Vitamin D: beyond bone

Advances in biomedical applications of vitamin D for VDR targeted management of obesity and cancer

BACKGROUND

1,25(OH)2D3 is a fat-soluble vitamin, involved in regulating Ca2+ homeostasis in the body. Its storage in adipose tissue depends on the fat content of the body. Obesity is the result of abnormal lipid deposition due to the prolonged positive energy balance and increases the risk of several cancer types. Furthermore, it has been associated with vitamin D deficiency and defined as a low 25(OH)2D3 blood level. In addition, 1,25(OH)2D3 plays vital roles in Ca2+-Pi and glucose metabolism in the adipocytes of obese individuals and regulates the expressions of adipogenesis-associated genes in mature adipocytes.

SCOPE AND APPROACH

The present contribution focused on the VDR mediated mechanisms interconnecting the obese condition and cancer proliferation due to 1,25(OH)2D3-deficiency in humans. This contribution also summarizes the identification and development of molecular targets for VDR-targeted drug discovery.

KEY FINDINGS AND CONCLUSIONS

Several studies have revealed that cancer development in a background of 1,25(OH)2D3 deficient obesity involves the VDR gene. Moreover, 1,25(OH)2D3 is also known to influence several cellular processes, including differentiation, proliferation, and adhesion. The multifaceted physiology of obesity has improved our understanding of the cancer therapeutic targets. However, currently available anti-cancer drugs are notorious for their side effects, which have raised safety issues. Thus, there is interest in developing 1,25(OH)2D3-based therapies without any side effects.

Resveratrol and Vitamin D: Eclectic Molecules Promoting Mitochondrial Health in Sarcopenia

Sarcopenia refers to the progressive loss and atrophy of skeletal muscle function, often associated with aging or secondary to conditions involving systemic inflammation, oxidative stress, and mitochondrial dysfunction. Recent evidence indicates that skeletal muscle function is not only influenced by physical, environmental, and genetic factors but is also significantly impacted by nutritional deficiencies. Natural compounds with antioxidant properties, such as resveratrol and vitamin D, have shown promise in preventing mitochondrial dysfunction in skeletal muscle cells. These antioxidants can slow down muscle atrophy by regulating mitochondrial functions and neuromuscular junctions. This review provides an overview of the molecular mechanisms leading to skeletal muscle atrophy and summarizes recent advances in using resveratrol and vitamin D supplementation for its prevention and treatment. Understanding these molecular mechanisms and implementing combined interventions can optimize treatment outcomes, ensure muscle function recovery, and improve the quality of life for patients.

Structure and the Anticancer Activity of Vitamin D Receptor Agonists

Vitamin D is a group of seco-steroidal fat-soluble compounds. The two basic forms, vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol), do not have biological activity. They are converted in the body by a two-step enzymatic hydroxylation into biologically active forms, 1α,25-dihydroxyvitamin D2 [ercalcitriol, 1,25(OH)2D2] and 1α,25-dihydroxyvitamin D3 [calcitriol, 1,25(OH)2D3], which act as classical steroid hormones. 1,25(OH)2D3 exerts most of its physiological functions by binding to the nuclear vitamin D receptor (VDR), which is present in most body tissues to provide support to a broad range of physiological processes. Vitamin D-liganded VDR controls the expression of many genes. High levels of 1,25(OH)2D3 cause an increase in calcium in the blood, which can lead to harmful hypercalcemia. Several analogs of 1,25(OH)2D3 and 1,25(OH)2D2 have been designed and synthesized with the aim of developing compounds that have a specific therapeutic function, for example, with potent anticancer activity and a reduced toxic calcemic effect. Particular structural modifications to vitamin D analogs have led to increased anticancer activity and reduced calcemic action with the prospect of extending work to provide future innovative therapies.

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

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

Comparative Performance Assessment of Novel Fluorescence Immunoassay POCTs for Measuring Circulating Levels of Vitamin-D

Vitamin D (Vit D) is a fat-soluble molecule acting like a hormone, and it is involved in several biological mechanisms such as gene expression, calcium homeostasis, bone metabolism, immune modulation, viral protection, and neuromuscular functions. Vit D deficiency can lead to chronic hypocalcemia, hyperparathyroidism, and many other pathological conditions; in this context, low and very low levels of 25-hydroxy-vitamin D (25-OH-D) were found to be associated with an increased risk of COVID-19 infection and the likelihood of many severe diseases. For all these reasons, it is important to quantify and monitor 25-OH-D levels to ensure that the serum/blood concentrations are not clinically suboptimal. Serum concentration of 25-OH-D is currently the main indicator of Vit D status, and it is currently performed by different assays, but the most common quantitation techniques involve immunometric methods or chromatography. Nevertheless, other quantitation techniques and instruments are now emerging, such as AFIAS-1® and AFIAS-10® (Boditech and Menarini) based on the immunofluorescence analyzer, that guarantee an automated system with cartridges able to give quick and reliable results as a point-of-care test (POCT). This work aims to compare AFIAS-1® and AFIAS-10® (Boditech and Menarini) Vit D quantitation with Ultra High-Performance Liquid Chromatography coupled with tandem mass spectrometry that currently represents the gold standard technique for Vit D quantitation. The analyses were performed in parallel on 56 samples and in different conditions (from fresh and frozen plasma) to assess the reliability of the results. Any statistically significant differences in methods, the fixed error, and the error proportional to concentration were reported. Results obtained in all conditions showed a good correlation between both AFIAS® instruments and LC-MS/MS, and we can affirm that AFIAS-1® and AFIAS-10® are reliable instruments for measuring 25-OH-D with accuracy and in a fast manner.

Synergistic effect of metformin and vitamin D3 on osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells under high d-glucose conditions

Introduction

Vitamin D3 plays a vital role in bone health, with low levels of vitamin D3 being related to skeletal fragility, fractures, and metabolic disorders such as diabetes. Metformin is known as an antihyperglycemic agent for regulating blood sugar. A correlation between diabetes mellitus and osteoporosis is attracting considerable interest, and research to find the prevention and treatment is gradually being studied. In this study, we investigated the effect of metformin and vitamin D3 on osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (AT-MSCs) under high d-glucose concentrations and optimized by combining vitamin D3 and metformin in the process.

Methods

ROS production of AT-MSCs under high d-glucose conditions was measured by DCFH-DA assay. The differentiated AT-MSCs were analyzed by Alizarin Red S staining and optical density measurement. The investigation involved the examination of osteogenic master genes' expressions using quantitative reverse transcription polymerase chain reaction (qRT-PCR) techniques.

Results

Interestingly, the results have shown that human AT-MSCs will exhibit high ROS accumulation and low osteogenic differentiation capabilities, indicated by low calcium deposition, as well as low expression of indicative genes such as ALP, Runx-2 under high d-glucose conditions. The combination of vitamin D3 and metformin remarkedly accelerated the osteogenic differentiation of AT-MSCs under high d-glucose concentrations more effectively than the administration of either agent.

Conclusions

This study partially explains an aspect of an in vitro model for pre-clinical drug screening for osteoporosis-related diabetic pathological mechanisms, which can be applied for further research on the prevention or treatment of osteoporosis in diabetic patients.

The improvement of homocysteine-induced myocardial inflammation by vitamin D depends on activation of NFE2L2 mediated MTHFR

OBJECTIVES

Myocardial inflammation underlies a broad spectrum of conditions that cause damage to the myocardium and lead to structural and functional defects. Homocysteine (Hcy) is closely related to the occurrence and development of cardiovascular diseases. We investigated the mechanism underlying the effects of vitamin D as a prophylactic treatment for Hcy-induced cardiac inflammation.

METHODS

The levels of 25(OH)D3 and Hcy were assessed using ELISA kits. Expression levels of the vitamin D receptor (VDR), NFE2 like bZIP transcription factor 2 (NFE2L2), methylenetetrahydrofolate reductase (MTHFR) and inflammatory factors were examined by Western blotting, immunohistochemistry and real time polymerase chain reaction. NFE2L2/MTHFR-knockdown HL-1 cells and NFE2L2+/- mouse were used to test the effects of vitamin D.

RESULTS

We found the levels of Hcy in the serum and myocardial tissue of mice in the Hcy + CCE group were lower than in the Hcy groups, which was opposed to the trend exhibited by the serum 25(OH)D3 level of mice. The mRNA and protein expression levels of the inflammatory factors in cardiac tissues and cardiomyocytes were strongly decreased by the Hcy treatment, compared to the Hcy + CCE/Hcy + 1,25(OH)2D3 groups. Moreover, the results revealed that the level of nuclear NFE2L2 in Hcy + CCE/Hcy + 1,25(OH)2D3 group was increased compared to Hcy group with a reciprocal decrease in the level of cytosolic NFE2L2 in vivo and in vitro. Similarly, the MTHFR mRNA and protein expression in the Hcy + CCE group was higher than the Hcy group. We determined that NFE2L2 promoted the expression of MTHFR. However, based on Hcy treatment, the combination of 1,25(OH)2D3 and MTHFR-/- reversed the decline in IL-6 and TNFα expression caused by 1,25(OH)2D3 alone. Chromatin immunoprecipitation and luciferase reporter assays showed the up-regulation effect of VDR on NFE2L2 and NFE2L2 on MTHFR.

CONCLUSIONS

Our findings indicate that vitamin D/VDR could improve Hcy-induced myocardial inflammation through activation of NFE2L2 mediated MTHFR.

Evaluation of 25(OH) vitamin D3 and quadriceps strength correlation in postmenopausal women: A cross-sectional study

BACKGROUND

Vitamin D deficiency is common in postmenopausal women and is associated with low vitamin D intake, increased age, decreased absorption. Especially at advanced age, vitamin D deficiency may increase muscle weakness and disbalance resulting in increased risk of fracture.

OBJECTIVES

This study aims to explore the correlation between 25(OH) vitamin D3 levels and quadriceps muscle strength in postmenopausal women.

METHODS

We evaluated bilateral qadriceps muscle strength in postmenopausal women with isokinetic test. We evaluated the correlation of muscle power with measurements of parathormone, vitamin D, Calcium, creatinine, alanine transaminase, alkaline phosphatase, total creatine kinase.

RESULTS

The mean vitamin D level of 95 participants included in the study was 18.24 ± 8.94 ng/ml. Vitamin D levels were found to be deficient (< 10 ng/ml) in 23 (24.1%), insufficient in 62 (65.26%) and normal in 10 (10.53%) of the 95 participants. A weak negative correlation was observed between participants' vitamin D levels and PT values (r=-0.271, p= 0.012). A moderate negative correlation was found between ALP and vitamin D levels (r=-0.317, p= 0.002). However, there was no significant correlation between vitamin D levels and the 60∘ and 90∘ flexion and extension peak torque values (All p values > 0.05).

CONCLUSIONS

Vitamin D levels and muscle strength weren't statistically significant. Few studies are available in the related literature, highlighting the need for further research to achieve a clearer consensus.

Influence of Vitamin D on Periodontal Inflammation: A Review

The active form of vitamin D is the hormonally active 1,25(OH)2D3 (Vit D) vitamin, which plays an important role in bone biology and host immunity. The vitamin D receptor (VDR) is a nuclear ligand-dependent transcription factor expressed by many cells. Ligation of VDR by VitD regulates a wide plethora of genes and physiologic functions through the formation of the complex Vit D-VDR signaling cascade. The influence of Vit D-VDR signaling in host immune response to microbial infection has been of interest to many researchers. This is particularly important in oral health and diseases, as oral mucosa is exposed to a complex microbiota, with certain species capable of causing disruption to immune homeostasis. In this review, we focus on the immune modulatory roles of Vit D in the bone degenerative oral disease, periodontitis.

Effect of Vitamin D Deficiency on Voice: A Review of the Literature

OBJECTIVE

The purpose of this study is to review the current literature on the effect of hypovitaminosis D on voice.

STUDY DESIGN

Narrative review.

METHODS

The literature search from electronic databases included PubMed/MEDLINE, EMBASE, SCOPUS, and Google Scholar. Search terms included voice, voice quality, voice disorders, larynx, laryngology, acoustic analysis, vitamin D, calcitriol, cholecalciferol, vitamin D deficiency, and vitamin D insufficiency. All studies on patients with vitamin D deficiency, which included subjective and objective voice assessments, were reviewed.

RESULTS

A total of 39 studies were retrieved. Only four studies met the above-mentioned inclusion criteria and hence were included in this review. The total number of subjects analyzed was 466. The subjective voice outcome measures used were the Voice Handicap Index-10 (VHI-10), self-reported phonatory symptoms, and the GRBAS scale. Objective voice outcome measures included fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, maximum phonation time, and dysphonia severity index.

CONCLUSION

Vitamin D deficiency has no significant effect on laryngeal muscles. There was no statistically significant difference in VHI-10 score, self-reported dysphonia, perceptual voice evaluation scores, or any of the acoustic measures between those with or without vitamin D deficiency.

[Effect of vitamin D3 on mild cognitive impairment in type 2 diabetic mice and its possible mechanism]

OBJECTIVE

To investigate the effect of vitamin D3 on mild cognitive impairment in type 2 diabetic mice and explore its possible mechanism.

METHODS

Male db/db mice were randomly divided into 4 groups: the diabetes mellitus (DM) group, the low dose [250 IU/(kg·d)], medium dose [500 IU/ (kg·d)] and high dose [1 000 IU/(kg·d)] vitamin D3 intervention groups. The db/m mice were enrolled as the normal control group. The mice in vitamin D3 groups were gavaged with corresponding concentration of vitamin D3 in corn oil, and the mice in the normal control group and the DM group were gavaged with corn oil. After being fed for 16 weeks, fasting blood glucose of mice in each group was measured at the end of 0, 4, 8 and 16 weeks, and the new object recognition experiment was conducted at the end of 16 weeks. At the end of the experiment, the hippocampi and cortices of mice in each group were collected, and the concentration of 5-hydroxytryptamine (5-HT) and interleukin-18 (IL-18) in the hippocampal tissues of mice in each group were determined by enzyme linked immunosorbent assay (ELISA). Immunohistochemical staining was used to observe the expression of nucleotide binding oligomerization domain-like receptor family pyrin domain-containing protein 3 (NLRP3) in the hippocampal tissues of the mice.

RESULTS

Compared with the normal control group, the fasting blood glucose of mice in DM group was significantly increased (P < 0.01). The exploration and discrimination index (DI) in the new object recognition experiment were significantly decreased (P < 0.05). The concentrations of 5-HT in the hippocampal tissues of mice were significantly decreased (P < 0.01). The concentrations of IL-18 in cortical tissues of mice were significantly increased (P < 0.01) and the positive expression of NLRP3 in the hippocampal tissues was higher. However, compared with the DM group, the fasting blood glucose of mice was significantly decreased in the medium and high dose vitamin D3 groups at the end of 8 and 16 weeks (P < 0.05 or P < 0.01). The exploration and DI of mice in the new object recognition experiment were significantly increased in high dose vitamin D3 group (P < 0.05). The concentrations of 5-HT in hippocampal tissues were significantly increased (P < 0.01) and the concentrations of IL-18 in cortical tissues were significantly decreased in the medium and high dose vitamin D3 groups (P < 0.01). The positive expression of NLRP3 in hippocampal tissues was reduced in all the vitamin D3 groups.

CONCLUSION

Vitamin D3 might reduce the inflammatory response by inhibiting the activity of NLRP3, and thus ameliorating mild cognitive impairment in type 2 diabetic mice.

EXPERIMENTAL CHOLECALCIFEROL SUPPLEMENTATION IN A HERD OF MANAGED ASIAN ELEPHANTS (ELEPHAS MAXIMUS)

Vitamin D supplementation may pose a significant health risk in species where levels of deficiency, sufficiency, and toxicity have not been clearly established, and species-specific research on vitamin D supplementation should be performed. This study documented the effect of vitamin D supplementation on serum vitamin D metabolites and other analytes of Ca homeostasis in Asian elephants (Elephas maximus). Six adult Asian elephants received PO supplementation with cholecalciferol at 300 IU/kg of body weight (BW) once a week for 24 wk. Serum was analyzed every 4 wk for 25-hydroxyvitamin D₂/D₃ [25(OH)D]; 24,25-dihydroxyvitamin D₂/D₃ [24,25(OH)₂D]; 1,25-dihydroxyvitamin D [1,25(OH)₂D]; parathyroid hormone (PTH); total Ca; ionized Ca (iCa); P; and Mg. After the supplement was discontinued, serum 25(OH)D₂/D₃ was measured every 4 wk until levels returned to baseline. At the start of the study, the average serum 25(OH)D₃ was nondetectable (<1.5 ng/ml). With cholecalciferol supplementation, 25(OH)D₃ increased at an average rate of 2.26 ng/ml per month and reached an average concentration of 12.9 ± 3.46 ng/ml at 24 wk. Both 24,25(OH)₂D₃ and 1,25(OH)₂D increased over time with supplementation from an average of <1.5 to 12.9 ng/ml and from 9.67 to 36.4 pg/ml, respectively. PTH, iCa, Ca, P, and Mg remained within reported normal ranges throughout supplementation. After the supplement was discontinued, serum 25(OH)D₃ demonstrated a slow decline to baseline, taking an average of 48 wk. Elephants demonstrated significant individual variation in response to supplementation and subsequent return to baseline. Supplementation of Asian elephants with a weekly dose of 300 IU/kg BW cholecalciferol for 24 wk appears to be effective and safe. Additional clinical studies would be necessary to investigate the safety of other routes of administration, dosages, and duration of vitamin D supplementation, as well as associated health benefits.

A meta-analysis of the association between vitamin D supplementation and the risk of acute respiratory tract infection in the healthy pediatric group

No previous meta-analysis had explored the association between vitamin D supplementation in healthy pediatrics and the risk of acute respiratory tract infections (ARTIs). Thus, we meta-analyzed the current evidence in this regard to provide sufficient knowledge about this risk-benefit ratio for vitamin D supplementation in this specific age group. We searched seven databases for randomized controlled trials (RCTs) that investigated the effect of vitamin D supplementation and ARTIs risk on a healthy pediatric population (0-18 years old). Meta-analysis was performed through R software. We included eight RCTs after the screening of 326 records according to our eligibility criteria. There were comparable infection rates between Vitamin D and placebo groups (OR = 0.98, 95% CI = 0.90-1.08, P-value = 0.62), with no significant heterogeneity among the included studies (I² = 32%; P-value = 0.22). Moreover, there was no significant difference between the two vitamin D regimens (OR = 0.85, 95% CI = 0.64-1.12, P-value = 0.32), with no considerable heterogeneity among the included studies (I² = 37%; P-value = 0.21). However, there was a significant reduction in Influenza A rates in the high-dose vitamin D group compared to the low dose one (OR = 0.39, 95% CI = 0.26-0.59, P-value < 0.001), with no heterogeneity among the included studies (I² = 0%; P-value = 0.72). Only two studies of 8,972 patients reported different side effects, with overall acceptable safety profile. Regardless of the dosing regimen used or the type of infection, in the healthy pediatric group, there is no evident benefit of using vitamin D to prevent or reduce the ARTI rates.

Molecular cloning, expression analysis and functional characterization of chicken cytochrome P450 27A1: A novel mitochondrial vitamin D3 25-hydroxylase

Vitamin D₃ is hydroxylated by cytochrome P450 (CYP) before exerting biological effects. The chicken CYP involved in vitamin D₃ 25-hydroxylation has yet to be cloned, and little is known about its functional characteristics, tissue distribution, and cellular expression. We identified a novel, full-length CYP27A1 gene cloned from chicken hepatocyte cDNA that encodes a putative protein of 518 amino acids. Swiss modeling revealed that chicken CYP27A1 has a classic open-fold form. Multisequence homology alignment determined that CYP27A1 contains conserved motifs for substrate recognition and binding. Quantitative real-time PCR analysis in 2-mo-old Partridge Shank broilers demonstrated that CYP27A1 mRNA levels were highest in the liver, followed by the thigh muscles, the breast muscles, and kidneys. The transcripts of CYP27A1 in breast muscles were significantly higher in males than in females. A subcellular localization analysis demonstrated that CYP27A1 was mainly expressed in the mitochondria. In vitro enzyme assays suggested that recombinant CYP27A1 hydroxylates vitamin D₃ at the C-25 position to form 25-hydroxyvitamin D₃ (25(OH)D₃). The K_m and V_max values for CYP27A1-dependent vitamin D₃ 25-hydroxylation were estimated to be 4.929 μM and 0.389 mol min^-1 mg^-1 protein, respectively. In summary, these results suggest that CYP27A1 encodes a mitochondrial CYP that plays an important physiologic role in the 25-hydroxylation of vitamin D₃ in chickens, providing novel insights into vitamin D₃ metabolism in this species.

Developmental defects and potential mechanisms in F1 generation of parents exposed to difenoconazole at different life stages of zebrafish (Danio rerio)

As a typical triazole fungicide, difenoconazole is extensively used to control plant diseases; however, its residue in environmental waters poses a risk to aquatic organisms. In this study, we investigated the acute toxicity of different life stages and sub-lethal toxicity in embryonic yolk sac stage of difenoconazole to zebrafish, and the developmental toxicity in F1 generation of parents exposed to difenoconazole at different life stages of zebrafish. Furthermore, we used transcriptomics to explore the potential mechanisms of difenoconazole on the F1 larvae of parents exposed to the chemical at the embryonic stage. The results of this study showed that developmental defects were observed in the F1 embryo/larvae of parents exposed to 3, 30, and 300 μg/L of difenoconazole at different (embryo, larval, juvenile, and adult) life stages, and exposure to difenoconazole at the embryonic stage caused more severe developmental toxicity than those at other life stages. Developmental defects (malformation, inhibition of heartbeat and body length) were observed in the F1 embryos and larvae of parents exposed to difenoconazole at the embryonic stage. In addition, the total cholesterol and triglyceride contents were significantly reduced in the F1 larvae, and RNA-seq analysis revealed significant alterations in the expression of nine genes (msmo1, hsd17b7, sc5d, tm7sf2, ebp, cyp2r1, lss, cyp51, and cyp27b1) in the steroid synthesis pathway. This is suggested that F1 larvae of parents exposed to difenoconazole at the embryonic stage show abnormalities in the steroid biosynthetic pathway. These results reveal the differences in toxicity of difenoconazole to zebrafish at different life stages, improve studies on difenoconazole toxicity to zebrafish, and provide a new perspective for assessing the risk of contaminants to aquatic organisms.

Influence of hypovitaminosis D during pregnancy on glycemic and lipid profile, inflammatory indicators and anthropometry of pregnant and newborn

BACKGROUND & AIMS

Hypovitaminosis D currently represents a public health problem and is related to the emergence of chronic diseases. Furthermore, this vitamin deficiency has been associated with pregnancy complications, and it can also influence newborn's growth and development. The purpose of this review is to understand the effects of vitamin D nutritional status on women during pregnancy, as well as its impact on newborn's health.

METHODS

Review of observational studies, published between 2020 and 2021. The research was carried out in the following databases: Pubmed and SciELO. The search terms used to select the articles were: vitamin D, 25(OH)D, serum levels, pregnancy, lactation, gene expression, maternal results, complications, pre-eclampsia, obesity, gestational diabetes, and children. As inclusion criteria, were considered observational studies that addressed the topic and answered the review aims.

RESULTS

52 articles were identified and at the end of the selection process, 19 articles were considered, in which they met all the established eligibility criteria. According to the findings in this review, hypovitaminosis D is related to gestational diabetes, pre-eclampsia and gestational weight gain, changes in laboratory parameters as well as outcomes in newborns.

CONCLUSIONS

Hypovitaminosis D can adversely influence pregnancy and newborn's health, evidencing the need to assess the nutritional status of vitamin D, as well as the existence, or not, of a clinic during pregnancy. It is important that new scientific evidence is published to support this hypothesis.

Potential benefits of vitamin D supplementation on pregnancy

BACKGROUND

The level of vitamin D in pregnant women and the effect of vitamin D supplementation are lack in Taiwan.

OBJECTIVE

To investigate the vitamin D serum level and the effect of its supplementation on pregnancy.

METHODS

We included 1048 pregnant women who underwent prenatal exam with known serum 25-hydroxyvitamin D3 [25(OH)D3] levels and delivery at the Mackay Memorial Hospital, Taipei, Taiwan during 2015-2018. A daily dose 2000 IU of vitamin D was given, starting at 12-16 weeks of pregnancy, to reach the level of 20 ng/mL, and then a maintenance dose of 800 IU/day was given. The other 3654 women without vitamin D supplementation delivered in 2018 served as control group. Pregnancy outcomes were recorded for analysis.

RESULTS

Over 80% of the 1048 pregnant women were vitamin D deficiency. There was an inverse correlation between serum vitamin D levels and maternal body mass index (p = 0.0366). We compared 375 women with serum vitamin D levels increased above 30 ng/mL after supplementation with control group. The rates of preterm birth, low birth weight, and postpartum hemorrhage between these 2 groups were 6.67% vs. 11.19% (p = 0.007), 6.40% vs. 10.0% (p = 0.025), and 1.33% vs. 3.20% (p = 0.04), respectively.

CONCLUSIONS

Vitamin D deficiency is very prevalent in pregnant women, especially those with high BMI, in Taiwan. It can be corrected by adequate vitamin D supplementation, which may decrease the risk of pregnancy complications and bring benefits to the fetus.

Circulating 25-hydroxyvitamin D is associated with metabolic phenotypes of obesity: National Food and Nutrition Surveillance

Different phenotypes of obesity are each related with different complications and comorbidities. We hypothesized that suboptimal vitamin D status is directly associated with an unhealthy metabolic status, especially if allied with obesity. This cross-sectional study was performed in the framework of the National Food and Nutrition Surveillance. Overall, 1098 men and women participated in this study. In addition to height and weight, serum concentrations of 25-hydroxyvitamin D (25(OH)D) and glycemic and lipidemic status were evaluated. Then participants were classified into 4 groups based on body mass index and lipidemic and glycemic profile status, as follows: hyperglycemic-dyslipidemic obese (HDO), hyperglycemic-dyslipidemic nonobese (HDNO), normoglycemic-normolipidemic obese (NNO), and normoglycemic-normolipidemic nonobese (NNNO). In this study, 31.6% of participants were classified as HDO, 7.5% as HDNO, 34.5% as NNO, and 26.4% as NNNO. The frequency of suboptimal vitamin D status was more prevalent in HDO (81.8%) than in other phenotypes (HDNO, 80%; NNO, 77.6%; NNNO, 73.8%; P = .015). In the multivariate model, suboptimal vitamin D status significantly increased the odds of being NNO (odds ratio [OR], 1.28; 95% CI, 0.84-1.95), HDNO (OR, 1.48; 95% CI, 0.77-2.83), and HDO (OR, 1.73; 95% CI, 1.11-2.7) compared with the NNNO group. Likewise, in multivariate model, per each unit (ng/mL) increment in 25(OH)D concentration, the odds of HDNO and HDO decreased significantly by 4% (OR, 0.96; 95% CI, 0.94-0.98) and 7% (OR, 0.93; 95% CI, 0.92-0.95), respectively. The results of the study showed a significant relationship between serum 25(OH)D concentrations and metabolic obesity phenotypes; these data confirm the association between suboptimal vitamin D status and metabolic complications, especially in obese individuals.

Protective role of vitamin D3 in a rat model of hyperthyroid-induced cardiomyopathy

Background and aim

Several studies have reported the cardioprotective effect of vitamin D. Thus, this study aimed to investigate the possible cardioprotective effect of vitamin D3 in hyperthyroid-induced cardiomyopathy rat model.

Experimental procedure

Rats were divided into 3 groups: control group; hyperthyroid group, rats were administrated l-thyroxine sodium daily for 4 weeks; and hyperthyroid + vitamin D3 treated group, rats were treated with l-thyroxine sodium for 4 weeks daily, and received the vitamin D3 for the same duration. After 4 weeks, electrocardiogram (ECG) was recorded. Then, blood samples were collected for biochemical analysis. After that, the final body weight was measured, and the rats were sacrificed. Finally, the hearts were excised, weighed and were prepared for histological examination by hematoxylin and eosin, and immunohistochemistry assessment of caspase-3 and proliferating cell nuclear antigen (PCNA).

Results

Hyperthyroid rats showed significant ECG changes, increased serum levels of cardiac biomarkers, fibroblast growth factor-23 (FGF23), malondialdehyde, antioxidant enzymes, tumor necrosis factor-alpha (TNF-α) and relative heart weight compared with the control rats. Vitamin D3 coadministration with l-thyroxine resulted in significant improvement in thyroid profile, ECG parameters, significant decrease of cardiac biomarkers, FGF23, malondialdehyde, TNF-α and relative heart weight, and significant decrease of the antioxidant enzymes compared with the hyperthyroid rats. The histological study was consistent with the biochemical results. Hyperthyroid rats showed upregulation of caspase-3 and PCNA in the myocardium compared with control group. Vitamin D3 treated rats showed downregulation of caspase-3 and PCNA.

Conclusion

Vitamin D3 provides cardioprotective effects in hyperthyroid rats.

Muscle plasticity is influenced by renal function and caloric intake through the FGF23-vitamin D axis

Skeletal muscle, the main metabolic engine in the body of vertebrates, is endowed with great plasticity. The association between skeletal muscle plasticity and two highly prevalent health problems: renal dysfunction and obesity, which share etiologic links as well as many comorbidities, is a subject of great relevance. It is important to know how these alterations impact on the structure and function of skeletal muscle because the changes in muscle phenotype have a major influence on the quality of life of the patients. This literature review aims to discuss the influence of a nontraditional axis involving kidney, bone, and muscle on skeletal muscle plasticity. In this axis, the kidneys play a role as the main site for vitamin D activation. Renal disease leads to a direct decrease in 1,25(OH)₂-vitamin D, secondary to reduction in renal functional mass, and has an indirect effect, through phosphate retention, that contributes to stimulate fibroblast growth factor 23 (FGF23) secretion by bone cells. FGF23 downregulates the renal synthesis of 1,25(OH)₂-vitamin D and upregulates its metabolism. Skeletal production of FGF23 is also regulated by caloric intake: it is increased in obesity and decreased by caloric restriction, and these changes impact on 1,25(OH)₂-vitamin D concentrations, which are decreased in obesity and increased after caloric restriction. Thus, both phosphate retention, that develops secondary to renal failure, and caloric intake influence 1,25(OH)₂-vitamin D that in turn plays a key role in muscle anabolism.

Vitamin D-A prominent immunomodulator to prevent COVID-19 infection

COVID-19 remains a life-threatening infectious disease worldwide. Several bio-active agents have been tested and evaluated in an effort to contain this disease. Unfortunately, none of the therapies have been successful, owing to their safety concerns and the presence of various adverse effects. Various countries have developed vaccines as a preventive measure; however, they have not been widely accepted as effective strategies. The virus has proven to be exceedingly contagious and lethal, so finding an effective treatment strategy has been a top priority in medical research. The significance of vitamin D in influencing many components of the innate and adaptive immune systems is examined in this study. This review aims to summarize the research on the use of vitamin D for COVID-19 treatment and prevention. Vitamin D supplementation has now become an efficient option to boost the immune response for all ages in preventing the spread of infection. Vitamin D is an immunomodulator that treats infected lung tissue by improving innate and adaptive immune responses and downregulating the inflammatory cascades. The preventive action exerted by vitamin D supplementation (at a specific dose) has been accepted by several observational research investigations and clinical trials on the avoidance of viral and acute respiratory dysfunctions. To assess the existing consensus about vitamin D supplementation as a strategy to treat and prevent the development and progression of COVID-19 disease, this review intends to synthesize the evidence around vitamin D in relation to COVID-19 infection.

Prevalence and novel risk factors for vitamin D insufficiency in elite athletes: systematic review and meta-analysis

BACKGROUND AND PURPOSE

Vitamin D insufficiency may be common among elite athletes, but prevalence is unclear, and some potentially important risk factors are uncertain. The present study aimed to (a) estimate the prevalence of vitamin D insufficiency in elite athletes, and (b) examine differences in prevalence between the sexes, and between adults and adolescents, from recent studies which used a contemporary definition of insufficiency.

METHODS

Four databases (Web of Science, SPORTDiscus, PubMed, and Sports Medicine and Education Index) were searched for studies in elite athletes. Literature selection, data extraction, and risk of bias assessment were conducted independently by two researchers. Vitamin D insufficiency was defined as 25(OH)D < 50 nmol/L. Meta-analysis was conducted, using R software x64 4.0.2, to provide estimates of prevalence of insufficiency for adults and adolescents, and to examine between-sex differences in risk of insufficiency.

RESULTS

From the initial 943 literature search hits, 51 studies were eligible with 5456 participants, 33 studies in adults (12/33 in winter and spring), 15 studies in adolescents (6/15 in winter and spring) and 3 studies with age of study participants not given. Prevalence of vitamin D insufficiency from meta-analysis was 30% (95% CI 22-39%) in adults and prevalence was higher, though not significantly so, at 39% (95% CI 25-55%) in adolescents. Differences in the prevalence of insufficiency between the sexes for the eight studies which provided within-study comparisons was not significant (RR = 1.0; 95% CI 0.79-1.26). Evidence quality was moderate.

CONCLUSIONS

Prevalence of vitamin D insufficiency (≤ 50 nmol/L) in elite athletes is high, suggesting a need for greater attention to prevention and treatment. Prevalence estimates in the present study are conservative due to a relative lack of studies in winter. While there was no evidence of higher risk among women than men in the present study, there was less evidence on women.

Maternal vitamin D levels correlate with fetal weight and bone metabolism during pregnancy: a materno-neonatal analysis of bone metabolism parameters

OBJECTIVES

Vitamin D plays an essential role in neonatal skeletal development and maternal weight gain during pregnancy. We aim to study the association between vitamin D status, maternal weight, and materno-neonatal bone metabolism parameters.

METHODS

From January to June 2017, we conducted this cross-sectional study among 103 pregnant women (21-42 years old) and their singletons. The levels of serum 25-(OH)D, PTH, P1NP, OC, and CTX were measured for mothers and neonates (cord blood). Serum vitamin D and OC were measured using chemiluminescence and two-site immunoradiometric assay, respectively. Meanwhile, P1NP, CTX, and PTH were measured by ELISA.

RESULTS

The average serum vitamin D levels from mothers were 15.1 ng/mL during pregnancy and 16.2 ng/mL in the umbilical cord. At baseline, vitamin D deficient mothers were more likely to have higher PTH (36.4 vs. 18 pg/mL; p=0.029) and lower P1NP levels (90 vs. 92.5 ng/mL; p=0.026). Also, vitamin D deficient status was associated with lower fetal weight (3,293 vs. 3,358 g; p=0.019). Maternal weight was significantly correlated with P1NP (65.86 vs. 109.35; p=0.001) and OC (14.52 vs. 18.24; p=0.038), as well as cord vitamin D level (13.31 vs. 18.46; p=0.039) among normal vs. overweight women. No significant differences were found for the correlation between maternal weight and fetal parameters except for fetal weight which significantly increased with the increase in maternal weight (overweight vs. obese women=3,280 vs. 3,560; p=0.06).

CONCLUSIONS

Maternal vitamin D status is associated with maternal and neonatal bone metabolism parameters as well as maternal and neonatal weight.

The association of vitamin D deficiency with hemogram-derived inflammatory biomarkers in children

BACKGROUND AND AIMS

One of the extraosseous effects of vitamin D is that it is a potent modulator of inflammatory processes. Many studies have demonstrated the inverse association between vitamin D and inflammation. Therefore, we hypothesize that vitamin D deficiency may affect the inflammatory markers derived from hemogram parameters [neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), lymphocyte to monocyte ratio (LMR), platelet distribution width (PDW), red blood cell distribution width (RDW)] in healthy children.

METHODS AND RESULTS

We conducted a retrospective study on healthy children. From 2015 to 2020, 16,321 children with simultaneous vitamin D and hemogram measurements were identified from electronic records. Participants were divided into 2 groups according to whether they had vitamin D deficiency or not. The relationship between vitamin D status and the levels of inflammatory markers was analyzed. All inflammatory markers showed statistically significant differences between vitamin D status (p < 0.001 for all). Vitamin D levels were significantly negatively correlated with NLR (r = -0.285), PLR (r = -0.257), PDW (r = -0.181), and positively correlated with LMR (r = 0.218), and RDW (r = 0.057). In logistic regression analysis, age (OR = 1.15, 95% CI: 1.14-1.16), gender (OR = 1.66, 95% CI: 1.54-1.78), LMR (OR = 0.96, 95% CI: 0.95-0.98), PLR (OR = 1.003, 95% CI: 1.001-1.004), and RDW (OR = 1.10, 95%CI: 1.07-1.13) were found to be independent predictors for vitamin D deficiency.

CONCLUSIONS

Statistically significant differences were detected between vitamin D status and inflammatory parameters. However, the difference between the median values of vitamin D groups was very small and the degree of correlation was very weak. Therefore, the clinical significance of the difference should be questioned.

The association between vitamin D levels and heart rate variability in patients with type 2 diabetes mellitus

To assess the association between serum vitamin D levels and heart rate variability in patients with type 2 diabetes mellitus (T2DM). This study included 469 patients who were retrospective assessed for eligibility from Changzhou Second People's Hospital, Affiliated Nanjing Medical University, between March 2013 and June 2020. A total of 191 T2DM patients were recruited and divided into 3 groups. A total of 191 patients were recruited. A significant difference was noted among groups for HbA1c (P < .001), serum uric acid (P = .048), and urea nitrogen (P = .043). The Vitamin D level in deficiency, insufficiency, and sufficient was 23.17, 38.89, and 63.01 nmol/L, respectively. The insufficient group had lower levels of percentage of normal-to-normal intervals differing by more than 50 milliseconds, and the square root of the mean of the squares of the differences between adjacent normal-to-normal R peak-to-R-peak time intervals than the sufficient vitamin D group. Furthermore, patients in deficiency and insufficiency group were associated with high level of low frequency power/high frequency power as compared with sufficient vitamin D group. Finally, serum 25-hydroxyvitamin D (25(OH)D) levels were positively correlated with rMSSD (P = .002). This study found that low serum 25(OH)D levels were associated with reduced heart rate variability parameters in patients with T2DM.

Correlation of Gut Microbiota, Vitamin D Status, and Pulmonary Function Tests in Children With Cystic Fibrosis

Background

Children with cystic fibrosis (CF) are expected to have suboptimal serum vitamin D status and altered gut microbiota. The altered gut microbiota is hypothesized to have a pro-inflammatory effect that further complicates the existing respiratory inflammation. Emerging evidence suggests an association between vitamin D and gut microbiota. The aim of this study was to assess the relationships between 25-hydroxyvitamin D [25(OH)D] status, pulmonary function, and fecal bacteria in children with CF.

Methods

In this cross-sectional study, a total of 35 children with CF (8.7 ± 2.83 years) and 24 controls without CF (9 ± 2.7 years) were included in this study. Serum 25(OH)D status was measured using the Elecsys vitamin D total II assay. In the CF group, gut microbiota composition was assessed using real-time PCR analysis. Pulmonary function tests (PFTs) were measured using spirometry. Comparisons between the CF and non-CF controls were conducted using the independent sample t-test. In the CF group, one-way analysis of variance (ANOVA) was used to assess differences in PFTs and gut microbiota composition across the three vitamin D subgroups. The correlations between 25(OH)D status and PFTs, or gut microbiota composition, and PFTs with gut microbiota composition were analyzed using the Pearson's correlation coefficient test.

Results

Children with CF had significantly lower serum 25(OH)D levels compared with children without CF (44.3 ± 22.4 vs. 59 ± 25.5, respectively, P = 0.026). Children with CF with optimal serum 25(OH)D level had significantly higher levels of Bacteroidetes, Firmicutes, and total bacteria (P = 0.007, P = 0.007, and P = 0.022, respectively). The level of Firmicutes was found to be significantly higher in mild forced expiratory volume in 1 s (FEV1) compared with moderate FEV1 (P = 0.032), whereas the level of the other bacteria species was comparable across FEV1 severity groups.

Conclusion

Our findings may encourage studies that target and modify gut microbiota to potentially achieve better outcomes in terms of respiratory function in CF.

Calcifediol for Use in Treatment of Respiratory Disease

Calcifediol is the prohormone of the vitamin D endocrine system (VDES). It requires hydroxylation to move to 1,25(OH)2D3 or calcitriol, the active form that exerts its functions by activating the vitamin D receptor (VDR) that is expressed in many organs, including the lungs. Due to its rapid oral absorption and because it does not require first hepatic hydroxylation, it is a good option to replace the prevalent deficiency of vitamin D (25 hydroxyvitamin D; 25OHD), to which patients with respiratory pathologies are no strangers. Correcting 25OHD deficiency can decrease the risk of upper respiratory infections and thus improve asthma and COPD control. The same happens with other respiratory pathologies and, in particular, COVID-19. Calcifediol may be a good option for raising 25OHD serum levels quickly because the profile of inflammatory cytokines exhibited by patients with inflammatory respiratory diseases, such as asthma, COPD or COVID-19, can increase the degradation of the active metabolites of the VDES. The aim of this narrative revision is to report the current evidence on the role of calcifediol in main respiratory diseases. In conclusion, good 25OHD status may have beneficial effects on the clinical course of respiratory diseases, including COVID-19. This hypothesis should be confirmed in large, randomized trials. Otherwise, a rapid correction of 25(OH)D deficiency can be useful for patients with respiratory disease.

Vitamin D and Pancreatitis: A Narrative Review of Current Evidence

Emerging research indicates that vitamin D metabolic disorder plays a major role in both acute pancreatitis (AP) and chronic pancreatitis (CP). This has been demonstrated by studies showing that vitamin D deficiency is associated with pancreatitis and its anti-inflammatory and anti-fibrotic effects by binding with the vitamin D receptor (VDR). However, the role of vitamin D assessment and its management in pancreatitis remains poorly understood. In this narrative review, we discuss the recent advances in our understanding of the molecular mechanisms involved in vitamin D/VDR signaling in pancreatic cells; the evidence from observational studies and clinical trials that demonstrate the connection among vitamin D, pancreatitis and pancreatitis-related complications; and the route of administration of vitamin D supplementation in clinical practice. Although further research is still required to establish the protective role of vitamin D and its application in disease, evaluation of vitamin D levels and its supplementation should be important strategies for pancreatitis management according to currently available evidence.

Manan N, Mohamad Alwi MN. Effect of vitamin D3-fortified fruit juice supplementation of 4000 IU daily on the recovery of iron status in childbearing-aged women with marginally low iron stores: Protocol for an 8-week, parallel group, double-blind randomized controlled trial

BACKGROUND

In recent years, emerging evidence has highlighted the role of vitamin D as an iron absorption enhancer by suppressing hepcidin concentration, albeit with an unclear underlying mechanism. Dietary-based approach in improving iron status has been widely practised, however, there is a scarcity in randomized controlled trials (RCT) to elucidate the effect of vitamin D-fortified juice on iron status recovery. Therefore, this study aims to investigate the effect of an 8-week vitamin D3-fortified fruit juice supplementation on iron status indicators in childbearing-aged women with marginally low iron stores.

METHODS

In a placebo-controlled, double-blind, RCT, a total of 120 women aged between 19-40 with serum ferritin < 20 μg/l and fulfilled the eligibility criteria will be randomized into consuming either vitamin D3-fortified fruit juices containing 4000 IU (100 mcg) (vitamin D) or placebo-fruit juices (placebo) daily for eight weeks. At every 4-week interval, 10 ml fasting blood sample, information on dietary habit and anthropometric measurement will be collected. A mixed model repeated-measures analysis of variance will be performed to determine the effect of the intervention and the interaction with time points for all iron and vitamin D status blood biomarkers.

DISCUSSION

Vitamin D supplementation in food fortification as a novel iron absorption enhancer might be a future and relevant alternative management of iron deficiency as opposed to the oral iron therapy that has poor adherence.

TRIAL REGISTRATION

Clinicaltrials.gov: registration number NCT04618289, registration date October 28, 2020, protocol ID JKEUPM-2020-033.

Vitamin D Deficiency Impacts Exposure and Response of Pravastatin in Male Rats by Altering Hepatic OATPs

This study aimed to determine the effect of vitamin D (VD) deficiency on the efficacy and pharmacokinetics of pravastatin and clarify whether the effects are mediated by Organic anion-transporting polypeptides (OATPs). Experiments were conducted in rats to explore the effect of VD deficiency on the pharmacodynamics and pharmacokinetics of pravastatin. In the pharmacodynamic study, rats were fed a VD-free or VD-supplement high-fat diet for 25–30 days, and plasma 25(OH)VD was dynamically monitored. The response of pravastatin (changes in blood lipids) on rats were then examined after 15 days of pravastatin treatment. In the pharmacokinetic study, rats were fed a VD-free or VD-supplement diet for 25–30 days. The pharmacokinetics of single oral dose pravastatin was then studied, and intestinal and hepatic Oatp1a1 and Oatp2b1 expression was determined using quantitative polymerase chain reaction (qPCR) and western blot. Furthermore, OATP1B1 and OATP2B1 expression in Huh7 cells with or without 1.25(OH)₂D were assessed via qPCR and western blot. For the pharmacodynamic study, the decrease of total cholesterol and increase of high-density lipoprotein cholesterol in VD-deficient rats were smaller than in VD-sufficient rats, indicating that VD deficiency reduced the response of pravastatin in rats. For the pharmacokinetic study, the plasma exposure slightly increased, and liver exposure decreased in VD-deficient rats, but not significantly. VD deficiency decreased the Oatp1a1 and Oatp2b1 expression in the liver, but not in the small intestine. Similarly, OATP1B1 and OATP2B1 protein levels in Huh7 cells were reduced when 1.25(OH)₂D was absent. In conclusion, VD deficiency can decrease the response of pravastatin in rats by reducing the liver pravastatin exposure and expression of hepatic OATPs, consistent with the extended hepatic clearance model theory.

Efficacy of Vitamin D Supplements in Prevention of Acute Respiratory Infection: A Meta-Analysis for Randomized Controlled Trials

Background: Previous systematic reviews and meta-analyses of randomized controlled trials (RCTs) have reported inconsistent results regarding the efficacy of vitamin D supplements in the prevention of acute respiratory infections (ARIs). Methods: We investigated these efficacy results by using a meta-analysis of RCTs. We searched PubMed, EMBASE, and the Cochrane Library in June 2021. Results: Out of 390 trials searched from the database, a total of 30 RCTs involving 30,263 participants were included in the final analysis. In the meta-analysis of all the trials, vitamin D supplementation showed no significant effect in the prevention of ARIs (relative risk (RR) 0.96, 95% confidence interval (CI) 0.91–1.01, I² = 59.0%, n = 30). In the subgroup meta-analysis, vitamin D supplementation was effective in daily supplementation (RR 0.83, 95% CI, 0.73–0.95, I² = 69.1%, n = 15) and short-term supplementation (RR 0.83, 95% CI, 0.71–0.97, I² = 66.8%, n = 13). However, such beneficial effects disappeared in the subgroup meta-analysis of high-quality studies (RR 0.89, 95% CI, 0.78–1.02, I² = 67.0%, n = 10 assessed by the Jadad scale; RR 0.87, 95% CI, 0.66–1.15, I² = 51.0%, n = 4 assessed by the Cochrane’s risk of bias tool). Additionally, publication bias was observed. Conclusions: The current meta-analysis found that vitamin D supplementation has no clinical effect in the prevention of ARIs.

Dairy Product Consumption and Type 2 Diabetes among Korean Adults: A Prospective Cohort Study Based on the Health Examinees (HEXA) Study

OBJECTIVES

It has been suggested that the consumption of dairy products helps lower the prevalence of type 2 diabetes (T2D). We investigated the association between the consumption of dairy products and T2D events in middle-aged Korean adults.

METHODS

We followed up 53,288 participants (16,895 male and 36,393 female) in the Health Examinees (HEXA) study. The consumption of dairy products was assessed using the self-administered food frequency questionnaire, and T2D was defined according to the 2015 treatment guidelines of the Korean Diabetes Association. Hazard ratios (HRs) and 95% confidence intervals (CIs) between the consumption of dairy products and the risk of T2D were calculated using Cox proportional hazards models after adjusting for potential confounders. Spline regression was used to better represent the association between the consumption of dairy products and the risk of T2D.

RESULTS

Among male, those with higher consumption of dairy products had a significantly lower risk of T2D than those who consumed essentially no dairy products (HR, 0.73; 95% CI, 0.58 to 0.91). In particular, consumption of yogurt (HR, 0.75; 95% CI, 0.60 to 0.93; p_trend=0.035) and cheese (HR, 0.66; 95% CI, 0.49 to 0.89; p_trend=0.005) was negatively associated with the incidence of T2D in male. In female, daily consumption of 1 serving of yogurt decreased the risk of T2D by 11%.

CONCLUSIONS

The association between the consumption of dairy products and the risk of T2D differed by sex and dairy product type. Further prospective studies are needed to confirm these associations.

The preventive effect of the combination of atorvastatin and nortriptyline in migraine-type headache: a randomized, triple-blind, placebo-controlled trial

BACKGROUND AND PURPOSE

Migraine ranked as the eighth cause of disability worldwide. Statins with anti-inflammatory and vasodilatory endothelial effects have been introduced as an option for the prevention of migraine-type headaches. The current study aimed to assess the efficacy and tolerability of atorvastatin for the prevention of migraine in adults.

METHOD

This prospective, triple-blind, randomized controlled clinical trial was performed in adult migraineurs from mid-July 2019 to late-April 2020. Patients were randomly assigned to receive atorvastatin or placebo in combination with nortriptyline for 24-weeks. The frequency of headache was the primary outcome, and intensity of the headache and quality of life (QOL) were the secondary outcomes for this study.

RESULTS

With 34 patients in each arm, 68 patients with migraines based on the International Headache Society (IHS) criteria were enrolled in the study. At week 24, patients in the atorvastatin group experienced significantly fewer migraine attacks than the placebo group (P-value = 0.004). Moreover, there were significant differences between the two groups in QOL at follow-up intervals of 14 (P-value = 0.001) and 24 (P-value < 0.001) weeks. However, no significant difference was observed in the intensity of headache was observed in both groups (P-value > 0.05). The most common adverse effects in intervention and control groups were constipation and insomnia, respectively.

CONCLUSION

In patients with migraine, prophylaxis with atorvastatin significantly improved the frequency of headache and QOL over 24 weeks compared with placebo with no effect on the intensity of headache. Statins seem to be a potential promising drug for prophylaxis of migraine headaches.

Improving vitamin D testing and supplementation in children with newly diagnosed cancer: A quality improvement initiative at Rady Children's Hospital San Diego

BACKGROUND

Vitamin D deficiency and insufficiency have been associated with poorer health outcomes. Children with cancer are at high risk for vitamin D deficiency and insufficiency. At our institution, we identified high variability in vitamin D testing and supplementation in this population. Of those tested, 65% were vitamin D deficient/insufficient. We conducted a quality improvement (QI) initiative with aim to improve vitamin D testing and supplementation among children aged 2-18 years with newly diagnosed cancer to ≥80% over 6 months.

METHODS

An inter-professional team reviewed baseline data, then developed and implemented interventions using Plan-Do-Study-Act (PDSA) cycles. Barriers were identified using QI tools, including lack of automated triggers for testing and inconsistent supplementation criteria and follow-up testing post supplementation. Interventions included an institutional vitamin D guideline, clinical decision-making tree for vitamin D deficiency, insufficiency and sufficiency, electronic medical record triggers, and automated testing options.

RESULTS

Baseline: N = 26 patients, four (15%) had baseline vitamin D testing; two (8%) received appropriate supplementation. Postintervention: N = 33 patients; 32 (97%) had baseline vitamin D testing; 33 (100%) received appropriate supplementation and completed follow-up testing timely (6-8 weeks post supplementation). Change was sustained over 24 months.

CONCLUSIONS

We achieved and sustained our aim for vitamin D testing and supplementation in children with newly diagnosed cancer through inter-professional collaboration of hematology/oncology, endocrinology, hospital medicine, pharmacy, nursing, and information technology. Future PDSA cycles will address patient compliance with vitamin D supplementation and impact on patients' vitamin D levels.

The Effect of Maternal Vitamin D Supplementation on Vitamin D Status of Exclusively Breast Feeding Mothers and Their Nursing Infants: A Systematic Review and Meta-analysis of Randomized Clinical Trials

The optimal vitamin D supplementation plan during lactation is unclear. We investigated the effect of maternal vitamin D supplementation on mother-infant dyads' vitamin D status during lactation. All controlled trials that compared vitamin D supplements to placebo or low doses of vitamin D in breastfeeding mothers were included. Pooled effect size and the associated 95% confidence interval (CI) for each outcome were estimated using random-effects models. A one-stage random-effect dose-response model was used to estimate the dose-response relation across different vitamin D dosages and serum 25-hydroxy vitamin D (25(OH)D) concentrations. We identified 19 clinical trials with 27 separate comparison groups (n = 3337 breastfeeding mothers). Maternal vitamin D supplement dosages were associated with circulating 25(OH)D concentrations in breastfeeding women in a non-linear fashion. Supplementation with 1000 IU of vitamin D/day increased serum 25(OH)D concentrations by 7.8 ng/mL while there was a lower increase in concentrations at vitamin D doses of >2000 IU/day (3.07 and 2.05 ng/mL increases between 2000 to 3000 and 3000 to 4000 IU/day, respectively). A linear relationship was observed between maternal vitamin D supplementation dosage and the infants' circulating 25(OH)D concentrations. Each additional 1000 IU of maternal vitamin D intake was accompanied by a 2.7 ng/mL increase in serum 25(OH)D concentration in their nursing infants. The subgroup analysis showed that maternal vitamin D supplementation was accompanied by a statistically significant increase in infants' 25(OH)D concentration in the trials with a duration of >20 weeks, vitamin D supplementation >1000 IU/day, East Indian participants, maternal BMI <25 kg/m2, and studies with an overall low risk of bias. Long-term maternal supplementation with vitamin D at a high dose (>6000 IU/day) effectively corrected vitamin D deficiency in both mothers and infants. Nevertheless, infants with 25(OH)D concentrations over 20 ng/mL may require a relatively low maternal dose to maintain vitamin D sufficiency.

STATEMENT OF SIGNIFICANCE

This study is the first dose-response analysis on the relation between circulating 25-hydroxy vitamin D (25(OH)D) and maternal vitamin D supplementation in mother-infant dyads. We also considered factors such as study design and population characteristics that may affect the outcomes of a given vitamin D trial that have been overlooked in previous reviews.

VITAMIN D STATUS OF INDOOR-HOUSED HOFFMANN'S TWO-TOED SLOTHS (CHOLOEPUS HOFFMANNI): A PILOT STUDY

Disorders of calcium homeostasis have been reported with some frequency in two-toed sloths, yet little investigation has been performed on vitamin D and mineral metabolism in these species. This study evaluates biomarkers involved in vitamin D and calcium metabolism in a group of nine managed Hoffmann's two-toed sloths (Choloepus hoffmanni), correlated with diet analysis. Serum was analyzed for both vitamin D₂ and D₃ metabolites, minerals (calcium [Ca], phosphorus [P], and magnesium [Mg]), parathyroid hormone (PTH), and ionized calcium (iCa). The diet was analyzed for proximate nutrients, minerals and vitamins D₂ and D₃, and feed intake was estimated. Average values reported for D₃ metabolites, including 25(OH)D₃, 1,25(OH)₂D₃, and 24,25(OH)₂D₃, were 25.1 ng/ml, 52.23 pg/ml, and 7.65 ng/ml, respectively. Average PTH was 0.22 pmol/L while average iCa was 1.46 mmol/L. Values reported for Ca, P, Mg were within expected ranges. Dietary concentration of D₃ was 6.7 ng/g and the average daily intake per sloth was 113.7 IU/kg body weight. No detectable levels of vitamin D₂ metabolites 25(OH)D₂, 1,25(OH)₂D₂, or 24,25(OH)₂D₂ were found in the diet or serum. These data will serve as a starting point for future investigations into the vitamin D metabolism and calcium homeostasis of two-toed sloths to improve the health in managed settings.

Mineral metabolism and COVID-19: is there a connection?

Due to global spread of COVID-19, the search for new factors that could influence its clinical course becomes highly important. This review summarize the relevant publications on the association between immune system and the main regulators of mineral homeostasis including. In addition, we have highlighted the various aspects of phosphorus-calcium metabolism related to the acute respiratory diseases and in particular to COVID-19. The data about the calcium-phosphorus metabolism in SARS-CoV-2 infection is required to understand the possible clinical implications and to develop new therapeutic and preventive interventions.

COVID-19 Mortality Risk Correlates Inversely with Vitamin D3 Status, and a Mortality Rate Close to Zero Could Theoretically Be Achieved at 50 ng/mL 25(OH)D3: Results of a Systematic Review and Meta-Analysis

BACKGROUND

Much research shows that blood calcidiol (25(OH)D3) levels correlate strongly with SARS-CoV-2 infection severity. There is open discussion regarding whether low D3 is caused by the infection or if deficiency negatively affects immune defense. The aim of this study was to collect further evidence on this topic.

METHODS

Systematic literature search was performed to identify retrospective cohort as well as clinical studies on COVID-19 mortality rates versus D3 blood levels. Mortality rates from clinical studies were corrected for age, sex, and diabetes. Data were analyzed using correlation and linear regression.

RESULTS

One population study and seven clinical studies were identified, which reported D3 blood levels preinfection or on the day of hospital admission. The two independent datasets showed a negative Pearson correlation of D3 levels and mortality risk (r(17) = -0.4154, p = 0.0770/r(13) = -0.4886, p = 0.0646). For the combined data, median (IQR) D3 levels were 23.2 ng/mL (17.4-26.8), and a significant Pearson correlation was observed (r(32) = -0.3989, p = 0.0194). Regression suggested a theoretical point of zero mortality at approximately 50 ng/mL D3.

CONCLUSIONS

The datasets provide strong evidence that low D3 is a predictor rather than just a side effect of the infection. Despite ongoing vaccinations, we recommend raising serum 25(OH)D levels to above 50 ng/mL to prevent or mitigate new outbreaks due to escape mutations or decreasing antibody activity.

Influence of 25-Hydroxy-Vitamin D Insufficiency on Maximal Aerobic Power in Elite Indoor Athletes: A Cross-Sectional Study

Background

The impact of vitamin D on musculoskeletal health is well-established, although its influence on physical performance is unclear. Therefore, we conducted this study to evaluate the impact of 25-hydroxy-vitamin D (25-OH vitamin D) concentrations with maximal aerobic power of professional indoor athletes.

Results

A total of 112 male professional athletes were included in this cross-sectional study, consisting of 88 handball and 24 ice hockey players. The maximal aerobic power was assessed with a standardized cycling ergometer test. Athletes were assigned to two groups according to their 25-OH vitamin D status: insufficient (< 30 ng/mL) and sufficient (≥ 30 ng/mL). Thirty-four players (30.4%) displayed insufficient (21.9 ± 5.9 ng/mL) and 78 (69.6%) sufficient 25-OH vitamin D concentrations (41.6 ± 8.6 ng/mL). Athletes with sufficient levels achieved a higher maximal aerobic power (3.9 ± 0.9 vs. 3.5 ± 0.8 W/kg, p = 0.03) compared to those with insufficient levels.

Conclusions

There is a high prevalence of 25-OH vitamin D insufficiency in professional indoor athletes, even in summer. Insufficient 25-OH vitamin D concentrations were associated with lower maximal aerobic power in male professional indoor athletes. Further, the 25-OH vitamin D concentration was identified as the only independent predictor of maximal aerobic power in these athletes, highlighting the impact of 25-OH vitamin D on physical performance. Therefore, 25-OH vitamin D concentrations of ≥ 30 ng/mL should be maintained to ensure optimal physical performance in these athletes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-021-00363-1.

Vitamin D status and systemic redox biomarkers in adults with obesity

BACKGROUND & AIMS

Vitamin D has been proposed to have a protective role against oxidative stress. The present study was conducted to test the hypothesis that suboptimal levels of 25(OH)D are related to oxidative/antioxidative biomarkers in adults independently of obesity.

METHODS

In this case-control study, 140 subjects with obesity and 90 age- and sex-matched 25(OH)D sufficient normal weight controls were selected. Subjects with obesity were categorized as 25(OH)D sufficient, insufficient, and deficient based on their serum 25(OH)D concentrations. Serum malondialdehyde (MDA), total oxidant status (TOS), and total antioxidant capacity (TAC) as well as erythrocytes superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) along with serum paraoxonase-1 (PON1) and arylesterase (AREase) activities were assessed.

RESULTS

Serum concentrations of 25(OH)D were inversely correlated with BMI, WC, fat mass, and visceral fat. Serum levels of MDA and TOS, and erythrocyte SOD activities were significantly higher, whereas, serum TAC, PON1, and AREase were significantly lower in subjects with obesity compared to the controls (p < 0.0001). 25(OH)D deficient obese subjects exhibited higher serum levels of MDA as well as erythrocyte SOD activity (p < 0.05) and lower serum levels of TAC (p < 0.0001), PON1 (p < 0.05), and AREase (p < 0.0001) compared to obese subjects with 25(OH)D sufficiency and controls even when adjusted for BMI.

CONCLUSIONS

The present findings demonstrated a strong association between the severity of 25(OH)D deficiency and oxidative/antioxidative related parameters independently of obesity.

Role of vitamin D in regulating COVID-19 severity-An immunological perspective

Vitamin D, a key nutrient/prohormone classically associated with skeletal health, is also an important immunomodulator, with pleotropic effects on innate and adaptive immune cells. Outcomes of several chronic, autoimmune, and infectious diseases are linked to vitamin D. Emergent correlations of vitamin D insufficiency with coronavirus-induced disease 2019 (COVID-19) severity, alongside empirical and clinical evidence of immunoregulation by vitamin D in other pulmonary diseases, have prompted proposals of vitamin D supplementation to curb the COVID-19 public health toll. In this review paper, we engage an immunological lens to discuss potential mechanisms by which vitamin D signals might regulate respiratory disease severity in severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infections, vis a vis other pulmonary infections. It is proposed that vitamin D signals temper lung inflammatory cascades during SARS-CoV2 infection, and insufficiency of vitamin D causes increased inflammatory cytokine storm, thus leading to exacerbated respiratory disease. Additionally, analogous to studies of reduced cancer incidence, the dosage of vitamin D compounds administered to patients near the upper limit of safety may serve to maximize immune health benefits and mitigate inflammation and disease severity in SARS-CoV2 infections. We further deliberate on the importance of statistically powered clinical correlative and interventional studies, and the need for in-depth basic research into vitamin D-dependent host determinants of respiratory disease severity.

Vitamin D3 alleviates cognitive impairment through regulating inflammatory stress in db/db mice

Patients with type 2 diabetes mellitus (T2DM) have a higher risk to develop cognitive impairment. Several studies reported the potential roles of vitamin D in prevention of cognitive impairment, but the mechanism remains unclear. The present study aims to investigate the protective effects of vitamin D3 on cognitive impairment in db/db mice and to explore the possible mechanism. Twelve-week-old male db/db mice were randomly administrated with low, medium, and high dose of vitamin D3 (LVD, MVD, and HVD groups, respectively) and equivalent volume vitamin D3 solvent (corn oil, DM group) intragastrically. Eight age-matched db/m mice were given equivalent volume corn oil as normal group. After 16 weeks of vitamin D3 treatment, the concentrations of fasting serum glucose in three vitamin D3 groups (especially the 1,000 IU/kg·bw dose) were significantly decreased compared with DM group. Pathology revealed that the neuron damage was reduced in vitamin D3 groups. MVD intervention significantly shortened the escape latency on day 5 and extended time in the target quadrant. Mice in HVD group had significantly higher exploration time and discrimination index compared with the DM group mice. Moreover, vitamin D3 treatment has increased the phosphorylation of cAMP-response element-binding protein and the expression of brain-derived neurotrophic factor and vitamin D receptor. This treatment, meanwhile, has decreased the expression of tumor necrosis factor-α, the phosphorylation of inhibitor kappa Bα (IκBα), and nuclear factor-κB p65 (NF-κB p65) in the hippocampus of db/db mice. These results suggest that vitamin D3 alleviated cognitive impairment in the hippocampus of db/db mice. Down-regulation of the NF-κB signaling pathway-related proteins IκBα and p65 might be one of the possible mechanisms.

Mechanism and adverse effects of COVID-19 drugs: a basic review

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronavirus disease 2019 (COVID-19) is chronic, inflammatory. Although the exact mechanisms of COVID-19 have not been yet discovered some drugs are found helpful for its treatment. These drugs which are divided into some lines therapies, have demonstrated to be helpful for COVID-19 patients based on immune basic and its antiviral properties of the disease. Previous studies have been indicated that deterioration of COVID-19 condition is associated with a weaker immune system. Most of these therapies impact on the immune system and immune cells. Beside many beneficial effects of these drugs, some adverse effects (AE) have been reported in many experiments and clinical trials among patients suffering from COVID-19. In this review, we conclude some AEs of vitamin-D, zinc, remdesivir, hydroxychloroquine or chloroquine, azithromycin, dexamethasone, amantadine, aspirin reported in different papers and we continue the rest of the drugs in second part of our review article.

The role of vitamin D in reducing SARS-CoV-2 infection: An update

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is having a disastrous impact on global health. Recently, several studies examined the potential of vitamin D to reduce the effects of SARS-CoV-2 infection by modulating the immune system. Indeed, vitamin D has been found to boost the innate immune system and stimulate the adaptive immune response against SARS-CoV-2 infection. In this review, we provide a comprehensive update of the immunological mechanisms underlying the positive effects of vitamin D in reducing SARS-CoV-2 infection as well as a thorough survey of the recent epidemiological studies and clinical trials that tested vitamin D as a potential therapeutic agent against COVID-19 infection. We believe that a better understanding of the histopathology and immunopathology of the disease as well as the mechanism of vitamin D effects on COVID-19 severity will ultimately pave the way for a more effective prevention and control of this global pandemic.

Changes in Bone Turnover, Inflammatory, Oxidative Stress, and Metabolic Markers in Women Consuming Iron plus Vitamin D Supplements: a Randomized Clinical Trial

We aimed to investigate whether combination of vitamin D and iron supplementation, comparing vitamin D alone, could modify bone turnover, inflammatory, oxidative stress, and metabolic markers. Eighty-seven women with hemoglobin (Hb) ≤ 12.7 g/dL and 25OHD ≤ 29 ng/mL vitamin D deficiency/insufficiency aged 18-45 years were randomly assigned into two groups: (1) receiving either 1000 IU/day vitamin D3 plus 27 mg/day iron (D-Fe); (2) vitamin D3 plus placebo supplements (D-P), for 12 weeks. In D-Fe group, significant decrease in red blood cells (RBC) (P = 0.001) and hematocrit (Hct) (P = 0.004) and increases in mean corpuscular hemoglobin concentration (MCHC) (P = 0.001), 25OHD (P < 0.001), osteocalcin (P < 0.001), high-density cholesterol (HDL) (P = 0.041), and fasting blood sugar (FBS) (P < 0.001) were observed. D-P group showed significant decrease in RBC (P < 0.001), Hb (P < 0.001), Hct (P < 0.001), mean corpuscular volume (MCV) (P = 0.004), mean corpuscular hemoglobin (MCH) (P < 0.001), MCHC (P = 0.005), serum ferritin (P < 0.001), and low-density cholesterol (LDL) (P = 0.016) and increases of 25OHD (P < 0.001), osteocalcin (P < 0.001), C-terminal telopeptide (CTX) (P = 0.025), triglyceride (TG) (P = 0.004), FBS (P < 0.001), and interleukin-6 (IL-6) (P = 0.001) at week 12. After the intervention, the D-P group had between-group increases in mean change in the osteocalcin (P = 0.007) and IL-6 (P = 0.033), and decreases in the RBC (P < 0.001), Hb (P < 0.001), Hct (P < 0.001), and MCV (P = 0.001), compared with the D-Fe group. There were significant between-group changes in MCH (P < 0.001), MCHC (P < 0.001), ferritin (P < 0.001), and serum iron (P = 0.018). Iron-vitamin D co-supplementation does not yield added benefits for improvement of bone turnover, inflammatory, oxidative stress, and metabolic markers, whereas, vitamin D alone may have some detrimental effects on inflammatory and metabolic markers. IRCT registration number: IRCT201409082365N9.

Association of Vitamin D Receptor Gene Polymorphisms with Serum Vitamin D Levels in a Greek Rural Population (Velestino Study)

BACKGROUND/AIM

An alarming increase in vitamin D deficiency even in sunny regions highlights the need for a better understanding of the genetic background of the vitamin D endocrine system and the molecular mechanisms of gene polymorphisms of the vitamin D receptor (VDR). In this study, the serum levels of 25(OH)D3 were correlated with common VDR polymorphisms (ApaI, BsmI, FokI, and TaqI) in 98 subjects of a Greek homogeneous rural population.

METHODS

25(OH)D3 concentration was measured by ultra-HPLC, and the VDR gene polymorphisms were identified by quantitative real-time PCR followed by amplicon high-resolution melting analysis.

RESULTS

Subjects carrying either the B BsmI (OR: 0.52, 95% CI: 0.27-0.99) or t TaqI (OR: 2.06, 95%: 1.06-3.99) allele presented twice the risk for developing vitamin D deficiency compared to the reference allele. Moreover, subjects carrying 1, 2, or all 3 of these genotypes (BB/Bb, Tt/tt, and FF) demonstrated 2-fold (OR: 2.04, 95% CI: 0.42-9.92), 3.6-fold (OR: 3.62, 95% CI: 1.07-12.2), and 7-fold (OR: 6.92, 95% CI: 1.68-28.5) increased risk for low 25(OH)D3 levels, respectively.

CONCLUSIONS

Our findings reveal a cumulative effect of specific VDR gene polymorphisms that may regulate vitamin D concentrations explaining, in part, the paradox of vitamin D deficiency in sunny regions, with important implications for precision medicine.

Effect of 1-year oral cholecalciferol on a metabolic profile and blood pressure in poor-controlled type 2 diabetes mellitus: an open-label randomized controlled pilot study

PURPOSE

Hypovitaminosis D has been associated with many cardio-metabolic disorders, although their pathogenetic link still remains unclear. Our aim was to evaluate whether 1-year vitamin D (D) supplementation could improve glycemic control, lipid profile, systolic (SBP) and diastolic (DBP) blood pressure levels and body composition.

METHODS

In an open-label randomized-controlled pilot study, thirty poor-controlled (HbA1c > 59 mmol/mol) type 2 diabetic patients (age 71.5 ± 3.2 years, M/F 21/9, BMI 29.8 ± 3.6 kg/m²) with hypovitaminosis D (25OHD 22.0 ± 11.3 nmol/l) were randomized to cholecalciferol supplementation (500 UI/kg p.o. weekly, + D) or observation (- D) for one year. Changes in parameters of glucose, lipid and blood pressure control at 3, 6, 9 and 12 months vs. baseline were assessed.

RESULTS

One-year D supplementation restored D status and had a beneficial effect on fasting glucose (FG, mean percentage changes ± SD, - 1.8% ± 23.1 vs. + 18.8% ± 30.0), glycosylated haemoglobin (HbA1c, - 13.7% ± 14.5 vs. - 4.2% ± 14.1), SBP (- 13.4% ± 8.5 vs. - 2.4% ± 12.6) and HDL-cholesterol levels (- 2.1% ± 14.0 vs. - 10.9% ± 12.9; p < 0.05 for all comparisons) in + D vs. - D patients, respectively. In the former, a reduction in HBA1c, SBP and DBP levels, BMI, fat mass index (FMI) and ratio (FMR) was observed after 1 year (p < 0.05 for all comparisons vs. baseline). We noticed a relationship between 1-year mean percentage changes of serum 25OHD and SBP levels (R = - 0.36, p < 0.05).

CONCLUSION

One-year cholecalciferol supplementation, able to restore D status, significantly improves FG, HbA1c, SBP and HDL-cholesterol levels in patients with poor-controlled type 2 diabetes mellitus and D deficiency.