Contribution of body mass index, waist circumference, and 25-OH-D3 on the risk of pre-diabetes mellitus in the Chinese population.

This study aimed to investigate the associations between body mass index (BMI), waist circumference (WC), 25-hydroxy-vitamin D3 (25-OH-D3), and the risk of pre-diabetes mellitus (PDM), as well as their predictive values in identifying PDM. A total of 1688 participants were included in this cross-sectional investigation. Spearman's correlation analysis was used to assess the relationships between candidate indicators and PDM. The impact of indicators on PDM risk was determined by multivariate logistic regression. The receiver operating characteristic (ROC) analysis was performed to evaluate the prognostic value of indicators. Our study indicated a positive correlation between WC, BMI, and 25-OH-D3 and PDM. WC (OR = 1.05, 95% CI = 1.04-1.06, p < 0.001), BMI (OR = 1.11, 95% CI = 1.08-1.15, p < 0.001), and 25-OH-D3 (OR = 1.01, 95% CI = 1.00-1.02, p = 0.037) and an increased risk of PDM. Additionally, the ROC analysis demonstrated that WC (AUC = 0.651, Specificity = 55.00%, Sensitivity = 67.900%) had a higher diagnostic value for predicting PDM compared to the other variables (BMI, 25-OH-D3, TG, TC, LDL-C, HDL-C, and UA). A cut-off value of WC > 80.5 cm predicted PDM with both good sensitivity and specificity. Additionally, the cut-off value of waist circumference (WC) for men with prediabetes was 86.500, while for women with prediabetes, it was 76.500.

When to suspect infantile hypercalcemia-1?

PURPOSE: The screening test to suspect infantile hypercalcemia-1 (HCINF1) is the measure of 25(OH)D3/24,25(OH)2D3 ratio at mass spectroscopy (MS). When the ratio is > 80, the gold standard for the diagnosis is genetic analysis. Given its limited availability, MS may not represent a screening test and most cases of HCINF1 remain undiagnosed. Aim of the study is to identify cut-offs of serum calcium and PTH useful to suspect patients with HCINF1. METHODS: We compared the levels of total serum calcium and PTH of 6 patients with HCINF1 harboring biallelic CYP24A1 pathogenic variants with 3 different control groups: (1) 12 subjects wild type for CYP24A1; (2) 12 subjects matched for age and sex; (3) 12 subjects matched for vitamin D levels. We validated the cut-offs, testing the number of adult patients affected by HCINF1 reported in the literature that could be identified using these cut-offs. RESULTS: A serum calcium level > 9.6 mg/dL showed the highest sensitivity (100%) and specificity (91%) in the comparison between homozygous and wild-type subjects. A serum PTH index < 0.315 showed the highest sensitivity (100%) and specificity (83.3%). A serum calcium level > 9.6 mg/dL was able to identify all adult HCINF1 patients whereas a PTH ratio < 0.315 identified 89.8% of the cases. Superimposable results were obtained using the other control groups. CONCLUSION: Patients with serum calcium levels higher than 9.6 mg/dL and a PTH index lower than 0.315 are likely to be affected by HCINF1. Their diagnosis may be confirmed using MS and genetic analysis.

Differential performance regarding the relationship of C3-epi-25(OH)D3 levels and %C3-epi-25(OH)D3 with common pediatric diseases: a case control study.

BACKGROUND: Recently, the C3-epimer of 25-hydroxyvitamin D [C3-epi-25(OH)D] has become a topic of interest among 25-hydroxyvitamin D [25(OH)D] metabolites. Although it can lead to an overestimation of vitamin D storage, its relationship with disease occurrence remains controversial, possibly related to the great extent of tracking of 25(OH)D by C3-epi-25(OH)D over time. This study aimed to investigate the differential performance of C3-epi-25(OH)D3 and its percentage [%C3-epi-25(OH)D3] with respect to 20 common paediatric diseases. METHODS: This study involved 805 healthy children and adolescents and 2962 patients with common paediatric diseases. We investigated sex, age, and seasonal differences in C3-epi-25(OH)D3 and %C3-epi-25(OH)D3 levels; their variations on 20 common paediatric diseases; and their degree of correlation with 25(OH)D3 levels and various diseases. RESULTS: Among the healthy underage participants, C3-epi-25(OH)D3 and %C3-epi-25(OH)D3 changed similarly, with no sex differences. Moreover, their levels were higher in the infant period than in the other periods (t = 5.329-5.833, t = 4.640-5.711, all Padj < 0.001), and in spring and summer than in autumn and winter (t = 3.495-6.061, t = 3.495-5.658, all Padj < 0.01). Under healthy and disease conditions, C3-epi-25(OH)D3 was positively correlated with 25(OH)D3 (ρ = 0.318 ~ 0.678, all P < 0.017), whereas %C3-epi-25(OH)D3 was not, except in patients with nephrotic syndrome (ρ=-0.393, P = 0.001). Before and after adjusting for 25(OH)D3, the relationship of C3-epi-25(OH)D3 with the diseases was notably different. However, it was almost consistent for %C3-epi-25(OH)D3. Our results indicated that %C3-epi-25(OH)D3 was associated with short stature, nephrotic syndrome, lymphocytic leukaemia, rickets, paediatric malnutrition, and hypovitaminosis D (OR = 0.80 ~ 1.21, all P < 0.05). CONCLUSIONS: The %C3-epi-25(OH)D3 can correct the properties of C3-epi-25(OH)D3 to better track 25(OH)D3 and may be more suitable for exploring its pathological relevance. Further detailed studies of each disease should be conducted.

Discordant Health Implications and Molecular Mechanisms of Vitamin D in Clinical and Preclinical Studies of Prostate Cancer: A Critical Appraisal of the Literature Data.

Clinical and preclinical studies have provided conflicting data on the postulated beneficial effects of vitamin D in patients with prostate cancer. In this opinion piece, we discuss reasons for discrepancies between preclinical and clinical vitamin D studies. Different criteria have been used as evidence for the key roles of vitamin D. Clinical studies report integrative cancer outcome criteria such as incidence and mortality in relation to vitamin D status over time. In contrast, preclinical vitamin D studies report molecular and cellular changes resulting from treatment with the biologically active vitamin D metabolite, 1,25-dihydroxyvitamin D3 (calcitriol) in tissues. However, these reported changes in preclinical in vitro studies are often the result of treatment with biologically irrelevant high calcitriol concentrations. In typical experiments, the used calcitriol concentrations exceed the calcitriol concentrations in normal and malignant prostate tissue by 100 to 1000 times. This raises reasonable concerns regarding the postulated biological effects and mechanisms of these preclinical vitamin D approaches in relation to clinical relevance. This is not restricted to prostate cancer, as detailed data regarding the tissue-specific concentrations of vitamin D metabolites are currently lacking. The application of unnaturally high concentrations of calcitriol in preclinical studies appears to be a major reason why the results of preclinical in vitro studies hardly match up with outcomes of vitamin D-related clinical studies. Regarding future studies addressing these concerns, we suggest establishing reference ranges of tissue-specific vitamin D metabolites within various cancer entities, carrying out model studies on human cancer cells and patient-derived organoids with biologically relevant calcitriol concentrations, and lastly improving the design of vitamin D clinical trials where results from preclinical studies guide the protocols and endpoints within these trials.

25(OH)D3 improves granulosa cell proliferation and IVF pregnancy outcomes in patients with endometriosis by increasing G2M+S phase cells.

BACKGROUND: The 25-hydroxyvitamin D3 (25 (OH) D3) is crucial for follicular development. This study aimed to investigate the relationship between the level of 25 (OH) D3 in endometriosis patients, pregnancy outcomes of in vitro fertilization (IVF), and the underlying mechanism. METHODS: The 25 (OH) D3 levels in serum and follicular Fluid (FF) samples were detected using enzyme-linked immunosorbent assay (ELISA). Clinical features and pregnancy outcomes of endometriosis patients were also compared between the deficient group (< 20 ug/ml) and the adequate group (≥ 20 ug/ml). The effects of 25 (OH) D3 on the proliferation and cell cycle of human ovarian granulosa cells were respectively detected by CCK-8 assay and flow cytometry (FCM). The differentially expressed genes (DEGs) in granulosa cells of endometriosis and tubal infertility patients were screened from GEO database. The effects of 25 (OH) D3 on the expressions of CDKN2D, PPARA, TGFB2 and THBD were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot. RESULTS: The levels of 25 (OH) D3 in serum and FF samples were decreased in endometriosis patients. The deficient group had fewer embryos that can be transferred, lower quality embryos and lower clinical pregnancy rates. Adequate 25 (OH) D3 levels in FF samples was a protective factor for live birth outcome in endometriosis patients. 25 (OH) D3 enhanced the proliferation capacity of granulosa cells (the concentration of 10 nM was the most significant) and increased the proportion of G2M + S phase cells. The expression of CDKN2D was decreased and TGFB2 and THBD were significantly upregulated. CONCLUSIONS: 25 (OH) D3 deficiency may be associated with poor IVF pregnancy outcomes in endometriosis patients. 25 (OH) D3 promotes ovarian granulosa cell proliferation by promoting the ability of cells to divide, and may accelerate cell cycle progression by up-regulating THBD and down-regulating CDKN2D expression.

25-hydroxyvitamin D3 inhibits oxidative stress and ferroptosis in retinal microvascular endothelial cells induced by high glucose through down-regulation of miR-93.

BACKGROUND: The decrease of vitamin D plays a critical role in diabetes mellitus (DM)-induced oxidative stress and vascular endothelial injury. Therefore, we investigated the effect and mechanism of 25-hydroxyvitamin D3 (25 (OH) D3) on oxidative stress and ferroptosis induced by high glucose in human retinal microvascular endothelial cells (hRMVECs). And the objective of this paper was to propose a new strategy for the prevention and treatment of diabetic retinopathy (DR). METHODS: First, hRMVECs were transfected with mimics NC or miR-93. After that, cells were treated with 100 nM / 500 nM 25 (OH) D3 and then cultured in a high glucose (30 mM) environment. Subsequently, qRT-PCR was employed to detect the expression level of miR-93; CCK-8 for the proliferation of cells in each group; biochemical tests for the level of intracellular reactive oxygen species (ROS), malondialdehyde (MDA), reduced glutathione (GSH) and ferrous ion (Fe2+); and Western blot for the expression of ferroptosis-related proteins glutathione peroxidase 4 (GPX4) and SLC7A11). RESULTS: Under a high glucose environment, 25 (OH) D3 at 100 nM/500 nM could significantly promote the proliferation of hRMVECs, remarkably decrease the level of intracellular ROS/MDA, and up-regulate the level of GSH. Besides, 25 (OH) D3 greatly reduced Fe2+ level in the cells while increased protein level of GPX4 and SLC7A11. Subsequently, we found that high glucose induced miR-93 expression, while 25 (OH) D3 markedly decreased high glucose-induced miR-93 overexpression. Furthermore, overexpression of miR-93 inhibited the functions of 25 (OH) D3 by activating ROS (ROS and MDA were up-regulated while GSH was down-regulated) and inducing Fe2+ (Fe2+ level was up-regulated while GPX4 and SLC7A11 level was down-regulated) in cells. CONCLUSION: 25 (OH) D3 may inhibit oxidative stress and ferroptosis in hRMVECs induced by high glucose via down-regulation of miR-93.

The role of 25(OH)D3 and circRNAs in early diagnosis of gestational diabetes mellitus.

OBJECTIVE: To explore the relationship between 25(OH)D3 and circular RNAs (circRNAs) in the early diagnosis of gestational diabetes mellitus (GDM) and to screen for biological markers for early prediction of GDM. METHODS: A cohort study was conducted using samples and data collected from pregnant women registered at the Li Huili hospital in China between April 2018 and January 2020. Four circRNAs (hsa_circ_0003218, hsa_circ_0002968, hsa_circ_0007430, and hsa_circ_0006260) were selected as potential biomarkers, and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to measure their concentration in the serum and to analyze their correlation with 25(OH)D3. The Pearson correlation test was used to assess the correlation between the 25(OH)D3, circRNAs, and various clinical variables. The area under the receiver operating characteristic (ROC) curve was used to assess the diagnostic value of circRNAs and 25(OH)D3 in the early stage of pregnancy. RESULTS: Weight, body mass index (BMI), triglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and 25(OH)D3 were found to be risk factors for GDM. The level of 25(OH)D3 correlated significantly with HDL-C with a correlation coefficient of 0.298 (p < 0.05). The expression of hsa_circ_0003218 was significantly downregulated in the GDM group (p < 0.05). Hsa_circ_0002968, hsa_circ_0007430, and hsa_circ_0006260 did not show any differential expression between the two groups (p > 0.05). Furthermore, hsa_circ_0003218 level correlated significantly with 25(OH)D3 and the correlation coefficient was 0.357 (p < 0.05). The AUC of hsa_circ_0003218 combined with 25(OH)D3 was 0.789 ([0.700-0.877], p < 0.001), with sensitivity and specificity of 63.04% and 80.65%, respectively. CONCLUSIONS: Hsa_circ_0003218 and 25(OH)D3 may jointly participate in the metabolic process of GDM. Thus, the combination of 25(OH)D3 and hsa_circ_0003218 represents a potential biomarker for the prediction of GDM in the early stages of pregnancy.

Association of serum 25-hydroxyvitamin D3, fibroblast growth factor-23, and C1q/tumor necrosis factor-related protein-3 with coronary artery calcification in nondialysis chronic kidney disease patients.

OBJECTIVE: To assess serum 25-hydroxyvitamin D3 (25(OH)D3), fibroblast growth factor 23 (FGF23), and C1q/tumor necrosis factor-related protein-3 (CTRP3) levels in nondialysis chronic kidney disease (CKD) patients and their relationship with coronary artery calcification (CAC). METHODS: One hundred and twenty-eight patients diagnosed with CKD were selected and all underwent cardiac computed tomography. CAC was assessed using the Agatston score, and coronary artery calcification score (CACs) >10 was identified as CAC. The differences in serum 25(OH)D3, FGF23, and CTRP3 levels between the CAC and non-CAC groups were analyzed. Their correlation with CACs was assessed by Spearman's analysis, and logistic regression analysis was used to find risk factors for CAC. RESULTS: Compared to the non-CAC group, the CAC group was older (64.21 ± 9.68 years), with a higher percentage of hypertension (93.10%) and diabetes (63.80%) and higher levels of serum CTRP3 [1079.20 (644.4-1567.2) ng/mL]. However, there was no significant difference in serum 25(OH)D3 and FGF23 between these two groups. The high level CTRP3 group had a higher prevalence of CAC (61.5%). Logistic regression results showed that age, diabetes, decreased 25(OH)D3 (odds ratio (OR) = 0.95, p = .030) and high levels of CTRP3 (OR = 3.19, p = .022) were risk factors for CAC in nondialysis CKD patients. CONCLUSIONS: Serum CTRP3 levels progressively increased with the progression of kidney disease, while 25(OH)D3 levels progressively decreased. Decreased 25(OH)D3 and high levels of CTRP3 are associated with CAC in patients with nondialysis CKD.

Bioavailability of vitamin D biofortified pork meat: results of an acute human crossover study in healthy adults.

Vitamin D intakes are concerningly low. Food-based strategies are urgently warranted to increase vitamin D intakes and subsequently improve 25-hydroxyvitamin D (25(OH)D) concentrations. This acute randomised three-way crossover study investigated the efficacy of vitamin D biofortified pork derived from pigs exposed to UVB light to increase serum 25(OH)D3 concentrations, compared to a dose-matched vitamin D3 supplement and control pork in adults (n = 14). Blood samples were obtained at baseline and then 1.5, 3, 6, 9 and 24 h postprandially. There was a significant effect of time (p < 0.01) and a significant treatment*time interaction (p < 0.05). UV pork and supplement significantly increased within-group serum 25(OH)D3 concentrations over timepoints (p < 0.05) (max. change 0.9 nmol/L (2.2%) UV pork, 1.5 nmol/L (3.5%) supplement, 0.7 nmol/L (1.9%) control). Vitamin D biofortified pork modestly increased 25(OH)D3 concentrations and produced a similar response pattern as a dose-matched vitamin D supplement, but biofortification protocols should be further optimised to ensure differentiation from standard pork.

[Applying Serum Vitamin D Metabolites in the Assessment of Renal Impairment in Diabetic Kidney Disease of Type 2 Diabetes Mellitus Patients: A Retrospective Study].

Objective: Total 25(OH)D (t-25[OH]D), a marker traditionally used in the assessment of vitamin D (VitD) in the human body, includes 25(OH)D 2, 25(OH)D 3, and C 3-epimers-25(OH)D 3(C 3-epi). In this study, we analyzed the relationship between serum VitD metabolites and renal impairment in patients with diabetic kidney disease (DKD). Methods: We covered, in the study, 339 subjects, including 114 otherwise healthy controls (HC), 74 type 2 diabetes mellitus (DM) patients with no glomerular filtration dysfunction, and 151 DKD patients. According to the results of combined evaluation of estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR), the DKD patients were further divided into four subgroups, stage 2 subgroup of patients of DM combined with stage-2 chronic kidney disease (CKD2), stage 3 subgroup of patients of DM combined with CKD3, stage 4 subgroup of patients of DM combined with CKD4, and stage 5 subgroup of patients of DM combined with CKD5. The levels of 25(OH)D 2, 25(OH)D 3, and C 3-epi were measured by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and the activity level of 25(OH) 3 (AVitD 3), t-25(OH)D concentration, 25(OH)D 2/25(OH)D 3 ratio, C 3-epi/t-25(OH)D ratio, and C 3-epi/AVitD 3 ratio were calculated. Results: The levels of 25(OH)D 3, t-25(OH)D, and AVitD 3 were lower in the DKD group than those in the DM and HC groups (all P<0.05). C 3-epi/t-25(OH)D ratio and C 3-epi/AVitD 3 ratio were higher in the DKD group than those in the HC group (all P<0.05). The levels of 25(OH)D 3, t-25(OH)D, AVitD 3, and C 3-epi were lower in the stage 5 subgroup than those in the stage 2 and stage 3 subgroups (all P<0.05). The levels of 25(OH)D 3, t-25(OH)D, and C 3-epi were lower in the stage 4 subgroup than those in the stage 3 subgroup (all P<0.05). The 25(OH)D 3, t-25(OH)D, and AVitD 3 levels were lower in the stage 4 subgroup than those in the stage 2 subgroup (all P<0.05). Conclusions: UPLC-MS/MS can be used to perform accurate evaluation of VitD nutritional status in DKD patients. DKD patients have decreased levels of serum t-25(OH)D, 25(OH)D 3, and AVitD 3, all of which progressively decrease along with the rise in CKD staging. The trend of C 3-epi and 25(OH)D 3 changes were not consistent.

Physiological levels of 25-hydroxyvitamin D3 induce a suppressive CD4+ T cell phenotype not reflected in the epigenetic landscape.

1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ), the active metabolite of vitamin D3 has a strong impact on the differentiation and function of immune cells. Here we analysed the influence of its precursor 25-hydroxyvitamin D3 (25(OH)D3 ) on the differentiation of human CD4+ T cells applying physiological concentrations in vitro. Our data show that 25(OH)D3 is converted to its active form 1,25(OH)2 D3 by T cells, which in turn supports FOXP3, CD25 and CTLA-4 expression and inhibits IFN-γ production. These changes were not reflected in the demethylation of the respective promoters. Furthermore, we investigated the impact of vitamin D3 metabolites under induced Treg (iTreg) polarization conditions using TGF-ß. Surprisingly, no additive effect but a decreased percentage of FOXP3 expressing cells was observed. However, the combination of 25(OH)D3 or 1,25(OH)2 D3 together with TGF-ß further upregulated CD25 and CTLA-4 and significantly increased soluble CTLA-4 and IL-10 secretion whereas IFN-γ expression of iTreg was decreased. Our data suggest that physiological levels of 25(OH)D3 act as potent modulator of human CD4+ T cells and autocrine or paracrine production of 1,25(OH)2 D3 by T cells might be crucial for the local regulation of an adaptive immune response. However, since no epigenetic changes are detected by 25(OH)D3 a rather transient phenotype is induced.

Evaluation of bone health in patients with mucopolysaccharidosis.

INTRODUCTION: This study aimed to evaluate the relationship between clinical findings, height and weight standard deviation scores, 25-hydroxyvitamin D3 (25(OH)D3) level, and dual-energy X-ray absorptiometry (DXA) results in patients diagnosed with mucopolysaccharidosis (MPS), where effective current treatments such as enzyme replacement therapy (ERT) can be accessed. MATERIALS AND METHODS: 25(OH)D3 level was measured in 126 patients with MPS (17 with MPS I, 14 with MPS II, 18 with MPS III, 33 with MPS IVA, and 44 with MPS VI; 24-524 months). DXA was performed in 45 of these patients (8 with MPS I, 4 with MPS II, 4 with MPS III, 12 with MPS IVA, and 17 with MPS VI; 62-197 months; all patients were under 18 when DXA was performed) to assess bone mineral density (BMD) of the lumbar spine. RESULTS: In total, 67.5% patients had a short stature, and 50% of them were underweight for their age. Of the patients, 13.5% were immobile, 28.6% had 25(OH)D3 deficiency, and 30.2% had an insufficient level of 25(OH)D3. BMD z score of 45 patients was - 2.5 ± 1.7. In 40% patients, it was < - 2. However, after correction for height-for-age z score (HAZ), HAZ-adjusted BMD z score was - 0.1 ± 0.9. In 2.2% patients, it was < - 2. CONCLUSION: The low BMD z score prevalence reported with DXA was misleadingly higher in children with MPS and short stature. To prevent exposure to unnecessary antiresorptive treatments in these children, the effect of severe short stature and bone geometry on DXA measurements should be considered; further studies on bone health are warranted.

Interlaboratory comparison of 25-hydroxyvitamin D assays: Vitamin D Standardization Program (VDSP) Intercomparison Study 2 - Part 1 liquid chromatography - tandem mass spectrometry (LC-MS/MS) assays - impact of 3-epi-25-hydroxyvitamin D3 on assay performance.

An interlaboratory comparison study was conducted by the Vitamin D Standardization Program (VDSP) to assess the performance of liquid chromatography - tandem mass spectrometry (LC-MS/MS) assays used for the determination of serum total 25-hydroxyvitamin D (25(OH)D), which is the sum of 25-hydroxyvitamin D2 (25(OH)D2) and 25-hydroxyvitamin D3 (25(OH)D3). A set of 50 single-donor samples was assigned target values for concentrations of 25(OH)D2, 25(OH)D3, 3-epi-25-hydroxyvitamin D3 (3-epi-25(OH)D3), and 24R,25-dihydroxyvitamin D3 (24R,25(OH)2D3) using isotope dilution liquid chromatography - tandem mass spectrometry (ID LC-MS/MS). VDSP Intercomparison Study 2 Part 1 includes results from 14 laboratories using 14 custom LC-MS/MS assays. Assay performance was evaluated using mean % bias compared to the assigned target values and using linear regression analysis of the test assay mean results and the target values. Only 53% of the LC-MS/MS assays met the VDSP criterion of mean % bias ≤ |±5%|. For the LC-MS/MS assays not meeting the ≤ |±5%| criterion, four assays had mean % bias of between 12 and 21%. Based on multivariable regression analysis using the concentrations of the four individual vitamin D metabolites in the 50 single-donor samples, the performance of several LC-MS/MS assays was found to be influenced by the presence of 3-epi-25(OH)D3. The results of this interlaboratory study represent the most comprehensive comparison of LC-MS/MS assay performance for serum total 25(OH)D and document the significant impact of the lack of separation of 3-epi-25(OH)D3 and 25(OH)D3 on assay performance, particularly with regard to mean % bias.

Interlaboratory comparison of 25-hydroxyvitamin D assays: Vitamin D Standardization Program (VDSP) Intercomparison Study 2 - Part 2 ligand binding assays - impact of 25-hydroxyvitamin D2 and 24R,25-dihydroxyvitamin D3 on assay performance.

An interlaboratory comparison study was conducted by the Vitamin D Standardization Program (VDSP) to assess the performance of ligand binding assays (Part 2) for the determination of serum total 25-hydroxyvitamin D [25(OH)D]. Fifty single-donor samples were assigned target values for concentrations of 25-hydroxyvitamin D2 [25(OH)D2], 25-hydroxyvitamin D3 [25(OH)D3], 3-epi-25-hydroxyvitamin D3 [3-epi-25(OH)D3], and 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] using isotope dilution liquid chromatography-tandem mass spectrometry (ID LC-MS/MS). VDSP Intercomparison Study 2 Part 2 includes results from 17 laboratories using 32 ligand binding assays. Assay performance was evaluated using mean % bias compared to the assigned target values and using linear regression analysis of the test assay mean results and the target values. Only 50% of the ligand binding assays achieved the VDSP criterion of mean % bias ≤ |± 5%|. For the 13 unique ligand binding assays evaluated in this study, only 4 assays were consistently within ± 5% mean bias and 4 assays were consistently outside ± 5% mean bias regardless of the laboratory performing the assay. Based on multivariable regression analysis using the concentrations of individual vitamin D metabolites in the 50 single-donor samples, most assays underestimate 25(OH)D2 and several assays (Abbott, bioMérieux, DiaSorin, IDS-EIA, and IDS-iSYS) may have cross-reactivity from 24R,25(OH)2D3. The results of this interlaboratory study represent the most comprehensive comparison of 25(OH)D ligand binding assays published to date and is the only study to assess the impact of 24R,25(OH)2D3 content using results from a reference measurement procedure.

Early pregnancy vitamin D insufficiency and gestational diabetes mellitus.

OBJECTIVES: To test the hypothesis that a link existed between vitamin D levels in the first trimester and gestational diabetes mellitus (GDM). METHODS: The 25-hydroxyvitamin D3 levels were tested in the first trimester and pregnant outcomes were followed up in 1726 women. RESULTS: Only 5.9% of pregnant women have sufficient 25(OH)D3 . More women with GDM are in the status of 25(OH)D3 insufficiency than women with normal glucose tolerance (NGT) (p < 0.05). Age (odds ratio [OR]: 1.047, 95% confidence interval [CI]: 1.014-1.081), pre-pregnancy body mass index (BMI) (OR: 1.132, 95%CI: 1.092-1.173) were risk factors of GDM while 25-(OH) D3 (OR: 0.979, 95%CI: 0.960-0.999) was a protective factor. After adjusted for maternal age and pre-pregnancy BMI, 25(OH)D3 insufficiency (<30 ng/mL) is an independent predictor of GDM (OR: 2.122, 95%CI: 1.084-4.155); 25(OH)D3 level correlated with fasting blood glucose in the first trimester negatively. CONCLUSION: Vitamin D insufficiency in early pregnancy was significantly associated with an increased risk for GDM in Chinese women.

The Relationship of 25(OH)D3 with Diabetes Mellitus and the Mediation Effect of Lipid Profile in Chinese Rural Population of Henan Province.

Background and Objectives: Studies suggest that vitamin D is involved in the development of type 2 diabetes mellitus (T2DM) and influences serum lipids levels, while lipid disorders are also closely related to T2DM. This study attempts to explore the complex relationship of serum 25(OH)D3, serum lipids, and T2DM among Chinese population. Materials and Methods: A cross-sectional study was carried out among 2326 subjects. The chi-square (χ2) test was applied to compare the prevalence of T2DM or dyslipidemia between two serum 25(OH)D3 levels. Linear regression was applied to analyze the correlation between serum lipids and 25(OH)D3 contents. Univariate and logistic analysis were used to explore the relationship between two lipid levels and T2DM. Mediation analysis was used to explore whether serum lipids mediate the relationship between two serum 25(OH)D3 levels and T2DM. Results: Compared to subjects with 25(OH)D3 ≥ 30 ng/mL, subjects with 25(OH)D3 < 30 ng/mL were higher in the prevalence of T2DM. The occurrences of high TG and low HDL-C were significantly higher in vitamin D deficiency and insufficiency than those in vitamin D sufficiency. Serum 25(OH)D3 content showed a reverse correlation with TC, TG, and LDL-C, but positive correlation with HDL-C. The odds ratios (ORs) (95% confidence intervals, 95%CI) of T2DM by comparing TG ≥ 2.26 mmol/L vs. TG < 2.26 mmol/L and HDL-C < 1.04 mmol/L vs. HDL-C ≥ 1.04 mmol/L in all participants were 2.48 (1.94-3.18) and 1.37 (1.07-1.75), respectively. Serum TG or HDL-C level partially mediated the relationship between two 25(OH)D3 level and T2DM. Conclusions: Serum 25(OH)D3 < 30 ng/mL seems to be associated with T2DM or dyslipidemia (high TG and low HDL-C) in our study, but there is still no proof of a cause-effect relationship. Moreover, serum TG or HDL-C level partially mediated the relationship between 25(OH)D3 levels and T2DM.

The application value of serum 25(OH)D3, uric acid, triglyceride, and homeostasis model assessment of insulin resistance in male patients with hyperuricemia combined with hypogonadism.

BACKGROUND: The purpose of this study was to investigate the application value of serum 25(OH)D3, uric acid, triglyceride (TG), and homeostasis model assessment of insulin resistance (HOMA-IR) in male patients with hyperuricemia combined with hypogonadism. METHODS: From August 2018 to August 2020, a total of 198 male patients with primary hyperuricemia were prospectively enrolled in our hospital for inpatient treatment in the department of Metabolism and Endocrinology. They are divided into normal gonadal function group (normal group, n = 117) and hypogonadal function group (hypogonadism group, n = 81), according to free testosterone (FT) level, International Index of Erectile Function (IIEF-5), and androgen deficiency in the aging male (ADAM) questionnaires. Laboratory indexes were compared between two groups. Multivariate logistic regression was applied to analyze the influencing factors of hypogonadism. RESULTS: Among the 198 hyperuricemia patients, 40.91 % were hypogonadism. Compared with the normal group, the BMI, waist circumference (WC), and the prevalence of non-alcoholic fatty liver disease (NAFLD), hyperlipidemia (HLP), and obesity (OB) in the hypogonadism group were higher, and the difference was statistically significant (P < 0.05, respectively). The levels of fasting plasma glucose (FPG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), triacylglycerol (TG), serum uric acid (SUA), alanine transaminase (ALT) of hypogonadism group were higher than those of normal group, while the levels of TT, FT, E2, 25(OH)D3 of hypogonadism group were lower than those of normal group (P < 0.05, respectively). Pearson's linear correlation was used to analyze the correlation between the indicators with significant differences in general data and laboratory indicators and hypogonadism. BMI, WC, HOMA-IR, TG, SUA, TT, FT, 25(OH)D3, E2 were positively correlated with hypogonadism (r = 0.556, 0.139, 0.473, 0.143, 0.134, 0.462, 0.419, 0.572, 0.601, P = 0.012, 0.027, 0.018, 0.019, 0.028, 0.029, 0.030, 0.009, 0.003, respectively). Taking the above indicators as independent variables and hypogonadism as the dependent variable, logistic regression analysis found that the risk factors for hypogonadism were SUA, WC, BMI, HOMA-IR, TG, TT, FT, E2, and 25(OH) D3. CONCLUSIONS: Serum 25(OH)D3, SUA, HOMA-IR, TG levels were positively correlated with male hyperuricemia patients with hypogonadism. They have important application value in the diagnosis of male hyperuricemia patients with hypogonadism.

Native vs. active vitamin D in children with chronic kidney disease: a cross-over study.

BACKGROUND: The rationale for the prescription of vitamin D analogues in patients with chronic kidney disease (CKD) is still a matter of debate. We aimed to compare native vs. active forms of vitamin D on pre-dialysis children with CKD and evaluate effects on calcium (Ca), phosphorus (P), and parathyroid hormone (PTH). METHODS: Thirty children with pre-dialysis CKD were enrolled in a prospective cross-over study. Patients were randomly classified into two groups. Group A received native cholecalciferol while group B received alfacalcidol for 3 months. After 1 month (washout period), patients were switched to receive the opposite form for another 3 months. Serum Ca, P, alkaline phosphatase (ALP), PTH, and 25(OH)D3 were measured at study start (BL-1), end of first period (FU-1), before second period (BL-2), and after second period (FU-2). RESULTS: There was significant increase in levels of 25(OH)D3 after administration of either native or active vitamin D in the first period in both groups (p < 0.001 and < 0.001, respectively) and also in the second period for both groups (p = 0.02 and < 0.001, respectively). There was no significant difference between both groups regarding changes in serum Ca (1st period; p = 0.770 and 2nd period; p = 0.412), serum P (1st period; p = 0.835, 2nd period; p = 0.052), and serum PTH (1st period; p = 0.250, 2nd period; p = 0.539). CONCLUSION: Alfacalcidol and native vitamin D3 were equally effective in decreasing PTH levels and increasing serum 25(OH)D3 in pre-dialysis CKD patients. There was no significant difference between the two forms regarding changes in serum Ca or P. Graphical abstract.

Effects of 25(OH)D3 supplementation during late gestation on the serum biochemistry and reproductive performance of aged sows and newborn piglets.

The purpose of this study was to investigate the effects of diet type (normal or low Ca and P diets) and 25(OH)D3 supplementation (with or with not 2000 IU/kg 25(OH)D3 ) during late gestation on the serum biochemistry and reproductive performance of aged sows and newborn piglets. A total of 40 sows, which are at their 7th parity, were divided into four groups: control group (standard diet), low Ca group, 25(OH)D3 group and low Ca plus 25(OH)D3 group respectively (10 in each group). The blood of sows on day 100 and 114 of gestation and newborn piglets was collected for serum biochemical analyses. Results showed that the reproductive performance of sows was not influenced by diet type or 25(OH)D3 supplementation (p > 0.05). And the addition of 25(OH)D3 to diet low Ca group caused that the content of serum TG in sows on day 100 of gestation was not different from that of the control group (p > 0.05). The addition of 25(OH)D3 significantly decreases the content of serum TG in sows on day 114 of gestation (p < 0.05). The addition of 25(OH)D3 significantly increased the content of serum UREA and CREA in newborn piglets (p < 0.05). Overall, feeding 2000 IU/kg 25(OH)D3 to aged sows at late gestation had no effects on reproductive performance, but partly contributed to keeping serum TG balance in sows and may indicate increased pressure on kidneys in newborn piglets.

Placental and Cord Blood Telomere Length in Relation to Maternal Nutritional Status.

BACKGROUND: The uterine environment may be important for the chromosomal telomere length (TL) at birth, which, in turn, influences disease susceptibility throughout life. However, little is known about the importance of specific nutritional factors. OBJECTIVES: We assessed the impact of multiple maternal nutritional factors on TL in placenta and cord blood. METHODS: In a population-based mother-child cohort in northwestern Argentina, we measured maternal weight, BMI, body fat percentage (BFP), and several nutrients [selenium, magnesium, calcium, zinc, manganese, iodine, vitamin B-12, folate, 25-hydroxycholecalciferol (25(OH)D3)], hemoglobin, and homocysteine in maternal whole blood, serum, plasma, or urine during pregnancy (mean gestational week 27). We measured the relative TL (rTL) in placenta (n = 99) and cord blood (n = 98) at delivery by real-time PCR. Associations were evaluated by multivariable-adjusted linear regression. RESULTS: The women's prepregnancy BMI (kg/m2; mean ± SD: 23.7 ± 4.1), body weight (55.4 ± 9.9 kg), and BFP (29.9 ± 5.5%), but not height (153 ± 5.3 cm), were inversely associated with placental rTL (P < 0.01 for all), with ∼0.5 SD shorter rTL for an IQR increase in prepregnancy body weight, BMI, or BFP. Also, impedance-based BFP, but not lean body mass, in the third trimester was associated with shorter placental rTL. In addition, serum vitamin B-12 (232 ± 96 pmol/L) in pregnancy (P = 0.038), but not folate or homocysteine, was associated with shorter placental rTL (0.2 SD for an IQR increase). In contrast, plasma 25(OH)D3 (46 ± 15 nmol/L) was positively associated with placental rTL (P < 0.01), which increased by 0.4 SD for an IQR increase in 25(OH)D3. No clear associations of the studied maternal nutritional factors were found with cord blood rTL. CONCLUSIONS: Maternal BMI, BFP, and vitamin B-12 were inversely associated, whereas 25(OH)D3 was positively associated, with placental TL. No association was observed with cord blood TL. Future studies should elucidate the role of placental TL for child health.