out of 64 in the Vitamin D supplemented group developed diabetes.

CONCLUSIONS

Vitamin D supplementation in prediabetes subjects significantly lowered FPG, 2-h plasma glucose and A1C levels.

Vitamin D deficiency, serum leptin and osteoprotegerin levels in older diabetic patients: an input to new research avenues

The aim of this study was to assess the effects of single oral bolus of 300,000 IU Vitamin D3 on serum levels and on bone and metabolic parameters in diabetic patients. This study is a Phase IV, randomized, double-blind, placebo-controlled, monocenter clinical trial. Thirty patients, 60 years or older, with type 2 diabetes mellitus, and diabetic foot complications, were enrolled and monitored for 24 weeks: 14 were treated with Vitamin D3 and 16 with placebo. Parameters including glucose, adiponectin, leptin, osteoprotegerin (OPG), 25-hydroxyvitamin D [25(OH)D], beta-CrossLaps, osteocalcin, bone-specific isoenzyme of alkaline phosphatase, tumor necrosis factor-α and parathyroid hormone were measured at screening and baseline and 12 and 24 weeks after treatment. Analysis of covariance was used to compare treatment groups. Analysis of the data detected a significant increase in 25(OH)D serum levels both at 12 and 24 weeks with respect to baseline values only in the treated patients. Significant variations with respect to baseline values were noted in OPG (P = 0.0085) and in leptin (P = 0.0442) levels: these were lower in the placebo group at week 24 but higher in the treated group. Vitamin D3 supplementation significantly increased serum leptin and OPG levels. Further, large-scale clinical trials are warranted to confirm these results.

Mechanisms underlying therapeutic effects of 1,25(OH)2D3 against experimental ulcerative colitis in mice

AIM: To explore the mechanisms underlying the therapeutic effects of 1,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] against experimental ulcerative colitis (UC).

METHODS: Thirty Balb/c mice were randomly assigned to groups A to E: control group, model group, low-, medium-, and high-dose intervention groups. Groups B-E were given 5% DSS solution for seven days to induce UC, while group A was given equal volume of distilled water. On days 1, 3, 5, and 7, groups C-E were intraperitoneally injected with 50, 100 and 200 ng of 1,25(OH)₂D₃, respectively. Disease activity index (DAI) and histopathological score (HPS) were calculated. The protein expression of interferon-γ (IFN-γ), interleukin (IL)-17 and IL-4 in colonic tissues was measured by immunohistochemistry.

RESULTS: Compared to the control group, the DAI and HPS were significantly higher in the model group (7.33 ± 1.03 vs 0.33 ± 0.52, 12.00 ± 0.63 vs 0.17 ± 0.41, both P < 0.01). Compared to the model group, the DAI (2.83 ± 0.40, 2.83 ± 0.75, 2.33 ± 0.52) and HPS (10.83 ± 0.98, 7.50 ± 0.84, 6.67 ± 0.52) significantly decreased in the three intervention groups (all P < 0.01). The expression of IFN-γ and IL-17 was significantly higher in the model group than in the control group (both P < 0.01), and was significantly lower in the intervention groups than in the model group (all P < 0.01). IL-4 expression was significantly lower in the model group than in the control group (P < 0.01), and was significantly higher in the intervention group than in the model group (P < 0.01).

CONCLUSION: 1,25(OH)₂D₃ can maintain local immune balance in the colonic mucosa and reduce inflammation in ulcerative colitis.