Optimal Vitamin D Supplementation Levels for Cardiovascular Disease Protection

Vitamin D Supplementation in Critically Ill-Narrative Review

BACKGROUND

Studies have shown a high prevalence of vitamin D deficiency in critically ill patients, and these patients are at higher risk for pneumonia and have increased incidence of sepsis and mortality. In this study, we reviewed available literature from randomized controlled trials (RCTs) on vitamin D supplementation in critically ill patients and summarized the evidence in this narrative review.

METHODS

Randomized controlled trials that included vitamin D supplementation as an intervention were eligible for inclusion. No limits were set regarding vitamin D dosage or route of administration, as well as for primary and secondary outcomes. A search was conducted in MEDLINE via PubMed for eligible RCTs. References from systematic reviews (SRs) and meta-analyses (MAs) were screened, and Clinicaltrials.gov was searched for ongoing studies.

RESULTS

A total of 21 RCTs involving 3166 patients were analyzed. There was a large heterogeneity in terms of patients' characteristics and inclusion criteria. Only six studies included patients with vitamin D levels < 50 nmol/L. Regarding clinically important outcomes, most of the studies did not show differences between the intervention and control group in terms of mortality, intensive care unit (ICU) or hospital length of stay (LoS).

CONCLUSIONS

There is great variability in trial designs regarding the selection of patients, dosage, dosing intervals and routes of administration of vitamin D supplements. Better study designs are mandatory for future clinical research, with measuring and reporting basal vitamin D levels before randomization. Since variability in supplementation regimes limits the possibility of data synthesis, standardized protocols for vitamin D supplementation should be used in clinical trial settings.

Effects of vitamin D supplementation on cardiometabolic parameters among patients with metabolic syndrome: A systematic review and GRADE evidence synthesis of randomized controlled trials

Various pathophysiologic mechanisms were proposed to underlie the effect of vitamin D on MetS components. In this systematic review, we reviewed randomized control clinical trials to verify whether vitamin D supplementation (VDS) at different doses is effective concomitantly in controlling high-density lipoprotein cholesterol (HDL-c), triglycerides (TG), fasting glucose level, blood pressure, and central obesity in adults diagnosed with MetS. The following scientific databases were searched from 1998 until April 2023: EMBASE, MEDLINE (PubMed), Web of Science, Latin American and Caribbean Health Sciences Literature (Lilacs), the Cochrane Central Register of Controlled Trials, clinicaltrial.gov, and Google Scholar. No language restrictions were applied. Seven studies were included, and they showed a high level of heterogeneity. All studies reported a significant increase in serum 25(OH)D levels in the intervention groups. Of these, only two noted a significant decrease in triglyceride (TG) level and waist circumference. However, the certainty levels of the evidence rating were very low and low for triglyceride (TG) level and waist circumference, respectively, and moderate for fasting glucose level, blood pressure, and HDL-c. In conclusion, despite these benefits, considering the low certainty, the evidence does not support that VDS decreases triglyceride (TG) level and waist circumference in adults with MetS.

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

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

Prevalence and Related Risk Factors of Vitamin D Deficiency in Saudi Children with Epilepsy

BACKGROUND

Vitamin D has a role in the pathogenesis of many medical disorders, especially those of the central nervous system. It is essential in maintaining the bone health of children. However, patients with epilepsy are at high risk of developing vitamin D deficiency due to antiseizure medications (ASMs). Therefore, we aimed to assess the prevalence of vitamin D deficiency and related risk factors in children with epilepsy.

METHODS

This is the baseline report of a pragmatic, randomized, controlled, open-label trial that assessed the impact of vitamin D supplementation in preventing vitamin D deficiency (NCT03536845). We included children with epilepsy aged 2-16 years who were treated with ASMs from December 2017 to March 2021. Children with preexisting vitamin D metabolism problems, vitamin-D-dependent rickets, malabsorption syndromes, renal disease, and hepatic disease were excluded. The baseline demographic data, anthropometric measurements, seizure types, epilepsy syndromes, ASMs, and seizure control measures were recorded. Blood tests for vitamin D (25-hydroxyvitamin D [25(OH)D), serum calcium, serum phosphorus, and parathyroid hormone levels were performed. Based on vitamin D concentration, patients were categorized as deficient (&lt;50 nmol/L), insufficient (74.9-50 nmol/L), or normal (&gt;75 nmol/L).

RESULTS

Of 159 recruited children, 108 (67.92%) had generalized seizures, 44 (27.67%) had focal seizures, and 7 (4.4%) had unknown onset seizures. The number of children receiving monotherapy was 128 (79.0%) and 31 (19.1%) children were receiving polytherapy. The mean vitamin D concentration was 60.24 ± 32.36 nmol/L; 72 patients (45.28%) had vitamin D deficiency and 45 (28.3%) had vitamin D insufficiency. No significant difference in vitamin D concentration was observed between children receiving monotherapy and those receiving polytherapy. The main risk factors of vitamin D deficiency were obesity and receiving enzyme-inducer ASMs.

CONCLUSIONS

The prevalence of vitamin D deficiency was high among children with epilepsy. Obese children with epilepsy and those on enzyme-inducer ASMs were at increased risk for vitamin D deficiency. Further studies are needed to establish strategies to prevent vitamin D deficiency.

The impacts of vitamin D supplementation in adults with metabolic syndrome: A systematic review and meta-analysis of randomized controlled trials

Background: Studies have shown the association of vitamin D status with the development of metabolic syndrome (MetS), which has attracted an extensive research interest with inconsistent results. Therefore, we hypothesized that vitamin D supplementation (VDS) will benefit adults with MetS.

Aims: To test our hypothesis, we performed a meta-analysis to evaluate the effect of VDS on MetS in adults using relevant biomarkers such as anthropometric parameters, blood pressure, blood lipid profile, glycemia, oxidative stress and vitamin D toxicity (VDT).

Methods: Randomized controlled trials published in PubMed, Web of Science, embase and the Cochrane Library between 2012 and 2022 on the effect of VDS on MetS in adults were searched. The language was limited to English. A meta-analysis performed using RevMan 5.4 and Stata 14.0 software, sensitivity analysis, and evaluation of the risk of bias and general quality of the resulting evidence were conducted.

Results: Eventually, 13 articles were included in this meta-analysis. Overall, VDS significantly increased the endline serum 25-hydroxyvitamin D levels as compared to the control [MD:17.41, 95% CI (14.09, 20.73), p < 0.00001]. VDS did not affect waist circumference, body mass index, body fat percentage and VDT biomarkers, but decreased waist-to-hip ratio and blood pressure (p < 0.01). VDS significantly decreased fasting plasma glucose (FPG) [MD: 3.78; 95% CI (−6.52, −1.03), p = 0.007], but did not affect the levels of blood high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglyceride (TG). Pooled estimate of nine papers indicated a significant reduction of fasting insulin (FI) (p = 0.006), and homeostasis model assessment of insulin resistance (p = 0.0001). The quantitative insulin check index levels were moderately increased (p = 0.007) without any impact on the glycosylated hemoglobin type A1C (HbA1c). For the oxidative stress parameters, VDS significantly lowered the levels of malondialdehyde and hypersensitive C-reactive protein (p < 0.05).

Conclusion: Results of this meta-analysis demonstrate that VDS only reduces insulin resistance and hypertension but not the blood lipid profile and HbA1c. It appears that the evidence for the benefit of VDS in adults with MetS is inconclusive. Further clinical studies are still needed.

Vitamin D, Vitamin D-Binding Proteins, and VDR Polymorphisms in Individuals with Hyperglycaemia

Vitamin D reportedly plays an important role in the pathogenesis of diabetes mellitus; however, this role is unclear and debated. This study investigated the association between 25(OH) vitamin D, vitamin D-binding proteins, and vitamin D receptor (VDR) polymorphisms in healthy individuals and those with prediabetes and type 2 diabetes mellitus (T2D) from South Africa. A cross-sectional study was conducted involving subjects of mixed ancestry aged ≥20 years. Males presented with higher mean 25(OH) vitamin D levels than females, while females exhibited significantly higher serum vitamin D-binding protein levels. Significant differences in mean 25(OH) vitamin D levels were observed in normo-glycaemic, prediabetes, screen-detected DM, and known DM individuals. Vitamin D receptor SNPs Fok1 and Taq1 were not associated with glycaemic status. Fok1 was not associated with 25(OH) vitamin D deficiency, while Taq1 was associated with vitamin D insufficiency. This study showed a high prevalence of vitamin D deficiency/insufficiency in this South African population, with decreased vitamin D levels observed in hyperglycaemic individuals, which was not linked to either vitamin D-binding protein or polymorphisms in Fok1 of the VDR gene. These results may be used as a platform for further research into diagnosis and treatment of hyperglycaemia.

Cholecalciferol supplementation lowers leptin and TMAO but increases NO and VEGF-A levels in obese vitamin D deficient patients: Is it one of the potential cardioprotective mechanisms of vitamin D?

Background

Vitamin D deficiency is one of the most common health issues in developed countries. Obese patients are most at risk of having serum 25-hydroxyvitamin D₃ (25(OH)D₃) levels that are too low due to the accumulation of vitamin D in adipose tissue. While the effects of a deficiency on the skeletal or immune system are known, the effects on the cardiovascular system are not yet clear. Our study investigates the effect of cholecalciferol supplementation in obese patients on selected biomarkers associated with cardiovascular diseases (CVDs).

Methods

The study enrolled 33 obese patients with insufficient 25(OH)D₃ levels. For three months, the subjects supplemented with cholecalciferol at a dose of 2000 IU/day. Concentrations of nitric oxide (NO), vascular endothelial growth factor A (VEGF-A), leptin, trimethylamine N-oxide (TMAO) and soluble suppression of tumorigenicity 2 (sST2) were measured in baseline samples using ELISA (BioTek EPOCH). 25(OH)D₃ levels measured on Beckman Coulter DXI 800 by chemiluminescence method.

Results

After supplementation, 25(OH)D₃ levels increased significantly. Normal levels were achieved in most patients. A statistically significant reduction leptin and TMAO levels was observed. At the same time, NO and VEGF-A levels increased statistically significantly.

Conclusion

This study indicates that restoring normal 25(OH)D₃ levels in obese people reduces the concentration of pro-inflammatory factors associated with cardiovascular diseases. Reducing inflammation and the potential impact on vascular reactivity leads to the conclusion that cholecalciferol supplementation in obese patients may benefit the cardiovascular system.

Safety Data in Patients with Autoimmune Diseases during Treatment with High Doses of Vitamin D3 According to the “Coimbra Protocol”

Background: In 2013, the group of Cicero Coimbra, Brazil, reported the clinical efficacy of high doses of vitamin D3 in patients suffering from autoimmune skin disorders (“Coimbra protocol”, CP). However, hypercalcemia and the subsequent impaired renal function may be major concerns raised against this protocol. Methods: We report for the first time for a broad spectrum of autoimmune diseases in 319 patients (mean age (±SD) 43.3 ± 14.6 years, 65.5% female, 34.5% male) safety data for high doses of orally applied vitamin D3 (treatment period: up to 3.5 years) accompanied by a strict low-calcium diet and regular daily fluid intake of at least 2.5 L. Results: Mean vitamin D3 dose was 35,291 ± 21,791 IU per day. The measurement of more than 6100 single relevant laboratory parameters showed all mean values (±SD) within the normal range for total serum calcium (2.4 ± 0.1 mmol/L), serum creatinine (0.8 ± 0.2 mg/dL), serum creatinine associated estimated GFR (92.5 ± 17.3 mL/min), serum cystatin C (0.88 ± 0.19 mg/L), serum TSH (1.8 ± 1 mIU/L), and for 24 h urinary calcium secretion (6.9 ± 3.3 mmol/24 h). We found a very weak relationship between the dosage of oral vitamin D3 and the subsequent calcium levels, both in serum and in urinary excretion over 24 h, respectively. Conclusions: Our data show the reliable safety of the CP in autoimmune patients under appropriate supervision by experienced physicians.

The influence of CYP2R1 polymorphisms and gene-obesity interaction with hypertension risk in a Chinese rural population

BACKGROUND AND AIMS

Several studies have reported that variants in CYP2R1 have been linked with an increased risk of hypertension. However, the interaction between CYP2R1 variants and environmental factors on the susceptibility of hypertension remained unclear. Therefore, this study evaluated the influence of CYP2R1 polymorphisms on hypertension susceptibility, and explored the interaction effect of CYP2R1 variations and obesity on the disease.

METHODS AND RESULTS

We included 766 incident hypertension cases matched with non-hypertension controls in a 1:1 ratio by sex, age (within 3 years). Two loci in CYP2R1 gene (rs10766197 and rs12794714) were genotyped by TaqMan probe assays. The concentration of 25-hydroxyvitamin-D was determined by human enzyme-linked immunosorbent assay (ELISA) kits. The associations of CYP2R1 polymorphisms and risks of vitamin D deficiency (VDD) were analyzed by logistic regression. Multifactor dimensionality reduction (MDR) was used to analyze the gene-environment interaction. Multiple logistic regression was used to examine the effect of CYP2R1 gene variations, and the interaction between CYP2R1 variation and obesity on hypertension susceptibility. The results showed that rs10766197 (GG vs. AA) and rs12794714 (GG vs. AA) polymorphisms were both associated with an increased risk of VDD (OR = 1.49, 95% confidence interval (CI) = 1.08-2.05 and OR = 1.63, 95% CI = 1.19-2.25, respectively), after adjustment for potential risk factors. We also found that rs12794714 polymorphism was significantly associated with elevated risk of hypertension under the dominant model (OR = 1.26, 95% CI = 1.01-1.56). In addition, the interactions between rs12794714 with both general obesity (OR = 3.93, 95% CI = 2.72-5.68) and central obesity (OR = 3.22, 95% CI = 2.29-4.52) have significant effects on hypertension susceptibility.

CONCLUSIONS

The study provided further evidence that CYP2R1 variation was associated with a higher risk of hypertension in Chinese rural population. The interaction between CYP2R1 rs12794714 and obesity may increase the risk of hypertension.

Recovery of limb perfusion and function after hindlimb ischemia is impaired by arterial calcification

Medial artery calcification results from deposition of calcium hydroxyapatite crystals on elastin layers, and osteogenic changes in vascular smooth muscle cells. It is highly prevalent in patients with chronic kidney disease, diabetes, and peripheral artery disease (PAD), and when identified in lower extremity vessels, it is associated with increased amputation rates. This study aims to evaluate the effects of medial calcification on perfusion and functional recovery after hindlimb ischemia in rats. Medial artery calcification and acute limb ischemia were induced by vitamin D3 (VitD3 ) injection and femoral artery ligation in rats. VitD3 injection robustly induced calcification in the medial layer of femoral arteries in vivo. Laser Doppler perfusion imaging revealed that perfusion decreased and then partially recovered after hindlimb ischemia in vehicle-injected rats. In contrast, VitD3 -injected rats showed markedly impaired recovery of perfusion following limb ischemia. Accordingly, rats with medial calcification showed worse ischemia scores and delayed functional recovery compared with controls. Immunohistochemical and histological staining did not show differences in capillary density or muscle morphology between VitD3 - and vehicle-injected rats at 28 days after femoral artery ligation. The evaluation of cardiac and hemodynamic parameters showed that arterial stiffness was increased while cardiac function was preserved in VitD3 -injected rats. These findings suggest that medial calcification may contribute to impaired perfusion in PAD by altering vascular compliance, however, the specific mechanisms remain poorly understood. Reducing or slowing the progression of arterial calcification in patients with PAD may improve clinical outcomes.

Cystatin C, Vitamin D and Thyroid Function Test Profile in Chronic Kidney Disease Patients

BACKGROUND

The progression of chronic kidney disease (CKD) is concomitant with complications, including thyroid dysfunction, dyslipidemia and cardiovascular diseases. The aim of this study is to determine serum cystatin C levels, and the prevalence of vitamin D deficiency and thyroid dysfunction in CKD patients.

METHODS

A cross-sectional study was conducted involving 140 CKD patients (stages 1-5) that were referred to a renal clinic. Demographic data was collected and thyroid function tests, serum 25-OH-vitamin D, cystatin C levels, and routine biochemistry tests were determined using cobas 6000 analyzer.

RESULTS

129 (92.1%) of CKD patients had elevated serum cystatin C levels and there was a stepwise increase from stage 1-5. Overt hypothyroidism was present in one patient and nine had subclinical hypothyroidism. There was a stepwise reduction in serum 25-OH-vitamin D levels from stage 2-5, 31 (22.1%) had vitamin D insufficiency and 31 (22.1%) presented with deficiency.

CONCLUSIONS

25-OH-vitamin D deficiency and thyroid disorders are exhibited in chronic kidney disease patients and the severity of the former rises with disease progression, as indicated by elevated cystatin C levels. Routine screening and timely intervention is recommended so as to reduce the risk of cardiovascular diseases.

Effects of Vitamin D Supplementation on Lipid Profile in Adults with the Metabolic Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Metabolic syndrome (MetS) increases the risk of cardiovascular disease, with atherogenic dyslipidemia being a major contributing factor.

METHODS

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to assess whether vitamin D supplementation (VDS) alleviates dyslipidemia in adults with MetS. Scientific databases (PUBMED, MEDLINE, CINAHL, EMBASE, Cochrane Library, ClinicalTrials.gov, International Clinical Trials Registry Platform) and the gray literature were searched for randomized controlled trials of VDS, reporting on blood lipids. A narrative review, meta-analyses, sensitivity analyses, and appraisal of the risk of bias and overall quality of evidence produced were conducted.

RESULTS

Seven studies were included, and four were meta-analyzed. The risk of bias was generally low, and the final quality of evidence was low or very low. VDS, whether in high or low dose, significantly increased endline vitamin D blood levels; did not affect total, low-density, high-density cholesterol levels, and novel lipid-related biomarkers; yet, significantly increased triglycerides (TG) levels compared with placebo (MD: 30.67 (95%CI: 4.89-56.45) mg/dL; p = 0.02 for low-dose VDS; and MD: 27.33 (95%CI: 2.06-52.59) mg/dL; p = 0.03 for high-dose VDS). Pertaining heterogeneity was high (I² = 86%; and I² = 51%, respectively), and some included studies had significantly higher baseline TG in the intervention arm. The sensitivity analyses revealed robust results.

CONCLUSION

VDS seems not to affect blood lipids in adults with MetS.

An Update on Vitamin D Metabolism

Vitamin D is a steroid hormone classically involved in the calcium metabolism and bone homeostasis. Recently, new and interesting aspects of vitamin D metabolism has been elucidated, namely the special role of the skin, the metabolic control of liver hydroxylase CYP2R1, the specificity of 1α-hydroxylase in different tissues and cell types and the genomic, non-genomic and epigenomic effects of vitamin D receptor, which will be addressed in the present review. Moreover, in the last decades, several extraskeletal effects which can be attributed to vitamin D have been shown. These beneficial effects will be here summarized, focusing on the immune system and cardiovascular system.

25-Hydroxyvitamin D status, vitamin D intake, and skin cancer risk: a systematic review and dose-response meta-analysis of prospective studies

Sun exposure is a major environmental risk factor for skin cancers and is also an important source of vitamin D. However, while experimental evidence suggests that vitamin D may have a protective effect on skin cancer risk, epidemiologic studies investigating the influence of 25-hydroxyvitamin D (25(OH)D) level and/or vitamin D intake on skin cancer risk are conflicting. A systematic review and dose–response meta-analyses of prospective studies was conducted to clarify these associations. Relevant studies were identified by searching the PubMed database up to 30th August 2019. Random effects dose–response meta-analyses were used to estimate summary relative risks (SRRs) and 95% confidence intervals (CIs). Overall, thirteen prospective studies were included. Circulating level of 25(OH)D was associated with higher risks of melanoma (SRR (95% CI) per 30 nmol = 1.42 (1.17–1.72)) and keratinocyte cancer (KC) (SRR (95% CI) per 30 nmol/L = 1.30 (1.13–1.49)). The SRR (95% CI) per 30 nmol/L increase in 25(OH) D level was 1.41 (1.19–1.67), and 1.57 (0.64–3.86), for basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs), respectively. However, while we found that vitamin D intake (from diet, supplemental and total) was not associated with risks of melanoma and SCC, vitamin D intake was associated with slightly increased BCC risk, albeit with no heterogeneity across skin cancer type. This meta-analysis suggests positive associations between circulating 25(OH)D level and risk of melanoma and KC, however, this finding is most likely confounded by sun exposure. We found no associations between vitamin D intake skin cancers, except positive associations with BCC risk.

Vitamin D Deficiency and the Risk of Cerebrovascular Disease

Vitamin D deficiency has been clearly linked to major chronic diseases associated with oxidative stress, inflammation, and aging, including cardiovascular and neurodegenerative diseases, diabetes, and cancer. In particular, the cardiovascular system appears to be highly sensitive to vitamin D deficiency, as this may result in endothelial dysfunction and vascular defects via multiple mechanisms. Accordingly, recent research developments have led to the proposal that pharmacological interventions targeting either vitamin D deficiency or its key downstream effects, including defective autophagy and abnormal pro-oxidant and pro-inflammatory responses, may be able to limit the onset and severity of major cerebrovascular diseases, such as stroke and cerebrovascular malformations. Here we review the available evidence supporting the role of vitamin D in preventing or limiting the development of these cerebrovascular diseases, which are leading causes of disability and death all over the world.

The effect of physical activity on dose-relationship between serum 25-hydroxyvitamin D and cardiovascular health events in older adults

BACKGROUND AND AIMS

Reverse J- or U-shaped associations between serum 25-hydroxyvitamin D (25[OH]D) concentrations and cardiovascular outcomes have been reported, which need clarifications in older adults. Physical activity, correlating with both serum 25[OH]D concentration and cardiovascular health, may have an effect on the dose-relationships.

METHODS AND RESULTS

At baseline, 2790 participants aged 65 years and over, free of vitamin D supplementation use, had assays for serum 25[OH]D concentrations and health related characteristics and measurements, were followed up for cardiovascular events and death by up to 7 and 15 years, respectively. The dose-response associations of serum 25[OH]D concentrations with cardiovascular events and mortality risk were examined using Cox regression models. After adjusting for physical activity and other covariates, serum 25[OH]D concentration was non-linearly associated with cardiovascular mortality risk (U-shaped, P = 0.009). According to the Institute of Medicine categories, the HR(95% CI) of cardiovascular mortality risk separately in deficient (<25 nmol/L), inadequate (25 to < 50 nmol/L) and potentially harmful (≥125 nmol/L) level was 1.67 (0.23, 12.01), 1.66 (1.25, 2.20) and 2.21 (0.30, 16.37), respectively. The risk of 25[OH]D inadequacy for cardiovascular mortality was significantly attenuated by increased physical activity, especially leisure activity (P for trend = 0.008 and 0.021, respectively). No significant finding was observed for incident cardiovascular events.

CONCLUSION

Both lower and higher serum 25[OH]D concentrations were associated with risk of cardiovascular mortality in Chinese community-dwelling older adults. Physical activity may attenuate the cardiovascular mortality risk of vitamin D inadequacy, but its role in individuals with higher 25[OH]D concentrations remains unclear.

The Use of Dietary Supplements Among African and Caribbean Women Living in the UK: A Cross-Sectional Study

Previous studies have shown that the use of dietary supplements is associated with the prevention of birth defects, negative pregnancy outcomes and cardiovascular diseases. However, there might be some ethnic disparities in supplement usage suggesting that women who could benefit from it are not frequent users. This study aimed to characterise the use of dietary supplement among Black African and Black Caribbean women living in the United Kingdom (UK). Furthermore, it evaluated possible associations between the use of dietary supplements and health and diet awareness. A total of 262 women self-ascribed as Black African and Black Caribbean living in the UK completed a comprehensive questionnaire on socio-demographic factors, diet, use of supplements and cultural factors. The main outcome variable was the regular use of any type of dietary supplement. Use of vitamin D and/or calcium was also explored. A stepwise logistic regression analysis was applied to identify predictors of regular use of dietary supplements. A total of 33.2% of women reported regular use of any dietary supplements and 16.8% reported use of vitamin D and/or calcium. There were no significant ethnic differences in the use of dietary supplements. Reporting use of the back of food packaging label (odds ratio (OR) 2.21; 95% CI 1.07–4.55); a self-rated healthy diet (OR 2.86; 95% CI 1.19–6.91) and having cardiovascular disease (CVD), hypertension and/or high cholesterol (OR 3.81; 95% CI 1.53–9.49) increased the likelihood of using any dietary supplement. However, having poorer awareness decreased the likelihood (OR 0.94; 95% CI 0.88–0.99) of using any dietary supplement. For the use of vitamin D and/or calcium supplements, the main predictor was having CVD, hypertension and/or high cholesterol (OR 4.43; 95% CI 1.90–10.35). The prevalence of dietary supplement use was low among African and Caribbean women. Thus, awareness of potential benefits of some dietary supplements (e.g., vitamin D) among the Black population should be promoted.

Serum vitamin D levels in acute stroke patients

Background

Vitamin D deficiency has been proposed as a risk factors of cerebrovascular stroke.

Objectives

The aim of this study was firstly, to assess the serum level of vitamin D in cerebral stroke patients and secondly, to examine if its deficiency was associated with stroke severity and outcome.

Methods

We utilized a case-control study design and recruited 138 acute stroke patients and 138 age- and sex-matched controls from subjects attending outpatient clinic for other reasons. All participants were subjected to full general and neurological examination. Brain imaging CT and/or MRI was performed. Blood samples were collected for measurement of serum level of vitamin D (ng/ml) by ELISA, alkaline phosphatase, serum calcium, and phosphorous. The stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) and stroke outcome was assessed by modified Rankin Scale (mRS).

Results

Stroke patients had significant lower levels of vitamin D compared with the control group. Vitamin D deficiency remained significantly associated with the NIHSS stroke severity score and the mRS 3-month stroke outcome after controlling for other significant factors such as age, dyslipidemia, and infarction size using multivariable logistic regression analysis.

Conclusion

Our results demonstrated that stroke patients suffer from vitamin D deficiency, which was associated with both stroke severity and poor outcome. Vitamin D supplementation could exert a therapeutic role in the management of cerebral stroke.

Vitamin D status and cardiovascular outcome

INTRODUCTION

Vitamin D is classically involved in maintaining bone and mineral health, but it has been shown to exert many extraskeletal functions, including pleiotropic effects on cardiovascular system.

MATERIALS AND METHOD

This review aims to summarize evidences in literature about vitamin D and cardiovascular outcome.

RESULTS AND CONCLUSIONS

Calcitriol or 1,25(OH)₂D, the active hormone, binds to the specific nuclear receptor VDR, which is expressed in rat and human heart and vasculature and has effects on myocardiocytes, smooth cells, and endothelial cells. 25-Hydroxy-vitamin D (25OHD) represents the biomarker of vitamin D levels and reflects vitamin D status. There is consistent evidence that low serum 25OHD levels are associated with increased risk of cardiovascular diseases, including hypertension, coronary artery disease, ischemic heart disease, heart failure, stroke, and type 2 diabetes. Randomized-controlled trials and Mendelian randomization studies so far have not succeeded in proving a benefit of vitamin D supplementation. However, the latter investigations are affected by some methodological limitations, and therefore, it is still unclear if vitamin D deficiency has a causative role in cardiovascular diseases or is rather a marker of poor health in chronic disease.

Safety and tolerability of Vitamin D3 5000 IU/day in epilepsy

PURPOSE

Preclinical and early clinical research indicates that Vitamin D3 may reduce seizures in both animal models and open-label clinical trials.

METHODS

This is an initial report of an ongoing pilot study of oral Vitamin D3 5000 IU/day in subjects with drug-resistant epilepsy. After Institutional Review Board (IRB) approval and informed consent, subjects with ;less than one focal onset or generalized tonic-clonic seizure per month were enrolled. Subjects entered a 4-week baseline, followed by a 12-week treatment period. Serum 25, OH Vitamin D3, Blood Urea Nitrogen (BUN), creatinine, and calcium levels were monitored at baseline and at 6 and 12 weeks.

RESULTS

High-dose Vitamin D3 5000 IU/day was well tolerated. Serum 25, OH Vitamin D3 levels increased significantly at six and twelve weeks. Vitamin D insufficiency, defined as a 25, OH Vitamin D3 level of <20 ng/ml normalized in all subjects with insufficient vitamin D levels. Median seizure frequency declined from 5.18 seizures per month to 3.64 seizures per month at 6 weeks and to 4.2 seizures per month at 12 weeks. The median percent change in seizure frequency was -26.9% at six weeks, and -10.7% at 12 weeks (not significant, Wilcoxon Signed Rank Test, P > 0.34).

CONCLUSIONS

High-dose oral Vitamin D3, 5000 IU/day was safe and well tolerated in subjects with epilepsy. Vitamin D levels increased significantly at 6 and 12 weeks but never exceeded potentially toxic levels, defined as >100 ng/ml. To reduce variability, we will now recruit subjects who only have three or more seizures per month.

Effect of Plasma Level of Vitamin D on Postoperative Atrial Fibrillation in Patients Undergoing Isolated Coronary Artery Bypass Grafting

Objective

Postoperative atrial fibrillation (PoAF) is a common complication after coronary artery bypass grafting (CABG). The aim of the present study was to evaluate the association between development of PoAF and vitamin D levels in patients undergoing isolated CABG.

Methods

This prospective randomized clinical trial was conducted on the patients with isolated CABG. The study was terminated when 50 patients in both PoAF(+) group and PoAF(-) group were reached. Development of AF until discharge period was assessed. Vitamin D level was measured immediately after AF; it was measured on the discharge day for the patients without PoAF. Predictive values of the independent variables were measured for the development of PoAF.

Results

The groups were separated as PoAF(-) group (66% male, mean age 58.18±10.98 years) and PoAF(+) group (74% male, mean age 61.94±10.88 years). 25(OH) vitamin D level (OR=0.855, 95% CI: 0.780-0.938, P=0.001) and > 65 years (OR=3.525, 95% CI: 1.310-9.483, P=0.013) were identified as an independent predictor of postoperative AF after CABG surgery in multivariate analysis. The cut-off level for 25(OH) vitamin D level in receiver-operating characteristic curve analysis was determined as 7.65 with sensitivity of 60% and specificity of 64% for predicting PoAF (area under the curve: 0.679, P=0.002).

Conclusion

Vitamin D level is considered an independent predictor for development of PoAF. Lower vitamin D levels may be one of the reasons for PoAF.

Vitamin D Is Inversely Related to Obesity: Cross-Sectional Study in a Small Cohort of Serbian Adults

Objective: Vitamin D (vitD) mediates numerous health conditions other than bone health and mineralization. Its role in cardiometabolic condition is still inconclusive. Methods: We conducted a cross-sectional study in 87 apparently healthy Serbian adults. We assessed their dietary intake, anthropometric and biochemical parameters, blood pressure, and vitD status (as serum 25-hydroxyvitamin D, 25(OH)D). Unexpectedly, the status was significantly higher in January than in July. Therefore, we pooled the data from two time points, to enhance the statistical power for carrying out association analyses. We employed linear regression models to evaluate the associations between vitD status and the obesity biomarkers of serum lipids and blood pressure. Results: Mean vitD intake of 3.85 ± 4.71 μg in the cohort was below recommended. Of the subjects in the pooled cohort, 60.58% were vitD deficient (with serum 25(OH)D below 50 nmol/L), with the majority of them being women who were overweight. VitD status tended to be inversely related to percent body fat and waist/height ratio in the crude regression model. After age and gender adjustment, the status was significantly related to waist circumference, waist/height ratio, and waist/hip ratio (β = -0.116, 95% confidence interval [CI]: -0.206, -0.025, β = -0.001, 95% CI: -0.001, 0.000, and β = -0.001, 95% CI: -0.001, 0.000, respectively). These associations remained only within women. Fully adjusted models supported the notion of vitD being independently associated with central adiposity, regardless of age, gender, and total obesity. Conclusions: In apparently healthy adults with low vitD intake, vitD status was inversely associated with obesity parameters, pronouncedly in women. Our data support the need for development and implementation of public health policies on increasing vitD intake also as part of obesity management strategies.

Vitamin D and critical illness: what endocrinology can learn from intensive care and vice versa

The prevalence of vitamin D deficiency in intensive care units ranges typically between 40 and 70%. There are many reasons for being or becoming deficient in the ICU. Hepatic, parathyroid and renal dysfunction additionally increases the risk for developing vitamin D deficiency. Moreover, therapeutic interventions like fluid resuscitation, dialysis, surgery, extracorporeal membrane oxygenation, cardiopulmonary bypass and plasma exchange may significantly reduce vitamin D levels. Many observational studies have consistently shown an association between low vitamin D levels and poor clinical outcomes in critically ill adults and children, including excess mortality and morbidity such as acute kidney injury, acute respiratory failure, duration of mechanical ventilation and sepsis. It is biologically plausible that vitamin D deficiency is an important and modifiable contributor to poor prognosis during and after critical illness. Although vitamin D supplementation is inexpensive, simple and has an excellent safety profile, testing for and treating vitamin D deficiency is currently not routinely performed. Overall, less than 800 patients have been included in RCTs worldwide, but the available data suggest that high-dose vitamin D supplementation could be beneficial. Two large RCTs in Europe and the United States, together aiming to recruit >5000 patients, have started in 2017, and will greatly improve our knowledge in this field. This review aims to summarize current knowledge in this interdisciplinary topic and give an outlook on its highly dynamic future.

Diet-induced vitamin D deficiency has no effect on acute post-stroke outcomes in young male mice

Recent observational studies have reported that patients with low circulating levels of vitamin D experience larger infarct volumes and worse functional outcomes after ischemic stroke compared to those with sufficient levels. However, it is unknown whether a causal relationship exists between low vitamin D levels and poor stroke outcome. This study aimed to assess the effect of vitamin D deficiency on acute outcomes post-stroke. Male C57Bl6 mice (six week old) were assigned to either a control or vitamin D deficient diet for four weeks prior to stroke. Stroke was induced by 1 h middle cerebral artery occlusion (MCAO) with reperfusion. At 24 h, we assessed functional outcomes, infarct volume, quantified immune cells in the brain by immunofluorescence and examined susceptibility to lung infection. ELISAs showed that the plasma level of hydroxyvitamin D₃ was 85% lower in mice fed the vitamin D-deficient diet compared with the control group. Despite this, vitamin D deficiency had no impact on functional outcomes or infarct volume after stroke. Further, there were no differences in the numbers of infiltrating immune cells or bacterial load within the lungs. These data suggest that diet-induced vitamin D deficiency has no effect on acute post-stroke outcomes.

Impact of vitamin D depletion during development on mouse sperm DNA methylation

Suboptimal environmental conditions during development can substantially alter the epigenome. Stable environmentally-induced changes to the germline epigenome, in particular, have important implications for the health of the next generation. We showed previously that developmental vitamin D depletion (DVD) resulted in loss of DNA methylation at several imprinted loci over two generations. Here, we assessed the impact of DVD on genome-wide methylation in mouse sperm in order to characterize the number, extent and distribution of methylation changes in response to DVD and to find genes that may be susceptible to this prevalent environmental perturbation. We detected 15,827 loci that were differentially methylated in DVD mouse sperm vs. controls. Most epimutations (69%) were loss of methylation, and the extent of methylation change and number of CpGs affected in a region were associated with genic location and baseline methylation state. Methylation response to DVD at validated loci was only detected in offspring that exhibited a phenotypic response to DVD (increased body and testes weight) suggesting the two types of responses are linked, though a causal relationship is unclear. Epimutations localized to regions enriched for developmental and metabolic genes and pathway analyses showed enrichment for Cadherin, Wnt, PDGF and Integrin signaling pathways. These findings show for the first time that vitamin D status during development leads to substantial DNA methylation changes across the sperm genome and that locus susceptibility is linked to genomic and epigenomic context.

Serum vitamin D deficiency and vitamin D receptor gene polymorphism are associated with increased risk of cardiovascular disease in a Chinese rural population

Several studies have reported a conflicting association between vitamin D deficiency, vitamin D receptor (VDR) polymorphism, and the risk of cardiovascular disease (CVD). We hypothesized that serum 25(OH)D concentrations and single nucleotide polymorphisms (SNPs) of the VDR were associated with and increased risk of CVD. A total of 2378 adults residing in rural parts of China participated in this study. Ultimately, 1142 individuals, including 638 CVD patients and 504 control subjects were included in the study. Logistic regression and restricted cubic spines regression were used to determine the correlation between 25(OH)D and the risk of CVD. Allele frequency and genotype distribution were analyzed between CVD patients and control subjects, and haplotype analysis was used to evaluate the combined effect of VDR SNPs on CVD pathogenesis. In the adjusted model, the odds ratio (95% confidence interval (CI)) of the CVD in the sufficient vitamin D group was 0.76 (0.60-0.96)when compared with the vitamin D deficient group. At 25(OH)D doses of less than 20 ng/mL, there was a dose-response relationship between 25(OH)D and CVD risk. Moreover, the rs3847987 SNP was associated with fasting plasma glucose (FPG) and triglyceride (TG) in CVD patients. In all models, there was a significant association between rs2189480 and CVD, especially in females and those aged ≥55 years. In these groups, rs3847987 SNPs were significantly different, especially in females. Compared with the ACA haplotype, the AAA and CCA haplotypes were associated with increased risk of CVD. In conclusion, our results suggested that serum 25(OH)D levels and VDR SNPs are closely related with CVD pathogenesis.

Nontraditional Cardiovascular Biomarkers and Risk Factors: Rationale and Future Perspectives

The primary prevention of cardiovascular (CV) disease depends on the capacity to identify subjects at higher risk long before the occurrence of CV clinical manifestations. Traditional risk factors do not cover fully prediction of individual risk. Moreover, there is an area of gray for patients at intermediate CV risk, which offers wide margins of improvement. These observations highlight the need for new additive tools for a more accurate risk stratification. An increasing number of candidate biomarkers have been identified to predict CV risk and events, although they generally give only a moderate increase when added to currently available predictive scores. The approach utilizing a relative small number of biomarkers in multiple combinations, but only weakly related to each other or unrelated, thus belonging to independent-pathways, and so able to catch the multidimensional characteristic of atherosclerosis, appears promising. We discuss vitamin D and bone turnover biomarkers, hepatitis C virus, and psycho-emotional factors that may reflect alternative pathways over those generally considered for atherosclerosis (e.g., aspects directly related to inflammation and thrombosis). These new biomarkers could facilitate a more accurate assessment of CV risk stratification if incorporated in the current risk assessment algorithms.

Vitamin D3 Supplementation Reduces Subsequent Brain Injury and Inflammation Associated with Ischemic Stroke

Acute inflammation can exacerbate brain injury after ischemic stroke. Beyond its well-characterized role in calcium metabolism, it is becoming increasingly appreciated that the active form of vitamin D, 1,25-dihydroxyvitamin D₃ (1,25-VitD₃), has potent immunomodulatory properties. Here, we aimed to determine whether 1,25-VitD₃ supplementation could reduce subsequent brain injury and associated inflammation after ischemic stroke. Male C57Bl6 mice were randomly assigned to be administered either 1,25-VitD₃ (100 ng/kg/day) or vehicle i.p. for 5 day prior to stroke. Stroke was induced via middle cerebral artery occlusion for 1 h followed by 23 h reperfusion. At 24 h post-stroke, we assessed infarct volume, functional deficit, expression of inflammatory mediators and numbers of infiltrating immune cells. Supplementation with 1,25-VitD₃ reduced infarct volume by 50% compared to vehicle. Expression of pro-inflammatory mediators IL-6, IL-1β, IL-23a, TGF-β and NADPH oxidase-2 was reduced in brains of mice that received 1,25-VitD₃ versus vehicle. Brain expression of the T regulatory cell marker, Foxp3, was higher in mice supplemented with 1,25-VitD₃ versus vehicle, while expression of the transcription factor, ROR-γ, was decreased, suggestive of a reduced Th17/γδ T cell response. Immunohistochemistry indicated that similar numbers of neutrophils and T cells were present in the ischemic hemispheres of 1,25-VitD₃- and vehicle-supplemented mice. At this early time point, there were also no differences in the impairment of motor function. These data indicate that prior administration of exogenous vitamin D, even to vitamin D-replete mice, can attenuate infarct development and exert acute anti-inflammatory actions in the ischemic and reperfused brain.

Serum 25-hydroxyvitamin D levels in patients with skin diseases including psoriasis, infections, and atopic dermatitis

The pathogenetic role of vitamin D as well as its clinical correlation in inflammatory skin diseases is still uncertain. This study aimed to compare serum levels of 25(OH) vitamin D (calcidiol) in outpatients suffering from different skin diseases using the same laboratory method in one study. In routine serum samples of 1,532 patients from the previous 12 months we identified retrospectively 180 (mean age 49.4 years, 80 female, 100 male) and 205 (mean age 36.3 years, 116 female, 89 male) patients with psoriasis (PSO) and atopic dermatitis (AD), respectively. Clinical disease activity and quality of life was evaluated using Physicians Global Assessment Scores (PGA), Dermatology Life Quality Index (DLQI), and a Visual Analog Scale for pruritus in AD, respectively. The median 25(OH)D serum level of all patients (22.97 ng/mL, range 2.61–96.0, n = 1,461) was significantly lower in comparison to healthy controls (41.6 ng/mL, range 16.9–77.57, p < 0.0001, n = 71). In PSO and AD we measured 21.05 ng/mL (44% < 20 ng/mL) and 22.7 ng/mL (39% < 20 ng/mL), respectively (p = 0.152). Among all subgroups, patients with severe acute or chronic infectious skin diseases had the lowest median 25(OH)D serum levels (17.11 ng/mL, n = 94, 66% <20 ng/mL, p < 0,001 vs. AD, p = 0,007 vs. PSO). For PSO and AD there was no significant correlation between 25(OH)D levels and PGA scores and DLQI values, respectively, or the extent of pruritus in AD. 25(OH)D serum levels in inflammatory skin diseases might correlate more with the type of disease and the degree of inflammation than with clinical activity itself.

Hypovitaminosis D in patients with heart failure: effects on functional capacity and patients' survival

Chronic heart failure is a major cause of morbidity and mortality, but its prognosis remains poor. Vitamin D hormone has many extra-skeletal functions including a positive impact on the cardiovascular system, and has been proposed for mortality risk evaluation in heart failure patients. The aim of the present study was to evaluate vitamin D status in heart failure patients, measured by high performance liquid chromatography coupled with mass spectrometry and to correlate serum 25 hydroxy-vitamin D (25OHD) levels with functional (peak VO₂%) and mortality (Metabolic Exercise Cardiac Kidney Index) heart failure parameters. We enrolled 261 consecutive patients diagnosed with heart failure; all patients underwent a comprehensive clinical and biochemical characterization, and serum 25OHD levels were measured by high performance liquid chromatography coupled with mass spectrometry. Cardiopulmonary test parameters and Metabolic Exercise Cardiac Kidney Index of mortality risk were measured in all patients. Serum 25OHD levels ranged between 2 and 45 ng/ml (mean 17 ± 9 ng/ml); most patients (87%) showed hypovitaminosis D, and 25% showed severe vitamin D deficiency (serum 25OHD < 10 ng/ml). Patients with 25OHD < 10 ng/ml had significantly lower cardiopulmonary test VO₂/kg, peak VO₂% and significantly higher N-terminalproBrain natriuretic peptide and Metabolic Exercise Cardiac Kidney Index, than patients with 25OHD > 10 ng/ml. Patients with peak VO₂% < 50% showed significantly lower 25OHD compared to those with peak VO₂% > 50%. There was a significant, positive correlation (r = 0.16, p = 0.008) between 25OHD levels and peak VO₂%, and an inverse correlation with Metabolic Exercise Cardiac Kidney Index (r = -0.21, p < 0.001), even when adjusted for age, Body Mass Index, MDRD, N-terminalproBrain natriuretic peptide. In conclusion, our findings show that vitamin D levels are associated with functional and mortality heart failure prognosis parameters.

Serum 25-hydroxyvitamin D and the risk of stroke in Hong Kong Chinese

Low vitamin D levels have been associated with various cardiovascular diseases; however, whether it is associated with stroke remains inconclusive. We aimed to evaluate the association between serum 25-hydroxyvitamin D and risk of stroke. We conducted a cohort study consisting of 3,458 participants from the Hong Kong Osteoporosis Study aged ≥45 at baseline, examined between 1995 and 2010 and followed up using electronic medical records. Ischaemic and haemorrhagic stroke were defined using the ICD-9 code. In multivariable Cox-proportional hazard regression, quintiles 1 and 4 were significantly associated with increased risk of stroke when compared to the highest quintile (Quintile 1: HR, 1.78; 95 % CI, 1.16–2.74 and quintile 4: HR, 1.61; 95 % CI, 1.07–2.43). A similar association was observed in both men and women. In subgroup analysis, the association was specifically observed for ischaemic stroke, but not haemorrhagic stroke. Using a penalized regression spline, the association between vitamin D and risk of stroke was in a reverse J-shape, with the lowest risk of stroke being observed at 25(OH)D levels between 70 and 80 nmol/l. In conclusion, a low vitamin D level is associated with increased risk of ischaemic stroke; however, whether high vitamin D level is also associated with increased risk of stroke requires further study.

Supplementary Material to this article is available at www.thrombosis-online.com.

Vitamin D3 for the Treatment of Epilepsy: Basic Mechanisms, Animal Models, and Clinical Trials

There is increasing evidence supporting dietary and alternative therapies for epilepsy, including the ketogenic diet, modified Atkins diet, and omega-3 fatty acids. Vitamin D3 is actively under investigation as a potential intervention for epilepsy. Vitamin D3 is fat-soluble steroid, which shows promise in animal models of epilepsy. Basic research has shed light on the possible mechanisms by which Vitamin D3 may reduce seizures, and animal data support the efficacy of Vitamin D3 in rat and mouse models of epilepsy. Very little clinical data exist to support the treatment of human epilepsy with Vitamin D3, but positive findings from preliminary clinical trials warrant larger Phase I and II clinical trials in order to more rigorously determine the potential therapeutic value of Vitamin D3 as a treatment for human epilepsy.

Older Swedish Adults with High Self-Perceived Health Show Optimal 25-Hydroxyvitamin D Levels Whereas Vitamin D Status Is Low in Patients with High Disease Burden

Controversy pervades the definition of adequate and optimal vitamin D status. The Institutes of Medicine have recommended serum 25(OH)D levels above 50 nmol/L based upon evidence related to bone health, but some experts, including the Endocrine Society and International Osteoporosis Foundation, suggest a minimum serum 25(OH)D level of 75 nmol/L to reduce the risk of falls and fractures in older adults. In a cross-sectional study, we compared vitamin D status in people ≥75 years selected from four groups with a frailty phenotype, combined with a control group free from serious illness, and who considered themselves completely healthy. Only 13% of the 169 controls were vitamin D deficient (S-25(OH)D) < 50 nmol/L), in contrast with 49% of orthopedic patients with hip fractures (n = 133), 31% of stroke patients (n = 122), 39% of patients visiting the hospital's emergency department ≥4 times a year (n = 81), and 75% of homebound adult residents in long-term care nursing homes (n = 51). The mean vitamin D concentration of the healthy control group (74 nmol/L) was similar to a suggested optimal level based on physiological data and mortality studies, and much higher than that of many officially recommended cut-off levels for vitamin D deficiency (<50 nmol/L). The present study provides a basis for planning and implementing public guidelines for the screening of vitamin D deficiency and vitamin D treatment for frail elderly patients.

Maternal vitamin D depletion alters DNA methylation at imprinted loci in multiple generations

Background

Environmental perturbation of epigenetic mechanisms is linked to a growing number of diseases. Characterizing the role environmental factors play in modifying the epigenome is important for disease etiology. Vitamin D is an essential nutrient affecting brain, bone, heart, immune and reproductive health. Vitamin D insufficiency is a global issue, and the role in maternal and child health remains under investigation.

Methods

We used Collaborative Cross (CC) inbred mice to characterize the effect of maternal vitamin D depletion on offspring phenotypic and epigenetic outcomes at imprinted domains (H19/Igf2, Snrpn, Dlk1/Gtl2, and Grb10) in the soma (liver) and germline (sperm). We assessed outcomes in two generations of offspring to determine heritability. We used reciprocal crosses between lines CC001/Unc and CC011/Unc to investigate parent of origin effects.

Results

Maternal vitamin D deficiency led to altered body weight and DNA methylation in two generations of offspring. Loci assayed in adult liver and sperm were mostly hypomethylated, but changes were few and small in effect size (<7 % difference on average). There was no change in total expression of genes adjacent to methylation changes in neonatal liver. Methylation changes were cell type specific such that changes at IG-DMR were present in sperm but not in liver. Some methylation changes were distinct between generations such that methylation changes at the H19ICR in second-generation liver were not present in first-generation sperm or liver. Interestingly, some diet-dependent changes in body weight and methylation were seemingly influenced by parent of origin such that reciprocal crosses exhibited inverse effects.

Conclusions

These findings demonstrate that maternal vitamin D status plays a role in determining DNA methylation state in the germline and soma. Detection of methylation changes in the unexposed second-generation demonstrates that maternal vitamin D depletion can have long-term effects on the epigenome of subsequent generations. Differences in vitamin D-dependent epigenetic state between cell types and generations indicate perturbation of the epigenetic landscape rather than a targeted, locus-specific effect. While the biological importance of these subtle changes remains unclear, they warrant an investigation of epigenome-wide effects of maternal vitamin D depletion.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0276-4) contains supplementary material, which is available to authorized users.