Causal relationship between obesity and vitamin D status: bi-directional Mendelian randomization analysis of multiple cohorts

Genome-wide Mendelian randomization mapping the influence of plasma proteome on major depressive disorder

Plasma proteins play critical roles in a series of biological processes and represent a major source of translational biomarkers and drug targets. In this study, we performed Mendelian randomization (MR) to explore potential causal associations of protein quantitative trait loci (pQTL, n = 54,219) with major depressive disorder (MDD) using summary statistics from the PGC (n = 143,265) and further replicated in FinnGen cohort (n = 406,986). Subsequently, gene expression quantitative trait loci (eQTL) of identified proteins were leveraged to validate the primary findings in both PGC and FinnGen cohorts. We implemented reverse causality detection using bidirectional MR analysis, Steiger test, Bayesian co-localization and phenotype scanning to further strengthen the MR findings. In primary analyses, MR analysis revealed 2 plasma protein significantly associated with MDD risk at Bonferroni correction (P < 3.720 × 10-5), including butyrophilin subfamily 2 member A1 (BTN2A1, OR = 0.860; 95 % CI, 0.825-0.895; P = 1.79 × 10-5) and butyrophilin subfamily 3 member A2 (BTN3A2, OR = 1.071; 95 % CI, 1.056-1.086; P = 3.89 × 10-6). Both the identified proteins had no reverse causality. Bayesian co-localization indicated that BTN2A1 (coloc.abf-PPH4 = 0.620) and BTN3A2 (coloc.abf-PPH4 = 0.872) exhibited a shared variant with MDD, a finding that was subsequently validated by HEIDI test. In the replication stage, BTN2A1 and BTN3A2 were successfully validated in the FinnGen cohort. This study genetically determined BTN2A1 and BTN3A2 were associated with MDD and these findings may have clinical implications for MDD prevention.

Investigating potential drug targets for the treatment of glioblastoma: a Mendelian randomization study

Glioblastoma (GBM), one of the most aggressive brain tumors, has a 5-year survival rate of less than 5%. Current standard therapies, including surgery, radiotherapy, and temozolomide (TMZ) chemotherapy, are limited by drug resistance and the blood-brain barrier. Integrating expression quantitative trait loci (eQTL) and protein quantitative trait loci (pQTL) data has shown promise in uncovering disease mechanisms and therapeutic targets. This study combined eQTL and pQTL analyses to identify potential GBM-related genes and circulating plasma proteins for therapeutic exploration. Using transcriptomic data from The Cancer Genome Atlas (TCGA), we identified 2,528 differentially expressed genes, including GPX7 and CXCL10. eQTL-MR analysis identifies GBM-associated differentially expressed genes and constructs a protein-protein interaction (PPI) network.Integrating pQTL data from the deCODE database, pQTL-MR, and colocalization analyses validated the therapeutic potential of GPX7 and CXCL10.These findings provide new perspectives on GBM biology and suggest actionable targets for therapy. Despite limitations due to sample size and population-specific data, this study highlights GPX7 and CXCL10 as promising candidates for further investigation and lays the foundation for targeted GBM treatments.

Establishing the relationships between obesity and genetically predicted serum micronutrient levels: a multivariable Mendelian randomization analysis

BACKGROUND

Previous observational studies have indicated that circulating micronutrients may influence obesity risk. This study aimed to explore the causal relationship between micronutrient levels and obesity through multivariable Mendelian randomization (MR) analysis.

METHODS

Single nucleotide polymorphisms (SNPs) significantly associated with 15 micronutrients (selenium, zinc, copper, calcium, beta-carotene, folate, iron, magnesium, potassium, and vitamins A, B6, B12, C, D, and E) from published genome-wide association studies (GWAS) were used as instrumental variables (IVs). Three obesity-related datasets were obtained from the GWAS. Inverse variance weighted (IVW) is the main method used for MR analysis. Leave-one-out analysis, MR-Pleiotropy Residual Sum and Outlier method (MR-PRESSO), weighted median, and MR-Egger method were used to assess pleiotropy and heterogeneity.

RESULTS

Genetically predicted levels of circulating selenium and calcium are causally related to the risk of obesity (calcium odds ratio [OR]: 1.478, 95% confidence interval [CI] 1.128-1.935, p = 0.005; selenium OR: 1.478, 95% CI 1.128-1.935, p = 0.005). Multivariate MR analysis suggested a causal relationship between circulating selenium and calcium levels and obesity risk (calcium OR: 1.625, 95% CI 1.260-2.097; selenium OR: 1.080, 95% CI 1.003-1.163, p = 0.041). The p-value obtained in the Cochrane Q test, MR-Egger intercept test, and MR-PRESSO were > 0.05, suggesting no significant evidence of pleiotropy or heterogeneity.

CONCLUSION

Our study revealed, for the first time, a positive correlation between elevated circulating calcium and selenium levels and an increased obesity risk. These findings provide valuable insights into obesity's underlying mechanisms. Nevertheless, further large-scale clinical studies are required to confirm our results.

LEVEL OF EVIDENCE

Level III, Mendelian randomization.

Causal Effects of 25-Hydroxyvitamin D on Metabolic Syndrome and Metabolic Risk Traits: A Bidirectional Two-Sample Mendelian Randomization Study

Background/Objectives: Individuals with metabolic syndrome (MetS) present reduced 25(OH)D levels. We performed a two-sample Mendelian randomization (MR) study to investigate whether causal relationships exist between 25(OH)D levels and MetS/MetS risk traits, including waist circumference, body mass index (BMI), hypertension (systolic/diastolic blood pressure), triglyceride, high-density lipoprotein cholesterol, and glucose levels. Methods: We employed genetic variants related to 25(OH)D levels from the SUNLIGHT Consortium and a European genome-wide association study meta-analysis, including UK Biobank (UKB) data, as well as variants for MetS and MetS risk traits from UKB and multiple European consortia. Several MR methods were used, i.e., inverse-variance weighted, weighted median, and MR-Egger regression. Heterogeneity and horizontal pleiotropy analyses were performed to ensure the stability of candidate single-nucleotide polymorphisms (SNPs) as the instrumental variable. We first conducted univariable MR to investigate the relationship between 25(OH)D levels and MetS, including its related risk traits, and subsequently performed multivariable MR to adjust for potential confounders. Results: This study did not provide evidence of a causal relationship between 25(OH)D levels and MetS/MetS risk traits. However, we found that several risk traits of MetS, such as waist circumference, BMI, and TG, had an inverse-causal relationship with 25(OH)D levels, suggesting that 25(OH)D levels could be secondary consequences of metabolic illnesses. Conclusions: We identified no causal relationship between 25(OH)D levels and MetS/MetS risk factors. However, 25(OH)D levels may result from MetS traits.

Application of Mendelian randomized analysis method in Vitamin D research: A 10-year bibliometric analysis

Vitamin D is an open-cyclic steroidal trace organic compound that plays a crucial role in human metabolism and nutritional health. In recent years, Mendelian randomization (MR) has emerged as a widely adopted method for analyzing causal relationships, particularly in studying the association between Vitamin D and related diseases. However, no bibliometric analyses have been conducted to explore the research hotspots and trends regarding Vitamin D status in MR studies. This study utilized the Web of Science Core Collection as a source database and retrieved articles on Vitamin D status in MR published from 2014 to 2024. Bibliometric and visualization analyses utilized VOSviewer, Microsoft Excel 2021, and Scimago Graphica. An in-depth analysis of country or region, authors, journals, keywords, and references were performed to provide insights into the content related to the field. A total of 186 documents authored by 1122 contributors across 30 countries were identified. China and the University of Bristol had the highest publication counts, with 94 and 19 articles, respectively. The nutrients published the largest number of articles, and J Brent Richards was the largest contributors. The most frequently used keywords included "Mendelian randomization," "Vitamin D," "25-hydroxyVitamin D," "obesity," and "Type 2 Diabetes." The current research focuses on using MR methods to explore the associations between Vitamin D status and metabolic, cardiovascular, immune skin, psychiatric and neurological diseases. The related research in this field will continue to increase in the next few years, which is a promising research prospect in this field. This study systematically reviews the literature from the past decade, revealing research hotspots and trends in the field of Vitamin D status within MR studies. This information will provide a strong reference for readers and researchers.

Potential drug targets for systemic lupus erythematosus identified through Mendelian randomization analysis

So far, there is no clear pathogenesis and no cure for systemic lupus erythematosus (SLE). The therapeutic benefits of existing drug therapies are far from ideal. The proteome is a major source of therapeutic targets. Therefore, new drug targets for SLE need to be discovered. Based on the STROBE-Mendelian randomization (MR) checklist, we performed MR to explore potential drug targets for SLE, using genome-wide association study summary statistics of plasma and cerebrospinal fluid (CSF) and further replicated in the external validation. Bidirectional MR, reverse causality testing by Steiger filtering, Bayesian co-localization were used. In addition, protein-protein interaction networks (PPI) were performed to reveal potential associations between proteins and current SLE drugs. At false discovery rate (FDR) significance (PFDR < .05), MR analysis revealed 8 proteins. Five proteins decreased the SLE risks, whereas the other 3 proteins increased the SLE risks. None of the 8 proteins had reverse causality except sICAM-1. Bayesian co-localization suggested that 5 proteins shared the same variant with SLE. PPI network suggested that intercellular adhesion molecular 1 (ICAM-1), Fc-gamma-RIIb (FCG2B) and N-terminal pro-B-type natriuretic peptide (N-terminal pro-BNP) interacted with targets of current SLE medications. Our integrative analysis revealed that SLE risk is causally associated with ICAM-1, FCG2B, and N-terminal pro-BNP. These 3 proteins have the potential to become drug targets of SLE, especially for ICAM-1 and FCG2B. More further studies are also warranted to support this finding.

Associations between hypovitaminosis D, adiposity indices and insulin resistance in adolescents: mediation analyses from NHANES 2011-2018

BACKGROUND

As all kown, both hypovitaminosis D and insulin resistance (IR) have been linked to adiposity. However, the extent of adiposity's mediating influence on the hypovitaminosis D-IR relationship among adolescents remains to be elucidated. Additionally, the intricate effects of obesity and blood lipid profiles on IR are not yet fully understood.

METHODS

We conducted a comprehensive analysis of NHANES data from 2011 to 2018, examining the correlation between adiposity indices such as Body Mass Index (BMI), Fat Mass Index (FMI, defined as the ratio of fat mass to height squared), hypovitaminosis D, and IR. We employed the XGBoost algorithm to identify key factors significantly influencing IR, thereby deepening our insight into the link between adiposity and insulin resistance. Furthermore, we applied mediation analysis to precisely assess the mediating role of adiposity indices in the relationship between hypovitaminosis D and IR.

RESULTS

Our study revealing significant correlations between adiposity indices, hypovitaminosis D, and IR after variable adjustment. Notably, subgroup analysis indicated a pronounced hypovitaminosis D -adiposity association in female adolescents, which was not observed in males. The XGBoost algorithm pinpointed obesity and blood lipid indicators significantly affecting IR, with total fat mass, triglyceride, cholesterol, BMI, and FMI ranked by descending importance. Mediation analysis disclosed that adiposity indices mediate a substantial portion of the hypovitaminosis D -IR relationship, with FMI (43.84%, p < 0.001) and BMI (40.87%, p < 0.001) showing significant mediating effects.

CONCLUSION

The study confirmed significant correlations between adiposity indices, hypovitaminosis D, and IR in adolescents, with gender-specific differences in the hypovitaminosis D -adiposity link. Cholesterol was found to have a more substantial influence on IR than BMI and FMI. Furthermore, FMI was identified as a more potent mediator of the hypovitaminosis D-IR relationship compared to BMI, highlighting its importance in the pathophysiology of insulin resistance in adolescents.

Characterization of gene-environment interactions for vitamin D through variance quantitative trait loci: a UK Biobank-based genetic epidemiology study

BACKGROUND

Understanding gene-environment interactions associated with vitamin D status may refine nutrition and public health strategies for vitamin D deficiency. Recent methodological advances have enabled the identification of variance quantitative trait loci (vQTLs) where gene-environment interactions are enriched.

OBJECTIVES

The study aims to identify vQTLs for serum 25-hydroxy vitamin D (25OHD) concentrations and characterize potential gene-environment interactions of vQTLs.

METHODS

We conducted vQTL discovery for 25OHD using a newly developed quantile integral linear model in the UK Biobank individuals of European (N = 313,514), African (N = 7800), East Asian (N = 2146), and South Asian (N = 8771) ancestries, respectively. We tested for interactions between the identified vQTL lead variants and 18 environmental, biological, or lifestyle factors, followed by multiple sensitivity analyses.

RESULTS

We identified 19 independent vQTL lead variants (P < 5 × 10-8) in the European ancestry population. No vQTLs were identified in the non-European ancestry populations, likely because of limited sample sizes. A total of 32 interactions were detected with a false discovery rate <0.05. Although known gene-season of measurement interactions were confirmed, additional interactions were identified involving modifiable risk factors, including time spent outdoors and body mass index. The magnitudes of these interactions were consistent within each locus upon adjusting for the season of measurement and other covariates. We also identified a gene-sex interaction at a vQTL that implicates DHCR7. Integrating transcript- and protein-level evidence, we found that the sex-differentiated genetic associations may act through sex-biased expression of DHCR7 isoforms in skin tissues because of alternative splicing.

CONCLUSIONS

Through the lens of vQTLs, we identified additional gene-environment interactions affecting vitamin D status in addition to the season of measurement. These findings may provide new insights into the etiology of vitamin D deficiency and encourage personalized prevention and management of associated diseases for at-risk individuals.

Knowledge, attitude and practices regarding vitamin D among adults in Ghana: a cross-sectional study

BACKGROUND

Vitamin D deficiency is a major public health concern, affecting approximately half of the world's population, partly due to limited public knowledge about vitamin D sources. However, there is lack of data on awareness, knowledge, attitudes, and practices regarding vitamin D in high-risk countries like Ghana. We investigated vitamin D awareness, knowledge and its associated factors in the Ghanaian population.

METHODS

This cross-sectional study involved 515 adults from Jaman South Municipal between January and June 2024. Questionnaires were used to obtain data on demographics, clinical characteristics, awareness and knowledge, attitude and practices towards vitamin D. Binary logistic regression analysis was used to determine the independent predictors of knowledge and practices regarding vitamin D. SPSS (version 26.0) was used for all statistical analysis. P < 0.05 was considered statistically significant.

RESULTS

Awareness, knowledge, attitude and practice level towards vitamin D was 61%, 56.9%, 63.7% and 73.2% respectively. Aged between 18-24 yrs [(aOR = 4.106, 95% CI: (1.523-11.072); p = 0.005)], being single [(aOR = 0.243, 95% CI: (0.065-0.904); p = 0.035)], having basic [(aOR = 0.216, 95% CI: (0.068-0.685); p = 0.009)] or secondary education [(aOR = 0.151, 95% CI: (0.073-0.313); p < 0.001)] and speaking English [(aOR = 3.553, 95% CI: (1.519-8.313); p = 0.003)] were the independent predictors of adequate knowledge on vitamin D. Having basic [(aOR = 9.058, 95% CI: (2.449-33.509); p = 0.001)] or secondary education [(aOR = 5.252, 95% CI: (2.508-10.996); p < 0.001)] increased the likelihood of good practices.

CONCLUSION

There is high awareness but reduced knowledge on Vitamin D among the general public in Jaman South. Age, education, employment status, language were the factors associated with knowledge and practice regarding vitamin D. There is need for extensive health educational campaigns to the public to boost the knowledge levels on the importance of Vitamin D.

Revealing potential drug targets in schizophrenia through proteome-wide Mendelian randomization genetic insights

BACKGROUND

Schizophrenia (SCZ) is a severe, chronic mental disorder with no current cure. Identifying novel pharmacological targets is crucial for developing more effective treatments.

METHODS

We performed two-sample Mendelian randomization (MR) analyses to estimate the associations between cerebrospinal fluid (CSF) containing 154 proteins and plasma containing 734 proteins and risk of SCZ. Bidirectional MR analysis, steiger filtering, bayesian colocalization, phenotypic scanning, and validation analysis were examined to validate the assumptions of MR. For proteins significantly associated with SCZ identified by MR, we explored their potential impact on brain structures, including cortical surface area (SA), thickness (TH), and the volume of subcortical structures.

RESULTS

MR analysis identified 13 protein-SCZ pairs at Bonferroni significance (P < 5.63 × 10-5). Notably, the genetically proxied protein level of neuromedin B (NMB) was associated with an increased risk for SCZ (odds ratio [OR] = 1.41; 95 % CI, 1.27 to 1.58; P = 6.68 × 10-10). Bayesian colocalization suggested that NMB shares genetic variations with SCZ. Further, NMB interacts with target proteins of current SCZ drugs and was validated in the UK Biobank. The genetically proxied NMB was positively associated with an increase in the surface area (SA) of the parahippocampal gyrus (β = 8.93 mm2, 95 % CI, 1.58 to 16.3, P = .02). Additionally, an increase in the genetically proxied SA of the parahippocampal gyrus was inversely associated with the risk of SCZ (OR = 0.996, 95 % CI, 0.993 to 0.999, P = .04).

CONCLUSIONS

The findings suggest that NMB may represent a promising target for pharmacological intervention in SCZ. This warrants further investigation into the specific constituents involved, which could have potential for follow-up studies.

Effects of supplemental 25-hydroxyvitamin D3 on growth performance, physiological responses, and gene expression of skeletal muscle growth of finishing beef cattle

The objective of this experiment was to evaluate the effects of 25-hydroxyvitamin D3 (25(OH)D3) supplementation on growth performance, carcass characteristics, meat quality, and the expression of genes related to anabolism of skeletal muscle in finishing beef cattle. One hundred and twenty Nellore bulls (initial body weight [BW] = 376 ± 20 kg) were blocked by initial BW, allocated to 24 pens (5 bulls/pen) and pens were assigned to one of three treatments during a 96 d feeding experiment: control: high-concentrate basal diet (11% roughage; NEg = 1.16 Mcal/kg dry matter) with no supplemental 25(OH)D3 (0 mg of 25(OH)D3; n = 8 pens); basal diet containing supplemental 25(OH)D3 to provide 1 mg/animal/d (1 mg of 25(OH)D3; n = 8 pens), 3) basal diet containing supplemental 25(OH)D3 to provide 3 mg/animal/d (3 mg of 25(OH)D3; n = 8 pens). The dietary supplementation of 25(OH)D3 did not affect final BW, dry matter intake, average daily gain, and feed efficiency (P ≥ 0.32). Dressing percentage increased quadratically (P = 0.03) and Longissimus muscle area tended to increase quadratically (P = 0.09) with increasing levels of 25(OH)D3 supplementation. A treatment × day interaction was observed for plasma concentration of 25(OH)D3 (P < 0.001). No difference in plasma 25(OH)D3 concentration between treatments was observed at the beginning of the experiment (P > 0.05), but on days 37 and 95, plasma 25(OH)D3 was greater (P ≤ 0.05) for bulls fed 3 mg, followed by 1 mg, and 0 mg of 25(OH)D3. No effects of dietary supplementation of 25(OH)D3 were observed on meat quality attributes (P ≥ 0.24), except for meat pH that linearly increased (P < 0.01). The percentage of fat in the carcasses decreased linearly (P = 0.03) with increasing levels of 25(OH)D3 supplementation, followed by a numerical increase (P = 0.11) in the percentage of muscle. The gene expression of insulin-like growth factor-2 (IGF2), mammalian target of rapamycin, and myostatin tended (P ≤ 0.10), and IGF1 increased linearly (P = 0.04) with increasing levels of 25(OH)D3. In summary, the inclusion of 25-hydroxyvitamin D3 in feedlot diets may go beyond regulating calcium metabolism and meat quality only. Dietary supplementation of 1 mg of 25(OH)D3 for finishing beef cattle increased carcass dressing percentage and Longissimus muscle area by the upregulation of genes associated with skeletal muscle growth insulin-like growth factor-1 and 2, mammalian target of rapamycin, and myostatin.

The effect of vitamin D on the lipid profile in individuals with overweight or obesity: A meta-analysis and systematic review of randomized controlled trials

BACKGROUND AND AIM

Previous studies have reported on the relationship between vitamin D and the lipid profile in individuals with obesity or overweight, but results have been inconsistent. Hence, we conducted this meta-analysis and systematic review of randomized controlled trials to assess the effect of vitamin D on the lipid profile in individuals with overweight or obesity.

METHODS

A meticulous search strategy was used in various databases, and article published up to November 2023 were included. The DerSimonian and Laird random effects model was applied to compute the weighted mean difference (WMD) and 95 % confidence intervals (CI) of the intervention on each variable.

RESULTS

Vitamin D supplementation did not yield significant alterations in LDL-C (WMD: 2.10 mg/dL, CI: -5.20-9.41, p = 0.572), HDL-C (WMD: 1.49 mg/dL, 95 % CI: -1.55-4.55, P = 0.337), and TC concentrations (WMD: -1.99 mg/dL, CI: -8.21-4.22, P = 0.530). Conversely, a significant decrease in TG levels was observed studies conducted in individuals with comorbidities (WMD: -6.03 mg/dL, 95 % CI: -11.92 to -0.15, p = 0.044), vitamin D doses of ≥ 50000 IU/week (WMD: -20.87 mg/dL, 95 % CI: -39.63 to -2.11, P = 0.029), and subjects with baseline TG concentrations ≥ 150 mg/dl (WMD: -25.95 mg/dL, 95 % CI: -51.51 to -0.40, p = 0.046).

CONCLUSION

According to our study findings, vitamin D has significant effect on the hypertriglyceridemia in individuals with obesity or overweight. However, vitamin D has no significant effect on the LDL-C, HDL-C, and TC concentrations in individuals with obesity or overweight.

Fat Distribution as a Determinant of Vitamin D Status: A Cross-Sectional Study of Adults in the United States

BACKGROUND

This study aimed to elucidate correlations between obesity-related indicators and vitamin D (VD) status in a nationally representative sample of U.S. adults.

METHODS

We analysed data from 9168 adults aged 20-59 years obtained from the 2011-2018 National Health and Nutrition Examination Survey. Serum 25 hydroxyvitamin D [25(OH)D] levels were measured and categorised into quartiles. Anthropometric measurements, including weight, waist circumference, and fat mass in various body regions quantified through dual-energy X-ray absorptiometry, were collected. Multiple imputation was employed to replace missing data. The importance of obesity-related indicators and serum 25(OH)D concentration was explored using multiple linear regression adjusted for demographics, lifestyle factors, dietary intake, and clinical biomarkers, and stepwise regression.

RESULTS

Weight, waist circumference, and fat mass across all body regions were inversely associated with serum 25(OH)D levels (all p < 0.001). Notable differences were observed between men and women. Stepwise regression revealed a strong inverse correlation between visceral adipose tissue and serum 25(OH)D concentration in men [β 95% CI: -13.04 (-18.10, -7.99), p < 0.001], whereas in women, only weight was significantly correlated with serum 25(OH)D concentration [β 95% CI: -0.20 (-0.28, -0.12), p < 0.001]. Demographic attributes, seasonal sunlight exposure, dietary VD, calcium, phosphorus, and magnesium intake, and biomarkers including alkaline phosphatase and creatinine also emerged as significant predictors.

CONCLUSIONS

Besides conventional obesity measures, abdominal fat metrics exhibit robust associations with VD deficiency, especially in men. Public health initiatives and clinical management strategies for hypovitaminosis D in obese populations should consider nuanced aspects of adiposity distribution alongside other demographic, lifestyle, and dietary factors influencing VD.

Vitamin D alleviates HFD-induced hepatic fibrosis by inhibiting DNMT1 to affect the TGFβ1/Smad3 pathway

Increasing evidence points toward vitamin D (VD) having lipometabolism and immune-related properties to protect against related metabolic diseases through influencing DNA methylation with inconsistent results. Simultaneously, its relatively precise molecular metabolism on the progression of metabolic-associated fatty liver disease (MAFLD) remains uncertain. Here, we report an unprecedented role and possible mechanism for VD supplementation on the alleviation of high-fat diet (HFD)-induced MAFLD. Over time, our results demonstrated that metabolic disorders in the HFD-induced MAFLD were aggravated with a certain time-response dependence and accompanied by reduced VD metabolites. All these could be alleviated under sufficient VD supplementation in vivo and vitro. It was partially by inhibiting the expressions of DNMT1 to reverse the epigenetic patterns on the VD metabolism genes and TGFβR1, which ultimately triggered the TGFβ1/Smad3 pathway to result in the development of MAFLD. Furthermore, the protective effects of VD were weakened by the treatment with gene silencing of DNMT1.

The effect of active vitamin D supplementation on body weight and composition: A meta-analysis of individual participant data

BACKGROUND & AIMS

Obesity is associated with vitamin D (VitD) deficiency. However, previous studies showed mixed effects of VitD (25-hydroxyVitD/calcidiol) supplementation on body weight. The biological actions of VitD require the hydroxylation of inactive VitD into active VitD (1.25-dihydroxyVitD/calcitriol). This step is highly regulated; therefore, supplementing with inactive VitD might not be sufficient to overcome the potential adverse health effects of VitD deficiency. The objective of this study was to conduct a systematic review and individual participant data (IPD) meta-analysis of data acquired from randomised placebo-controlled calcitriol trials (RCTs) to determine the effects of calcitriol on body weight and weight-related parameters.

METHODS

Studies were identified from MEDLINE, EMBASE, and CENTRAL databases up to January 27, 2024, and excluded those involving dialysis or cancer patients. We obtained IPD from eligible trials and assessed bias using the Cochrane Collaboration risk-of-bias tool and methodological quality using the Heyland Methodological Quality Score. The study was prospectively registered with PROSPERO (CRD42017076202).

RESULTS

Although none of the studies reported information regarding our primary objective, we obtained IPD for 411 patients, with 206 randomised to receive calcitriol and 205 to placebo. This dataset enabled us to conduct an IPD meta-analysis with 17,084 person-months of follow-up (median: 11 months). Meta-analysis showed that calcitriol does not alter body weight, BMI, waist circumference, fat mass or lean body mass compared to placebo. Adjusting for age and sex did not alter the outcomes.

CONCLUSIONS

In conclusion, this systematic review and IPD meta-analysis indicate that calcitriol does not affect body weight in normal-weight postmenopausal women and lean patients with type 1 diabetes nor in people suffering from obesity, type 2 diabetes and chronic kidney disease. Whether calcitriol lowers body weight in VitD-sufficient people with obesity remains to be elucidated.

A bibliometric analysis and visualization of literature on the relationship between vitamin D and obesity over the last two decades

OBJECTIVE

The purpose of this study was to employ bibliometric analysis to visualize hot spots and evolving trends in the studies on the relationship between vitamin D and obesity.

METHODS

From the Web of Science Core Collection database, articles on vitamin D and obesity from 2001 to 2021 were retrieved. For the bibliometric visualization analysis, CiteSpace was employed. Some of the figures were created using GraphPad software.

RESULTS

4454 pieces of articles and reviews were found, with an average citation of 30.68 times. There are many more published papers in the area of "nutrition dietetics" (1166, 26.179 %). The United States possesses the largest number of publications (1297, 29.12 %) and demonstrates definitive leadership in this field. The League of European Research Universities generates a higher percentage of publications (256, 5.748 %) than other institutions. Major studies are funded by the United States Department of Health and Human Services (531, 11.922 %) and the National Institutes of Health, USA (528, 11.855 %). The top five keywords with the highest co-occurrence frequency are "obesity" (1260), "vitamin d" (943), "insulin resistance" (651), "risk" (642), and "d deficiency" (636). The biggest keyword cluster was #0 "adolescent" among the 18 keyword clusters. The three latest keywords in the keyword burst were "mineral density"、"d insufficiency" and "25 hydroxyvitamin d concentration".

CONCLUSION

This bibliometric analysis shows an overview of the current status of the research on the association between vitamin D and obesity. The prevalence of vitamin D deficiency and the relationship between vitamin D and metabolic syndrome in obese individuals remains hot topics. We speculate that the effect of obesity on vitamin D levels and bone mineral density, and the influence of vitamin D insufficiency on various body systems in obese populations will be future trends.

The impact of vitamin D status on lipid profiles and atherogenic dyslipidemia markers in children and adolescents with obesity

BACKGROUND AND AIM

Adequate serum vitamin D levels correlate with a more favorable lipid profile compared to deficient levels. Despite the well-established prevalence of vitamin D deficiency in children with obesity, studies investigating its influence on lipid profiles in this population are scarce. We explored the impact of vitamin D status on lipid profiles and markers of atherogenic dyslipidemia in a cohort of children and adolescents with obesity.

METHODS AND RESULTS

A total of 271 Caucasian children and adolescents with overweight/obesity and a control group of 54 pediatric patients with normal weight. All participants underwent outpatient visits for the assessment of clinical parameters and venous blood collection for biochemical analysis such as triglycerides (TG)/HDL-C ratio, LDL-C/HDL-C ratio, atherogenic index of plasma AIP), vitamin D level. Individuals with obesity displayed severe vitamin D deficiency (25-OH-D ≤10 ng/ml) at a higher frequency compared to those with normal weight (p = 0.03). In patients with overweight/obesity and low 25-OH-D levels show higher values of glycemia (p = 0.001), insulin resistance (HOMA-IR and TRYG p < 0.001), TG (p < 0.001), TG/HDL-C (p = 0.001), AIP (p < 0.001), SBP (p = 0.01), and DBP (p = 0.04). In normal-weight individuals with low 25-OH- D levels an increased values of glycemia (p = 0.01), insulin resistance (HOMA-IR p = 0.01 and TRYG p = 0.002), TG (p = 0.01), TG/HDL-C (p = 0.02), AIP (p = 0.01). A direct correlation between 25-OH-D levels and metabolic parameters is observed.

CONCLUSIONS

A correlation between vitamin D levels and the lipid/atherosclerotic profile was recorded. Vitamin D deficiency may represent a preventable and easily treatable cardiometabolic risk factor, emphasizing the importance of early intervention and preventive measures.

Translational approach to establish the cardiometabolic health effects and mechanisms of action of fish nutrients-it takes a village

People use dietary supplements to offset nutritional deficiencies and manage metabolic dysfunction. While the beneficial effect of fish proteins on glucose homeostasis is well established, the ability of fish peptides to replicate the protein findings is less clear. With financial support from a programmatic Canadian Institutes of Health Research (CIHR) Team grant, we aimed to identify salmon peptide fractions (SPFs) with the potential to mitigate metabolic dysfunction. Additionally, the grant aims included assessing whether vitamin D, a nutrient commonly found in salmon, could potentiate the beneficial effects of salmon peptides. In parallel, technologies were developed to separate and filter the isolated peptides. We employed an integrative approach that combined nutritional interventions in animal models and human subjects to identify metabolic pathways regulated by salmon peptides and other fish nutrients. This combination of interdisciplinary expertise revealed that a SPF could be a therapeutic tool used in the prevention and management of cardiometabolic diseases. Herein, we present a perspective of our CIHR funded grant that utilized a translational approach to establish the cardiometabolic health effects and mechanisms of action of fish nutrients: from animal models to clinical trials.

Effects of vitamin D supplementation on metabolic syndrome parameters in patients with obesity or diabetes in Brazil, Europe, and the United States: A systematic review and meta-analysis

Plasma 25-dihydroxyvitamin D levels appear reduced in patients with obesity or type 2 diabetes, as reported in several observational studies. However, the association between these reduced hormone levels and metabolic parameters is unclear. In any case, vitamin D supplementation in patients with Metabolic Syndrome is standard. Still, the impacts of this supplementation on conditions such as glycemia, blood pressure, and lipidemia are debatable. Based on this question, we carried out a systematic review and meta-analysis of randomized clinical trials in Brazil, Europe, and the United States that analyzed the effects of vitamin D supplementation on Metabolic Syndrome parameters in patients with obesity or type 2 diabetes. Our search yielded 519 articles and included 12 randomized controlled trials in the meta-analysis. Vitamin D supplementation had no effect on any of the outcomes analyzed (fasting blood glucose and insulinemia, glycated hemoglobin, HOMA index, systolic and diastolic blood pressure, weight, waist circumference, total cholesterol, LDL and HDL, and triglycerides). However, subgroup analyses indicated that using vitamin D up to 2000 IU daily reduced participants' fasting blood glucose and glycated hemoglobin. Furthermore, the intervention reduced diastolic blood pressure only in participants with vitamin D deficiency. At least two studies showed a high risk of bias using the Rob2 protocol. According to the GRADE protocol, the evidence quality varied from moderate to very low. These results indicate that vitamin D supplementation does not improve patients' metabolic parameters and that the association between plasma 25-dihydroxyvitamin D levels and Metabolic Syndrome may not be causal but caused by other confounding characteristics. However, in any case, the quality of evidence is still low, and more randomized clinical trials are essential to clarify these relationships.

The association between dynamic changes in vitamin D and frailty alterations: A prospective analysis of UK Biobank participants

BACKGROUND

Frailty is a common geriatric syndrome associated with reduced reserves and increased vulnerability to stressors among older adults. Vitamin D deficiency has been implicated in frailty, as it is essential for maintaining musculoskeletal functions. The relationship between dynamic changes in vitamin D levels and frailty over time has not been extensively studied.

METHODS

This study utilized data from the UK Biobank. Baseline and longitudinal changes in vitamin D levels were measured. Frailty status was assessed using both the frailty phenotype and frailty index approaches and classified as robust, pre-frail, or frail. Changes in frailty status were assessed by frailty phenotype at baseline (2006-2010) and the follow-up (2012-2013). Mixed effect model was performed to examine the association between vitamin D levels and frailty status. Using multistate transition models, we assessed the impact of increasing vitamin D levels on the probabilities of transitioning between robust, pre-frail, and frail states.

RESULTS

Based on the frailty phenotype, 287 926 individuals (64.8%) were identified as having various degrees of frailty (median age 58.00 [51.00, 64.00] years, 55.9% females). Using the frailty index approach, 250 566 individuals (56%) were found to have different levels of frailty (median age 59.00 [51.00, 64.00] years, 55.3% females). Baseline vitamin D levels were found to be significantly associated with frailty status (frailty phenotype: ORfrail 0.78, 95% CI [0.76, 0.79], P < 0.001; frailty index: ORfrail 0.80, 95% CI [0.78, 0.81], P < 0.001). Dynamic changes in vitamin D levels were also found to be associated with changes in frailty over time. Furthermore, increasing vitamin D levels were associated with a transition from frailty to a healthier status. A higher degree of vitamin D (estimated at 1 nmol/L) was associated with a lower risk of transitioning from robust to prefrail (HR 0.997, 95% CI [0.995, 0.999]) and from prefrail to frail (HR 0.992, 95% CI [0.988, 0.995]).

CONCLUSIONS

This study highlights the importance of vitamin D in the context of frailty. Low vitamin D levels are associated with increased frailty risk, while increasing vitamin D levels may contribute to improving frailty status. Recognizing the relationship between vitamin D levels and frailty can inform personalized management and early interventions for frail individuals. Further research is needed to explore the potential effects of vitamin D interventions on frailty and deepen our understanding of the biological connections between vitamin D and frailty.

Association Between Body Mass Index (BMI), Vitamin D, and Testosterone Levels

Introduction Obesity is measured scientifically by calculating body mass index (BMI). Body mass index in men is linked to various hormonal imbalances. This study aims to observe the relationships between BMI, vitamin D, and testosterone levels in patients attending the outpatient clinic at Hayatabad Medical Complex, Peshawar, Pakistan. Methods This observational cross-sectional study involved 272 patients, presenting to the medical outpatient department from January 1st, 2023, to December 31st, 2023. Body mass index, serum vitamin D, and testosterone levels were measured for each participant. Body mass index was categorized into normal, overweight, and obese. Statistical analysis was calculated, including descriptive statistics, logistic regression, and correlation analysis to evaluate associations between these variables. Results The mean BMI of the participants was 25.82 ± 7.88 kg/m². A significant inverse correlation was observed between BMI and vitamin D levels (r = -0.79, p < 0.001) and between BMI and testosterone levels (r = -0.87, p < 0.001). A positive correlation was found between vitamin D and testosterone levels (r = 0.87, p < 0.001). Logistic regression analysis revealed that higher BMI in the range of overweight or above was associated with a 2.5-fold increase in the likelihood of vitamin D deficiency (odds ratio (OR) = 2.50, 95% CI = 1.8-3.5, p < 0.001) and a 3.1-fold increase in the likelihood of low testosterone levels (OR = 3.10, 95% CI = 2.2-4.3, p < 0.001). Conclusion In this study, higher BMI is significantly associated with lower vitamin D and testosterone levels. These findings suggest that addressing obesity could help mitigate hormonal imbalances, such as vitamin D deficiency and low testosterone, which are linked to metabolic health risks. It can also be hypothesized that obesity can be a risk factor for vitamin D and testosterone deficiency.

Nutrigenetic Investigations in Preeclampsia

Background: Preeclampsia is a leading cause of pregnancy-related maternal and fetal morbidity and mortality. Although its precise cause and prevention remain unclear, risk factors such as overweight and inadequate nutrient intake (e.g., calcium, folic acid, and vitamin D) are known to increase its incidence. Recent research has focused on the genetic predisposition to preeclampsia, identifying polymorphisms that may affect enzyme or receptor function. This study aims to review existing literature examining the relationship between genetic polymorphisms, BMI (body mass index), and nutrient levels in preeclampsia to develop more actionable therapeutic strategies. Methods: A systematic review was conducted to analyze studies on the nutrigenetic relationship between BMI, micronutrients, and preeclampsia. Results: A total of 17 studies investigating 12 genes related to BMI and 10 studies exploring 3 genes in relation to micronutrient levels were included in the analysis. Several polymorphisms associated with preeclampsia were found to be influenced by maternal BMI or serum vitamin levels. The interactions between certain gene variants and these factors suggest that both BMI and micronutrient status may modify the risk of developing preeclampsia in genetically predisposed individuals. Conclusions: Our findings emphasize the potential for reanalyzing existing data by categorizing based on genotype and nutrient levels. This approach could yield more personalized dietary and therapeutic recommendations for managing preeclampsia. In the future, genetic information may support the development of tailored nutritional counseling during pregnancy to mitigate preeclampsia risk.

Obesity influencing circulating levels of nutrients: Evidence from Mendelian randomization study

Observational studies have established that obesity is associated with nutritional deficiencies, but the exact causality remains uncertain. Thus, this Mendelian randomization (MR) study aimed to identify the causal associations between obesity and circulating levels of nutrients. Single-nucleotide polymorphisms associated with obesity (body mass index and waist-hip ratio), were extracted from a genome-wide association study of 694,649 European ancestry. Summary-level data for minerals (copper, selenium, zinc, calcium, magnesium, and potassium), and vitamins (folate, vitamins A, C, E, B6, and B12), albumin were obtained from the publicly available integrative epidemiology unit OpenGWAS database psychiatric genomics consortium. Inverse-variance weighted method several sensitivity analyses were conducted. Genetically predicted higher body mass index significantly decreased circulating levels of magnesium (β = -0.07, 95% confidence interval [CI]: -0.10 to -0.03, P = 1.47 × 10-4), folate (β = -0.07, 95% CI: -0.10 to -0.04, P = 5.61 × 10-5), vitamin A (β = -0.11, 95% CI: -0.14 to -0.07, P = 3.10 × 10-9), vitamin E (β = -0.10, 95% CI: -0.13 to -0.06, P = 1.84 × 10-8), albumin (β = -0.15, 95% CI: -0.17 to -0.12, P = 9.89 × 10-28); whereas genetically predicted higher waist-hip ratio decreased circulating levels of magnesium (β = -0.07, 95% CI: -0.11 to -0.02, P = 1.87 × 10-3), folate (β = -0.07, 95% CI: -0.11 to -0.03, P = 9.87 × 10-4), vitamin C (β = -0.08, 95% CI: -0.12 to -0.04, P = 2.40 × 10-4), albumin (β = -0.08, 95% CI: -0.11 to -0.04, P = 3.72 × 10-5). The study supports a causal effect of obesity on lower circulating levels of nutrients. Our findings highlight the necessity of adjuvant nutrients in obesity management.

VDR gene TaqI (rs731236) polymorphism affects gut microbiota diversity and composition in a Caucasian population

Background

The VDR gene is identified as a crucial host factor, influencing the gut microbiota. The current research focuses on an observational study that compares gut microbiota composition among individuals with different VDR gene TaqI polymorphisms in a Caucasian Spanish population. This study aims to elucidate the interplay between genetic variations in the VDR gene and the gut microbial composition.

Methods

87 healthy participants (57 men, 30 women), aged 18 to 48 years, were examined. Anthropometric measures, body composition, and dietary habits were assessed. VDR gene polymorphism TaqI rs731236 was determined using TaqMan assays. The V3 and V4 regions of the 16S rRNA gene were sequenced to study bacterial composition, which was analyzed using QIIME2, DADA2 plugin, and PICRUSt2. Statistical analyses included tests for normal distribution, alpha/beta diversity, ADONIS, LEfSe, and DESeq2, with established significance thresholds.

Results

No significant differences in body composition or dietary habits were observed based on VDR genotypes. Dietary intake analysis revealed no variations in energy, macronutrients, or fiber among the different VDR genotypes. Fecal microbiota analysis indicated significant differences in alpha diversity as measured by Faith's Phylogenetic Diversity index. Differential abundance analysis identified taxonomic disparities, notably in the genera Parabacteroides and Butyricimonas.

Conclusion

Overall, this study suggests potential associations between genetic variations in the VDR gene and the composition and function of gut microbiota.

Relationship between Vitamin D Insufficiency, Lipid Profile and Atherogenic Indices in Healthy Women Aged 18-50 Years

Although vitamin D insufficiency has been correlated with an increased risk of cardiovascular disease (CVD), there are few data on the association between 25-hydroxyvitamin D (25(OH)D) and atherogenic indices predictive of CVD. This study investigated the relationship of vitamin D status with lipid profile and atherogenic indices in adult women in Morocco. Three hundred women aged 18 to 50 years from Meknes were included. Fasting 25(OH)D and lipid concentrations were assayed by a one-step electrochemiluminescence-based immunoassay and an enzymatic method, respectively. Atherogenic indices (atherogenic index of plasma (AIP), atherogenic coefficient (AC), non-HDL cholesterol (non-HDL-C), Castelli risk indices I and II (CRI-I and II), and CHOLIndex (CI)) were calculated using conventional lipid parameters. Logistic regression models and operating characteristic curve (ROC) analysis were used to assess the relationship of the variables and estimate the threshold of 25(OH)D levels associated with high atherogenic indices. 25(OH) D below 20 ng/mL was significantly associated with an enhanced risk of hypertriglyceridemia and elevated values of AIP, AC, non-HDL-C, and CRI-I with an OR (95% CI) of 4.904 (1.856-12.959), 3.637 (2.149-6.158), 3.589 (1.673-7.700), 2.074 (1.215-3.540), and 2.481 (1.481-4.123), respectively. According to the ROC analysis, the likelihood of hypertriglyceridemia and high values of AIP, AC, non-HDL-C, and CRI-I were associated with 25(OH)D thresholds ≤15.15 ng/mL, ≤17.5 ng/mL, ≤19.8 ng/mL, ≤20.1 ng/mL, and ≤19.5 ng/mL, respectively, all p < 0.01. Based on the atherogenic indices, this study indicates that vitamin D below 20 ng/mL may increase the risk of cardiovascular disease in adult women. Additional health measures are essential to raise awareness among women and health professionals of preventing and controlling cardiovascular risk factors, particularly among young individuals.

Serum vitamin D concentrations and sleep disorders: insights from NHANES 2011-2016 and Mendelian Randomization analysis

OBJECTIVE

This investigation seeks to examine the association between serum vitamin D concentrations and the prevalence of sleep disorders, additionally elucidating the causal relationship via Mendelian Randomization (MR) analysis.

MATERIALS AND METHODS

This research employed data from the National Health and Nutrition Examination Survey (NHANES) 2011-2016, focusing on adults aged 20-50 years reporting sleep disorders. The research encompassed 4913 American adults. Weighted multivariable logistic regression models and cubic spline analyses were utilized to evaluate the association between serum vitamin D concentrations and the incidence of sleep disorders. Additionally, a two-sample Mendelian Randomization analysis was performed to evaluate the potential causal link between serum vitamin D concentrations and the risk of sleep disorders.

RESULTS

Within the 2011-2016 NHANES cohort of the U.S. population, a notable inverse association was detected between serum vitamin D concentrations and sleep disorders (β =  - 3.81, 95% CI: - 6.10 to - 1.52, p = 0.003). After multivariate adjustments, a higher incidence of sleep disorders was associated with lower vitamin D Concentrations (OR 1.52, 95% CI 1.10-2.10, trend p = 0.014). Restricted cubic spline regression analysis indicated a linear association between serum vitamin D concentrations and sleep disorders(non-linearity p > 0.05). Lastly, the two-sample MR analysis yielded evidence supporting a potential causal connection between serum vitamin D concentrations and sleep disorders, with each unit increase in genetically predicted serum vitamin D reducing the odds ratio to 0.78 (95% CI 0.61-0.99, p = 0.044).

CONCLUSIONS

These results imply that lower vitamin D concentrations in the population might correlate with a heightened risk of sleep disorders, suggesting the importance of considering vitamin D supplementation when treating sleep disorders.

Association of Genotypes of ANGPTL3 with Vitamin D and Calcium Concentration in Cardiovascular Disease

One of the leading causes of mortality worldwide is cardiovascular disease, which is influenced by some variables, including calcium and vitamin D. This study aimed to assess the relationship between Angiopoietin-Like 3 (ANGPTL3) gene polymorphisms with vitamin D and calcium levels in cardiovascular disease (CVD) patients. In this research, 1002 people participated. Participants' anthropometric parameters, and FBG, calcium, and vitamin D were assessed. Blood samples were used to extract DNA. Taqman®-based polymerase chain reaction (PCR) was used to conduct genetic analysis for the rs10789117 and rs17458195. Statistical analysis was applied to determine differences across subgroups and the relationship between polymorphisms and disease. Age, body mass index (BMI), fasting Blood Sugar (FBG), phenylalanine ammonia-lyase (PAL), and smoking history were significantly correlated with CVD. Vitamin D was statistically associated with rs10789117 and rs17458195 in non-CVD individuals. In the moderate group, individuals with the C allele in rs10789117 showed a tenfold increase in vitamin D deficiency compared to those with the A allele. However, in rs11207997, individuals with the T allele had 5 to 6 times higher vitamin D deficiency than those with the C allele in all groups. This research demonstrates the relationship between some ANGPTL3 gene polymorphisms and complement levels in CVD patients. It may be concluded that individuals carrying these variants would likely benefit from using vitamin D and calcium supplements to avoid CVD.

Vitamin D supplementation for women during pregnancy

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Bibliometric analysis of vitamin D and obesity research over the period 2000 to 2023

Background

Globally, the incidence rates of obesity and its related diseases, such as cardiovascular diseases and type 2 diabetes, are continuously rising, posing a significant public health challenge. Studies have indicated a potential correlation between vitamin D deficiency and obesity. However, a quantitative analysis of the studies related vitamin D and obesity is lacking. This investigation aims to fill this gap by providing a comprehensive bibliometric analysis to uncover the collaborative networks, research hotspots, and evolutionary trends within the field of vitamin D and obesity research.

Methods

This study retrieved literature related to vitamin D and obesity from the Web of Science database spanning from 2000 to 2023. Bibliometric analysis was conducted using tools such as HistCite, VOSviewer, and CiteSpace to excavate multi-dimensional information including countries, institutions, authors, journals, citations, and keywords.

Results

A total of 6,144 records were retrieved, involving 123 countries, 6,726 institutions, and 28,156 authors, published in 1,551 journals. The number of published papers and citations showed a generally increasing trend. The United States led in terms of publication volume and influence, with journals such as Nutrients and Obesity Surgery having the highest publication counts. Nasser M. Al-Daghri was the most prolific and influential author. Keyword clustering revealed that research topics covered metabolic health, nutrition, immunity, and bariatric surgery. Citation burst analysis indicated a shift in research focus from the relationship between dietary calcium and obesity to the preventive effects of vitamin D supplementation on metabolic diseases.

Conclusion

The application of bibliometric methods to analyze the research literature in the fields of obesity and vitamin D has provided a comprehensive understanding of the collaborative networks, key research focus, and evolutionary trends in this field, offering insights for guiding future research directions.

Vitamin D status of pregnant women with obesity in the UK and its association with pregnancy outcomes: a secondary analysis of the UK Pregnancies Better Eating and Activity Trial (UPBEAT) study

Prenatal vitamin D deficiency is widely reported and may affect perinatal outcomes. In this secondary analysis of the UK Pregnancies Better Eating and Activity Trial, we examined vitamin D status and its relationship with selected pregnancy outcomes in women with obesity (BMI ≥ 30 kg/m2) from multi-ethnic inner-city settings in the UK. Determinants of vitamin D status at a mean of 17 ± 1 weeks' gestation were assessed using multivariable linear regression and reported as percent differences in serum 25-hydroxyvitamin D (25(OH)D). Associations between 25(OH)D and clinical outcomes were examined using logistic regression. Among 1089 participants, 67 % had 25(OH)D < 50 nmol/l and 26 % had concentrations < 25 nmol/l. In fully adjusted models accounting for socio-demographic and anthropometric characteristics, 25(OH)D was lower among women of Black (% difference = -33; 95 % CI: -39, -27), Asian (% difference = -43; 95 % CI: -51, -35) and other non-White (% difference = -26; 95 % CI: -35, -14) ethnicity compared with women of White ethnicity (n 1086; P < 0·001 for all). In unadjusted analysis, risk of gestational diabetes was greater in women with 25(OH)D < 25 nmol/l compared with ≥ 50 nmol/l (OR = 1·58; 95 % CI: 1·09, 2·31), but the magnitude of effect estimates was attenuated in the multivariable model (OR = 1·33; 95 % CI: 0·88, 2·00). There were no associations between 25(OH)D and risk of preeclampsia, preterm birth or small for gestational age or large-for-gestational-age delivery. These findings demonstrate low 25(OH)D among pregnant women with obesity and highlight ethnic disparities in vitamin D status in the UK. However, evidence for a greater risk of adverse perinatal outcomes among women with vitamin D deficiency was limited.

Relationship of serum and dietary vitamin D with high cardiometabolic risk in Mexican systemic lupus erythematosus patients: A cross-sectional study

Objetive: Serum and dietary vitamin D could influence clinical disease activity and cardiometabolic outcomes in systemic lupus erythematosus (SLE). This study aimed to assess the relationship of serum and dietary vitamin D with cardiometabolic risk in Mexican SLE patients and healthy subjects (HS).Methods: 224 SLE patients and 201 HS were included in this cross-sectional study. Serum calcidiol was measured using a competitive enzyme-linked immunosorbent assay (ELISA). Vitamin D dietary intake was assessed by collecting three 24h food records. Dietary patterns (DPs) were identified using principal component analysis (PCA). Cardiometabolic status was analyzed through biochemical measurements and cardiometabolic indexes.Results: Calcidiol deficiency (<20 ng/mL) was associated with 1.66-fold higher risk of excess weight by body mass index (BMI) (≥25 kg/m2) (p = .02), 2.25-fold higher risk to low high-density lipoprotein-cholesterol (HDL-C) (<40 mg/dL) (p < .001), and 1.74-fold higher risk to high triglycerides (TG) ≥150 mg/dL (p = .02). Inadequate vitamin D dietary intake was associated with 1.92-fold higher risk of presenting non-healthy waist circumference (WC) (>80 cm) (p < .01), 2.05-fold higher risk of android waist to hip ratio (WHR ≥85) (p < .01), and 1.72-fold higher risk to excess weight (p = .02). Non-adherence to a DP rich in vitamin D food sources was associated with higher WC, WHR, triglycerides, and lower high-density lipoprotein-cholesterol (HDL-C); furthermore, in HS, non-adherence to the DP rich in vitamin D food sources provided 2.11-fold higher risk to calcidiol deficiency.In Cconclusion: A pattern of Calcidiol deficiency, inadequate vitamin D dietary intake, and non-adherence to a DP rich in vitamin D food sources was related to high cardiometabolic risk in SLE patients and HS.

Low vitamin D levels are linked with increased cardiovascular disease risk in young adults: a sub-study and secondary analyses from the ACTIBATE randomized controlled trial

PURPOSE

Vitamin D deficiency is related to metabolic disturbances. Indeed, a poor vitamin D status has been usually detected in patients with cardiovascular disease (CVD). However, the relationship between vitamin D and CVD risk factors in young adults remains controversial at present. This study aimed to examine the association between circulating 25-hydroxivitamin D (25(OH)D) and CVD risk factors in young adults.

METHODS

The present cross-sectional study included a cohort of 177 young adults aged 18-25 years old (65% women). 25(OH)D serum concentrations were assessed using a competitive chemiluminescence immunoassay. Fasting CVD risk factors (i.e., body composition, blood pressure, glucose metabolism, lipid profile, liver, and inflammatory markers) were determined by routine methods. A panel of 63 oxylipins and endocannabinoids (eCBs) was also analyzed by targeted metabolomics.

RESULTS

Circulating 25(OH)D concentrations were inversely associated with a wide range of CVD risk factors including anthropometrical (all P ≤ 0.005), body composition (all P ≤ 0.038), glucose metabolism (all P ≤ 0.029), lipid profile (all P < 0.035), liver (all P ≤ 0.011), and pro-inflammatory biomarkers (all P ≤ 0.030). No associations of serum 25(OH)D concentrations were found with pro-inflammatory markers (all P ≥ 0.104), omega-6 and omega-3 oxylipins, nor eCBs concentrations or their analogs (all P ≥ 0.05).

CONCLUSION

The present findings support the idea that 25(OH)D could be a useful predictor of CVD risk in young individuals.

Relationship between Circulating 25-Hydroxyvitamin D and Metabolic Syndrome in Chinese Adults: A Large Nationwide Longitudinal Study

OBJECTIVE

This study investigated the association of circulating levels of 25-hydroxyvitamin D (25[OH]D) with the risk of metabolic syndrome (MetS) and its components in adults.

METHODS

This nationwide cohort involved 23,810 Chinese adults attending annual health evaluations. Serum 25(OH)D levels, MetS status, and covariates were determined at each examination. Among them, 8146, 3310, and 1971 completed two, three, and more than three evaluations, respectively. A hybrid mixed-effects and Cox regression model was employed to determine the cross-sectional and longitudinal relationships.

RESULTS

The odds ratios (ORs) and 95% confidence intervals (CIs) of MetS were significantly lower in individuals within quartile 4 (vs. 1) of serum 25(OH)D for both between-individual (0.43 [0.35, 0.52]) and within-individual comparisons (0.60 [0.50, 0.73]), respectively (all p-trends < 0.001). Among the MetS components, the corresponding ORs (95% CI) in between- and within-individual comparisons were 0.40 (0.29, 0.54) and 0.26 (0.19, 0.36) for abdominal obesity, 0.49 (0.41, 0.58) and 0.78 (0.66, 0.93) for high triglycerides, 0.70 (0.59, 0.82) and 0.75 (0.64, 0.87) for hypertriglyceridemia, 0.48 (0.39, 0.59) and 0.87 (0.71, 1.07) for low HDL cholesterol, and 0.92 (0.76, 1.12) and 0.49 (0.41, 0.59) for hypertension, respectively. Decreased hazard ratios (95% CIs) in quartile 4 (vs. 1) of 25(OH)D were found for MetS (0.80 [0.65, 1.00]), high triglycerides (0.76 [0.62, 0.92]), abdominal obesity (0.77 [0.63, 0.96]), and low HDL cholesterol (0.64 [0.50, 0.81]).

CONCLUSIONS

Decreased concentrations of serum 25(OH)D correlate significantly to a heightened MetS risk and specific components. Our findings underscore the potential preventive function of circulating vitamin D concerning metabolic disorders.

Prevalence of Micronutrient Deficiencies in Preoperative Bariatric Patients in a New Zealand Tertiary Centre

PURPOSE

A potential complication of bariatric surgery is development of nutritional deficiencies. Study aims were to assess prevalence of micronutrient deficiencies in preoperative bariatric patients and to examine for ethnic differences.

METHODS

Retrospective analysis of 573 patients that underwent bariatric surgery at Counties Manukau District Health Board was carried out. Mean preoperative levels of albumin, calcium, phosphate, folate, vitamin B12, vitamin D, magnesium, haemoglobin, haematocrit, mean cell volume, mean cell haemoglobin, ferritin, iron, and transferrin were calculated. Chi square, fisher exact test, and multiple logistic regression was used to assess for differences in prevalence of micronutrient deficiencies across ethnicities.

RESULTS

The most common micronutrient deficiency was vitamin D (30.85%). There were statistically significant differences in vitamin D deficiency across ethnicities (p < 0.0001). Asians had the highest prevalence of vitamin D deficiency (60%), followed by Pacifica (44.57%), and Māori (31.68%). Asians were more likely to have vitamin D deficiency compared to NZ/Other Europeans (OR = 14.93, p < 0.001). Vitamin D deficiency was associated with higher BMI (OR = 1.05, p = 0.008). The second most common deficiency was iron (21.1%). Asians had the highest prevalence of iron deficiency (44%), followed by Māori (27.95%), and Pacifica (19.57%) (p = 0.0064). Compared to NZ/Other Europeans, Asians (OR = 4.26) and Māori (OR = 1.78) were more likely to be iron deficient (p = 0.004). Female gender was associated with iron deficiency (OR = 2.12, p = 0.007).

CONCLUSION

Vitamin D and iron are the most common micronutrient deficiencies among preoperative bariatric patients in this cohort and ethnic differences were seen. There may be a role for preoperative supplementation in these at-risk ethnic groups.

Weight reduction among females undergoing laparoscopic ventral hernia repair: The role of Calcium and Vitamin D3

Objective

To evaluate the role of Vitamin-D and calcium supplementation on preoperative weight reduction in obese women before laparoscopic ventral hernia repair.

Methods

This double-blind clinical trial was conducted at the affiliated health centers of King Faisal University, Al-Ahsa, Saudi Arabia from January 2021 to December 2021. It included forty-five obese women aged 24-56 years, with body mass index (BMI) of 34.0-48.0kg/m2. They were randomly allocated into two groups; the Group-A (N=22) included obese women who received supplementation of 5000IU cholecalciferol (Vitamin-D3), and 1000mg calcium daily for 12 months, while the Group-B (N=23) received no treatment. Measurement of change in weight and BMI and comparison of their pre-operative weight reduction, laparoscopic operative time, and length of hospital stay was done.

Results

There were no differences in patients' biographic data between the two groups. During the study, Vitamin-D level in the patients increased and there was a significant positive association with weight loss. In group-A, the mean weight loss was 11.8±3.5 kg. At the end of first year, their BMI decreased from 36.1±1.6kg/m2 at baseline to 29.7±2.6 kg/m2, whereas in-group-B, the mean weight loss was 6.8±3.1 kg and their BMI decreased from 36.9±2.69kg/m2 at baseline to 32.7±0.93kg/m2. The operation time and the length of hospital stay were shorter in group-A (107 vs.128.min) and (3 vs. 5 days) respectively as compared to Group-B.

Conclusion

Vitamin-D and calcium supplementation contributes to a remarkable weight reduction of preoperative obese female patients, which in turn is associated with significantly better outcome of laparoscopic repair of ventral hernia.

Relationship between Vitamin D3 Deficiency, Metabolic Syndrome and VDR, GC, and CYP2R1 Gene Polymorphisms

The presence of vitamin D3 deficiency associated with the presence of metabolic syndrome (MS) has important public health effects. This study aims to investigate the relationship between vitamin D3 deficiency, MS and vitamin D3 receptor (VDR), GC Vitamin D binding protein (GC), and cytochrome P450 family 2 subfamily R member 1 (CYP2R1) gene polymorphisms, and genes whose encoded proteins are responsible for vitamin D3 metabolism and transport. A total of 58 participants were included in this study (age 39 ± 12 years) and were selected over a 12-month period. They were divided into four groups, depending on the presence of polymorphisms in VDR, GC, and CYP2R1 genes and their weight status. At baseline, in months 3, 6, and 12, biochemical parameters including 25(OH)D3, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, and homeostatic model assessment (HOMA index), the insulin resistance indicator were measured. Our results show that all subjects in the polymorphism group supplemented with vitamin D3 reached an optimal level of vitamin D3 associated with high concentrations of 25(OH)D3. Weight loss was most significant in patients in the POW group (overweight patients).

Effects of Vitamin D Supplementation on Central Hemodynamic Parameters and Autonomic Nervous System in Obese or Overweight Individuals

BACKGROUND

Previous studies have been inconsistent in demonstrating beneficial cardiovascular effects of vitamin D supplementation.

OBJECTIVE

To evaluate the effects of vitamin D3 supplementation on central hemodynamic parameters and autonomic activity in obese/overweight individuals with low vitamin D levels (<30ng/dl).

METHODS

Adults 40-65 years old with body mass index ≥25<40 kg/m2 were enrolled in this prospective, randomized, double-blind clinical trial (NCT05689632). Central hemodynamics was assessed using the oscillometric method (Mobil-O-Graph®), and heart rate variability using a Polar heart rate monitor (Kubios® software). Patients (n=53) received a placebo in the control group (CO, n=25) or vitamin D3 (VD, n=28) 7000 IU/day, and were evaluated before (W0) and after 8 weeks (W8) with a significance level of 0.05.

RESULTS

The groups were homogeneous regarding age (51±6 vs 52±6 years, p=0.509) and vitamin D levels (22.8±4.9 vs 21.7±4.5ng/ml, p=0.590). At W8, the VD group had significantly higher levels of vitamin D (22.5 vs 35.6ng/ml, p<0.001). Only the VD group showed a significant reduction in systolic blood pressure (SBP; 123±15 vs 119±14mmHg, p=0.019) and alkaline phosphatase (213±55 vs 202±55mg/dl, p=0.012). The CO group showed an increase in augmentation pressure (AP: 9 vs 12 mmHg, p=0.028) and augmentation index (AIx: 26 vs 35%, p=0.020), which was not observed in the VD group (AP: 8 vs 8 mmHg, AIx: 26 vs 25%, p>0.05). VD group showed an increase in the parasympathetic nervous system index (PNSi) (-0.64±0.94 vs -0.16±1.10, p=0.028) and the R-R interval (866±138 vs 924±161 ms, p= 0.026).

CONCLUSION

In this sample, eight weeks of daily vitamin D supplementation resulted in an improvement in blood pressure levels and autonomic balance.

The risk of metabolic syndrome is associated with vitamin D and inflammatory status in premenopausal and postmenopausal Algerian women

BACKGROUND

This first cross-sectional study examined whether vitamin D status and proinflammatory cytokines may be associated with metabolic syndrome (MetS) in Algerian women regarding their menopausal status.

METHODS

Fasting plasma glucose (FPG), lipids, insulin, 25(OH)D, PTH, adiponectin, resistin, TNFα, and IL-6 levels were assessed in 277 participants aged 18-74 years. MetS was diagnosed according to NCEP-ATPIII criteria. The association of vitamin D deficiency, IL-6, and TNFα with components of MetS was analyzed by the logistic regression.

RESULTS

Among a cohort of 277 participants, the prevalence of MetS in 115 premenopausal vs. 162 postmenopausal women was 54.02 vs. 68.1%. Cut-offs for vitamin D deficiency were 15.7 vs. 13 ng/mL, 51.07 vs. 41 pg/mL for IL-6 and 8.28 vs. 9.33 pg/mL for TNFα, respectively. 25(OH)D levels were positively correlated with adiponectin levels, while negatively with HOMA-IR in postmenopausal-MS + women. Adjustment for age and BMI reveals a significant association between vitamin deficiency and high FPG (OR: 2.92 vs. 2.90), TG (OR:2.79 vs. 3.51), BP (OR:2.20 vs. 1.92), and low HDL-c (OR:2.26 vs. 3.42), respectively. A significant association was also detected in postmenopausal women between IL-6 and high FPG (OR5.11, p = 0.03), BP (OR:3.13, p = 0.04), and low HDL-c (OR5.01, p = 0.02), while TNFα was associated with high BP in postmenopausal women (OR: 3.70, p = 0.01), and inversely with TG in premenopausal women (OR: 0.16, p = 0.04).

CONCLUSION

This study highlighted that severe vitamin D deficiency increases MetS score and was closely associated with four components of MetS, more potently in postmenopausal women, probably related with estrogens. Abdominal obesity, as influential component of MetS, may be involved in enhancing vitamin D deficiency, and dysregulating some metabolic hormones such as adiponectin, resistin and insulin, that contributes in onset an inflammatory state, through the increase in IL-6 and TNFα levels. These findings need to be improved by expanding investigation to a large cohort of participants.

The association between circulating 25-hydroxyvitamin D and pancreatic cancer: a systematic review and meta-analysis of observational studies

PURPOSE

The relationship between circulating 25-hydroxyvitamin D [25(OH)D] and pancreatic cancer has been well studied but remains unclear. The purpose of this study was to elucidate the association between circulating 25(OH)D and pancreatic cancer by using a meta-analytic approach.

METHODS

PubMed, Embase, and Wed of Science databases were searched through October 15, 2022. A random or fixed-effects model was used to estimate the pooled odds ratio (OR), risk ratio (RR), hazard ratio (HR) and their 95% confidence intervals (CIs).

RESULTS

A total of 16 studies including 529,917 participants met the inclusion criteria, of which 10 reported incidence and 6 reported mortality. For the highest versus lowest categories of circulating 25(OH)D, the pooled OR of pancreatic cancer incidence in case-control studies was 0.98 (95% CI 0.69-1.27), and the pooled HRs of pancreatic cancer mortality in cohort and case-control studies were 0.64 (95% CI 0.45-0.82) and 0.78 (95% CI 0.62-0.95), respectively. The leave-one-out sensitivity analyses found no outliers and Galbraith plots indicated no substantial heterogeneity.

CONCLUSION

Evidence from this meta-analysis suggested that high circulating 25(OH)D levels may be associated with decreased mortality but not incidence of pancreatic cancer. Our findings may provide some clues for the treatment of pancreatic cancer and remind us to be cautious about widespread vitamin D supplementation for the prevention of pancreatic cancer.

Vitamin D and cardiovascular diseases: A narrative review

Cardiovascular diseases (CVD) and vitamin D deficiency are becoming highly prevalent among general populations. Despite plausible biological mechanisms for the role of vitamin D in cardio-protection, a cause-and-effect relationship has not yet been established. The interest in vitamin D as a potential therapeutic target to attenuate cardiovascular risk has been raised. The question about the benefit of vitamin D supplementation for cardiovascular outcomes cannot be answered certainly for the moment. The association between hypovitaminosis D and CVD has been proven by some studies while other studies deny any such link. The present narrative review gives a comprehensive overview of studies on the potential impact of hypovitaminosis D on CVD. The potential role of vitamin D supplementation in the management of CVD is also evaluated. Particular emphasis is paid to those studies that achieve a high level of scientific evidence.

Inferring Causal Relationships Between Metabolites and Polycystic Ovary Syndrome Using Summary Statistics from Genome‑Wide Association Studies

Polycystic ovary syndrome (PCOS) is a disorder characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovarian morphology. Previous studies have suggested that metabolites may play a pivotal mediating role in the progression of phenotypic variations. Although several metabolites had been identified as potential markers for PCOS, the relationship between blood metabolites and PCOS was not comprehensively explored. Previously, Pickrell et al. designed a robust approach to infer evidence of a causal relationship between different phenotypes using independently putative causal SNPs. Our previous paper extended this approach to make it more suitable for cases where only a few independently putative causal SNPs were identified to be significantly associated with the phenotypes (i.e., metabolites). When the most significant SNPs in each independent locus (the independent lead SNPs) with p-values of < 1 × 10-5 were used, 3 metabolites (2-tetradecenoyl carnitine, threitol, 1-docosahexaenoylglycerophosphocholine) causally influencing PCOS and 2 metabolites (asparagine and phenyllactate) influenced by PCOS were identified, (relative likelihood r < 0.01). Under a less stringent threshold of r < 0.05, 7 metabolites (trans-4-hydroxyproline, glutaroyl carnitine, stachydrine, undecanoate, 7-Hoca, N-acetylalanine and 2-hydroxyisobutyrate) were identified. Taken together, this study can provide novel insights into the pathophysiological mechanisms underlying PCOS; whether these metabolites can serve as biomarkers to predict PCOS in clinical practice warrants further investigations.

Machine learning-based prediction of vitamin D deficiency: NHANES 2001-2018

Background

Vitamin D deficiency is strongly associated with the development of several diseases. In the current context of a global pandemic of vitamin D deficiency, it is critical to identify people at high risk of vitamin D deficiency. There are no prediction tools for predicting the risk of vitamin D deficiency in the general community population, and this study aims to use machine learning to predict the risk of vitamin D deficiency using data that can be obtained through simple interviews in the community.

Methods

The National Health and Nutrition Examination Survey 2001-2018 dataset is used for the analysis which is randomly divided into training and validation sets in the ratio of 70:30. GBM, LR, NNet, RF, SVM, XGBoost methods are used to construct the models and their performance is evaluated. The best performed model was interpreted using the SHAP value and further development of the online web calculator.

Results

There were 62,919 participants enrolled in the study, and all participants included in the study were 2 years old and above, of which 20,204 (32.1%) participants had vitamin D deficiency. The models constructed by each method were evaluated using AUC as the primary evaluation statistic and ACC, PPV, NPV, SEN, SPE, F1 score, MCC, Kappa, and Brier score as secondary evaluation statistics. Finally, the XGBoost-based model has the best and near-perfect performance. The summary plot of SHAP values shows that the top three important features for this model are race, age, and BMI. An online web calculator based on this model can easily and quickly predict the risk of vitamin D deficiency.

Conclusion

In this study, the XGBoost-based prediction tool performs flawlessly and is highly accurate in predicting the risk of vitamin D deficiency in community populations.

The causal relationship between 25-hydroxyvitamin D and serum lipids levels: A bidirectional two-sample mendelian randomization study

Serum vitamin D levels were linked to lipid metabolism in observational studies, but the exact mechanism was unclear. Several studies have attempted to decipher the relationship between 25(OH)D and lipid levels. Conventional observational studies are vulnerable to confounding. Mendelian randomization (MR) analysis can better control for confounding factors and reverse causality, allowing for the inference of causal association. We, therefore, sought to use MR to investigate the possible causal relationship between 25(OH)D and blood lipid levels (HDL cholesterol, LDL cholesterol, triglycerides, and total cholesterol). A bidirectional two-sample Mendelian randomization (MR) was performed on data primarily from European ancestors. In addition, the potential causal effect of lipids on 25(OH)D was assessed by regressor-based multivariate magnetic resonance (MVMR). The single-nucleotide polymorphisms (SNPs) related to 25(OH)D were selected from a large-scale genome-wide association study (GWAS) database named IEU GWAS, and the SNPs associated with the four blood lipids were chosen from UK Biobank (UKB) lipid GWAS. When blood lipids were the outcome, the results of bidirectional two-sample MR demonstrated that 25(OH)D exhibited a negative causal association with TG, TC, and LDL-C: β = - 0.23, 95% CI = -0.28 to -0.19, P<0.001; β = - 0.16, 95% CI: - 0.30 to-0.03, P < 0.05; β = - 0.11, 95% CI: - 0.23 to 0, P < 0.05. There was no causal relationship between 25(OH)D and HDL-C (β = 0.05, 95% CI: - 0.11 to 0.20, P = 0.56). When setting blood lipids as exposure, TG and 25(OH)D, β = -0.13, 95% CI: - 0.15 to -0.10, P < 0.05; TC and 25(OH)D, β = -0.11, 95% CI: - 0.15 to -0.07, P < 0.05; HDL-C and 25(OH)D, β = 0.02, 95% CI: 0 to 0.03, P = 0.07; LDL-C and 25(OH)D, β = -0.08, 95% CI: - 0.11 to -0.05, P < 0.05). Our MVMR study also showed a significant relationship between genetically determined lipid traits and 25(OH)D levels (TG and 25(OH)D, P < 0.05; TC and 25(OH)D, P < 0.05). In all MR analyses, there was no horizontal pleiotropy (all P > 0.05), or statistical heterogeneity. The "Leave-one-out" sensitivity analysis confirmed the stability of our results. MR Studies have shown a bidirectional causal relationship between genetically-determined 25(OH)D levels and serum TG and TC levels. The findings have potential implications for etiological understanding and disease prevention.

Vitamin D and cancer

The role of vitamin D in the prevention of chronic diseases including cancer, has received a great deal of attention during the past few decades. The term "Cancer" represents multiple disease states with varying biological complexities. The strongest link between vitamin D and cancer is provided by ecological and studies like observational, in preclinical models. It is apparent that vitamin D exerts diverse biological responses in a tissue specific manner. Moreover, several human factors could affect bioactivity of vitamin D. The mechanism(s) underlying vitamin D initiated anti-carcinogenic effects are diverse and includes changes at the muti-system levels. The oncogenic environment could easily corrupt the traditional role of vitamin D or could ensure resistance to vitamin D mediated responses. Several researchers have identified gaps in our knowledge pertaining to the role of vitamin D in cancer. Further areas are identified to solidify the role of vitamin D in cancer control strategies.

Vitamin D, Cognition, and Alzheimer's Disease: Observational and Two-Sample Mendelian Randomization Studies

Background

Observational studies have found that vitamin D supplementation is associated with improved cognition. Further, recent Mendelian randomization (MR) studies have shown that higher vitamin D levels, 25(OH)D, may protect against Alzheimer's disease. Thus, it is possible that 25(OH)D may protect against Alzheimer's disease by improving cognition.

Objective

We assessed this hypothesis, by examining the relationship between 25(OH)D levels and seven cognitive measurements.

Methods

To mitigate bias from confounding, we performed two-sample MR analyses. We used instruments from three publications: Manousaki et al. (2020), Sutherland et al. (2022), and the Emerging Risk Factors Collaboration/EPIC-CVD/Vitamin D Studies Collaboration (2021).

Results

Our observational studies suggested a protective association between 25(OH)D levels and cognitive measures. An increase in the natural log of 25(OH)D by 1 SD was associated with a higher PACC score (BetaPACC score = 0.06, 95% CI = (0.04-0.08); p = 1.8×10-10). However, in the MR analyses, the estimated effect of 25(OH)D on cognitive measures was null. Specifically, per 1 SD increase in genetically estimated natural log of 25(OH)D, the PACC scores remained unchanged in the overall population, (BetaPACC score = -0.01, 95% CI (-0.06 to 0.03); p = 0.53), and amongst individuals aged over 60 (BetaPACC score = 0.03, 95% CI (-0.028 to 0.08); p = 0.35).

Conclusions

In conclusion, our MR study found no clear evidence to support a protective role of increased 25(OH)D concentrations on cognitive performance in European ancestry individuals. However, our study cannot entirely dismiss the potential beneficial effect on PACC for individuals over the age of 60.

Poor vitamin D status was associated with increased appendicular fat deposition in US Adults: Data from 2011-2018 National Health and Nutrition Examination Survey

The aim of the study was to explore the relationship between serum 25-hydroxyvitamin D [25(OH)D] concentrations and regional body fat deposition in 2011-2018 National Health and Nutrition Examination Survey participants aged 18 to 59 years. We hypothesized that serum 25(OH)D concentrations were negatively associated with total, appendicular, and truncal fat deposition. Serum 25(OH)D concentration was categorized into sufficient (≥75.0 nM), insufficient (50.0-74.9 nM), and deficient (<50.0 nM) groups. Fat mass (FM) was measured by dual-energy X-ray absorptiometry, and FM index (FMI) was calculated by dividing FM (kg) with height2 (m2). Multivariant linear regression and Granger causal analysis were performed to assess the causal relationship between vitamin D status and regional FMIs. Overall serum 25(OH)D concentrations were negatively associated with total (β = -0.029, standard error [SE] = 0.002), trunk (β = -0.015, SE = 0.001), arms (β = -0.004, SE = 3.09 × 10-4), and legs (β = -0.010, SE = 0.001) FMIs in all participants (P < .001, respectively); however, after stratified by vitamin D status and BMI, the negative associations were only observed in individuals with vitamin D deficiency and obesity. The causal analysis indicated that serum 25(OH)D concentrations may causally reduce the arms (F = 4.917, probability [P] = 0.007), legs (F = 5.783, P = 0.003), and total (F = 3.202, P = 0.041) FMIs except for trunk FMI but not vice versa. In conclusion, poor vitamin D status was associated with increased total and appendicular body fat deposition in US adults, particularly in participants with obesity.

From the Sun to the Cell: Examining Obesity through the Lens of Vitamin D and Inflammation

Obesity affects more than one billion people worldwide and often leads to cardiometabolic chronic comorbidities. It induces senescence-related alterations in adipose tissue, and senescence is closely linked to obesity. Fully elucidating the pathways through which vitamin D exerts anti-inflammatory effects may improve our understanding of local adipose tissue inflammation and the pathogenesis of metabolic disorders. In this narrative review, we compiled and analyzed the literature from diverse academic sources, focusing on recent developments to provide a comprehensive overview of the effect of vitamin D on inflammation associated with obesity and senescence. The article reveals that the activation of the NF-κB (nuclear factor kappa B subunit 1) and NLRP3 inflammasome (nucleotide-binding domain, leucine-rich-containing, pyrin domain-containing-3) pathways through the toll-like receptors, which increases oxidative stress and cytokine release, is a common mechanism underlying inflammation associated with obesity and senescence, and it discusses the potential beneficial effect of vitamin D in alleviating the development of subclinical inflammation. Investigating the main target cells and pathways of vitamin D action in adipose tissue could help uncover complex mechanisms of obesity and cellular senescence. This review summarizes significant findings related to opportunities for improving metabolic health.

Association between the serum vitamin D level and prevalence of obesity/abdominal obesity in women with infertility: a cross-sectional study of the National Health and Nutrition Examination Survey data

AIMS

To explore the relationship between vitamin D and obesity and abdominal obesity in women with infertility.

MATERIAL AND METHODS

We screened the data from National Health and Nutrition Examination Survey (NHANES) 2013-2016. A total of 201 infertile women between the ages of 20 and 40 years were included in our study. To estimate the independent association of vitamin D with obesity and abdominal obesity, we used weighted multivariate logistic regression models and cubic spline analyses.

RESULTS

Among infertile women in the NHANES 2013-2016 database, serum vitamin D levels were significantly and negatively associated with body mass index (ß= -0.96, 95% CI: -1.40, -0.51, p < 0.001)and waist circumference (ß= -0.40, 95% CI: -0.59, -0.22, p < 0.001), respectively. After multivariable adjustment, lower vitamin D levels were found to be associated with a higher prevalence of obesity (OR: 8.290, 95% CI: 2.451-28.039, p for trend = 0.001) and abdominal obesity (OR: 4.820, 95%CI: 1.351-17.194, p for trend =0.037). Spline regression showed linearity of the associations between vitamin D and obesity/abdominal obesity (p for nonlinearity > 0.05).

CONCLUSION

Our findings suggested that a decreased vitamin D might correspond to a higher prevalence of obesity in infertile women, which reminded us to pay more attention to the supplement of vitamin D in obese infertile women.

Longitudinal study of vitamin D status among Thai individuals in a sun-abundant country

Background

Vitamin D deficiency is a major public health problem worldwide, even in countries with abundant sunshine. Understanding the risk factors for vitamin D deficiency is important to inform public health recommendations. We conducted a longitudinal analysis of vitamin D status in Thai individuals to assess changes in vitamin D status over time and identify potential determinants.

Study design

This study is a long term prospective cohort study.

Methods

Of the 1239 participants who were employees of the Electricity Generating Authority of Thailand, serum 25-hydroxyvitamin D (25(OH)D) levels were measured by liquid chromatography/tandem mass spectrometry from samples collected in 2009 and 2019.

Results

There was a significant 14.8% increase in serum total 25(OH)D (P < 0.001) from 2009 to 2019, which resulted from significant increases in both 25(OH)D3 and 25(OH)D2. The epimeric form of 25(OH)D2 also increased significantly, while there was no increase in the epimeric form of 25(OH)D3. A univariate analysis showed significant associations between increased total 25(OH)D and increasing age, male sex, and lower body mass index. After controlling for baseline vitamin D status, multivariate regression analyses found that the direction of association and significance from univariate analyses persisted for total 25(OH)D and 25(OH)D3. However, a univariate association found between female sex and an increase in 25(OH)D2 was not significant in multivariate regression analysis.

Conclusions

A long-term trend of improved vitamin D status was found among Thai adult individuals over a 10-year period; however, improvements were less noticeable in women.