Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline

Vitamin D: What role in obesity-related cancer?

Obesity is an important risk factor for incidence and death for many types of cancer. Vitamin D reduces risk of incidence and death for many types of cancer. This review outlines the mechanisms by which obesity increases risk of cancer, how vitamin D reduces risk of cancer, and the extent to which vitamin D counters the effects of obesity in cancer. Vitamin D is a partial ally against some of obesity's pro-carcinogenic effects, notably by reducing inflammation and regulating sex hormone receptors, leptin resistance, cellular energy metabolism, the microbiome, and hypoxia. However, it can act stronger in against the renin-angiotensin system, insulin resistance, and oxidative stress in cancer. Additionally, excess fat tissue sequesters vitamin D and, along with its dilution in increased body volume, further reduces its bioavailability and serum concentration, limiting its protective effects against cancer. In conclusion, while vitamin D cannot reverse obesity, it plays a significant role in mitigating its pro-carcinogenic effects by targeting several mechanisms.

Vitamin D deficiency and its potential associations on the health status of older patients with chronic obstructive pulmonary disease in rural Crete, Greece: A cross-sectional study

BACKGROUND & AIMS

While low vitamin D levels are common in Chronic Obstructive Pulmonary Disease (COPD) and have been associated with various adverse COPD-related outcomes, data on vitamin D status in rural COPD cohorts is limited. Therefore, the present study aimed to assess the prevalence of Vitamin D deficiency among patients with COPD living in rural areas and explore its potential association on the overall health status.

METHODS

This cross-sectional study included 138 participants >40 years with COPD from the prospective "COlaborative care vs usual CARE in primary care patients with COPD" (COCARE) study. Sociodemographic characteristics, medical history, patient's health-related quality of life (HRQoL) with the COPD Assessment Test (CAT), fatigue with the Fatigue Severity Scale (FSS), phycological parameters with Patient Health Questionnaire-9 (PHQ-9) and General Anxiety Disorder-7 (GAD-7), sleep disorders with the COPD and Asthma Sleep Impact Scale (CASIS), Athens Insomnia Scale (AIS) and the Epworth Sleepiness Scale (ESS) were collected. Vitamin D deficiency was defined as levels of 25-hydroxy (OH)-Vitamin D below 20 ng/mL. Multiple logistic regression analysis was conducted to test for associations of Vitamin D deficiency with CAT, FSS, PHQ-9, GAD-7, CASIS, AIS, and ESS, adjusting for age, gender, smoking status, comorbidities, and seasonality.

RESULTS

Most of the participants were male (70 %) with a mean age of 68 ± 9 years and a mean Body Mass Index (BMI) of 30 ± 6 kg/m2. Moreover, 33 % of the participants had Vitamin D deficiency. Vitamin D deficiency increased the odds for worse HRQoL (CAT≥10 OR: 2.3, CI: 0.9-6.4, p = 0.008), greater fatigue severity (FSS, OR: 1.2, CI: 0.4-3.1, p = 0.756), more depressive (PHQ-9≥5, OR: 2.9, CI: 1.1-7.4, p = 0.024), anxiety (GAD-7, OR: 0.8, CI: 0.3-2.1, p = 0.592) and insomnia symptoms (AIS score OR: 1.1, CI: 0.7-5, p = 0.29), excessive daytime sleepiness (ESS, OR: 1.1, CI: 0.7-5, p = 0.29), and lower sleep quality (CASIS OR: 2.5, CI: 0.9-6.5, p = 0.006).

CONCLUSION

In conclusion, our findings indicate that Vitamin D deficiency is positively associated with numerous negative health outcomes of patients with COPD, including worse HRQoL, fatigue, depression, anxiety and sleep disorders. However, further research is needed to determine the role of Vitamin D in the health status of these patients.

Synergistic impact of 25-hydroxyvitamin D and physical activity on incident depression: Evidence from a prospective cohort and genome-wide data

BACKGROUND

The relationship between 25-hydroxyvitamin D [25(OH)D] levels, physical activity (PA), and depression risk remains underexplored. This study examines how combinations of 25(OH)D and PA influence depression.

METHODS

We conducted a longitudinal analysis using data from the English Longitudinal Study of Ageing, including cognitively healthy adults aged 50 years and older at baseline. Baseline measurements of PA and 25(OH)D were taken, with depression as the primary outcome. Multivariate Cox proportional hazards models were used, with and without interaction terms. Furthermore, two-sample Mendelian randomization (MR) analyses were performed.

RESULTS

A total of 4146 participants (mean age: 66.0 years; 52.1 % female) were followed for eight years. Multivariate-adjusted hazard ratios (HRs) for depression were 0.71 (95 % CI: 0.61-0.83) for those with high 25(OH)D and PA (P = 0.005), 0.79 (95 % CI: 0.63-0.99) for those younger than 65 (P = 0.042), and 0.65 (95 % CI: 0.53-0.80) for those 65 and older (P = 0.041). A significant interaction between low 25(OH)D and PA was found in the younger group (HR: 1.43, 95 % CI: 1.03-1.99, P = 0.034). High 25(OH)D and PA independently reduced depression risk by 7.2 % and 7.7 %, respectively, with a 23.1 % reduction when combined. Mendelian randomization confirmed these findings.

CONCLUSIONS

High 25(OH)D levels are linked to lower depression risk. The combination of high 25(OH)D and PA provides synergistic protection, particularly in older adults, emphasizing the need for vitamin D supplementation and PA in depression prevention.

Hypoparathyroidism: diagnosis, management and emerging therapies

Hypoparathyroidism is characterized by inadequate parathyroid hormone (PTH) secretion or action and results in hypocalcaemia, and can lead to hyperphosphataemia and hypercalciuria. Most cases of hypoparathyroidism occur as a complication of surgery, with the remainder due to causes including autoimmune disease, genetic causes, infiltrative diseases, mineral deposition or due to abnormalities in serum levels of magnesium. Hypoparathyroidism can cause multisystem disease, with long-term complications resulting from ectopic calcification as well as renal complications with nephrocalcinosis, nephrolithiasis and renal impairment in addition to respiratory, cardiac or neurological manifestations. Conventional therapy consists of oral calcium salts and active vitamin D but it has limitations, including fluctuations in serum levels of calcium and a high pill burden, and can increase the risk of long-term complications. By contrast, PTH replacement therapy can effectively achieve normal serum levels of calcium, and lower serum levels of phosphate. The long-acting PTH analogue, palopegteriparatide, has been shown to normalize urine levels of calcium. In addition, PTH replacement therapy reduces the pill burden. Palopegteriparatide is also associated with improved quality of life in comparison to conventional therapy. This Review summarizes current recommendations regarding the pathophysiology, evaluation and management of hypoparathyroidism and also references the 2022 international hypoparathyroidism guidelines. Palopegteriparatide has now been approved as PTH replacement therapy for hypoparathyroidism. Emerging therapies will also be presented in this Review.

Vitamin D deficiency in relation to different phenotypes of prediabetes: a population-based study

PURPOSE

Vitamin D deficiency is implicated in the development of prediabetes. However, it is unclear whether vitamin D deficiency showed any relationship with different phenotypes of prediabetes. This study was designed to address this issue.

METHODS

We included participants from the National Health and Nutrition Examination Survey 2011-2016. Prediabetes is classified into the following phenotypes: an isolated defect (that is, impaired fasting glucose [IFG], impaired glucose tolerance [IGT], or impaired hemoglobin A1c[IA1c]), two defects (that is, IFG+IGT, IFG+IA1c, or IGT+IA1c), or three defects (that is, IFG+IGT+IA1c). Multivariate logistic regression analysis was used to obtain the odds ratio (OR) and 95% confidence intervals (CIs).

RESULTS

A total of 4126 participants (2332 with prediabetes and 1794 with normal glycemia) were included in this study. Multivariate logistic regression analysis showed that prediabetes was associated with an increased odds of vitamin D deficiency than normal glycemia (OR 1.216, 95% CI 1.023-1.444). Further analysis showed that prediabetes phenotypes of IGT+IFG (OR 1.549, 95% CI 1.050-2.283) and IFG+IGT + IA1c (OR 1.507, 95% CI 1.062-2.138) had an increased odds of vitamin D deficiency. The odds of vitamin D deficiency was higher in individuals with glucose-defined prediabetes, but not in those with HbA1c-defined prediabetes when compared with individuals with normal glycemia.

CONCLUSION

Prediabetes was associated with an increased odds of vitamin D deficiency, and glucose-defined prediabetes might be a better predictor of vitamin D deficiency.

Vitamin D status, vitamin D receptor polymorphisms, and risk of cardiometabolic multimorbidity

BACKGROUND

The prevalence of cardiometabolic multimorbidity (CMM) has increased substantially in recent years. Previous studies have established the associations between vitamin D, vitamin D receptor (VDR) polymorphisms, and the risk of individual cardiometabolic disease (CMD). However, the role of these factors in the progression of CMD to CMM or mortality remains unclear. This study aimed to investigate the associations between vitamin D, VDR polymorphisms, and the dynamic progression of CMM, as well as to explore the potential modification effect of VDR polymorphisms.

METHODS

Data for this cohort study were extracted from the UK Biobank. CMM was defined as the coexistence of at least two CMDs, including type 2 diabetes (T2D), coronary heart disease (CHD), and stroke. A multi-state model was used to analyze associations between serum 25(OH)D, VDR polymorphisms and the dynamic progression of CMM.

RESULTS

The sample included 396,192 participants. Over a median follow-up of 13.8 years, 55,772 individuals experienced at least one CMD and 28,624 died. Compared to participants with 25(OH)D < 25 nmol/L, those with 25(OH)D ≥ 75 nmol/L had HRs of 0.70 (95% CI, 0.67, 0.72) for baseline to first CMD (FCMD), 0.74 (95% CI, 0.67, 0.82) for FCMD to CMM, 0.66 (95% CI, 0.62, 0.70) for baseline to death, 0.84 (95% CI, 0.77, 0.92) for FCMD to death, and 0.85 (95% CI, 0.70, 1.03) for CMM to death. L-shaped relationships of these associations were noted, with a threshold around 45 nmol/L. The rs1544410 (BsmI) T alleles may have a detrimental effect, while the rs11568820 (Cdx2) T alleles may exert a protective effect in the early stages of CMM progression. Additionally, VDR polymorphisms significantly modified the association between serum 25(OH)D and certain stages of CMM progression.

CONCLUSIONS

Maintaining adequate vitamin D levels, as a readily implementable intervention strategy, not only reduces the risk of initial CMD but also delays the progression to CMM or death. Risk stratification based on VDR polymorphisms provides further insights for developing personalized prevention strategies.

(-)-Epigallocatechin-3-gallate and chlorogenic acid in combination with vitamin D as a therapeutic approach for letrozole-induced polycystic ovary syndrome (PCOS) rats: Biochemical and hormonal modulation

Treatment with phytochemicals have shown promising results in managing various diseases including Polycystic ovary syndrome (PCOS) which is an endocrine gynecological disorder affecting reproductive aged women. This study has demonstrated that Epigallocatechin-3-gallate (EGCG) and chlorogenic acid (CGA) in combination with vitamin D can significantly reduce PCOS like characteristics including ovarian cysts, hyperandrogenism, fasting blood glucose level, insulin resistance, hyperlipidaemia, ROS formation, oxidative stress, DNA damage, and ovarian histomorphology in letrozole induced PCOS rats. PCOS was induced in female Wistar rats by giving 1 mg/kg/day letrozole for 21 days through oral gavage. EGCG (100 mg/kg/day) and CGA (120 mg/kg/day) in combination with vitamin D (25 mcg/kg/day) was given orally for 15 days, from day 21-35. Metformin treatment was used as a positive control. Histological, microscopic analysis, and chemiluminescent immunoassays were performed to evaluate decrement in PCOS like symptoms. Nitric oxide (RNS) production, antioxidant status, and the generation of reactive oxygen species (ROS) were also assessed. Ovary homogenates and plasma samples of rats were also examined for markers of protein, lipid, and DNA oxidation. Activities of enzymatic antioxidants (superoxide dismutase, catalase, glutathione reductase, Paraoxonase-1 status) were also evaluated. EGCG + vitamin D and CGA + vitamin D has been found to restore hormonal balance by modulating steroidogenic enzymes, they also improved antioxidant enzyme activity including SOD, catalase, glutathione reductase, PON-1 arylesterase, PON-1 CMPAase, etc. Similarly, EGCG + vitamin D and CGA + vitamin D treatment have shown efficacy in normalizing the estrus cycle, reducing ovarian cysts, and improving ovarian histomorphology. They also assisted in alleviating triglycerides and cholesterol levels and maintained liver function enzymes level. However, EGCG + vitamin D proves to have better therapeutic potential modulates glucose metabolic pathways, by reducing blood glucose levels, advanced glycation end product formation, decreasing ROS generation and oxidative stress; consequently, lowers hyperandrogenism and insulin resistance. Overall, EGCG + vitamin D treatment offers a comprehensive approach in managing PCOS by targeting multiple pathways associated with this disorder, making it a potential alternative to conventional therapies.

Nonlinear associations of serum vitamin D levels with advanced liver disease and mortality: a US Cohort Study

Background

Vitamin D deficiency is prevalent and linked to chronic diseases; its association with advanced liver disease progression requires clarification.

Objectives

To investigate the association between vitamin D levels and risks of liver cirrhosis, hepatocellular carcinoma (HCC), and mortality, and assess risk changes after achieving sufficiency post-supplementation.

Design

This was a retrospective cohort study.

Methods

Utilized TriNetX US data (3,905,594 patients, 2000-2024). Adults with vitamin D deficiency (20.00-30.00 ng/mL) were compared with those with sufficient levels (30.01-80.00 ng/mL). Follow-up was initiated from the first vitamin D test or start of supplementation to minimize immortal time bias. Propensity score matching (1:1) balanced >20 baseline confounders.

Results

After matching, 1,204,760 patients with vitamin D deficiency and 1,204,760 with sufficient vitamin D levels were included. Vitamin D deficiency was associated with an increased risk of liver cirrhosis (hazard ratio (HR), 1.30; 95% confidence interval (CI), 1.25-1.36), HCC (HR, 1.22; 95% CI, 1.08-1.37), and all-cause mortality (HR, 1.14; 95% CI, 1.13-1.16). Achieving sufficient vitamin D levels reduced the risk of all-cause mortality (HR, 0.93; 95% CI, 0.88-0.99) and aligned HCC outcomes (HR, 1.16; 95% CI, 0.68-2.00). However, it did not significantly reduce the risk of liver cirrhosis (HR, 2.05; 95% CI, 1.69-2.50). Dose-response analysis showed a U-shaped relationship for liver cirrhosis and HCC, with the lowest risks at 40-60 ng/mL.

Conclusion

Serum vitamin D levels showed a nonlinear association with liver cirrhosis and HCC risk; deficiency independently increased the risks for cirrhosis, HCC, and mortality. Supplementation achieving sufficiency reduced mortality and normalized HCC risk but not cirrhosis risk, potentially reflecting limitations in reversing established disease. The lowest liver disease risk was associated with vitamin D levels of 40-60 ng/mL in this cohort, although causality and the clinical benefit of targeting this specific range require confirmation.

Effect of vitamin D supplementation on glycemic control in children and adolescents with type 1 diabetes mellitus: Data from a controlled clinical trial

AIM

To evaluate the effect of vitamin D supplementation on vitamin D deficiency (VDD) and glycemic control in children and adolescents with type 1 diabetes mellitus (T1DM).

METHODS

This controlled clinical trial involved children and adolescents with T1DM for at least one year. Participants with VDD (25(OH)D < 30 ng/mL) were allocated to the intervention group and oral supplementation with cholecalciferol was prescribed at a dose of 2000 IU/day for 12 weeks. Sociodemographic, clinical, laboratory, lifestyle,anthropometric data and the Fok-I polymorphism (rs2228570) vitamin D receptor were collected. The effect of the intervention was assessed using Glass's Delta.

RESULTS

Of the 133 participants, 77.4 % were assigned to the intervention group (n = 103). Serum 25(OH)D concentration increased from 19.2 ± 6.2 to 30.9 ± 10.1 ng/mL (Glass's Delta = 1.2; CI 0.8/-1.4).A minimal effect was showed on glycemic control (Glass's Delta = 0.1; CI -0.2/0.4). A higher dose of insulin (β = -4.6; CI -8.1/-1.1; p = 0.010) and a high BMI (β = -0.3; CI - 0.6/-0.01; p = 0.059) were associated with lower serum 25(OH)D concentration, and sedentary (β = 0.20; CI - 0.1/0.7; p = 0.004) associated with higher HbA1C after 12 weeks of supplementation.

CONCLUSION

Oral cholecalciferol supplementation was effective in correcting VDD. This study identified the minimal effect of this intervention on glycemic control.

Association of calcium supplement with risk of incident arrhythmia

BACKGROUND AND AIMS

Calcium plays a crucial role in cardiac electrophysiology, but the association between calcium supplement and the risk of incident arrhythmia remains unclear.

OBJECTIVE

To investigate the relationship between habitual calcium supplement and incident risk of cardiac arrhythmia.

METHODS

We conducted a prospective study of 480,972 participants from the UK Biobank. Habitual calcium supplement was treated as the main exposure. The primary outcome was the incidence of arrhythmias, including atrial fibrillation/flutter (AF/AFL), ventricular arrhythmia (VA), and bradyarrhythmia. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After a median follow-up of 11.69 years, 46,609 incident arrhythmia cases were documented, including 36,406 AF/AFL, 5,370 VA, and 14,226 bradyarrhythmia. After multivariable adjustment, calcium supplement was associated with an increased risk of total arrhythmias (HR 1.11, 95% CI 1.05-1.19), AF/AFL (HR 1.20, 95% CI 1.12-1.28), VA (HR 1.14, 95% CI 1.07-1.21), and bradyarrhythmia (HR 1.18, 95% CI 1.11-1.26). Significant interactions were observed between calcium supplement and estimated glomerular filtration rate, diabetes, cardiovascular disease, and polygenic risk score for AF (all p for interaction < 0.05).

CONCLUSIONS

Calcium supplement was associated with an increased risk of incident arrhythmia. Careful evaluation of the potential arrhythmic risk is warranted when considering calcium supplement in individuals with clinical indications.

Effect of Vitamin D Deficiency on Development of Slipped Capital Femoral Epiphysis

OBJECTIVE

Slipped capital femoral epiphysis (SCFE) is one of the most common hip disorders in adolescents, often linked to obesity. However, other factors, such as vitamin D deficiency, may also contribute to SCFE development. This study investigates the impact of vitamin D deficiency on SCFE development in a large cohort.

METHODS

We utilized the TriNetX national database to query pediatric patients with documented calcidiol levels. Patients with a recorded visit below the age of 9 and subsequent documented calcidiol levels were followed until SCFE occurrence or age 18. Patients were categorized into vitamin D adequate (≥ 30 ng/mL) and deficient (< 30 ng/mL) groups. Propensity score matching was performed using a multivariable logistic regression model to adjust for baseline characteristics, including age, sex, race, and body mass index percentile. Significance testing was conducted using the Fisher exact test and χ 2 tests to compare SCFE risk between the cohorts, with a significance level set at P <0.05.

RESULTS

On preliminary analysis, 98,045 patients met the inclusion criteria. After matching, 34,552 individuals in both vitamin D deficient and adequate groups were included, with an average age of 8.4 years at the time of their first visit and 50% females. SCFE occurred in 136 (0.39%) and 48 (0.14%) patients in the vitamin D deficient and adequate groups, respectively ( P < 0.0001). Vitamin D deficiency significantly increased SCFE risk, with a relative risk of 2.8 (95% CI: 2-3.9; P < 0.0001) and a hazard ratio of 1.6 (95% CI: 1.1-2.2; P < 0.0001).

CONCLUSION

This study, one of the largest to date, establishes a significant association between vitamin D deficiency and SCFE development. After controlling for potential confounding variables, including body mass index, individuals with vitamin D deficiency were ∼2.83 times more likely to develop SCFE. The study findings highlight the need for further research to evaluate whether supplementation could mitigate this risk of developing SCFE.

LEVEL OF EVIDENCE

Level III.

Associations between serum and seminal vitamin D levels and sperm parameters

AIM

To examine the association between serum/seminal plasma vitamin D levels and sperm parameters, the possible effects of serum/seminal vitamin D on sperm motility via seminal intracellular calcium measurement, and the antioxidant effect via malondialdehyde (MDA) measurement.

METHODS

This prospective study was conducted on 87 male patients. Serum vitamin D levels of patients were evaluated and grouped based on their serum vitamin D levels: low (<50 nmol/L), normal (50-75 nmol/L), and high (>75 nmol/L). Sperm characteristics were evaluated. Seminal plasma vitamin D, intracellular calcium, and MDA concentrations were measured using Liquid Chromatography Mass Spectrometry (LC-MS/MS), High-performance liquid chromatography (HPLC), and fluorescence plate reader methods, respectively.

RESULTS

Patients with normal serum vitamin D levels had higher total progressive motile sperm concentrations (14.0 vs. 8.5 vs. 4 million/mL, p = 0.037) and higher normal sperm morphology (6% vs. 4% vs. 3%, p = 0.020) compared to those with low and high levels. No correlations were found between serum vitamin D levels and seminal vitamin D (r = 0.052, p = 0.468), MDA (r = -0.048, p = 0.791), and intracellular calcium levels (r = 0.064, p = 0.929). Seminal intracellular calcium levels were significantly correlated with total (r = 0.241, p = 0.024) and progressive (r = 0.217, p = 0.043) sperm motility.

CONCLUSIONS

There were positive correlations between serum vitamin D levels, total progressive motile sperm concentration, and normal sperm morphology. However, serum vitamin D levels were not correlated with seminal vitamin D levels and showed no correlations with potential mechanisms of action, reflected by intracellular calcium and MDA concentrations. Conversely, intracellular calcium levels were positively correlated with both total and progressive sperm motility, suggesting that intracellular calcium plays an essential role in sperm motility.

Association Between Vitamin D Level and Clinical Outcomes of Assisted Reproductive Treatment: A Systematic Review and Dose-Response Meta-Analysis

The investigation about association between vitamin D level and clinical outcomes of assisted reproductive treatment showed various outcomes. This study aimed to review the correlation between vitamin D and outcomes of assisted reproductive treatment. The search was registered on the PROSPERO database (CRD42023458040). PubMed, Embase, Medline, ClinicalTrials.gov, and Cochrane databases were searched up to July 2023. Twenty-three observational studies were selected for meta-analysis. Comparing groups with deficient and 'insufficient + sufficient' vitamin D level, meta-analysis showed positive correlation between clinical pregnancy rate and vitamin D (OR 0.81, 95%CI: 0.70, 0.95, P = 0.0001). Comparing groups with 'deficient + insufficient' and sufficient vitamin D level, meta-analysis showed positive correlation between vitamin D and clinical pregnancy rate (OR 0.71, 95%CI: 0.55, 0.91, P = 0.006), vitamin D and live birth rate (OR 0.69, 95%CI: 0.54, 0.89, P = 0.003). Subgroup analysis did not show the source of high heterogeneity. No correlation was found in biochemical pregnancy rate, ongoing pregnancy rate, miscarriage rate and implantation rate. In dose-response meta-analysis, a nonlinear association was found between vitamin D levels and outcomes when levels are below approximately 24 ng/L. The study shows that vitamin D level is associated with clinical pregnancy rate and live birth rate. Low vitamin D level does not influence biochemical pregnancy rate, ongoing pregnancy rate, miscarriage rate and implantation rate. Furthermore, 24 ng/L may be a possible threshold of vitamin D concentration in assisted reproduction therapy.

Association between dyslipidemia and vitamin D deficiency: a cross-sectional study in Chinese healthy population

Background

Given the global prevalence of vitamin D deficiency, this study examines the association between serum 25-hydroxyvitamin D (25(OH)D) levels and lipid profiles, including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG).

Methods

In a cross-sectional analysis at the Yuhuan People's Hospital Physical Examination Center, 1535 asymptomatic individuals underwent anthropometric assessment and blood sampling. Serum 25(OH)D levels were quantified by a chemiluminescent immunoassay, while lipid parameters were evaluated by an enzymatic method on a fully automated analyzer.

Results

The mean serum 25(OH)D level of the participants was 49.6 ± 15.3 nmol/L, with 54.7% demonstrating vitamin D deficiency. Female participants had significantly lower mean 25(OH)D levels (46.2 ± 13.7 nmol/L) than males (54.1 ± 16.0 nmol/L, P < 0.001). After adjustment for age and BMI, multivariate ordinal logistic analysis revealed a 1.71-fold higher dyslipidemia-associated risk of vitamin D deficiency in the population (OR=1.71, 95% CI=1.07-2.79), more pronounced in females(OR=2.84, 95% CI=1.17-8.09) compared to males (OR=1.44, 95% CI=0.82-2.58). Notably, vitamin D deficiency was significantly associated with elevated LDL-C levels in females (OR=5.17, 95% CI=1.47-32.96), in contrast to males.

Conclusion

This study highlights a significant association between 25(OH)D deficiency and an increased risk of dyslipidemia, especially in females, highlighting the importance of considering gender-specific risk factors in the management of 25(OH)D deficiency.

Vitamin D supplementation in critically ill patients: a meta-analysis

Background

Vitamin D is commonly used in clinical practice, while its clinical significance in critically ill patients remains controversial. Therefore, we aimed to perform a systemic review and meta-analysis to investigate the effect of vitamin D on this patient population.

Methods

We searched for randomized controlled trials (RCTs) in PubMed, Embase, and the Cochrane Library databases from inception until August 15, 2024. Studies evaluating critically ill adult patients who received vitamin D compared to controls were included. The primary outcome was short-term mortality. We used the Cochrane risk of bias tool and GRADE system to evaluate the study quality and evidence. Secondary outcomes were changes in serum 25-hydroxyvitamin D levels, mechanical ventilation (MV) duration, and length of stay (LOS) in the ICU or hospital. We also conducted meta-regression, subgroup analyses, and trial sequential analysis (TSA) to explore the potential heterogeneity among the included trials.

Results

Nineteen RCTs with 2,754 patients were eligible. Overall, vitamin D significantly increased serum 25-hydroxyvitamin D levels and significantly reduced the short-term mortality (risk ratio [RR] = 0.83; 95%CI, 0.70-0.98; p = 0.03, I 2 = 13%), duration of MV (MD = -2.96 days; 95% CI, -5.39 to -0.52; I 2 = 77%; p = 0.02) and ICU LOS (MD = -2.66 days; 95% CI, -4.04 to -1.29, I 2 = 70%; p = 0.0001) but not hospital LOS (MD = -0.48 days; 95% CI, -2.37 to 1.40; I 2 = 31%; p = 0.61). The meta-regression analysis revealed that the proportion of MV (MV%) accounted for the source of heterogeneity, and the subgroup analyses based on MV% suggested that the MV group was more likely to benefit from vitamin D applications than the partly MV group in all the predefined outcomes (all p values<0.05). TSA for short-term mortality suggested that more data is required to confirm our main conclusion.

Conclusion

Vitamin D supplementation increased serum 25-hydroxyvitamin D levels and significantly benefited critically ill patients, especially those with MV.

Systematic review registration

https://inplasy.com/inplasy-2022-10-0074/, INPLASY2022100074.

Placental and cord serum inflammatory cytokines and children's domain-specific neurodevelopment at 18 months: effect modification by maternal vitamin D status

BACKGROUND

Epidemiological studies that have simultaneously explored the effects of placental and cord blood inflammatory cytokine levels on neurodevelopment in offspring, as well as the role of maternal vitamin D in these associations, are lacking. To investigate the associations of placental and cord blood inflammatory cytokine levels with neurodevelopment in 18-month-old children, and the potential modification effect by maternal vitamin D.

METHODS

Based on the Ma'anshan birth cohort, the current study involved 1241 mother-child pairs. The placental inflammatory cytokine mRNA expression levels, cord serum inflammatory cytokine concentrations, and maternal serum vitamin D concentrations were determined. Children's neurodevelopmental outcomes were defined as the Chinese version of the Ages and Stages Questionnaire (Third Edition) subdomain scores below the established cutoff scores. Generalized linear models were utilized to assess the effects of placental and cord serum inflammatory cytokines on neurodevelopmental outcomes and to examine the modification effects of maternal vitamin D.

RESULTS

After adjusting for confounders, each one-unit increase in placental IL-6 (OR = 1.30, 95% CI: 1.09, 1.55, P-FDR = 0.024), IL-8 (OR = 1.25, 95% CI: 1.05, 1.49, P-FDR = 0.036), and IFN-γ level in the cord serum (OR = 1.74, 95% CI: 1.16, 2.61, P-FDR = 0.042) was associated with an increased risk of fine motor delay. Elevated levels of placental TNF-α (OR = 1.38, 95% CI: 1.12, 1.69, P-FDR = 0.012), IL-6 (OR = 1.29, 95% CI: 1.04, 1.61, P-FDR = 0.042), and IL-8 (OR = 1.31, 95% CI: 1.06, 1.62, P-FDR = 0.036) were associated with an increased risk of personal-social delay. Stratified analyses showed that lower maternal vitamin D levels (< 20 ng/mL) moderated the associations between inflammatory markers and delays in fine motor, gross motor, and personal-social subdomains.

CONCLUSIONS

Elevated levels of specific inflammatory cytokines in the placenta and umbilical cord blood were associated with developmental delays on a parental-reported screening tool. Maternal vitamin D status can modify the adverse effects of the intrauterine pro-inflammatory milieu on the neurodevelopment of children.

Unveiling the Link Between Vitamin D, Hashimoto's Thyroiditis, and Thyroid Functions: A Retrospective Study

BACKGROUND/OBJECTIVES

Hashimoto's thyroiditis (HT) is an autoimmune disease influenced by genetic factors and environmental triggers that affect immune system function. Data suggest that vitamin D may also play a role in the etiopathogenesis of HT.

METHODS

This retrospective study included patients admitted to the Endocrinology and Metabolic Diseases Outpatient Clinic. Data from individuals aged 18 years and older were analyzed, including serum levels of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-TG), and vitamin D. HT was diagnosed based on the presence of anti-TPO and/or anti-TG antibodies, while individuals with negative results for both were classified as non-HT. Thyroid function was categorized as euthyroid if TSH levels were between 0.55 mU/L and 4.78 mU/L and fT4 levels were between 0.89 ng/dL and 1.76 ng/dL; hypothyroid status was defined as TSH > 4.78 mU/L. Vitamin D levels were classified as deficient (<50 nmol/L), insufficient (50-74.9 nmol/L), or sufficient (≥75 nmol/L).

RESULTS

Of the total participants, 25,018 did not have HT, while 27,800 were diagnosed with HT. Vitamin D level was significantly higher in the HT group than the non-HT group (41.43 nmol/L and 39.44 nmol/L, p < 0.001). Vitamin D deficiency was present in 65.5% of the non-HT group and 62.1% of the HT group (p < 0.001). Subgroup analyses based on thyroid function showed that vitamin D levels were highest in the euthyroid HT group and similar in the euthyroid non-HT, hypothyroid non-HT, and hypothyroid HT groups (p < 0.001).

CONCLUSIONS

In conclusion, while vitamin D levels were higher in the HT group compared to the non-HT group, no clinically significant association between vitamin D levels and HT or autoantibody positivity was observed. Vitamin D deficiency was more prevalent in the hypothyroid group compared to the euthyroid group. This study suggests that although vitamin D deficiency may not be directly involved in the pathogenesis of HT, it may still play a role in modulating immune activity or influencing the disease phenotype..

Role of vitamin D in the development and progression of diabetic kidney disease: an overview of meta-analyses

Background

The effectiveness of vitamin D supplementation in the progression of diabetic kidney disease (DKD) remains controversial. Our review tries to provide a comprehensive summary of all the relevant articles in the area to assess the association of vitamin D deficiency with the development of DKD and the effect of vitamin D supplementation on the progression of DKD.

Methods

PubMed, Embase, Scopus, Cochrane Library and Web of Science were accessed from inception till June 2024 to obtain all the relevant meta-analyses assessing the function of vitamin D in the onset and prognosis of DKD. The summary data were extracted by two independent reviewers. A Measurement Tool to Assess Systematic Reviews (AMSTAR) 2 tool was used for the assessment of the methodological quality of the included meta-analyses.

Results

A total of 4579 articles were obtained from 5 databases in the initial search, of which 8 meta-analyses were included for the evidence synthesis. The methodological quality of the retrieved articles ranged from critically low to high. Serum vitamin D levels were significantly correlated with the prevalence of DKD. The review suggested that vitamin D supplementation could help in reducing proteinuria. However, no such changes were observed in other renal function parameters of DKD patients following vitamin D supplementation.

Conclusion

The current evidence indicates that vitamin D supplementation could be beneficial in reducing proteinuria among DKD patients.PROSPERO registration number: CRD42022375194.

25(OH)D3 and F-25(OH)D as indicators of chronic kidney disease progression in patients with rheumatoid arthritis

Vitamin D (VitD) deficiency has been associated with the development of rheumatoid arthritis (RA) and chronic kidney disease (CKD), but its exact role in patients with RA and CKD remains unclear. This cross-sectional study explored the relationship of 25(OH)D2, 25(OH)D3, and Free 25(OH)D [F-25(OH)D] with CKD progression in patients with RA. Patients with RA (n = 1514) were enrolled and divided into the mild, moderate, and severe CKD groups. Total 25(OH)D, 25(OH)D3, and F-25(OH)D in the moderate and severe CKD groups were lower than in the mild CKD group (all P < 0.05), while there were no differences in 25(OH)D2 levels (P = 0.095). As the severity of CKD progressed, total 25(OH)D, 25(OH)D3, and F-25(OH)D decreased (all Padj.<0.05). When progressing from moderate to severe CKD, only 25(OH)D3 decreased significantly (Padj.=0.014). Partial correlation and multiple logistic regression analyses revealed a significant association between 25(OH)D3 and the progression of CKD deterioration, as did F-25(OH)D (all P < 0.05). Further seasonal stratified analysis showed that this correlation existed only in spring, summer, and autumn for 25(OH)D3 and only in spring and summer for F-25(OH)D (P < 0.05). In conclusion, the serum 25(OH)D3 and F-25(OH)D levels may be indicators of CKD progression in patients with RA to plan for timely intervention and management.

Consequences of vitamin D deficiency or overdosage on follicular development and steroidogenesis in Normo and hypo calcemic mouse models

Vitamin D deficiency (VDD) is a widespread situation, linked to patients' dietary habits and/or geographical origins. On the other hand, hypervitaminosis D (VDO) is also a worldwide problem, mainly associated with uncontrolled self-administration. In this study, we investigated the effects of VDD and VDO on sex steroid production and ovarian histology in mice. In addition to addressing the rarely explored situation of VDO, the originality of our approach is to disconnect VDD/VDO situations from the well-known calciotrophic effect of vitamin D (VitD). Our data indicate that VDD led to a significant decrease in serum LH and FSH levels, independently of serum calcium levels. VDD was also associated with increased testosterone and reduced oestradiol levels. VDO animals showed increased LH and reduced testosterone levels. Hormonal changes in the VDO animal groups were correlated with a lower accumulation of transcripts of steroidogenic genes such as CYP11A1 and 3ß-HSD, whereas these transcripts were higher in the VDD groups. CYP19A1 transcripts were lower in VDD animals than in controls. This study highlights the complex interaction between vitamin D status, the regulation of reproductive hormones and, consequently, reproductive performance. It underlines the need for caution when oral vitamin D supplementation is chosen as a therapeutic action to boost female reproductive performance, as VDO can be as detrimental as VDD.

The Lebanese GRADE-based vitamin D guidelines: a paradigm for the MENA region

BACKGROUND

The Middle East and North Africa region are traditionally known as regions with a high prevalence of vitamin D deficiency. However, serum 25-hydroxyvitamin D (25OHD) levels seem to be increasing lately. We developed guidelines on the screening and supplementation of adult Lebanese patients with vitamin D. These guidelines address community-dwelling and institutionalized individuals.

METHODS

Our guideline panel consisted of clinical and methodology experts that formulated the guidelines questions. We conducted a systematic review to gather global data on fracture (CRD42019129540), regional data on vitamin D trials (CRD42014010488), and on patients' values and preferences (CRD42022320022). We also complemented the latter with results from a cross-sectional local study. We followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology to assess the quality and certainty of evidence, and to develop recommendations.

RESULTS

For community-dwelling and institutionalized Lebanese adult population, the panel suggests no screening for vitamin D deficiency, over screening for vitamin D deficiency (conditional recommendation, based on very low certainty evidence). For community-dwelling Lebanese adult population, the panel suggests no supplementation with calcium and vitamin D, over supplementation (conditional recommendation, based on moderate certainty evidence). For institutionalized Lebanese adult population, the panel suggests supplementation with calcium and vitamin D, over no supplementation (conditional recommendation, based on moderate certainty evidence). The guidelines also identify high-risk subgroups, more likely to benefit from screening and supplementation. In community dwelling and institutionalized Lebanese adult individuals, for whom there is a decision to supplement with calcium and vitamin D, the panel suggests supplementation with a daily vitamin D equivalent of 600-2000 IU, as compared to doses higher than 2000 IU (conditional recommendation, very low certainty evidence).

CONCLUSION

The Lebanese GRADE-based vitamin D guidelines recommend against population screening and vitamin D supplementation. Subgroups at high risk are identified. The guidelines take into account contextual factors, and allow their adoption or adaptation in countries in the region.

Associations of Gestational Exposure to Air Pollution With Maternal Vitamin D Levels: A Meta-Analysis

CONTEXT

Maternal vitamin D level is an important determinant of pregnancy and child health outcomes. Exposure to air pollution is suspected to increase the risk of vitamin D deficiency, but the evidence is scarce.

OBJECTIVE

We investigated the association between air pollution during pregnancy and maternal vitamin D levels.

METHODS

A total of 15 935 pregnant women from 5 birth cohorts in Europe and the United States were included. Averaged concentrations of nitrogen oxides, fine and coarse particles, and composition of fine particles from conception until vitamin D measurement were estimated at participants' residential addresses using land-use regression or other spatiotemporal models. Cohorts measured vitamin D as 25(OH)D or 25(OH)D3 levels in serum or plasma at early or mid-pregnancy. We defined suboptimal vitamin D levels as levels below 20 ng/mL. We performed logistic regression models for each cohort to estimate the association between air pollution exposure and suboptimal vitamin D levels and pooled cohort-specific estimates in a random-effect meta-analysis. Models were adjusted for sociodemographic and lifestyle characteristics and month of conception.

RESULTS

We found an association between particulate matter (PM)2.5 and higher odds of suboptimal vitamin D levels (ie, below 20 ng/mL) (odds ratio per 5 μg/m3 increase in PM2.5, 1.43; 95% CI: 1.02, 1.99). There was no association between other air pollutant exposure and vitamin D levels.

CONCLUSION

PM2.5 exposure might contribute to suboptimal levels of vitamin D in pregnancy. Reducing air pollution exposure should be a priority because vitamin D deficiency may adversely influence offspring development.

Development and validation of prediction model for vitamin D deficiency in Chinese college students (a dynamic online nomogram predicting vitamin D deficiency for Chinese college students)

OBJECTIVE

This study aims to develop a model for predicting vitamin D deficiency in Chinese college students using easily accessible clinical characteristics.

METHODS

Data were derived from a cross-section study of the Vitamin D status in Chinese college students in September, 2020. Totally 1,667 freshmen from 26 provinces, autonomous districts or municipalities were analyzed. A LASSO regression model was used to select predictors and the significant factors were used to construct the logistic regression model expression and the nomogram. The prediction model was subjected to100 bootstrap resamples for internal validation to assess its predictive accuracy. Calibration and discrimination were used to assess the performance of the model. A dynamic online nomogram was conducted to make the model easy to use. The clinical use was evaluated by a decision curve analysis.

RESULTS

Gender, region of original residence, milk and yogurt intake, puffed foods intake, outdoor activity duration, UV protection index and "taken calcium or vitamin D supplements within 3 months" were identified as significant predictors of vitamin D deficiency among Chinese college students. The model demonstrated good calibration with a 100 bootstraps analysis. The C-index was 0.677 and the bias-adjusted C-index was 0.668 in internal validation with 100 bootstrap resamples. The decision curve analysis showed a threshold probability between 0.5 and 0.8, using the model added more benefit than considering all patients are deficient or not deficient.

CONCLUSIONS

The performance of this vitamin D deficiency prediction model is commendable, and the dynamic online nomogram was proved to be a user-friendly screening tool for identifying high-risk subjects among Chinese college students. However, external validation is imperative to ensure the model's generalizability.

Vitamin D for primary dysmenorrhea and endometriosis-related pain - A systematic review of registered RCTs

OBJECTIVE

This systematic review investigates the potential role of vitamin D supplement in alleviating pain associated with primary dysmenorrhea or endometriosis by analysing registered randomised controlled trials (RCTs).

METHODS

We comprehensively searched the WHO International Clinical Trials Registry Platform to identify registered RCTs that assessed the effects of vitamin D supplement on pain outcomes in people with primary dysmenorrhea or endometriosis. The primary outcomes of interest were pain severity/intensity, pain duration, pain medication usage and pain-related outcome measurements.

RESULTS

Seven registered RCTs were included in this systematic review. These RCTs had diverse doses and treatment durations of vitamin D supplement used as intervention. They also had either high or some concerns of risk of bias, according to Cochrane risk of bias version 2 assessment. Substantial heterogeneities were generally observed across the seven RCTs. When measured using a validated tool visual analogue scale (VAS), pain severity was significantly lower at the end of treatment when compared with placebo (mean difference MD -1.12, 95% confidence interval [-2.16, -0.07], I2=81%, 5 studies, n = 308). This significant difference was observed in the primary dysmenorrhea RCTs, but not the endometriosis RCTs.

CONCLUSION

This systematic review identified vitamin D may reduce pain associated with primary dysmenorrhea, though a low certainty of evidence was available. Future studies that use standardised doses and treatment duration in accordance with the latest clinical practice guidelines are needed to explore any potential benefits vitamin D may have for people with these conditions.

Antioxidant Supplementation in Childhood Obesity: A Path to Improved Metabolic Health?

Childhood obesity is linked to heightened oxidative stress, a key driver of endothelial dysfunction, inflammation, and metabolic complications. Antioxidants, including Vitamins C and E, are vital in neutralizing free radicals and mitigating oxidative damage. This non-systematic review examines the potential advantages of antioxidant supplementation in pediatric obesity, focusing on its effects on vascular health, insulin sensitivity, and inflammatory processes. Emerging data suggest that antioxidants may improve endothelial function, reduce blood pressure, and enhance metabolic homeostasis in obese children. However, the long-term efficacy and safety of antioxidant supplementation remain uncertain, necessitating further rigorous randomized controlled trials. A deeper understanding of antioxidants' role in pediatric obesity could unlock novel therapeutic approaches for managing obesity-related complications and improving children's overall health outcomes.

Influence of Vitamin D on Developmental Defects of Enamel (DDE) in Children and Adolescents: A Systematic Review

Background/Objectives: This systematic review aims to investigate the potential association between vitamin D levels and the occurrence of developmental enamel defects (DDE) in children, including conditions like molar-incisor hypomineralization (MIH) and hypomineralized second primary molars (HSPMs). DDEs, which occur during tooth development, can result in significant aesthetic and functional issues, and their exact etiology remains unclear, with both genetic and environmental factors contributing. Among environmental factors, vitamin D deficiency has been proposed as a possible risk factor, given its role in enamel mineralization. Methods: A thorough literature search was conducted in PubMed, Scopus, and Embase. The search strategy included terms such as "vitamin D", "vitamin D deficiency", "developmental defects of enamel", "enamel hypoplasia", "molar-incisor hypomineralization", and "hypomineralized second primary molars". Studies were included if they were original human observational research (cohort, case-control, or cross-sectional) conducted in children under 18 years of age or involving maternal-child cohorts. Ten studies were included in the analysis, with a total of 15,891 participants. The primary data extracted from the selected studies included the following: study design, participants' age, sample size, vitamin D status in relation to developmental defects of enamel, and statistical significance Results: The findings were mixed, with only a few studies suggesting a significant association between low vitamin D levels and the presence of DDEs. Specifically, one study found a link between insufficient maternal vitamin D levels during pregnancy and an increased number of teeth affected by MIH in children. However, the majority of the studies did not report a significant association. Conclusions: This review concludes that while there is some evidence to suggest a possible relationship between vitamin D and DDEs, more research is needed to confirm these findings and better understand the underlying mechanisms.

A case-control study on vitamin D receptor gene polymorphisms in patients with Parkinson's disease in Bangladesh

Parkinson's disease (PD) is a neurodegenerative disorder with a multifactorial etiology. This study aimed to investigate the association between vitamin D receptor (VDR) gene polymorphisms (ApaI, BsmI, FokI and TaqI) and the risk of PD in a Bangladeshi population. A case-control study was conducted with 100 PD patients and 100 age- and sex-matched healthy controls. Serum vitamin D levels were measured using a chemiluminescent immunoassay, and VDR gene polymorphisms were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Genetic models (allele, dominant, recessive and additive models) were used to assess the association between each polymorphism and PD risk. The mean age of the patients with PD was 63 years, with 65% being male, while the control group had a mean age of 54.5 years and 60% were male. In genetic models, the T allele of the ApaI gene demonstrated a significant association with PD (OR 1.92, 95% CI 1.20-3.13, p-value 0.007). This significant association persisted across both recessive and additive models (for recessive model: OR 2.17, 95% CI 1.10-4.55, p-value 0.027 and for additive model: OR 2.78, 95% CI 1.22-6.67, p-value 0.015). Similarly, the T allele of the FokI gene was found to be significantly associated with PD (OR 2.27, 95% CI 1.43-3.57, p-value 0.001). This association was also evident in both dominant and additive models (for dominant model: OR 2.56, 95% CI 1.45-4.55, p-value 0.001 and for additive model: OR 3.03, 95% CI 1.67-5.56, p-value 0.001). Conversely, no significant associations were observed for the genetic polymorphisms of the BsmI and TaqI genes across any of the genetic models examined. The findings suggest that specific VDR gene polymorphisms, particularly ApaI and FokI, are significantly associated with the risk of PD in the Bangladeshi population.

The Quantification of Vitamin D in Humans: A Promising, Non-Invasive and Cost-Effective Method to Measure 25-Hydroxyvitamin D

BACKGROUND

Vitamin D intake and synthesis are essential. Vitamin D deficiency is increasing across all age groups, raising concerns regarding public health. Serum 25(OH)D is measured to define vitamin D deficiency. However, its quantification in non-invasively collected biological matrices is still poorly studied. This study aimed to assess 25(OH)D levels in unconventional matrices using cost-effective analytical methods.

METHODS

Serum, urine, and saliva were collected from 62 healthy, non-smoking volunteers, 25-44 years of age. Biological samples were analysed using the Enzyme-Linked Immunosorbent Assay (ELISA). The serum was additionally analysed via the chemiluminescent microparticle immunoassay (CMIA), which was used as a benchmark.

RESULTS

We observed a linear correlation (Pearson r = 0.44; p = 0.05) between the benchmark and ELISA-measured 25(OH)D urinary levels. After stratification by sex, the correlation was stronger and significant only in females (Pearson r = 0.62; p = 0.04). Salivary 25(OH)D levels did not correlate with serum levels for both ELISA and CMIA measures. Subjects with a CMIA serum-based deficiency showed lower urinary 25(OH)D levels (p = 0.04).

CONCLUSION

Our study opens up the possibility of using urinary 25(OH)D levels as a proxy measurement of vitamin D. Such an approach may allow future investigations on the association between environmental factors and vitamin D assessed in non-invasively collected biological matrices via cost-effective analytical methods.

The Optimal Protective 25-Hydroxyvitamin D Level for Different Health Outcomes in Adults: A Brief Summary of Dose-Response Meta-Analyses

Vitamin D is very important for bone metabolism as well as for the prevention of various diseases, such as type 2 diabetes, cardiovascular disease and different types of cancer. Although vitamin D deficiency is widespread and an important public health problem, there exists controversy in the scientific community, with no established standard definition of adequate and deficient vitamin D status. To add new information on this topic, the aim of this brief opinion paper is to identify and discuss the optimal 25(OH)D concentration (range) for a reduction in the risk of various disease outcomes by summarizing dose-response reporting meta-analyses.

The Impact of Vitamin D in the Prevention of Influenza, COVID-19, and Dengue: A Review

Since its discovery, vitamin D (VD) has been known for its implications in maintaining bone homeostasis. However, in recent years it has been discovered that the vitamin D receptor is expressed on different cells of the immune system and that these cells can locally produce the active form of this molecule, calcitriol, strongly suggesting that this vitamin might play a key role in both branches of the immune system, innate and adaptive. Recent evidence has demonstrated that VD participates in the different protective phases of the immune system against invading microorganisms, including in the activation and production of antimicrobial peptides, in the inactivation of replication of infectious agents, in the prevention of the exposure of cellular receptors to microbial adhesion, and, more importantly, in the modulation of the inflammatory response. In recent years, the world has witnessed major outbreaks of an ancient infectious disease, dengue fever; the emergence of a pandemic caused by an unknown virus, SARS-CoV-2; and the resurgence of a common respiratory infection, influenza. Despite belonging to different viral families, the etiological agents of these infections present a common trait: their capacity to cause complications not only through their cytopathic effect on target tissues but also through the excessive inflammatory response produced by the human host against an infection. This review outlines the current understanding of the role that vitamin D plays in the prevention of the aforementioned diseases and in the development of their complications through its active participation as a major modulator of the immune response.

Vitamin D supplementation vs. placebo and incident type 2 diabetes in an ancillary study of the randomized Vitamin D and Omega-3 Trial

Observational and experimental evidence suggests that vitamin D plays a role in type 2 diabetes (T2D). However, prior randomized supplementation trials are limited to high-risk patients with prediabetes. Here we aim to evaluate whether vitamin D supplementation reduces risk of T2D in a general population of older US adults. The study design is an ancillary analysis (VITAL-T2D) of The Vitamin D and Omega-3 Trial (VITAL), a completed randomized, double-blind, placebo-controlled 2 × 2 trial of daily vitamin D3 (cholecalciferol; 2000 IU/day) and omega-3 fatty acids (1 g/day) for the primary prevention of cancer and cardiovascular disease. We also conducted a systematic review and meta-analysis of vitamin D trial (≥1000 IU/d cholecalciferol) vs. placebo and T2D risk. We analyzed 22,220 adults with mean age 67.2 years (SD = 7.1) without T2D at enrollment (2011 to 2014), randomized to vitamin D3 or placebo. Mean body mass index (BMI) was 27.5 kg/m2 (SD = 5.3), with 51% female and 17% Black race/ethnicity. A subcohort (n = 911) attended in-person visits at baseline and 2 years for glycemic trait analyses. Our meta-analysis included 3 additional trials (5205 participants; 936 T2D cases). The primary outcome for the VITAL-T2D is intention-to-treat effect of vitamin D vs. placebo for incident T2D. T2D incidence (cases/1000py) at median follow-up of 5.3 y was 3.98 for vitamin D and 4.37 for placebo (hazard ratio [HR] = 0.91; 95% confidence interval [CI] = 0.76, 1.09). Results did not differ by age, sex, BMI, or baseline 25-hydroxyvitamin D, and vitamin D had no effect on glycemic traits at 2 years. Meta-analysis of 4 trials (n = 5205; 936 T2D cases) obtained HR = 0.89 (CI = 0.80, 0.99). In conclusion, Vitamin D supplementation did not reduce T2D in older US adults, but a modest reduction was observed when meta-analyzed with prior trials. Trial Registration: ClinicalTrials.gov #NCT01633177. Systematic Review Registration: PROSPERO #CRD42019147562.

Vitamin D Status and Incidence of SARS-CoV-2 Reinfections in the Borriana COVID-19 Cohort: A Population-Based Prospective Cohort Study

A deficient vitamin D (VitD) status has been associated with SARS-CoV-2 infections, severity, and mortality. However, this status related to SARS-CoV-2 reinfections has been studied little. Our aim was to quantify the risk of reinfections considering VitD status before reinfection.

METHODS

We performed a population-based prospective cohort study in Borriana (Valencia Community, Spain) during 2020-2023, measuring 25-hydroxyvitamin D [25(OH)D] levels by electrochemiluminescence. Cox proportional hazards models were employed.

RESULTS

Of a total of 644 SARS-CoV-2 cases with confirmed laboratory tests, 378 (58.9%) were included in our study, with an average age of 38.8 years; 241 were females (63.8%), and 127 reinfections occurred (33.6%). SARS-CoV-2 reinfection incidence rates per 1000 person-days by VitD status were 0.50 for a deficient status (<20 ng/mL), 0.50 for an insufficient status (20-29 ng/mL), and 0.37 for a sufficient status (≥30 ng/mL). Compared with a sufficient VitD status, adjusted hazard ratios were 1.79 (95% confidence interval [CI] 0.89-3.59) for a deficient status and 1.59 (95% CI 1.06-2.38) for an insufficient status with a significant inverse dose-response (p = 0.02). These results can help improve nutritional actions against SARS-CoV-2 reinfections.

CONCLUSIONS

These results suggest that a VitD status lower than 30 ng/mL showed a higher risk of SARS-CoV-2 reinfection. Achieving and maintaining a sufficient VitD status is recommended to prevent reinfections.

Annual Vitamin D Status of World-Class British Swimmers Following a Standardised Supplementation Protocol for Three Years

Background/objectives: British swimmers are at a heightened risk of vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D): <50 nmol∙L-1) as their large indoor training volumes often restrict sunlight exposure, especially during the winter when daylight hours are reduced in the United Kingdom. Previous research has recommended supplementation with 4000 IU∙day-1 vitamin D3 from October to March to offset vitamin D losses. However, no current study has analysed this approach over multiple seasons to assess if this is an appropriate strategy. Methods: Using a quasi-experimental design, twenty-nine world-class British swimmers (aged 16-30 years) provided a 10 mL venous blood sample (fasted) as part of their routine haematological screening in the September of three consecutive years (2018, 2019, and 2020). Serum 25(OH)D was determined by radioimmunoassay, and this result determined the length of the standardised vitamin D3 protocol (<30 nmol∙L-1: 4000 IU∙day-1 from September to March; 30-79 nmol∙L-1: 4000 IU∙day-1 from October to March; >75 nmol∙L-1: no supplementation). Results: Mean serum 25(OH)D concentrations increased each year (2018: 76.4 ± 28.4 nmol∙L-1, 2019: 91.5 ± 24.8 nmol∙L-1, 2020: 115.0 ± 36.6 nmol∙L-1, p < 0.001), which coincided with the eradication of vitamin D deficiency after one season (prevalence, 2018: 10%, 2019: 0%, 2020: 0%). In September 2020, 35% of swimmers had a serum 25(OH)D > 125 nmol∙L-1, although it is currently debated whether this is a concern or a benefit for athletic populations. Conclusions: Supplementing with 4000 IU∙day-1 of vitamin D3 throughout the winter can increase the vitamin D status of swimmers. However, more frequent testing may be required to ensure that serum 25(OH)D remains within the sufficient range across the season (75-125 nmol∙L-1).

Vitamin D and Chronic Rhinosinusitis with Nasal Polyps: A Narrative Review and Perspectives

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a subtype of chronic rhinosinusitis (CRS) characterized by bilateral nasal polyps, primarily affecting adults. It is often associated with hyposmia and asthma and driven by persistent Th2 inflammation, particularly in Caucasian patients. The disease is recurrent and significantly impacts quality of life, yet its pathophysiology remains poorly understood. Management includes intranasal steroids, short courses of systemic corticosteroids, surgery for refractory cases, and biologics. However, despite these treatment options, disease control remains challenging. Low vitamin D levels have been associated with worse clinical outcomes, while supplementation studies show promise in improving symptoms in deficient patients. Emerging research suggests that vitamin D modulates immunity, fibroblast activity, and epithelial integrity, potentially contributing to CRSwNP pathogenesis, though the exact mechanisms remain unclear. This review synthesizes current research on vitamin D's role in systemic and local inflammation in CRSwNP. By highlighting its potential therapeutic implications, this work aims to guide future research and inform clinical practice. Additionally, it may serve as a foundation for understanding the broader impact of vitamin D deficiency in sinonasal diseases and other atopic conditions.

Association of serum parathyroid hormone within normal range with the prevalence and prognosis among adults with diabetes and prediabetes: insight from NHANES 2003-2006 data

Background

Previous research has established a link between high blood levels of parathyroid hormone (PTH) levels and hyperglycemia, as well as early mortality. However, the extent of this relationship and the predictive value of PTH for mortality risk in hyperglycemic populations have been minimally explored.

Methods

The National Health and Nutrition Examination Survey study conducted from 2003 to 2006 identified 932 adults with diabetes and 1645 adults with prediabetes. A weighted multivariate logistic regression analysis was utilized to examine the association between PTH levels and hyperglycemia. Furthermore, Cox proportional hazards regression models were employed to examine the correlation between PTH levels and both cardiovascular and overall mortality within the hyperglycemia cohort.

Results

(1) The research findings revealed a negative association between PTH levels (per 10-pg/mL increase) and diabetes status (OR, 0.79; 95% confidence interval (CI), 0.73-0.86). (2) There was a significant correlation between the risk of all-cause mortality (hazard ratios (HR), 1.13; 95% CI, 1.01-1.29) and cardiovascular disease mortality (HR, 1.39; 95% CI, 1.05-1.84) among individuals with diabetes for every 10-pg/mL increase in PTH levels.

Conclusion

The current research shows that individuals with elevated PTH spectrum within the normal range are less likely to have diabetes, while those with higher PTH levels in adults with diabetes are linked to worse outcomes, particularly cardiovascular mortality.

A Prospective Ultrasound Study of Whole Blood Metals and Incidence of Uterine Leiomyomata

BACKGROUND

Uterine leiomyomata (UL), hormone-dependent neoplasms, are a major source of gynecologic morbidity. Metals are hypothesized to influence UL risk through endocrine disruption, and their effects may vary by vitamin D status.

OBJECTIVE

We estimated associations of a metal mixture with incident UL, overall and by vitamin D status.

METHODS

We analyzed data from the Study of Environment, Lifestyle and Fibroids, a Detroit-area prospective cohort study of 1,693 black women 23-35 years of age. We measured concentrations of 17 metals/metalloids in whole blood and 25-hydroxyvitamin D [25(OH)D] in serum collected at baseline (2010-2012). Participants underwent ultrasonography at baseline and after 20 months to detect UL. We used Bayesian kernel machine regression to estimate adjusted associations (β ) of the metal mixture with probit of incident UL. We also ran Cox regression models with interaction terms to estimate incidence rate ratios (IRR) by vitamin D status.

RESULTS

Among 1,132 UL-free participants at baseline, 832 (73%) had vitamin D deficiency [25(OH)D < 20  ng / mL ] and 117 (10%) developed UL within 20 months. Increasing all metals from their 50th to 75th percentiles was weakly positively associated with UL overall [β = 0.06 ; 95% credible interval (CrI): - 0.03 , 0.16] and among vitamin D-deficient participants (β = 0.13 ; 95% CrI: 0.01, 0.24), driven by cadmium (overall and vitamin D-deficient) and mercury (vitamin D-deficient only). Increasing cadmium from its 25th to 75th percentile was positively associated with UL overall (β = 0.03 ; 95% CrI: - 0.05 , 0.11) and among vitamin D-deficient participants (β = 0.13 , 95% CrI: 0.02, 0.24). In Cox models, cadmium [IRR = 1.55 ; 95% confidence interval (CI): 1.07, 2.24, per 1-unit increase in standardized concentration] and mercury (IRR = 1.38 ; 95% CI: 0.99, 1.92) were positively associated with UL among vitamin D-deficient participants.

DISCUSSION

The metal mixture was positively associated with incident UL, but the association was weak and imprecise. We observed a stronger association among vitamin D-deficient participants that was driven by cadmium and mercury. https://doi.org/10.1289/EHP15218.

Relationship between life's essential 8, vitamin D, and cardiometabolic outcomes

AIMS

To assess the association between cardiovascular health (CVH) and cardiometabolic outcomes and the impact of vitamin D on the relationship. Additionally, we seek to analyze the predictive ability of CVH metrics for cardiometabolic outcomes.

METHODS

This cross-sectional study included 21,913 adult participants of the National Health and Nutrition Examination Survey (2007-2018). Logistic regression models and restricted cubic spline curves were employed to evaluate the association between CVH and cardiometabolic outcomes and analyze the influence of vitamin D on the relationship. Receiver operating characteristic curves were used to assess the predictive ability of CVH metrics for cardiometabolic outcomes.

RESULTS

The study included 21,913 participants, among whom 6193 (28.3%) were classified as having low CVH, 14,080 (64.3%) as having moderate CVH, and 1640 (7.5%) as having high CVH. CVH scores were significantly negatively correlated with cardiometabolic outcomes. Among the CVH metrics, blood glucose and blood pressure had higher predictive values for cardiovascular disease, chronic kidney disease, hypertension, and diabetes. Additionally, there was a significant interaction between CVH and vitamin D.

CONCLUSION

These findings underscore that higher CVH scores, assessed by Life's Essential 8, are associated with lower risks of cardiometabolic outcomes. Improving CVH contributes to reducing the burden of disease and promoting human health.

Strategies for preventing bone loss in populations with insufficient calcium and vitamin D intake

Calcium and vitamin D are essential nutrients for maintaining skeletal health, yet deficiencies in these nutrients are particularly widespread in regions such as Asia and Africa. Inadequate intake of these nutrients in these areas has been associated with diminished bone integrity and a rising incidence of osteoporosis. This review examines the underlying mechanisms of bone loss driven by calcium and vitamin D deficiencies, emphasizing their crucial roles in bone metabolism. It also presents strategies to improve nutrient intake, such as fortification of staple foods and supplementation, along with lifestyle modifications including increased physical activity, sun exposure, and dietary education, to prevent bone loss effectively. Special consideration is given to vulnerable populations, including older adults, individuals with limited sun exposure, and those with dietary restrictions, who are at higher risk of deficiency. The review further evaluates public health strategies, including government-initiated fortification and educational programs, as essential measures for tackling widespread nutrient deficiencies. Lastly, it explores future avenues for addressing calcium and vitamin D deficiencies, including the potential role of digital health tools, personalized nutrition, and innovative public health policies to alleviate the global burden of bone-related diseases.

Serum 25-hydroxyvitamin D levels and peripheral blood eosinophil percentages as predictive indicators for eosinophilic chronic sinusitis with nasal polyps

PURPOSE

Chronic rhinosinusitis (CRS) has a high incidence rate and different endotypes. Serum 25-hydroxyvitamin D (25(OH)D) deficiency is common in patients with eosinophilic and non-eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP and nECRSwNP, respectively). This study explored the relationship between serum 25(OH)D levels and CRS risk and determined the value of combining serum 25(OH)D with peripheral blood markers in distinguishing between ECRSwNP and nECRSwNP.

METHODS

This study enrolled 275 CRS patients and 298 healthy controls. The relationship between serum 25(OH)D levels and CRS risk was determined using logistic regression after propensity score matching (PSM). The efficiency of various peripheral blood markers in distinguishing between ECRSwNP and nECRSwNP was assessed using a decision-tree model.

RESULTS

The final analysis included 189 CRS patients and 189 controls after 1:1 PSM. Serum 25(OH)D levels were significantly lower in CRS patients than in controls. Patients with mild CRS showed higher serum 25(OH)D levels than those with moderate or severe CRS, and ECRSwNP patients had lower serum 25(OH)D levels than nECRSwNP patients (all Ps < 0.05). Eosinophil percentages and IgE levels were independent risk factors for ECRSwNP, whereas serum 25(OH)D was an independent protective factor. 25(OH)D deficiency increased the ECRSwNP risk (OR = 3.074, P = 0.04). An eosinophil percentage ≥ 5% and a 25(OH)D level < 61.8 nmol/L could be used to predict ECRSwNP, with training and test set accuracies of 89.7% and 85.7%, respectively.

CONCLUSION

Our findings suggest that serum 25(OH)D deficiency is an independent risk factor for CRS, especially ECRSwNP. Combining serum 25(OH)D levels with peripheral eosinophil percentages could be a promising biomarker for ECRSwNP.

Ocular haemodynamics in children with vitamin D deficiency

BACKGROUND

To evaluate the retinal and optic nerve head microvasculature in children with vitamin D deficiency using optical coherence tomography angiography (OCTA).

METHODS

This prospective, cross-sectional study included 74 eyes of 37 children with vitamin D deficiency (Group I) and 64 eyes of 32 healthy children (Group II). All participants underwent OCTA examinations. Foveal retinal thickness (FRT), peripapillary retinal nerve fibre layer (RNFL) thickness, vessel density (VD) in different sections of the retina, and optic disc were analysed and compared between the groups.

RESULTS

The mean ages, gender, mean intraocular pressures, and central corneal thickness levels were similar between the groups. The mean vitamin D levels measured from the venous blood samples of the participants were 11.42 ± 4.94 ng/mL in Group I and 26.03 ± 11.08 ng/mL in Group II, and the difference between these values was statistically significant (P < 0.001). There was no significant difference regarding optic disc capillary densities between the groups. However, compared with the Group II, Group I showed significantly higher values of FRT, and lower values of superficial whole, parafoveal and perifoveal VD (287.58 ± 12.43 mm vs 258.21 ± 22.68, P < 0.001, 50.85 ± 2.15% vs 51.77 ± 2.30%, P = 0.01, 54.05 ± 2.83% vs 55.18 ± 2.40%, P = 0.01, 51.27 ± 2.21% vs 52.11 ± 2.27%, P = 0.03, respectively). The vitamin D levels showed significantly negative correlation with FRT values in Group I (r = -0.439, P = 0.001).

CONCLUSIONS

Vitamin D deficiency seems to be associated with higher values of FRT and decreased levels of superficial VD. Retinal microvascular architecture may be affected in paediatric subjects who have vitamin D deficiency.

Impact of weight loss and lifestyle intervention on vitamin D in men with obstructive sleep apnea: The INTERAPNEA trial

INTRODUCTION

Vitamin D deficiency is commonly found among patients with obstructive sleep apnea (OSA). We aimed to determine the effect of an eight-week interdisciplinary weight loss and lifestyle intervention on circulating vitamin D levels in patients with moderate-to-severe OSA.

METHODS

89 men were assigned to a usual-care group (n = 49) or an 8-week interdisciplinary weight loss and lifestyle intervention combined with usual-care (n = 40). Evaluations were conducted at baseline, intervention endpoint (i.e., 8 weeks), and 6 months post-intervention. Serum 25-hydroxyvitamin D (25(OH)D) was determined using a chemiluminescence immunoassay. Sleep (i.e., sleep efficiency, apnea-hypopnea index [AHI], and oxygen desaturation index) and body weight and composition (i.e., fat mass, and visceral adipose tissue) variables were also determined.

RESULTS

Serum 25(OH)D concentrations showed an insufficient vitamin D status at baseline, which significantly increased (all p ≤ 0.034) at intervention endpoint (19 %) and at 6 months after intervention (45 %) in the intervention group to the point of potentially resolving vitamin D deficiency. Higher serum 25(OH)D concentrations were related to increased sleep efficiency and reduced AHI, oxygen desaturation index, and body weight and composition variables (all p < 0.001) from baseline to 6 months and from 8 weeks to 6 months after intervention. These results were also noted from baseline to 8 weeks, except for body composition (all p ≤ 0.007).

CONCLUSION

The intervention improved and potentially resolved vitamin D deficiency. Together with the improvement of adverse sleep patterns and body composition parameters, it may be considered as a promising approach in the treatment of OSA.

CLINICAL TRIAL REGISTRATION

(ClinicalTrials.gov NCT03851653).

Achieving clinical remission in asthma with mepolizumab: a subanalysis on vitamin D as a predictor of response

OBJECTIVE

Mepolizumab, an anti-IL-5 monoclonal antibody, has shown promise in reducing exacerbations and steroid dependency in severe eosinophilic asthma. This study aims to evaluate the effectiveness of mepolizumab in achieving clinical remission in asthma over 12 months and explore Vitamin D levels as a predictor of response.

METHOD

We assessed Asthma Control Questionnaire (ACQ) scores, spirometry, number of exacerbations, oral corticosteroid (OCS) use, and inhaled corticosteroid (ICS) use in 32 patients, observing significant clinical improvements. Data were collected 1 year prior to starting mepolizumab and one year after starting mepolizumab. Nasal polyps were not seen in all the patients, and computed tomography of para-nasal sinuses are not available for all the patients, so nasal polyps status are not evaluated to avoid any bias.

RESULT

Our results indicate that 12 patients achieved clinical remission after starting mepolizumab, with a strong correlation between higher Vitamin D levels and positive treatment outcomes. This suggests that optimizing Vitamin D levels could enhance the response to mepolizumab in asthma patients, and help in achieving better asthma control.

CONCLUSION

Mepolizumab is an effective treatment for severe eosinophilic asthma, significantly improving clinical outcomes and reducing corticosteroid use. This study highlights the importance of Vitamin D as a predictor of response to mepolizumab, suggesting that higher Vitamin D levels may enhance treatment efficacy.

Surveillance and Evaluation of Vitamin D Nutrition and Its Health Impact in Chinese Older Adults

Vitamin D is an essential fat-soluble vitamin for humans and vitamin D deficiency (VDD) affects all age groups, with older adults being at high risk of VDD. A deficiency in vitamin D has been associated with a range of health concerns in older adults, including osteomalacia and osteoporosis. Additionally, there is limited evidence suggesting that VDD may be associated with increased risk of developing cognitive impairment, muscle-wasting disorders, cardiovascular disease, type 2 diabetes mellitus, and mortality. This review synthesizes the latest research advances in China and abroad to provide detailed information on the current status of vitamin D nutritional monitoring, causes of deficiency, health risks, and proposed intake for reducing risk of diet-related noncommunicable diseases in the Chinese older adults.

Associations of the serum 25-hydroxyvitamin D with mortality among patients in osteopenia or osteoporosis

PURPOSE

The correlation between serum 25-hydroxy vitamin D [(25(OH)D] and mortality in patients with osteopenia or osteoporosis remains unclear. Therefore, this study examined the relationship between serum 25(OH)D and mortality in patients with osteopenia or osteoporosis.

METHODS AND RESULTS

This prospective cohort study included patients with osteopenia or osteoporosis from the National Health and Nutrition Examination Survey from 2001 to 2018. Multivariate Cox regression models examined the correlation between serum 25(OH)D and all-cause mortality, cardiovascular mortality (CVD), and cancer mortality. The cohort included 9282 adult participants with a median follow-up period of 97.01 months, including 1394 all-cause deaths, 413 CVD-related deaths, and 322 cancer deaths. In fully adjusted models, higher serum 25(OH)D levels (≥75.0 nmol/L) were associated with a lower risk of all-cause mortality (hazard ratio 0.54, 95 % confidence interval 0.41 to 0.73) and cardiovascular death (0.47, 0.29 to 0.76), using participants with low 25(OH)D levels (<25 nmol/L) as the reference. In addition, we found an L-shaped non-linear dose-response relationship between serum 25(OH)D and all-cause and cardiovascular mortality, with inflection points of 38.8 nmol/L and 53.6 nmol/L, respectively.

CONCLUSION

Higher serum 25(OH)D concentrations are strongly associated with a diminished risk of all-cause and CVD mortality in patients with osteopenia or osteoporosis. This association has a threshold effect. More in-depth intervention studies are needed to clarify underlying mechanisms.

Associations of a metal mixture and vitamin D with sleep duration among adolescents and young adults from the 2011-2018 NHANES cycles

INTRODUCTION

Heavy metal exposure has been associated with poor sleep, but little is known about the cumulative associations of multiple metals with sleep duration, particularly among adolescents. This study examined the association of blood lead (Pb), cadmium (Cd), and mercury (Hg) concentrations with sleep duration and possible effect modification by vitamin D.

METHODS

The study sample consisted of 16-25-year-olds (n = 2637) from the 2011-2018 National Health and Nutrition Examination Survey. The association of each blood metal and serum vitamin D level with self-reported sleep duration was examined through linear regression models. Interaction terms and stratified models tested the effect modification of metal association with sleep by vitamin D level or status. Cumulative and interactive associations among the metals and serum vitamin D were also estimated using Bayesian Kernel Machine Regression (BKMR).

RESULTS

In linear regressions, there was little evidence of an association between individual metals, vitamin D level, and sleep duration. Both linear regressions and BMKR models showed little indication of interactions among metals and vitamin D levels. BKMR results suggested an overall joint association, with longer sleep duration at higher percentile of the metal-vitamin D mixture (75th percentile vs 50th: β=0.07 hours; 95 % CrI: 0.01, 0.13).

CONCLUSION

In the context of low-level metal exposure, individual metals were unrelated to sleep duration. We found some evidence that higher levels of the mixture of blood Pb, Cd, Hg, and serum vitamin D level may be associated with slightly longer sleep duration, underscoring the importance of considering multiple environmental exposures. Additional analyses, especially in higher risk groups (e.g., higher exposures; higher prevalence or severity of vitamin D deficiency) are warranted.

A Causal Effect of Serum 25(OH)D Level on Appendicular Muscle Mass: Evidence From NHANES Data and Mendelian Randomization Analyses

BACKGROUND

Low serum vitamin D status was reported to be associated with reduced muscle mass; however, it is inconclusive whether this relationship is causal. This study used data from the National Health and Nutrition Examination Survey (NHANES) and two-sample Mendelian randomization (MR) analyses to ascertain the causal relationship between serum 25-hydroxyvitamin D [25(OH)D] and appendicular muscle mass (AMM).

METHODS

In the NHANES 2011-2018 dataset, 11 242 participants (5588 males and 5654 females) aged 18-59 years old were included, and multivariant linear regression was performed to assess the relationship between 25(OH)D and AMM measured by dual-energy X-ray absorptiometry. In two-sample MR analysis, 167 single nucleotide polymorphisms significantly associated with serum 25(OH)D at the genome-wide association level (p < 5 × 10-8) were applied as instrumental variables (IVs) to assess vitamin D effects on AMM in the UK Biobank (417 580 Europeans) using univariable and multivariable MR (MVMR) models.

RESULTS

In the NHANES dataset, serum 25(OH)D concentrations were positively associated with AMM (β = 0.013, SE = 0.001, p < 0.001) in all participants, after adjustment for age, race, season of blood collection, education, income, body mass index and physical activity. In stratification analysis by sex, males (β = 0.024, SE = 0.002, p < 0.001) showed more pronounced positive associations than females (β = 0.003, SE = 0.002, p = 0.024). In univariable MR, genetically higher serum 25(OH)D levels were positively associated with AMM in all participants (β = 0.049, SE = 0.024, p = 0.039) and males (β = 0.057, SE = 0.025, p = 0.021), but only marginally significant in females (β = 0.043, SE = 0.025, p = 0.090) based on IVW models was noticed. No significant pleiotropy effects were detected for the IVs in the two-sample MR investigations. In MVMR analysis, a positive causal effect of 25(OH)D on AMM was observed in the total population (β = 0.116, SE = 0.051, p = 0.022), males (β = 0.111, SE = 0.053, p = 0.036) and females (β = 0.124, SE = 0.054, p = 0.021).

CONCLUSIONS

Our results suggested a positive causal effect of serum 25(OH)D concentration on AMM; however, more researches are warranted to unveil the underlying biological mechanisms and evaluate the effects of vitamin D intervention on AMM.

The exploration of the relationship between hyperuricemia, gout and vitamin D deficiency

Our study aims to provide evidence concerning the relationship between hyperuricemia, gout and Vitamin D deficiency by analyzing data from Peking Union Medical College Hospital (PUMCH), the National Health and Nutrition Examination Survey (NHANES) database, and through Mendelian randomization (MR) analyses. Sample 1 involved patients from PUMCH (n = 13,532), and sample 2 involved participants from NHANES (Unweighted n = 22,860; weight n = 182,829,142). Logistic regression and restricted cubic spline analyses were applied to assess above relationship. A two-sample MR analysis was performed using the genome-wide association study summary statistics to identify the causal association between gout and 25-hydroxyvitamin D (25(OH)D). The results from both samples confirmed a positive correlation among hyperuricemia, gout and risk of Vitamin D deficiency. The restricted cubic spline showed positive dose-response relationship between uric acid and risk of Vitamin D deficiency and the minimal threshold of uric acid at 307.5 umol/L and 316.1 umol/L, respectively. Mediation analysis in the sample 2 found that about 29.4% of the total effect of gout on Vitamin D deficiency were mediated by serum uric acid, and 37.1% of which were mediated by body mass index.The results of our MR analysis supported a causal association between gout (IVW β(SE), -0.843 (0.337); P = .0123) and 25(OH)D. Sensitivity analysis and genetic risk scores approach confirmed the robustness and reliability of the above findings. Hyperuricemia and gout are both strong indicators of increased risk of Vitamin D deficiency. Findings highlight the causal effects of gout-associated genetic variants on 25(OH)D.

Retrospective real world study on vitamin D supplementation: Looking for the most effective molecule and its frequency of use

BACKGROUND & AIMS

There is still uncertainty regarding the optimal serum levels 25-Hydroxy-vitamin D [25(OH)D] and the most effective supplementation strategies, including the choice of molecule and its dosing frequency. The aim of the study is to compare the effects of calcifediol versus two different frequencies of cholecalciferol administration on vitamin D supplementation, and to identity the key parameters that predict response to treatment.

METHODS

This retrospective, real-world cohort study included 105 patients, who were divided into three groups. Group 1 (n = 21) received cholecalciferol 50,000 international units (UI) once a month, Group 2 (n = 27) received cholecalciferol 25,000 UI every two weeks, and Group 3 (n = 57) received calcifediol 0.266 mg (mg) once a month. The primary outcome measured was the delta increase in 25(OH)D levels after 6 months of treatment, compared to pre-treatment levels.

RESULTS

The study revealed a significant greater delta increase in 25(OH)D levels in Group 1, which received cholecalciferol 50,000 IU once a month, compared to the other two groups. However, multiple regression analysis indicated that neither the type of molecule nor the frequency of administration independently influenced the treatment outcome. Only pre-treatment serum 25(OH)D levels were found to significantly affect the outcome. Based on the receiver operating characteristic curve, serum 25(OH)D levels below 19.5 ng/dL were predictive of a doubling of pre-treatment values, with high sensitivity and specificity.

CONCLUSION

Pre-treatment serum 25(OH)D levels are valuable for selecting patients who should undergo supplementation. This finding suggests the importance of tailoring therapy according to the degree of vitamin D deficiency.

Reproductive Health Management of Female Adolescent Athletes With Relative-Energy Deficiency in Sport

The objective of this document is to guide the screening, diagnosis, and management of Relative Energy Deficiency in Sport (RED-S) in Adolescent/Young Adult (AYA) athletes to treat symptoms and reduce long-term sequelae with a focus on gynecologic aspects of the disorder. RED-S is a more comprehensive term for the condition previously known as the Female Athlete Triad. An overview of the clinical presentation, evaluation, and management of the reproductive health aspects of RED-S for female athletes is provided. For the purposes of this document, "female" refers to those designated female at birth, and "athlete" is defined as an individual who participates in regular physical activity. This document is intended for use by healthcare providers who care for female AYA athletes with RED-S.