Higher 25(OH)D2 is associated with lower 25(OH)D3 and 1,25(OH)2D3

Association of polychlorinated biphenyls with vitamin D among rural Chinese adults with normal glycaemia and type 2 diabetes mellitus

BACKGROUND

Endocrine function in patients with type 2 diabetes (T2DM) typically differs from those with normal glucose tolerance (NGT). However, few epidemiologic studies have explored how these differences impact the association between exposure to polychlorinated biphenyls (PCBs) and vitamin D levels.

METHODS

This study included 1,705 subjects aged 18-79 years from the Henan Rural Cohort [887 NGT and 818 T2DM]. Linear regression was applied to evaluate the associations between PCB exposure and vitamin D levels. Quantile g-computation regression (QG) and Bayesian kernel machine regression (BKMR) were applied to evaluate the impact of PCB mixtures on vitamin D levels. Interaction effects of ΣPCBs with HOMA2-%β and HOMA2-IR on vitamin D levels were assessed.

RESULTS

Plasma ΣPCBs was positively associated with 25(OH)D2 in the NGT group (β = 0.060, 95% CI: 0.028, 0.092). Conversely, in T2DM group, ΣPCBs was negatively associated with 25(OH)D3 and 25(OH)D (β = -0.049, 95% CI: -0.072, -0.026; β = -0.043, 95% CI: -0.063, -0.023). Similarly, both QG and BKMR analysis revealed a negative association between PCB mixture exposure and vitamin D levels in the T2DM group, contrary to the results observed in the NGT groups. Furthermore, the negative association of ΣPCBs with 25(OH)D2 and 25(OH)D disappeared or changed to a positive association with the increase of HOMA2-%β levels.

CONCLUSIONS

These findings suggest that decreased β cell function may exacerbate the negative effects of PCB exposure on vitamin D levels. Recognizing T2DM patients' sensitivity to PCBs is vital for protecting chronic disease health.

Vitamin D Deficiency in the Acute Phase of Stroke May Predict Post-stroke Depression: A Systematic Review and Meta-Analysis

OBJECTIVE

To conduct the association between vitamin D levels in the acute phase of stroke and post-stroke depression (PSD) in stroke patients.

METHODS

Five international databases (PubMed, Web of Science, Embase, Ovid MEDLINE(R), Cochrane Library) and one Chinese database (Wanfang Data) were searched for observational studies in any language reporting on PSD and vitamin D levels tested in the acute phase of stroke in stroke patients from inception to May 2024. Data extraction and study quality assessment were conducted by two authors independently. Qualitative and quantitative analyses of data were performed. The meta-analysis was registered in the PROSPERO database (CRD42023398581).

RESULTS

We included 7 studies containing 3537 participants in the systematic review and meta-analysis. All studies that met the inclusion and exclusion criteria were conducted in China. Vitamin D levels in the acute phase of stroke were lower in PSD patients compared with non-PSD patients (weighted mean difference = -14.97 nmol/L; 95% confidence interval = -19.54, -10.40). Stroke patients with vitamin D deficiency (<50 nmol/L) had an increased risk of PSD compared with stroke patients with vitamin D sufficiency (≥75 nmol/L) (odds ratio = 3.59; 95% confidence interval = 2.05, 6.27). However, the association between vitamin D insufficiency (50-75 nmol/L) and PSD were not statistically significant (odds ratio = 4.15; 95% confidence interval = 0.87, 19.78).

CONCLUSION

Vitamin D deficiency in the acute phase of stroke may be a risk factor for PSD.

Association of vitamin D and cognition in people with type 2 diabetes: a systematic review

CONTEXT

There is a high prevalence of vitamin D deficiency and impaired cognitive function in people with type 2 diabetes mellitus (T2DM).

OBJECTIVE

To critically and systematically review the literature on the association between vitamin D status and cognitive performance in people with type 2 diabetes.

DATA SOURCES

This review was conducted according to PRISMA recommendations. MEDLINE, SCOPUS, the Cochrane Library, and Web of Science databases were searched using the terms "Diabetes Mellitus, Type 2", "Cognitive Function", and "Vitamin D".

DATA EXTRACTION

Eight observational and 1 randomized study were included, containing data of 14 648 adult and elderly individuals (19-74 y). All extracted data were compiled, compared, and critically analyzed.

DATA ANALYSIS

There is no strong evidence that lower serum concentrations of vitamin D and vitamin D-binding protein are associated with worsening cognitive function in individuals with T2DM. Vitamin D supplementation (12 wk) improved the scores of some executive functioning tests, although there was no difference between low doses (5000 IU/wk) and high doses (50 000 IU/wk).

CONCLUSIONS

There is no high-quality evidence demonstrating an association between vitamin D status and cognitive function, or clinical benefits on cognition from vitamin D supplementation in individuals with T2DM. Future studies are needed. Systematic Review Registration: PROSPERO registration no. CRD42021261520.

An ultra-sensitive and high-throughput trapping-micro-LC-MS method for quantification of circulating vitamin D metabolites and application in multiple sclerosis patients

Quantitative analysis of the biologically-active metabolites of vitamin D (VitD), which are crucial in regulating various physiological and pathological processes, is important for clinical investigations. Liquid chromatography-tandem mass spectrometry (LC-MS) has been widely used for this purpose but existing LC-MS methods face challenges in achieving highly sensitive and accurate quantification of low-abundance VitD metabolites while maintaining high throughput and robustness. Here we developed a novel pipeline that combines a trapping-micro-LC-(T-µLC) with narrow-window-isolation selected-reaction monitoring MS(NWI-SRM) for ultra-sensitive, robust and high-throughput quantification of VitD metabolites in serum samples after derivatization. The selective-trapping and delivery approach efficiently removes matrix components, enabling high-capacity sample loading and enhancing sensitivity, throughput, and robustness. The NWI-SRM further improves the sensitivity by providing high selectivity. The lower limits of quantification (LOQs) achieved were markedly lower than any existing LC-MS methods: 1.0 pg/mL for 1,25(OH)2D3, 5.0 pg/mL for 24,25(OH)2D3, 30 pg/mL for both 25(OH)D2 and 25(OH)D3, all within a 9-min cycle. The method is applied to quantify VitD metabolites from 218 patients with multiple sclerosis. This study revealed negative correlations(r=- 0.44 to - 0.51) between the levels of 25(OH)D2 and all the three D3 metabolites in multiple sclerosis patients.

Isochromosome 12p Formation Regulates Vitamin D Metabolism in Testicular Cancer

Isochromosome 12p (iChr12p) is typical in almost all invasive testicular cancers. Increased copy number of genes on 12p is associated with the development of a clinically manifest tumor; however, the causative genes have not yet been identified. Chromosome 12 harbors many genes involved in Vitamin D metabolism. RNAseq analysis of Vitamin D receptor (VDR) genes from the TCGA cohort revealed that clustering of VDR expression signatures could differentiate between pure seminomas and non-seminomatous germ cell tumors (NSGCT). Using TCGA mRNA expression of anabolic (CYP2R1, CYP27A1 and CYP27B1) and catabolic (CYP24A1) Vitamin D enzymes, positive (PTHLH, IFNG, and TNF) and negative (FGF23) feedback regulators could also clearly distinguish between pure seminomas and NSGCT. We hypothesize that the regulation of Vitamin D metabolism might be disturbed through iChr12p formation, influencing testicular carcinogenesis via increased FGF23 and PTHLH expression. While FGF23 represses CYP27B1 and activates catabolism of active hormone, increased PTHLH secretion can lead to hypercalcemia via inactivation of VDR. In conclusion, testicular cancer is associated with extensive modifications in intratesticular Vitamin D homeostasis. Further research is needed to clarify whether Vitamin D deficiency causes the formation of iChr12p and whether Vitamin D deficiency via iChr12p genomic aberration is involved in testicular carcinogenesis.

Effect of vitamin D metabolites on bone histomorphometry in healthy black and white women: An attempt to unravel the so-called vitamin D paradox in blacks

An apparent vitamin D paradox, characterized by lower serum 25-hydroxyvitamin D (25(OH)D) levels and higher bone mineral density, is present in black population. In contrast, blacks have higher serum 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels. The effect of 1,25(OH)₂D on the skeleton is not fully understood. We examined serum 25(OH)D, 1,25(OH)₂D and bone histomorphometry in 50 black and white women (25 each) matched for age, menstrual status, and BMI. Histomorphometric indices related to bone structure, remodeling and mineralization were measured in cancellous bone in iliac bone biopsies. Data analyses led to the following results: 1) serum 25(OH)D was significantly lower and 1,25(OH)₂D was significantly higher in black than in white women, but neither blacks nor whites revealed significant correlation between these two vitamin D metabolites. 2) there was no significant difference in PTH levels between blacks and whites. 3) except for greater trabecular thickness (Tb.Th) in blacks, there were no significant differences in other histomorphometric variables between the two ethnic groups. 4) osteoid surface (OS/BS), unlabeled osteoid surface (ulOS/BS), and osteoblast surface (ObS/BS) significantly correlated with serum 1,25(OH)₂D levels. We conclude that lower serum 25(OH)D levels in blacks do not impair bone structure and remodeling, nor decrease bone mineralization. Higher serum 1,25(OH)₂D levels in blacks may help preserve bone mass by stimulating bone formation via increasing osteoblast number and function, but moderately inhibit terminal bone mineralization as shown by higher ulOS/BS.

Relationship between Serum 25OH-Vitamin D2 Level and Vitamin D Status of Children Aged 3-5 Years in China

Background: Vitamin D deficiency is prevalent globally and there is lack of evidence as to how 25(OH)D2 contributes to vitamin D status. The aim of this study was to describe vitamin D status and to assess the role of vitamin D2, a dietary vitamin D source, against the vitamin D status of children aged 3–5 years in China. Methods: Data were extracted from the Chinese National Nutrition and Health Surveillance (CNNHS) in 2013. The concentration of serum 25(OH)D2 and 25(OH)D3 was measured by using LC-MS/MS. Results: A total of 1435 subjects were enrolled and serum 25(OH)D were analyzed. The prevalence of total serum 25(OH)D < 30 nmol/L was 8.9%. Serum 25(OH)D2 was detected in 10.9% of the studied children. After adjusting for confounding factors, total 25(OH)D concentration was 8.48 nmol/L lower and odds ratio of vitamin D deficiency was 4.20 times (OR (95%CI): 4.20 (1.64, 10.77)) in children without 25(OH)D2 than those with 25(OH)D2 detected. Conclusions: Vitamin D deficiency was common among children aged 3–5 years in China. Vitamin D2 may play a role in preventing vitamin D deficiency in Chinese children aged 3–5 years.

Association of Dietary Vitamin D Intake, Serum 25(OH)D3, 25(OH)D2 with Cognitive Performance in the Elderly

Background: As life expectancy increases, cognitive performance decline in the elderly has become one of the major global challenges. We aimed to evaluate the association of dietary vitamin D (VD), serum 25-hydroxyvitamin D3 (25(OH)D₃), 25-hydroxyvitamin D2 (25(OH)D₂), and total 25-hydroxyvitamin (25(OH)D) concentration with cognitive performance in older Americans. Methods: The data from the National Health and Nutrition Examination Survey (NHANES), 2011–2014 was used. The cognitive performance was assessed by the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) Word Learning sub-test, Animal Fluency test, and Digit Symbol Substitution Test (DSST). A binary logistic regression model was applied to evaluate the association between VD and cognitive performance, and restricted cubic spline model was adopted to evaluate the dose–response relationship. Results: While comparing to the lowest dietary VD intake group, the multivariate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of the highest dietary VD intake group were 0.51 (0.36–0.72) for the Animal Fluency test score and 0.45 (0.31–0.66) for DSST score, respectively; and those of serum total 25(OH)D and 25(OH)D₃ concentration were 0.68 (0.47–0.97) and 0.62 (0.44–0.86) for DSST score. L-shaped relationships were identified for dietary VD intake, serum total 25(OH)D and 25(OH)D₃ concentration with cognition performance. The associations between dietary VD intake, serum total 25(OH)D and cognitive performance were non-significant when stratified by gender. Conclusions: The study indicates that dietary VD intake, serum total 25(OH)D and 25(OH)D₃ concentration were positively associated with cognitive performance. Further studies are needed to clarify the possible effects of dietary VD intake and serum 25(OH)D₂, 25(OH)D₃ on cognitive performance.

Bad Prognosis in Critical Ill Patients with COVID-19 during Short-Term ICU Stay regarding Vitamin D Levels

BACKGROUND AND AIMS

Vitamin D inadequacy may be involved in the mechanisms of SARS-CoV-2 infection and in potential risk factors for disease propagation or control of coronavirus disease 2019 (COVID-19). This study assessed a short-term evolution of vitamin D status and its influence upon different clinical parameters in critically ill patients with COVID-19.

METHODS

A prospective analytical study in which 37 critically ill volunteers between 41 and 71 years of age with COVID-19 were evaluated at baseline and three days of intensive care unit (ICU) stay. 25-OH-D₃ and 25-OH-D₂ were analyzed by liquid chromatography-tandem mass spectrometry and total 25-OH-D levels were calculated as the sum of both.

RESULTS

All patients presented low 25-OH-D levels at baseline, decreasing total 25-OH-D (p = 0.011) mainly through 25-OH-D₂ (p = 0.006) levels during ICU stay. 25-OH-D₂ levels decreased a mean of 41.6% ± 89.6% versus 7.0% ± 23.4% for the 25-OH-D₃ form during the ICU stay. Patients who did not need invasive mechanical ventilation presented higher levels of 25-OH-D₂ at baseline and follow-up. Lower 25-OH-D and 25-OH-D₃ levels were associated with higher D-dimer at baseline (p = 0.003; p = 0.001) and at follow up (p = 0.029), higher procalcitonin levels (p = 0.002; p = 0.018) at follow up, and lower percentage lymphocyte counts (p = 0.044; p = 0.040) during ICU stay.

CONCLUSIONS

Deficient vitamin D status in critical patients was established at the admission and further worsened after three days of stay. Lower vitamin D levels were related to key altered clinical and biochemical parameters on patients with SARS-CoV-2 infection. Given the different response of the 25-OH-D₃ and 25-OH-D₂ forms, it would be useful to monitor them on the evolution of the critically ill patient.

Association of Single Nucleotide Polymorphisms in the VDR and CYP27B1 Genes with Risk of Developing Vitamin D3 Deficiency

This study was carried out to investigate the relationship between common variants in two vitamin D pathway genes (VDR and CYP27B1) and vitamin D3 serum levels. In this study, serum vitamin D metabolite levels were measured in the blood samples of 200 patients with alopecia areata. Then, single nucleotide polymorphisms (SNPs) in VDR and CYP27B1 were analyzed using polymerase chain reaction (PCR)-sequencing. Sixty-three variations were observed in these genes (42 variations in CYP27B1 and 21 variations in VDR). A significant difference in Rs1544410 (odds ratio: 7, P < 0.0005) and rs4646536 (odds ratio: 4.043, P < 0.0005) variants was found between the patients and controls. The study showed the relationship between the two polymorphisms, Rs1544410 (odds ratio: 7, 95% CI, 1–8) and rs4646536 (odds ratio: 4.043, 95% CI, 3–14.038) on the genes VDR and CYP27B1, respectively, with increased risk of developing vitamin D3 insufficiency in the Iranian population. Therefore, SNPs in the VDR and CYP27B1 genes can be considered as prognostic biomarkers of the risk of developing vitamin D3 deficiency.

Genetic, environmental and biomarker considerations delineating the regulatory effects of vitamin D on central nervous system function

Studies show that vitamin D (vit-D) (25(OH)D), the bioactive metabolite (1,25(OH)2D3) and vit-D receptors (vit-D receptor; protein disulphide isomerase, family A member 3) are expressed throughout the brain, particularly in regions pivotal to learning and memory. This has led to the paradigm that avoiding vit-D deficiency is important to preserve cognitive function. However, presently, it is not clear if the common clinical measure of serum 25(OH)D serves as a robust surrogate marker for central nervous system (CNS) homeostasis or function. Indeed, recent studies report CNS biosynthesis of endogenous 25(OH)D, the CNS expression of the CYP group of enzymes which catalyse conversion to 1,25(OH)2D3 and thereafter, deactivation. Moreover, in the periphery, there is significant ethnic/genetic heterogeneity in vit-D conversion to 1,25(OH)2D3 and there is a paucity of studies which have actually investigated vit-D kinetics across the cerebrovasculature. Compared with peripheral organs, the CNS also has differential expression of receptors that trigger cellular response to 1,25(OH)2D3 metabolites. To holistically consider the putative association of peripheral (blood) abundance of 25(OH)D on cognitive function, herein, we have reviewed population and genetic studies, pre-clinical and clinical intervention studies and moreover have considered potential confounders of vit-D analysis.

Vitamin D level is associated with severity of coronary artery atherosclerosis and incidence of acute coronary syndromes in non-diabetic cardiac patients

INTRODUCTION

Ischaemic heart disease is the main cause of death in developed countries. There are many modifiable risk factors associated with coronary heart disease (CAD). A growing number of studies point to vitamin D deficiency as a risk factor for heart attacks and the conditions associated with cardiovascular disease. This study aimed to analyse the relationship between the level of 25-hydroxyvitamin D (25(OH)D) and the severity of coronary artery atherosclerosis and to study 25(OH)D levels in non-diabetic patients hospitalised due to acute coronary syndrome and those diagnosed with stable CAD.

MATERIAL AND METHODS

oronary angiography was performed prospectively in 410 successive cardiac patients. The severity of coronary artery atherosclerosis was assessed according to the Coronary Artery Surgery Study Score (CASSS). The plasma 25(OH)D level was assessed with the electrochemiluminescence method.

RESULTS

The 25(OH)D level proved to be one of the significant determinants of the CASSS (p < 0.05). In subjects without significant lesions in the coronary arteries the 25(OH)D level was significantly higher compared to patients with one- to three-vessel coronary atherosclerosis (p < 0.05). A significantly higher 25(OH)D level was noted in patients diagnosed with stable CAD compared to patients hospitalised due to acute coronary syndrome (p < 0.01).

CONCLUSIONS

Patients with one- to three-vessel atherosclerosis have a significantly lower 25(OH)D level compared to patients without significant lesions in the coronary arteries. A lower 25(OH)D level was observed in patients hospitalised due to acute coronary syndrome compared to patients diagnosed with stable CAD.

Is it necessary for all samples to quantify 25OHD2 and 25OHD3 using LC-MS/MS in clinical practice?

BACKGROUND

The demand for vitamin D testing is increasing in China. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) immunoassay is specific and accurate but requires expensive equipment, experienced operators, and complicated pretreatment of serum. Automated immunoassays are simple and convenient but only determine total 25-hydroxyvitamin D (25OHD). The objective of this study was to quantify 25OHD2 and 25OHD3 in patients to assist clinical physicians and laboratory directors in choosing the most appropriate method to determine 25OHD.

METHODS

Vitamin D testing was conducted for 23,695 patients in Peking Union Medical College Hospital from May 2015 to January 2017. Using this large data set, the prevalence and levels of 25OHD2 were analyzed. LC-MS/MS was used to separately determine 25OHD2 and 25OHD3.

RESULTS

25OHD2 (≥2.5 ng/mL) was detected in 16.4% (3877/23,695) of patients. Males had a significantly lower incidence of detectable 25OHD2 (p<0.01); 1077 (13.9%) samples contained detectable 25OHD2 (median: 3.7 ng/mL; 2.5%-97.5%: 2.5-17.2 ng/mL). For females, 2800 (17.5%) samples contained detectable 25OHD2 (median: 4.0 ng/mL; range: 2.5-20.6 ng/mL). Of the 3877 patients with detectable 25OHD2, males had a significantly higher level of 25OHD3 (p<0.01). There was no significant difference in total 25OHD. The proportion of 25OHD2 in total 25OHD was 1.3%-100%; 87.5% (3391/3877) of the samples contained <10 ng/mL 25OHD2. 25OHD2 negatively correlated with 25OHD3 (r=-0.197, p<0.01) and positively correlated with total 25OHD (r=0.217, p<0.01).

CONCLUSIONS

Prevalence of 25OHD2 in patients tested for vitamin D is relatively high in China. 25OHD2 is significantly negatively correlated with 25OHD3.

Vitamin D, Cognition and Alzheimer's Disease: The Therapeutic Benefit is in the D-Tails

Since its discovery during the epidemic of rickets in the early 1920s, the physiological effects of vitamin D on calcium/phosphorus homeostasis have been thoroughly studied. Along with the understanding of its actions on skeletal diseases and advances in cellular and molecular biology, this misnamed vitamin has gained attention as a potential player in a growing number of physiological processes and a variety of diseases. During the last 25 years, vitamin D has emerged as a serious candidate in nervous system development and function and a therapeutic tool in a number of neurological pathologies. More recently, experimental and pre-clinical data suggest a link between vitamin D status and cognitive function. Human studies strongly support a correlation between low levels of circulating 25-hydroxyvitamin D (25(OH)D) and cognitive impairment or dementia in aging populations. In parallel, animal studies show that supplementation with vitamin D is protective against biological processes associated with Alzheimer’s disease (AD) and enhances learning and memory performance in various animal models of aging and AD. These experimental observations support multiple mechanisms by which vitamin D can act against neurodegenerative processes. However, clinical interventional studies are disappointing and fail to associate increased 25(OH)D levels with improved cognitive outcomes. This review collects the current available data from both animal and human studies and discusses the considerations that future studies examining the effects of vitamin D status on neurocognitive function might consider.

Serum and urine vitamin D metabolite analysis in early preeclampsia

Vitamin D deficiency is common in pregnant women and may contribute to adverse events in pregnancy such as preeclampsia (PET). To date, studies of vitamin D and PET have focused primarily on serum concentrations vitamin D, 25-hydroxyvitamin D3 (25(OH)D3) later in pregnancy. The aim here was to determine whether a more comprehensive analysis of vitamin D metabolites earlier in pregnancy could provide predictors of PET. Using samples from the SCOPE pregnancy cohort, multiple vitamin D metabolites were quantified by liquid chromatography-tandem mass spectrometry in paired serum and urine prior to the onset of PET symptoms. Samples from 50 women at pregnancy week 15 were analysed, with 25 (50%) developing PET by the end of the pregnancy and 25 continuing with uncomplicated pregnancy. Paired serum and urine from non-pregnant women (n = 9) of reproductive age were also used as a control. Serum concentrations of 25(OH)D3, 25(OH)D2, 1,25(OH)₂D3, 24,25(OH)₂D3 and 3-epi-25(OH)D3 were measured and showed no significant difference between women with uncomplicated pregnancies and those developing PET. As previously reported, serum 1,25(OH)₂D3 was higher in all pregnant women (in the second trimester), but serum 25(OH)D2 was also higher compared to non-pregnant women. In urine, 25(OH)D3 and 24,25(OH)₂D3 were quantifiable, with both metabolites demonstrating significantly lower (P < 0.05) concentrations of both of these metabolites in those destined to develop PET. These data indicate that analysis of urinary metabolites provides an additional insight into vitamin D and the kidney, with lower urinary 25(OH)D3 and 24,25(OH)₂D3 excretion being an early indicator of a predisposition towards developing PET.

Vitamin D3 repletion versus placebo as adjunctive treatment of heart failure patient quality of life and hormonal indices: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Vitamin D status may influence heart failure (HF) patient outcomes by affecting b-type natriuretic peptide (BNP), parathyroid hormone (PTH), and enhancing cardiac contractility. Vitamin D deficiency is associated with morbidity and mortality in HF patients. The objective of this study was to determine if vitamin D3 at a comparatively high dose would replete 25-hydroxyvitamin D (25(OH)D) stores, improve BNP, PTH, cardiopulmonary function, reduce inflammatory markers, and improve quality of life (QOL) in HF patients.

METHODS

This was a 6 month, parallel group, double-blind, placebo-controlled, single clinic center, randomized trial of supplemental vitamin D3 using a dose of 10,000 IU daily or placebo in 40 vitamin D deficient or insufficient (25(OH)D level ≤ 32 ng/ml) patients with stable New York Heart Association Class II-III HF in a specialty cardiology clinic. All variables were measured at baseline and 6 months. Values between the two treatment groups were assessed using Student's t-test or Mann-Whitney Test. Univariate analysis of covariance was conducted to adjust for variance in baseline 25(OH)D.

RESULTS

All results were adjusted for baseline 25(OH)D. The change in BNP from baseline was ∆ +30 ± 950 pg/ml for treatment vs. placebo ∆ +400 ± 1900 pg/ml, p = 0.003. 25(OH)D serum levels rose by 49 ± 32 ng/ml in the treatment group vs 4 ± 10 ng/ml in the placebo group, p < 0.001. PTH and exercise chronotropic response index improved in the treatment group vs placebo group, respectively, but both were attenuated by adjustment ((∆-20 ± 20 pg/ml vs ∆ + 7 ± 53 pg/ml respectively (p = 0.01, adjusted p = 0.07)) and (∆ + 0.13 ± 0.26 vs. ∆-0.03 ± 02.9 respectively, p < 0.01, adjusted p = 0.17)). Other measured cardiopulmonary parameters remained unchanged. High sensitivity C-reactive protein (hsCRP) remained unchanged for women, but improved for men (∆-2 ± 4 treatment versus ∆2 ± 5 mg/L placebo, p = 0.05). QOL scores, including composite overall and clinical summary scores significantly improved in treatment compared to placebo (∆ + 10 ± 15 versus -6 ± 15, p < 0.01 and ∆ + 8 ± 14 versus -8 ± 18, p = 0.01, respectively).

CONCLUSIONS

Repletion of 25(OH)D may improve QOL in HF patients and may help to normalize BNP, PTH, and hsCRP.

TRIAL REGISTRATION

Clinicaltrials.gov, Trial Registration Number: NCT01636570 , First registered 3 July 2012.

Effects of Vitamin D2 Supplementation on Vitamin D3 Metabolism in Health and CKD

BACKGROUND AND OBJECTIVES

Vitamin D supplements are prescribed to correct low circulating concentrations of 25-hydroxyvitamin D. In CKD, vitamin D metabolism is complicated by decreased conversion of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D by CYP27B1 and possibly decreased conversion of 25-hydroxyvitamin D to 24,25-dihydroxyvitamin D by CYP24A1. The aim of this study was to determine the effects of vitamin D2 supplementation on vitamin D metabolism in health and CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a treatment-only intervention study of 25 individuals with CKD (eGFR<60 ml/min per 1.73 m2) and 44 individuals without CKD from three academic centers, all with screening 25-hydroxyvitamin D <30 ng/ml. Each participant was prescribed vitamin D2 (ergocalciferol) 50,000 IU orally twice weekly for 5 weeks. We tested whether changes in plasma concentrations of vitamin D metabolites and vitamin D metabolic ratios differed by CKD status. Plasma 1,25-dihydroxyvitamin D3-to-25-hydroxyvitamin D3 ratio and 24,25-dihydroxyvitamin D3-to-25-hydroxyvitamin D3 ratio were calculated as estimates of CYP27B1 and CYP24A1 function, respectively.

RESULTS

With treatment, plasma 25-hydroxyvitamin D2 and total 25-hydroxyvitamin D concentrations increased similarly for participants with and without CKD. For participants without CKD, 1,25-dihydroxyvitamin D2 increased (2.8±1.3-32.9±1.4 pg/ml), whereas 1,25-dihydroxyvitamin D3 decreased (45.6±1.9-14.6±1.9 pg/ml), resulting in no significant change in total 1,25-dihydroxyvitamin D; 1,25-dihydroxyvitamin D3-to-25-hydroxyvitamin D3 ratio decreased (3.0±0.2-1.7±0.2 pg/ng), and 24,25-dihydroxyvitamin D3-to-25-hydroxyvitamin D3 ratio increased (115.7±7.8-195.2±7.9 pg/ng). Individuals with CKD had lower baseline levels and smaller changes in magnitude for 1,25-dihydroxyvitamin D2 (2.1±1.6-24.4±1.6 pg/ml; P interaction =0.01), 1,25-dihydroxyvitamin D3-to-25-hydroxyvitamin D3 ratio (1.8±0.2-1.1±0.2 pg/ng; P interaction =0.05), and 24,25-dihydroxyvitamin D3-to-25-hydroxyvitamin D3 ratio (72.0±9.1-110.3±9.3 pg/ng; P interaction <0.001). Fibroblast growth factor-23 and parathyroid hormone were not significantly changed in either group.

CONCLUSIONS

Vitamin D2 supplementation decreases conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 and induces vitamin D3 catabolism as evidenced by changes in D3 metabolites and vitamin D metabolic ratios. These effects occur without significant changes in fibroblast growth factor-23 or parathyroid hormone and are blunted in CKD.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2017_08_02_CJASNPodcast_17_09.mp3.

Factors influencing pre-operative urinary calcium excretion in primary hyperparathyroidism

OBJECTIVE

Normal or elevated 24-hour urinary calcium (Ca) excretion is a diagnostic marker in primary hyperparathyroidism (PHPT). It is used to distinguish familial hypocalciuric hypercalcaemia (FHH) from PHPT by calculating the Ca/creatinine clearance ratio (CCCR). The variance of CCCR in patients with PHPT is considerable. The aim of this study was to analyse the parameters affecting CCCR in patients with PHPT.

DESIGN

The data were collected prospectively. Patients with sporadic PHPT undergoing successful surgery were included in a retrospective analysis.

PATIENTS

The analysis covered 381 patients with pre-operative workup 2 days before removal of a solitary parathyroid adenoma.

MEASUREMENTS

The impact of serum Ca and 25-hydroxyvitamin D3 (25-OH D3) on CCCR.

RESULTS

The coefficient of determination (R² ) in the multivariable model for CCCR consisting of age, Ca, 25-OH D3, 1,25-dihydroxyvitamin D3 (1,25-(OH)2 D3), testosterone (separately for males and females), intact parathyroid hormone (iPTH) and osteocalcin was 25.8%. The only significant parameters in the multivariable analysis were 1,25-(OH)2 D3 and osteocalcin with a drop in R² of 15.4% (P<.001) and 2.4% (P=.006), respectively. Bone mineral densities at the lumbar spine, distal radius and left femoral neck were not associated with CCCR (r=-.08, r=-.10 and r=-0.09).

CONCLUSIONS

In multivariable analysis, 1,25-(OH)2 D3 and osteocalcin were the only factors correlating with CCCR. Vitamin D3 replacement may therefore impair the diagnostic value of CCCR and increase the importance of close monitoring of urinary Ca excretion during treatment.

Effects of vitamin D and its metabolites on cell viability and Staphylococcus aureus invasion into bovine mammary epithelial cells

Vitamin D has been found have various biological effects that may be potent in preventing bovine mastitis. Two forms of vitamin D, vitamin D₂ (D₂) and vitamin D₃ (D₃), can be hydroxylated to functional metabolites in cattle. The objectives of the present study were to investigate the potential of vitamin D compounds for controlling bovine mastitis using in vitro cell models, and to compare the differences between D₂ and D₃ compounds. Results showed that D₂ compounds have comparable effects to their D₃ analogues on inhibiting MAC-T cell viability in vitro. S. aureus growth was inhibited by high concentrations of D₂, D₃, 25(OH)D₂ and 25(OH)D₃. 25(OH)D₂ and 25(OH)D₃ induced CYP24A1 expression but reduced VDR mRNA expression, whereas the expression of CYP27B1, occludin, and E-cadherin did not change. Additionally, the induction of CYP24A1 expression by 25(OH)D₃ was higher than that of 25(OH)D₂, which may contribute to their differences in inhibiting cell viability. S. aureus invaded into MAC-T cells and universally inhibited gene expressions. Pre-treat MAC-T cells with 25(OH)D₂ reduced S. aureus adhesion while pre-treatment with 25(OH)D₃ inhibited S. aureus invasion, but neither of the compounds attenuated the S. aureus-induced gene expression reduction. In conclusion, the present study shows that D₂ compounds have comparable effects on inhibiting cell viability and S. aureus invasion to their D₃ analogues in vitro, suggesting that D₂ and its metabolites have potential in controlling bovine mastitis.

Effects of High-Dose Vitamin D2 Versus D3 on Total and Free 25-Hydroxyvitamin D and Markers of Calcium Balance

CONTEXT

Controversy persists over: 1) how best to restore low serum 25-hydroxyvitamin D (25D) levels (vitamin D2 [D2] vs vitamin D3 [D3]); 2) how best to define vitamin D status (total [protein-bound + free] vs free 25D); and 3) how best to assess the bioactivity of free 25D.

OBJECTIVE

To assess: 1) the effects of D2 vs D3 on serum total and free 25D; and 2) whether change in intact PTH (iPTH) is more strongly associated with change in total vs free 25D.

DESIGN

Participants previously enrolled in a D2 vs D3 trial were matched for age, body mass index, and race/ethnicity. Participants received 50 000 IU of D2 or D3 twice weekly for 5 weeks, followed by a 5-week equilibration period. Biochemical assessment was performed at baseline and at 10 weeks.

SETTING AND PARTICIPANTS

Thirty-eight adults (19 D2 and 19 D3) ≥18 years of age with baseline 25D levels <30 ng/mL were recruited from an academic ambulatory osteoporosis clinic.

OUTCOME MEASURES

Serum measures were total 25D, free 25D (directly measured), 1,25-dihydroxyvitamin D, calcium, and iPTH. Urine measure was fasting calcium:creatinine ratio.

RESULTS

Baseline total (22.2 ± 3.3 vs 23.3 ± 7.2 ng/mL; P = .5) and free (5.4 ± 0.8 vs 5.3 ± 1.7 pg/mL; P = .8) 25D levels were similar between D2 and D3 groups. Increases in total (+27.6 vs +12.2 ng/mL; P = .001) and free (+3.6 vs +6.2 pg/mL; P = .02) 25D levels were greater with D3 vs D2. Percentage change in iPTH was significantly associated with change in free (but not total) 25D, without and with adjustment for supplementation regimen, change in 1,25-dihydroxyvitamin D, and change in calcium.

CONCLUSIONS

D3 increased total and free 25D levels to a greater extent than D2. Free 25D may be superior to total 25D as a marker of vitamin D bioactivity.

Influence of blanketing and season on vitamin D and parathyroid hormone, calcium, phosphorus, and magnesium concentrations in horses in New Zealand

The aims of the study were to determine the effect of season and blanketing on vitamin D synthesis in horses and examine the interaction between vitamin D and other analytes involved in calcium homeostasis. Twenty-one healthy horses at pasture were included; 5 were covered with standard horse blankets including neck rugs. Blood samples were collected for 13 mo and analyzed for 25-hydroxyvitamin D2 (25OHD2) and 25-hydroxyvitamin D3 (25OHD3), 1,25-dihydroxyvitamin D (1,25[OH]2D), ionized calcium (iCa), total calcium (tCa), phosphorus (P), total magnesium (tMg), and parathyroid hormone (PTH). Grass and hay samples were collected and analyzed for vitamin D, calcium, phosphorus, and magnesium. Climate data were also collected. The serum concentration of 25OHD3 in horses was either undetectable or below the detection limit of the assay, and the main form of 25OHD was 25OHD2. No differences in serum 25OHD2, 1,25(OH)2D, iCa, tCa, P, tMg, and PTH (P ≥ 0.05) concentrations were seen between the 2 groups. Associations were seen between iCa and PTH (P < 0.05), iCa and tMg (P < 0.05), and dietary vitamin D and 25OHD2 (P < 0.05). A strong seasonal trend was seen in serum 25OHD2 (P < 0.0001), which was higher during spring and summer when the amount of sunshine and UV radiation was higher. Parathyroid hormone and 1,25(OH)2D showed opposing trends with PTH higher in winter whereas 1,25(OH)2D was higher in summer. The results suggest that dietary vitamin D may be necessary for horses to fulfill their vitamin D requirements; however, further research is required to determine the contribution of vitamin D3 synthesis in the skin to the vitamin D status of the horse.

Effects of vitamin D2 or D3 supplementation on glycaemic control and cardiometabolic risk among people at risk of type 2 diabetes: results of a randomized double-blind placebo-controlled trial

AIMS

To investigate the effect of short-term vitamin D supplementation on cardiometabolic outcomes among individuals with an elevated risk of diabetes.

METHODS

In a double-blind placebo-controlled randomized trial, 340 adults who had an elevated risk of type 2 diabetes (non-diabetic hyperglycaemia or positive diabetes risk score) were randomized to either placebo, 100,000 IU vitamin D2 (ergocalciferol) or 100,000 IU vitamin D3 (cholecalciferol), orally administered monthly for 4 months. The primary outcome was change in glycated haemoglobin (HbA1c) between baseline and 4 months, adjusted for baseline. Secondary outcomes included: blood pressure; lipid levels; apolipoprotein levels; C-reactive protein levels; pulse wave velocity (PWV); anthropometric measures; and safety of the supplementation.

RESULTS

The mean [standard deviation (s.d.)] 25-hydroxyvitamin D [25(OH)D]2 concentration increased from 5.2 (4.1) to 53.9 (18.5) nmol/l in the D2 group, and the mean (s.d.) 25(OH)D3 concentration increased from 45.8 (22.6) to 83.8 (22.7) nmol/l in the D3 group. There was no effect of vitamin D supplementation on HbA1c: D2 versus placebo: -0.05% [95% confidence interval (CI) -0.11, 0.02] or -0.51 mmol/mol (95% CI -1.16, 0.14; p = 0.13); D3 versus placebo: 0.02% (95% CI -0.04, 0.08) or 0.19 mmol/mol (95% CI -0.46, 0.83; p = 0.57). There were no clinically meaningful effects on secondary outcomes, except PWV [D2 versus placebo: -0.68 m/s (95% CI -1.31, -0.05); D3 versus placebo -0.73 m/s (95% CI -1.42, -0.03)]. No important safety issues were identified.

CONCLUSIONS

Short-term supplementation with vitamin D2 or D3 had no effect on HbA1c. The modest reduction in PWV with both D2 and D3 relative to placebo suggests that vitamin D supplementation has a beneficial effect on arterial stiffness.

25-Hydroxyvitamin D concentration and all-cause mortality: the Melbourne Collaborative Cohort Study

Objective

To investigate relationships between mortality and circulating 25-hydroxyvitamin D (25(OH)D), 25-hydroxycholecalciferol (25(OH)D3) and 25-hydroxyergocalciferol (25(OH)D2).

Design

Case–cohort study within the Melbourne Collaborative Cohort Study (MCCS). We measured 25(OH)D2and 25(OH)D3in archived dried blood spots by LC–MS/MS. Cox regression was used to estimate mortality hazard ratios (HR), with adjustment for confounders.

Setting

General community.

Subjects

The MCCS included 29 206 participants, who at recruitment in 1990–1994 were aged 40–69 years, had dried blood spots collected and no history of cancer. For the present study we selected participants who died by 31 December 2007 (n2410) and a random sample (sub-cohort,n2996).

Results

The HR per 25 nmol/l increment in concentration of 25(OH)D and 25(OH)D3were 0·86 (95 % CI 0·78, 0·96;P=0·007) and 0·85 (95 % CI 0·77, 0·95;P=0·003), respectively. Of 5108 participants, sixty-three (1·2 %) had detectable 25(OH)D2; their mean 25(OH)D concentration was 11·9 (95 % CI 7·3, 16·6) nmol/l higher (P<0·001). The HR for detectable 25(OH)D2was 1·80 (95 % CI 1·09, 2·97;P=0·023); for those with detectable 25(OH)D2, the HR per 25 nmol/l increment in 25(OH)D was 1·06 (95 % CI 0·87, 1·29;Pinteraction=0·02). HR were similar for participants who reported being in good, very good or excellent health four years after recruitment.

Conclusions

Total 25(OH)D and 25(OH)D3concentrations were inversely associated with mortality. The finding that the inverse association for 25(OH)D was restricted to those with no detectable 25(OH)D2requires confirmation in populations with higher exposure to ergocalciferol.

Effects of vitamin D2-fortified breadv. supplementation with vitamin D2or D3on serum 25-hydroxyvitamin D metabolites: an 8-week randomised-controlled trial in young adult Finnish women

There is a need for food-based solutions for preventing vitamin D deficiency. Vitamin D3(D3) is mainly used in fortified food products, although the production of vitamin D2(D2) is more cost-effective, and thus may hold opportunities. We investigated the bioavailability of D2from UV-irradiated yeast present in bread in an 8-week randomised-controlled trial in healthy 20–37-year-old women (n33) in Helsinki (60°N) during winter (February–April) 2014. Four study groups were given different study products (placebo pill and regular bread=0 µg D2or D3/d; D2supplement and regular bread=25 µg D2/d; D3supplement and regular bread=25 µg D3/d; and placebo pill and D2-biofortified bread=25 µg D2/d). Serum 25-hydroxyvitamin D2(S-25(OH)D2) and serum 25-hydroxyvitamin D3(S-25(OH)D3) concentrations were measured at baseline, midpoint and end point. The mean baseline total serum 25-hydroxyvitamin D (S-25(OH)D=S-25(OH)D2+S-25(OH)D3) concentration was 65·1 nmol/l. In repeated-measures ANCOVA (adjusted for baseline S-25(OH)D as total/D2/D3), D2-bread did not affect total S-25(OH)D (P=0·707) or S-25(OH)D3(P=0·490), but increased S-25(OH)D2compared with placebo (P<0·001). However, the D2supplement was more effective than bread in increasing S-25(OH)D2(P<0·001). Both D2and D3supplementation increased total S-25(OH)D compared with placebo (P=0·030 andP=0·001, respectively), but D2supplementation resulted in lower S-25(OH)D3(P<0·001). Thus, D2from UV-irradiated yeast in bread was not bioavailable in humans. Our results support the evidence that D2is less potent in increasing total S-25(OH)D concentrations than D3, also indicating a decrease in the percentage contribution of S-25(OH)D3to the total vitamin D pool.

Associations of 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D With Bone Mineral Density, Bone Mineral Density Change, and Incident Nonvertebral Fracture

Relationships between 1,25-dihydroxyvitamin D (1,25(OH)2 D) and skeletal outcomes are uncertain. We examined the associations of 1,25(OH)2 D with bone mineral density (BMD), BMD change, and incident non-vertebral fractures in a cohort of older men and compared them with those of 25-hydroxyvitamin D (25OHD). The study population included 1000 men (aged 74.6 ± 6.2 years) in the Osteoporotic Fractures in Men (MrOS) study, of which 537 men had longitudinal dual-energy X-ray absorptiometry (DXA) data (4.5 years of follow-up). A case-cohort design and Cox proportional hazards models were used to test the association between vitamin D metabolite levels and incident nonvertebral and hip fractures. Linear regression models were used to estimate the association between vitamin D measures and baseline BMD and BMD change. Interactions between 25OHD and 1,25(OH)2 D were tested for each outcome. Over an average follow-up of 5.1 years, 432 men experienced incident nonvertebral fractures, including 81 hip fractures. Higher 25OHD was associated with higher baseline BMD, slower BMD loss, and lower hip fracture risk. Conversely, men with higher 1,25(OH)2 D had lower baseline BMD. 1,25(OH)2 D was not associated with BMD loss or nonvertebral fracture. Compared with higher levels of calcitriol, the risk of hip fracture was higher in men with the lowest 1,25(OH)2 D levels (8.70 to 51.60 pg/mL) after adjustment for baseline hip BMD (hazard ratio [HR] = 1.99, 95% confidence interval [CI] 1.19-3.33). Adjustment of 1,25(OH)2 D data for 25OHD (and vice versa) had little effect on the associations observed but did attenuate the hip fracture association of both vitamin D metabolites. In older men, higher 1,25(OH)2 D was associated with lower baseline BMD but was not related to the rate of bone loss or nonvertebral fracture risk. However, with BMD adjustment, a protective association for hip fracture was found with higher 1,25(OH)2 D. The associations of 25OHD with skeletal outcomes were generally stronger than those for 1,25(OH)2 D. These results do not support the hypothesis that measures of 1,25(OH)2 D improve the ability to predict adverse skeletal outcomes when 25OHD measures are available. © 2015 American Society for Bone and Mineral Research.