Vitamin D: extraskeletal health

Effects of vitamin D supplementation on maximal strength and power in athletes: a systematic review and meta-analysis of randomized controlled trials

Background

Vitamin D is thought to be a powerful modulator of skeletal muscle physiology. However, available data on the effects of vitamin D supplementation on muscle function in athletes are limited and with mixed results. This meta-analysis therefore, aimed to quantitatively summarize the up-to-date literature assessing the effects of vitamin D supplementation on muscle strength and power in athletes.

Methods

Sport Discus, PubMed, Cochrane Library and Web of Science were searched to identify randomized controlled trials (RCTs) that used one-repetition maximum (1RM) tests to assess maximal strength, and vertical jump to assess muscle power in athletes. The Cochrane Risk of Bias tool was used to evaluate the included RCTs for sources of bias. The standardized mean difference (SMD) was used as the effect size, interpreted together with its 95% confidence intervals (CI). The effect sizes were calculated on the changes from baseline between vitamin D and placebo groups for maximal strength results by upper body and lower body, and for power results.

Results

Eleven RCTs involving 436 athletes were included. The results indicated that if baseline serum 25(OH)D concentration was < 75 nmol/L, the treatment had a small effect on upper body muscle strength [SMD 0.25, 95% CI: (-0.44, 0.95), p = 0.47] and on lower body muscle strength [SMD 0.26, 95% CI: (-0.13, 0.65), p = 0.19]; if the baseline serum 25(OH)D concentration was ≥ 75 nmol/L, the treatment had a trivial effect on muscle power [SMD 0.15, 95% CI: (-0.42, 0.72), p = 0.61].

Discussion

This meta-analysis demonstrated that there is not a statistically significant effect of vitamin D supplementation on improving maximum strength and power, but highlights that further research is required addressing the key limitations in previous studies before definitive conclusions can be made.

Clinical Toxicology of Vitamin D in Pediatrics: A Review and Case Reports

Intoxication of vitamin D is not a common case in pediatrics. Vitamin D supplements are sold as OTC drugs; however, there is a lack of public education about the permissible limits of vitamin D intake which may lead to vitamin D toxicity (VDT). This review aims to give insights to readers or practitioners about the clinical toxicology of vitamin D in pediatrics, which includes the mechanism of VDT, case reports, and the management of vitamin D poisoning. VDT refers to serum 25(OH)D levels, particularly when the level exceeds 100 ng/mL (250 nmol/L) or is defined as hypervitaminosis D. Hypercalcemia is a common condition of vitamin D toxicity. Vitamin D and its metabolites in moderate levels can induce hypercalcemia, as indicated by the elevation of osteoclastic bone resorption, the presence of calcium in renal tubules, intestinal calcium intake (through increased production of calcium-binding protein in enterocytes), and the decrease of parathyroid hormone synthesis. VDT in pediatrics can be managed by discontinuing vitamin D intake; using activated charcoal, furosemide, prednisone, and calcitonin; rehydration using intravenous sodium chloride 0.9%; and dextrose fluid therapy. It is important for parents to be more careful when providing vitamin D to their children.

Development of Machine Learning Models for Predicting Osteoporosis in Patients with Type 2 Diabetes Mellitus-A Preliminary Study

Purpose

Diagnosing osteoporosis in T2DM based on bone mineral density (BMD) remains challenging. We sought to develop prediction models employing machine learning algorithms for use as screening instruments for osteoporosis in T2DM patients.

Patients and Methods

Data were collected from 433 participants and analyzed using nine categorical machine learning algorithms to select features based on demographic and clinical variables. Multiple classification models were compared using the area under the receiver operating characteristic curve (ROC-AUC), accuracy, sensitivity, specificity, the average precision (AP), precision, F1 score, precision-recall curves, calibration plots, and decision curve analysis (DCA) to determine the best model. In addition, 5-fold cross-validation was utilized to optimize the model, followed by an evaluation of feature significance using Shapley Additive exPlanations (SHAP). Using latent class analysis (LCA), distinct subpopulations were identified by constructing several discrete clusters.

Results

In this study, nine feature variables were identified to construct predictive models for osteoporosis in individuals with T2DM. The machine learning algorithms achieved an AP range of 0.444-1.000. The XGBoost model was selected as the final prediction model with an AUROC of 0.940 in the training set, 0.772 in the validation set for 5-fold cross-validation, and 0.872 in the test set. Using SHAP methodology, 25(OH)D was identified as the most important risk factor. Additionally, a 3-Class model was constructed using LCA, which categorized individuals into high, medium, and low-risk groups.

Conclusion

Our study developed a predictive model with high accuracy and clinical validity for predicting osteoporosis in type 2 diabetes patients. We also identified three subpopulations with varying osteoporosis risk using clustering. However, limited sample size warrants cautious interpretation of results, and validation in larger cohorts is needed.

Vitamin D and Probability of Developmental Disorders among Perinatally HIV-Affected and Unaffected Ugandan Children

We tested the hypothesis that vitamin D deficiency (VDD) is associated with higher developmental disorder probability in 604 children with perinatal HIV infection (CPHIV, n = 199), HIV exposed and uninfected (CHEU, n = 196), and HIV unexposed uninfected (CHUU, n = 201). Children at 6-18 years old and their adult caregivers were assessed at enrollment, 6, and 12-month follow-ups. Serum 25-hydroxyvitamin-D (25OHD) levels in children quantified per the NHANES protocol were used to define VD categories as VDD (25OHD < 20 ng/mL), VD insufficient (VDI, 20 ≤ 25OHD ≤ 25 ng/mL), and VD sufficient (VDS = reference group if 25OHD > 25 ng/mL). Perinatal HIV status per DNA polymerase chain reaction/HIV rapid diagnostic tests included: CPHIV, CHEU, and CHUU. Developmental stage was defined as pre-adolescent (age < 11) vs. adolescent (age ≥ 11) years. Caregiver responses to standardized questions from Behavioral Assessment System for Children, Third Edition (BASC-3), were used to calculate probability scores for four disorders, namely: autism (ASD), attention deficit & hyperactivity (ADHD), emotional behavioral disorder (EBD), functional impairment (FI), and resiliency at 0, 6 and 12 months. Multivariable longitudinal models estimated VD-associated standardized mean difference (SMD) and corresponding 95% confidence intervals (95% CI) in respective probability scores in Statistical Analysis Software (v.9.4). Baseline VDD vs. VDS predicted higher probability scores of moderate clinical importance for ASD, ADHD, EBD, and higher FI among pre-adolescents (SMD = 0.32 to 0.40, 95% CI: 0.00 to 0.74). VDD was not associated with resiliency or any developmental disorders among adolescents. VDD predicted higher developmental disorder and FI scores over 12 months in a developmental stage-dependent manner. This relationship requires further understanding to appropriately target future interventions.

Calcitriol Reduces the Inflammation, Endothelial Damage and Oxidative Stress in AKI Caused by Cisplatin

Cisplatin treatment is one of the most commonly used treatments for patients with cancer. However, thirty percent of patients treated with cisplatin develop acute kidney injury (AKI). Several studies have demonstrated the effect of bioactive vitamin D or calcitriol on the inflammatory process and endothelial injury, essential events that contribute to changes in renal function and structure caused by cisplatin (CP). This study explored the effects of calcitriol administration on proximal tubular injury, oxidative stress, inflammation and vascular injury observed in CP-induced AKI. Male Wistar Hannover rats were pretreated with calcitriol (6 ng/day) or vehicle (0.9% NaCl). The treatment started two weeks before i.p. administration of CP or saline and was maintained for another five days after the injections. On the fifth day after the injections, urine, plasma and renal tissue samples were collected to evaluate renal function and structure. The animals of the CP group had increased plasma levels of creatinine and of fractional sodium excretion and decreased glomerular filtration rates. These changes were associated with intense tubular injury, endothelial damage, reductions in antioxidant enzymes and an inflammatory process observed in the renal outer medulla of the animals from this group. These changes were attenuated by treatment with calcitriol, which reduced the inflammation and increased the expression of vascular regeneration markers and antioxidant enzymes.

Dietary supplementation of 25-hydroxycholecalciferol as an alternative to cholecalciferol in swine diets: A review

25-hydroxycholecalciferol (25-OHD₃ ) formed via hepatic hydroxylation from vitamin D, cholecalciferol, represents the precursor of the biologically active vitamin D hormone, 1,25-dihydroxyvitamin D. Due to a higher absorption rate and the omission of one hydroxylation, dietary supplementation of 25-OHD₃ instead of vitamin D₃ is considered to be more efficient as plasma concentrations of 25-OHD₃ are increased more pronounced. The present review summarises studies investigating potential beneficial effects on mineral homeostasis, bone metabolism, health status and performance in sows, piglets and fattening pigs. Results are inconsistent. While most studies could not demonstrate any or only a slight impact of partial or total replacement of vitamin D₃ by 25-OHD₃ , some experiments indicated that 25-OHD₃ might alter physiological processes when animals are challenged, for example, by a restricted mineral supply.

Vitamin D Status Is Negatively Related to Insulin Resistance and Bone Turnover in Chinese Non-Osteoporosis Patients With Type 2 Diabetes: A Retrospective Cross-Section Research

Background and Objectives

Vitamin D status is closely related to blood glucose and bone metabolism in patients with type 2 diabetes (T2DM). Vitamin D affects bone density and bone metabolism, leading to osteopenia and osteoporosis. Insulin resistance increases the risk of osteoporosis in patients with T2DM. Our previous studies have shown a negative correlation between insulin resistance and 25-hydroxy vitamin D [25(OH)D] levels. The aim of the present study was to determine the association between vitamin D status and insulin resistance and bone metabolism in patients with T2DM.

Subjects and Methods

A retrospective cross-section research was carried out among 109 non-osteoporosis patients with T2DM. Their fasting blood glucose (FBG), 25(OH)D, fasting blood insulin (FINS), glycosylated hemoglobin (HbA1c), serum creatinine (SCr), calcium (Ca), phosphorus (P), insulin-like growth factor-1 (IGF-1), bone alkaline phosphatase (BALP), body mass index (BMI), glomerular filtration rate (eGFR), homeostatic model estimates of insulin resistance (HOMA-IR), and calcium-phosphorus product were measured routinely.

Results

Both in men and women, 25(OH)D was negatively correlated with BALP (β = −0. 369, p ≤ 0.001)and HOMA-IR (β = −0.349, p ≤ 0.001), and positively associated with IGF-1(β = 0.672, p ≤ 0.05). There was a negative correlation between HOMA-IR and IGF-1 (β = −0.464, p ≤ 0.001), and a positive correlation between HOMA-IR and BALP (β = 0.344, p ≤ 0.05), adjusted by confounding factors.

Conclusion

Our study demonstrates that 25(OH)D concentrations are negatively correlated with insulin resistance and bone turnover. Insulin resistance increases with the decrease of 25(OH)D concentration, which can enhance bone turnover, and increases the risk of osteoporosis in non-osteoporosis patients with T2DM. This is the first study to clarify the relationship between serum vitamin D status, insulin resistance, and bone metabolism in non-osteoporosis patients with T2DM in China.

Vitamin D Dosing: Basic Principles and a Brief Algorithm (2021 Update)

Nowadays, in modern societies, many people can be at high risk to have low vitamin D levels. Therefore, testing of serum 25-hydroxy-vitamin D (25OH-D) levels should be performed before prescribing them vitamin D supplementation. However, in some cases the 25OH-D level assessment is not available at the right moment, e.g., due to mandatory quarantine of COVID-19 outpatients. Therefore, such patients could be advised to start taking moderate vitamin D doses (e.g., 4000 IU/day for adults), and their 25-OH-D levels could be checked later. The proposed algorithm also comprises vitamin D dosing principles when baseline 25OH-D levels are known.

[Vitamin D insufficiency in a healthy pediatric population. The importance of early prophylaxis]

Introduction

Introduction: vitamin D maintains the concentration of calcium and phosphorus within the physiological range, allowing normal metabolism and bone mineralization. Recently, vitamin D deficiency has been related not only with rickets but also with an increased risk of other pathologies. The aim of this descriptive, observational, cross-sectional study was to assess vitamin D concentration levels in a healthy pediatric population, as well as the current situation of prophylaxis. Vitamin D determination was measured by serum 25-hydroxyvitamin D (25(OH)D) concentration. Methods: a total of 258 healthy patients between 3 months and 15 years of age were enrolled (6.77 ± 3.95 years; 73.6 % were male). Results: the mean value of 25-hydroxyvitamin D was 26.60 ng/mL ± 8.02 ng/mL, and up to 20.9 % of the population showed insufficient levels. Statistically significant differences in vitamin D levels were observed between ages (p = 0.002), ethnicity groups (p = 0.038), and skin types (p = 0.000). In addition, a higher prevalence of vitamin D insufficiency in children who had never previously received vitamin D supplementation (41.6 %) was observed compared to those that had taken supplementation in the first year of life (16.7 %). Conclusion: our study shows a high prevalence of vitamin D deficiency among healthy children, and the benefit of prophylaxis with vitamin D supplementation.

Mechanisms Involved in the Relationship between Vitamin D and Insulin Resistance: Impact on Clinical Practice

Recent evidence has revealed anti-inflammatory properties of vitamin D as well as extra-skeletal activity. In this context, vitamin D seems to be involved in infections, autoimmune diseases, cardiometabolic diseases, and cancer development. In recent years, the relationship between vitamin D and insulin resistance has been a topic of growing interest. Low 25-hydroxyvitamin D (25(OH)D) levels appear to be associated with most of the insulin resistance disorders described to date. In fact, vitamin D deficiency may be one of the factors accelerating the development of insulin resistance. Vitamin D deficiency is a common problem in the population and may be associated with the pathogenesis of diseases related to insulin resistance, such as obesity, diabetes, metabolic syndrome (MS) and polycystic ovary syndrome (PCOS). An important question is the identification of 25(OH)D levels capable of generating an effect on insulin resistance, glucose metabolism and to decrease the risk of developing insulin resistance related disorders. The benefits of 25(OH)D supplementation/repletion on bone health are well known, and although there is a biological plausibility linking the status of vitamin D and insulin resistance supported by basic and clinical research findings, well-designed randomized clinical trials as well as basic research are necessary to know the molecular pathways involved in this association.

Vitamin D and COVID-19: Role of ACE2, age, gender, and ethnicity

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, disproportionally targets older people, particularly men, ethnic minorities, and individuals with underlying diseases such as compromised immune system, cardiovascular disease, and diabetes. The discrepancy in COVID-19 incidence and severity is multifaceted and likely involves biological, social, as well as nutritional status. Vitamin D deficiency, notably common in Black and Brown people and elderly, is associated with an increased susceptibility to many of the diseases comorbid with COVID-19. Vitamin D deficiency can cause over-activation of the pulmonary renin-angiotensin system (RAS) leading to the respiratory syndrome. RAS is regulated in part at least by angiotensin-converting enzyme 2 (ACE2), which also acts as a primary receptor for SARS-CoV-2 entry into the cells. Hence, vitamin D deficiency can exacerbate COVID-19, via its effects on ACE2. In this review we focus on influence of age, gender, and ethnicity on vitamin D-ACE2 interaction and susceptibility to COVID-19.

The associations between serum vitamin D, calcium and uterine fibroids in Chinese women: a case-controlled study

Objective

To investigate the associations between serum vitamin D, calcium and uterine fibroids in a Chinese female population.

Methods

In this case-control study, adult female patients with fibroids (cases) were compared with females without fibroids (controls) in terms of serum 25-hydroxyvitamin D (25OHD) and calcium levels.

Results

Out of 546 total participants (mean age, 41.68 ± 5.99 years; 279 with fibroids and 267 without fibroids), only 232 had serum 25OHD levels above the sufficient threshold (>20 ng/ml). In addition, females with fibroids had lower serum 25OHD levels versus those without fibroids. The prevalence of fibroids in females with deficient (<12 ng/ml) and insufficient (12–20 ng/ml) 25OHD levels were significantly higher than in females with sufficient (>20 ng/ml) 25OHD levels. Serum calcium levels were within normal range in both groups.

Conclusion

Hypovitaminosis D was highly prevalent among a population of Chinese females of reproductive-age, and serum 25OHD levels were lower in female patients with fibroids.

Vitamin D and COVID-19: It is time to act

Vitamin D (VitD) deficiency is considered a global problem and might be associated with increased susceptibility to COVID-19 illness. In the light of COVID-19 pandemic, VitD might be a promising agent for fighting the SARS-CoV-2, since VitD is involved in various pathophysiological mechanisms that occur during COVID-19 infection. High-dose VitD supplementation, particularly for risk groups, could be recommended to achieve and maintain optimal (range 40-60 ng/mL) serum 25-hydroxy vitamin D levels (marker of VitD status) both for COVID-19 prevention and treatment.

Unraveling the roles of vitamin D status and melanin during Covid‑19 (Review)

As the coronavirus disease 2019 (COVID‑19) continues to spread worldwide, it has become evident that the morbidity and mortality rates clearly vary across nations. Although several factors may account for this disparity, striking differences within and between populations indicate that ethnicity might impact COVID‑19 clinical outcomes, reflecting the 'color of disease'. Therefore, the role of key biological variables that could interplay with viral spreading and severity indices has attracted increasing attention, particularly among non‑Caucasian populations. Although the links between vitamin D status and the incidence and severity of COVID-19 remain elusive, several lines of emerging evidence suggest that vitamin D signaling, targeting several immune‑mediated pathways, may offer potential benefits at different stages of SARS-CoV-2 infection. Given that the vitamin D status is modulated by several intrinsic and extrinsic factors, including skin type (pigmentation), melanin polymers may also play a role in variable COVID‑19 outcomes among diverse population settings. Moreover, apart from the well‑known limiting effects of melanin on the endogenous production of vitamin D, the potential crosstalk between the pigmentary and immune system may also require special attention concerning the current pandemic. The present review article aimed to shed light on a range of mostly overlooked host factors, such as vitamin D status and melanin pigments, that may influence the course and outcome of COVID‑19.

Evaluation of Vitamin D Metabolism in Patients with Type 1 Diabetes Mellitus in the Setting of Cholecalciferol Treatment

In this prospective controlled study, we examined 25 adults with adequately controlled (HbA1c level < 8.0%) type 1 diabetes mellitus (T1DM) and 49 conditionally healthy adults, intending to reveal the diversity of vitamin D metabolism in the setting of cholecalciferol intake at a therapeutic dose. All patients received a single dose (150,000 IU) of cholecalciferol aqueous solution orally. Laboratory assessments including serum vitamin D metabolites (25(OH)D₃, 25(OH)D₂, 1,25(OH)₂D₃, 3-epi-25(OH)D₃ and 24,25(OH)₂D₃), free 25(OH)D, vitamin D-binding protein (DBP) and parathyroid hormone (PTH) as well as serum and urine biochemical parameters were performed before the intake and on Days 1, 3 and 7 after the administration. The studied groups had no significant differences in baseline parameters except that the patients with diabetes showed higher baseline levels of free 25(OH)D (p < 0.05). They also lacked a correlation between the measured and calculated free 25(OH)D in contrast to the patients from the control group (r = 0.41, p > 0.05 vs. r = 0.88, p < 0.05), possibly due to the glycosylation of binding proteins, which affects the affinity constant for 25(OH)D. The elevation of vitamin D levels after the administration of cholecalciferol was comparable in both groups, with slightly higher 25(OH)D₃ levels observed in the diabetes group throughout the study since Day 1 (p < 0.05). Overall, our data indicate that in patients with adequately controlled T1DM 25(OH)D₃ levels and the therapeutic response to cholecalciferol is similar to that in healthy individuals.

Vitamin D for prevention of sternotomy healing complications: REINFORCE-D trial

Background

Most cardiac surgery patients undergo median sternotomy during open heart surgery. Sternotomy healing is an arduous, very complex, and multifactorial process dependent on many independent factors affecting the sternum and the surrounding soft tissues. Complication rates for median sternotomy range from 0.5 to 5%; however, mortality rates from complications are very variable at 7–80%. Low calcidiol concentration below 80 nmol/L results in calcium absorptive impairment and carries a risk of bone loss, which is considered as a risk factor in the sternotomy healing process. The primary objective of this clinical trial is to compare the incidence of all postoperative sternotomy healing complications in two parallel patient groups administered cholecalciferol or placebo. The secondary objectives are focused on general patient recovery process: sternal bone healing grade at the end of the trial, length of hospitalization, number of days spent in the ICU, number of days spent on mechanical lung ventilation, and number of hospital readmissions for sternotomy complications.

Methods

This clinical trial is conducted as monocentric, randomized, double-blind, placebo-controlled, with planned enrollment of 600 patients over 4 years, approximately 300 in the placebo arm and 300 in the treatment arm. Males and females from 18 to 95 years of age who fulfill the indication criteria for undergoing cardiac surgery with median sternotomy can be included in this clinical trial, if they meet the eligibility criteria.

Discussion

REINFORCE-D is the first monocentric trial dividing patients into groups based on serum calcidiol levels, and with dosing based on serum calcidiol levels. This trial may help to open up a wider range of postoperative healing issues.

Trial registration

EU Clinical Trials Register, EUDRA CT No: 2016-002606-39. Registered on September 8, 2016.

Role of Vitamin D in Athletes and Their Performance: Current Concepts and New Trends

We are currently experiencing a vitamin D (VITD) deficiency pandemic across the world. Athletes have the same predisposition to low levels of vitamin D, the majority of its concentrations being below 20 ng/mL in a wide range of sports, especially in the winter months. Vitamin D is important in bone health, but recent research also points out its essential role in extraskeletal functions, including skeletal muscle growth, immune and cardiopulmonary functions and inflammatory modulation, which influence athletic performance. Vitamin D can also interact with extraskeletal tissues to modulate injury recovery and also influence the risk of infection. The data presented in this paper has triggered investigations in relation to the importance of maintaining adequate levels of vitamin D and to the possible positive influence supplementation has on immune and musculoskeletal functions in athletes, benefiting their performance and preventing future injuries. The objective of this review is to describe the latest research conducted on the epidemiology of vitamin D deficiency and its effects on sports performance and musculoskeletal health.

Getting underneath the skin: A community engagement event for optimal vitamin D status in an 'easily overlooked' group

BACKGROUND

Patient and public involvement and engagement (PPIE) is recognized as important for improved quality in health service provision and research. Vitamin D is one area where PPIE has potential to benefit public health initiatives, particularly for women and children with increased skin pigmentation (ie at high risk of deficiency) who are easily overlooked.

OBJECTIVE

We report findings from a community PPIE event that explored the knowledge, barriers and promoters for optimal vitamin D status amongst an exemplar high-risk and easily overlooked population group.

METHODS

Two researchers and one PPIE lead facilitated a single group discussion with twenty members of the Somali community from across west London. All attendees were women of reproductive age, or knew a mother and child that could benefit from a targeted initiative. The discussion was recorded, transcribed verbatim, organized and coded using NVivo 12 Pro to identify emergent themes underpinned by the Health Behaviour Model.

RESULTS

Attendees thought community safety and competing demands of technology and education impacted on sun exposure and lifestyle activity. Language barriers impacted on access to health care. Attendees also felt the mother figure was 'the most important' influencer of both child and wider community health.

DISCUSSION

Although further discourse is needed, this event emphasizes that it is important that the public voice is heard in informing, designing and evaluating appropriate public health interventions amongst specific ethnic groups. Insights from this Somali population have suggested benefit from using verbal health messages that are specifically targeted at mothers, compared with the general population.

Nutritional vitamin D in CKD: Should we measure? Should we treat?

Vitamin Ddeficiency is frequently present in patients affected by chronic kidney disease (CKD). Experimental studies demonstrated that Vitamin D may play a role in the pathophysiology of diseases beyond mineral bone disorders in CKD (CKD-MBD). Unfortunately, the lack of large and interventional studies focused on the so called "non-classic" effects of 25(OH) Vitamin D supplementation in CKD patients, doesn't permit to conclude definitely about the beneficial effects of this supplementation in clinical practice. In conclusion, treatment of nutritional vitamin D deficiency in CKD may play a central role in both bone homeostasis and cardiovascular outcomes, but there is not clear evidence to support one formulation of nutritional vitamin D over another in CKD.

Genetic Variation of the Vitamin D Binding Protein Affects Vitamin D Status and Response to Supplementation in Infants

CONTEXT

Single nucleotide polymorphisms (SNPs) of the vitamin D binding protein encoding the GC (group component) gene affect 25-hydroxyvitamin D (25OHD) concentrations, but their influence on vitamin D status and response to vitamin D supplementation in infants is unknown.

OBJECTIVE

To study GC genotype-related differences in 25OHD concentrations and the response to supplementation during a vitamin D intervention study in infants.

DESIGN

In this randomized controlled trial, healthy term infants received vitamin D3 (10 or 30 μg/d) from 2 weeks to 24 months of age. GC SNPs rs2282679, rs4588, rs7041, and rs1155563 were genotyped. rs4588/7041 diplotype and haplotypes of rs2282679, rs4588, and rs7041 (Haplo3SNP) and of all four SNPs (Haplo4SNP) were determined.

MAIN OUTCOME MEASURES

25OHD measured in cord blood at birth and at 12 and 24 months during intervention.

RESULTS

A total of 913 infants were included. Minor allele homozygosity of all studied GC SNPs, their combined haplotypes, and rs4588/rs7041 diplotype 2/2 were associated with lower 25OHD concentrations at all time points in one or both intervention groups [analysis of covariance (ANCOVA) P < 0.043], with the exception of rs7041, which did not affect 25OHD at birth. In the high-dose supplementation group receiving 30 μg/d vitamin D3, but not in those receiving 10 µg/d, genotype of rs2282679, rs4588, and rs7041; diplotype; and Haplo3SNP significantly affected intervention response (repeated measurement ANCOVA Pinteraction < 0.019). Minor allele homozygotes had lower 25OHD concentrations and smaller increases in 25OHD throughout the intervention.

CONCLUSIONS

In infants, vitamin D binding protein genotype affects 25OHD concentration and efficiency of high-dose vitamin D3 supplementation.

High doses of cholecalciferol alleviate the progression of hyperparathyroidism in patients with CKD Stages 3-4: results of a 12-week double-blind, randomized, controlled study

Background

Calcidiol insufficiency may accelerate the development of secondary hyperparathyroidism (SHPT). We tested the effect of a substantial increase in calcidiol on mineral metabolism in patients with chronic kidney disease (CKD).

Methods

Ninety-five patients with CKD Stages 3–4, parathyroid hormone (PTH) above 6.8 pmol/L and calcidiol below 75 nmol/L were randomized to receive either cholecalciferol 8000 IU/day or placebo for 12 weeks. The primary endpoint was difference in the mean change in iPTH after 12 weeks. The proportion of participants having a 30% reduction in PTH and the effect on hand grip strength, fatigue and different biochemical variables were also investigated.

Results

Baseline calcidiol was 57.5 ± 22 and 56.8 ± 22 nmol/L in the cholecalciferol and placebo groups, respectively. The corresponding concentrations of PTH were 10.9 ± 5 and 13.1 ± 9 pmol/L. Calcidiol increased to 162 ± 49 nmol/L in patients receiving cholecalciferol, and PTH levels remained constant at 10.5 ± 5 pmol/L. In the placebo group, calcidiol remained stable and PTH increased to 15.2 ± 11 pmol/L. The mean change in PTH differed significantly between the two groups (P < 0.01). The proportion of subjects reaching a 30% decrease in PTH did not differ. No effect on grip strength, fatigue, phosphate or fibroblast growth factor 23 was observed. Cholecalciferol treatment resulted in stable calcium concentrations and a substantial increase in calcitriol.

Conclusion

Treatment with high daily doses of cholecalciferol in patients with CKD Stages 3–4 halts the progression of SHPT and does not cause hypercalcaemia or other side effects.

Vitamin D receptor gene polymorphisms in ocular surface squamous cell neoplasms

PURPOSE

To investigate vitamin D receptor polymorphisms in ocular surface squamous cell neoplasm and to evaluate the relationship between the identified polymorphisms and susceptibility to ocular surface squamous cell neoplasm and the clinical course.

MATERIALS AND METHODS

A totala of 70 patients with ocular surface squamous cell neoplasm (study group) and 75 healthy age and gender-matched individuals (control group) were included in the study. Vitamin D receptor FokI and BsmI polymorphisms were examined. The relationships between histopathological diagnosis, recurrence rates, tumor stage, and identified polymorphisms were investigated.

RESULTS

Histopathologically, 43 of the cases were squamous cell carcinoma and 27 of the cases were conjunctival intraepithelial neoplasia. The frequency of FokI (FF, Ff, ff) and BsmI (BB, Bb, bb) polymorphism genotype of vitamin D receptor gene were similar in the groups. The frequency of polymorphism (heterozygous or homozygous) for BsmI (Bb and bb) was significantly higher (p = 0.046) in the study group, while no difference was found between the groups in terms of polymorphic carriers (heterozygous or homozygous) for FokI. There was no correlation between tumor stage, recurrence-polymorphism frequency, and patient age-polymorphism frequency.

CONCLUSION

It is known that active vitamin D inhibits the growth of cancer cells by binding to vitamin D receptor with regulation of genes responsible for cell proliferation. The presence of BsmI polymorphism in vitamin D receptor, in particular bb genotype and b allele, appears to be associated with the susceptibility of ocular surface squamous cell neoplasm. BsmI gene polymorphisms of vitamin D receptor might play an effective role in the formation, progression, and in the course of ocular surface squamous cell neoplasm.

Protective effect of calcitriol on rhabdomyolysis-induced acute kidney injury in rats

Glycerol injection in rats can lead to rhabdomyolysis, with the release of the intracellular muscle content to the extracellular compartment and acute kidney injury (AKI). Oxidative stress and the inflammatory processes contribute to the disturbances in renal function and structure observed in this model. This study evaluated the effect of calcitriol administration in AKI induced by rhabdomyolysis and its relationship with oxidative damage and inflammatory process. Male Wistar Hannover rats were treated with calcitriol (6 ng/day) or vehicle (0.9% NaCl) for 7 days and were injected with 50% glycerol or saline 3 days after the beginning of calcitriol or saline administration. Four days after glycerol or saline injection, urine, plasma and renal tissue samples were collected for renal function and structural analysis. The oxidative stress and the inflammatory processes were also evaluated. Glycerol-injected rats presented increased sodium fractional excretion and decreased glomerular filtration rates. These alterations were associated with tubular injury in the renal cortex. These animals also presented increased oxidative damage, apoptosis, inflammation, higher urinary excretion of vitamin D-binding protein and decreased cubilin expression in renal tissue. All these alterations were less intense in calcitriol-treated animals. This effect was associated with decreases in oxidative damage and inflammation.

Association between Vitamin D Levels and Nonalcoholic Fatty Liver Disease: Potential Confounding Variables

Nonalcoholic fatty liver disease (NAFLD), historically considered to be the hepatic component of the metabolic syndrome, is a spectrum of fat-associated liver conditions, in the absence of secondary causes, that may progress to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Disease progression is closely associated with body weight or fatness, dyslipidemia, insulin resistance, oxidative stress, and inflammation. Recently, vitamin D deficiency has been linked to the pathogenesis and severity of NAFLD because of vitamin D "pleiotropic" functions, with roles in immune modulation, cell differentiation and proliferation, and regulation of inflammation. Indeed, several studies have reported an association between vitamin D and NAFLD/NASH. However, other studies have failed to find an association. Therefore, we sought to critically review the current evidence on the association between vitamin D deficiency and NAFLD/NASH, and to analyze and discuss some key variables that may interfere with this evaluation, such as host-, environment-, and heritability-related factors regulating vitamin D synthesis and metabolism; definitions of deficient or optimal vitamin D status with respect to skeletal and nonskeletal outcomes including NAFLD/NASH; methods of measuring 25(OH)D; and methods of diagnosing NAFLD as well as quantifying adiposity, the cardinal link between vitamin D deficiency and NAFLD.

Vitamin D deficiency in patients with aggressive periodontitis

OBJECTIVES

Vitamin D deficiency is a frequent health problem worldwide, especially as fewer people spend much time in the sun. Vitamin D deficiency is linked to several infectious and inflammatory conditions, including periodontal disease. However, its role in aggressive periodontitis (AgP) has not been well studied. We evaluated the association between vitamin D concentration and periodontal disease, both AgP and chronic (CP) periodontitis.

METHOD AND MATERIALS

Forty-seven AgP 55 CP and 27 control subjects participated. All patients were tested for serum vitamin D concentration (25(OH)D), parathyroid hormone, and serum bone-related biomarkers (alkaline phosphatases, calcium, and phosphorus) regulated by vitamin D.

RESULTS

The patients with AgP had lower serum 25(OH)D concentration (11.22 ± 4.8 ng/ml) than controls (16.9 ± 6.4 ng/ml) and patients with CP (16.13 ± 8.3 ng/ml; overall p value 0.0002). These associations remained significant after adjustment for age and gender (p = 0.002). No significant differences were observed in any bone-related biomarker among the three groups, and no association was observed with periodontal disease indices.

CONCLUSIONS

Our results suggest that vitamin D deficiency may be a potential risk factor for AgP. Given the high prevalence of vitamin D deficiency in AgP patients, routine screening for vitamin D status may be advisable in these subjects.

Knowledge, Attitudes and Perceptions towards Vitamin D in a UK Adult Population: A Cross-Sectional Study

The prevalence of vitamin D deficiency in the United Kingdom is high, despite updated Scientific Advisory Committee on Nutrition (SACN) guidelines. Therefore, our aims were to identify population knowledge, attitudes and perceptions of vitamin D supplementation and factors contributing to supplement use in a UK adult population. A cross-sectional study was performed between April⁻June 2018 using a newly designed piloted questionnaire. Scores for knowledge were calculated as a percentage (Boland et al. 2015). Logistic regression analysis was used to predict supplement use. 209 participants (82% female), mean (±SD) age 34.9 (±12.3) completed the questionnaire. The mean (±SD) vitamin D knowledge score was 56.6% (±19.9%); only 48% were concerned about their vitamin D concentration and 57% did not take vitamin D. Most participants (86%) wished to learn more about vitamin D. Knowledge score (OR 2.5; p = 0.01; 95% CI 1.2⁻5.3), concern (OR 2.1; p = 0.03; 95% CI 1.0⁻4.2) and location (OR 0.3; p = 0.006; 95% CI 0.1⁻0.7) predicted supplemented use. Individuals living in England had 2.9 (95% CI 1.4⁻6.3) lower odds of taking vitamin D than those living in Scotland. As a result of these findings, this study suggests that vitamin D supplementation and fortification, alongside education strategies, may be an effective method for improving UK vitamin D health; however, more research is warranted.

Higher Levels of Serum 25-Hydroxyvitamin D Are Related to Improved Glucose Homeostasis in Women with Postmenopausal Osteoporosis

BACKGROUND

Postmenopausal osteoporosis (PMO) is associated with other comorbidities such as impaired glucose homeostasis and cardiovascular disease. Vitamin D insufficiency is highly prevalent and may be a common link between these disorders. However, the relationship between circulating 25-hydroxyvitamin D [25(OH)D] and insulin resistance in women with PMO has not been well evaluated. The aim of this study was to assess the relationship between circulating levels of 25(OH)D and parameters of glucose homeostasis in a cohort of women with PMO to establish a serum concentration threshold of 25(OH)D for improved glycemic parameters.

MATERIALS AND METHODS

This cross-sectional study included 40 women with PMO. We measured 25(OH)D serum levels and glucose homeostasis parameters (glucose and insulin levels, insulin sensitivity, and β-secretion index HOMA2-%S and HOMA2-%B, respectively). Anthropometric, biochemical, and clinical parameters and bone markers were also evaluated.

RESULTS

Circulating levels of 25(OH)D were related to glucose parameters (negatively with HOMA2-%B and insulin levels and positively with HOMA2-%S) in women with PMO, resulting in an indicator of insulin sensitivity independent of age, body mass index, percent body fat, and undercarboxylated osteocalcin. Patients with serum 25(OH)D ≥45 ng/mL showed lower HOMA2-%B values and insulinemia and greater HOMA2-%S.

CONCLUSIONS

Our results support the hypothesis that circulating 25(OH)D levels are related to improved glucose homeostasis in women with PMO. However, this relationship was apparent only in the presence of high circulating levels of 25(OH)D.

Vitamin D Levels of Out-Patients in Lithuania: Deficiency and Hypervitaminosis

Aim: Data on the prevalence of vitamin D deficiency in Lithuania are scarce. The aim was to assess the reserves of vitamin D in different age groups of out-patients, regarding the season of the year. Methods: Data on serum 25-hydroxyvitamin D (25(OH)D) levels from blood tests made in 2012–2014 were obtained from one laboratory, and a retrospective cross-sectional analysis was performed. Results: A total of 9581 subjects were included. The mean age of the participants was 33 ± 23 years. The mean levels of vitamin D were higher in males than in females (p < 0.001). The highest mean 25(OH)D levels were in 0–9-year-old group, the lowest were in the 10–19-year-old group and in the group of participants that were 70 years and older (p < 0.001). The lowest vitamin D status was found in January, February, March, and April. The highest status was found in August and September. Overall, vitamin D deficiency, sufficiency, and hypervitaminosis were detected in 67%, 21%, and 12% of cases, respectively. Most cases with hypervitaminosis were in the group of children up to 2 years of age. Conclusion: Vitamin D status demonstrated clear seasonality. Significant sex-related differences of vitamin D statuses were also determined. Vitamin D deficiency was very prevalent in almost all age groups. Young children (aged up to 2 years) are of special interest for further research involving other types of 25(OH)D assays, such as those based on high-performance liquid chromatography (HPLC), since the real prevalence of “true” vitamin D hypervitaminosis in Lithuania’s children is still to be determined.

Association between vitamin D and urinary tract infection in children

Purpose

The present study aimed to determine the relationship between serum 25-hydroxyvitamin D (25(OH)D) level and Urinary tract infections (UTIs) in children.

Methods

In this case-control study, 70 children with UTI (case group) were compared with 70 healthy children (control group) in terms of serum 25(OH)D levels. The children were between 1 month and 12 years of age. Serum 25(OH)D levels were measured using enzyme-linked immunosorbent assay (ELISA). The results were analyzed and compared between both groups.

Results

Among 70 children with UTI (case group), 5 children (7.2%) were male and 65 (92.8%) were female. Among the healthy children (control group), 9 (12.8%) and 61 children (87.2%) were male and female, respectively (P=0.39). The mean±standard deviation of age in the case and control groups were 53.2±35.6 and 36.1±60.2 months, respectively (P=0.24). The mean level of serum 25(OH)D in the case group was significantly higher than that of the control group (20.4±8.6 ng/mL vs. 16.9±7.4 ng/mL, P=0.01).

Conclusion

This study showed that there was a relationship between serum 25(OH)D levels and UTI in children. It seems that 25(OH)D plays a role in the pathogenesis of UTI.

Current therapies in alleviating liver disorders and cancers with a special focus on the potential of vitamin D

Background

Liver dysfunction is a topic of global concern with many advancing therapies being researched. Though vitamin D takes a center place, other therapies especially nutritional are also gaining ground. Vitamin D has gone beyond its role in skeletal disorders by showcasing its associations in other metabolic dysfunctions too.

Result

Epidemiological evidences show a correlation between the status of vitamin D and different forms of cancer. Vitamin D receptors and alterations in gene expression appear decisive in the development of chronic liver disorders. Nutritional status therefore plays a significant role in avoiding the complications related to liver dysfunctions, making it mandatory in maintaining vitamin D sufficiency in the body. Therapies with omega-3 fatty acids, antioxidants, amino acids, steroids also render benefits which could be further explored. Recent research on the progression of certain forms of liver cancer using vitamin D analogs like Seocalcitol EB 1089 has shown good promise.

Conclusion

The anti-inflammatory and immuno- regulatory properties of vitamin D makes its analogs, suitable candidates of better choice for the prevention and treatment of liver disorders and cancer.

Physiological serum 25-hydroxyvitamin D concentrations are associated with improved thyroid function-observations from a community-based program

PURPOSE

Vitamin D deficiency has been associated with an increased risk of hypothyroidism and autoimmune thyroid disease. Our aim was to investigate the influence of vitamin D supplementation on thyroid function and anti-thyroid antibody levels.

METHODS

We constructed a database that included 11,017 participants in a health and wellness program that provided vitamin D supplementation to target physiological serum 25-hydroxyvitmain D [25(OH)D] concentrations (>100 nmol/L). Participant measures were compared between entry to the program (baseline) and follow-up (12 ± 3 months later) using an intent-to-treat analysis. Further, a nested case-control design was utilized to examine differences in thyroid function over 1 year in hypothyroid individuals and euthyroid controls.

RESULTS

More than 72% of participants achieved serum 25(OH)D concentrations >100 nmol/L at follow-up, with 20% above 125 nmol/L. Hypothyroidism was detected in 2% (23% including subclinical hypothyroidism) of participants at baseline and 0.4% (or 6% with subclinical) at follow-up. Serum 25(OH)D concentrations ≥125 nmol/L were associated with a 30% reduced risk of hypothyroidism and a 32% reduced risk of elevated anti-thyroid antibodies. Hypothyroid cases were found to have higher mean serum 25(OH)D concentrations at follow-up, which was a significant positive predictor of improved thyroid function.

CONCLUSION

The results of the current study suggest that optimal thyroid function might require serum 25(OH)D concentrations above 125 nmol/L. Vitamin D supplementation may offer a safe and economical approach to improve thyroid function and may provide protection from developing thyroid disease.

Lack of association between vitamin D receptor polymorphisms ApaI (rs7975232) and BsmI (rs1544410) and osteoporosis among the Han Chinese population: A meta-analysis

In this study, we aimed to assess the relationship between vitamin D receptor gene polymorphisms and osteoporosis in the Han Chinese population. Articles regarding associations between vitamin D receptor polymorphisms (ApaI rs7975232 and BsmI rs1544410) and osteoporosis were retrieved from databases in November 2014. Eligible studies were tested by the Hardy-Weinberg equilibrium. The odds ratio and 95% confidence interval (95% CI) were analyzed to evaluate the strength of the associations. Pooled effect estimates were derived using a fixed-effect model and a random-effect model according to the heterogeneity of the test results. A subgroup analysis by study type and a sensitivity analysis based on studies that conform to the Hardy-Weinberg equilibrium and studies with postmenopausal women as participants were performed. This meta-analysis involved 15 eligible studies including 1580 cases and 1389 controls. The pooled estimated odds ratios in the dominant and additive genetic models were 0.73 (95% CI: 0.46-1.14, p=0.17) and 1.01 (95% CI: 0.77-1.33, p=0.81), respectively, for rs7975232 and 1.01 (95% CI: 0.81-1.26, p=0.91) and 1.01 (95% CI: 0.77-1.33, p=0.92), respectively, for rs1544410. The subgroup analysis showed that regardless of the dominant or additive genetic model, the effect of pooled odds ratios for rs7975232 and rs1544410 was insignificant. The sensitivity analysis also showed that the pooled effect was not significantly changed. In conclusion, no evidence of association is apparent between polymorphisms of vitamin D receptor genes and osteoporosis risk in the Han Chinese population.

Vitamin D supplementation reduces relapse rate in relapsing-remitting multiple sclerosis patients treated with natalizumab

BACKGROUND

Vitamin D insufficiency is common among multiple sclerosis patients, and hypovitaminosis D has been associated with multiple sclerosis (MS) risk and disease activity.

OBJECTIVE

To investigate how recommendations on vitamin D3 supplements affect 25-hydroxyvitamin D (25(OH)D) levels in patients with relapsing-remitting MS (RRMS) and to examine the clinical effects associated with changes in 25(OH)D levels.

METHODS

In this prospective cohort study, baseline blood samples were collected from 170 natalizumab-treated RRMS patients during winter 2009-2010 and were repeated the following winter. Vitamin D supplements were recommended according to standard clinical practice in our clinic to patients with serum 25(OH)D<50nmol/l at baseline. Information was obtained on annualized relapse-rate (ARR) the year prior to baseline and the following year.

RESULTS

We found that recommending vitamin D supplements in patients with vitamin D insufficiency was associated with a significant increase in serum 25(OH)D concentrations (p=5.1×10^-10), which was significantly related with decreases in ARR; for each nmol/l increase in Δ25(OH)D a -0.014 (95% CI -0.026 to -0.003) decrease in ΔARR was observed, p=0.02.

CONCLUSION

Correction of hypovitaminosis D in clinical practice by recommending oral D3 supplements resulted in increases in 25(OH)D levels in serum, which were associated with decreases in ARR in RRMS.

Inhibitor effect of paricalcitol in rat model of pentylenetetrazol-induced seizures

Vitamin D has various systemic effects on bone metabolism, modulation of the immune system, stabilization of the cell membrane, oxidative stress, inflammation, apoptosis, and various other hormones. Differing from active vitamin D, paricalcitol is a relatively safe VDR agonist due to its relatively few side effects. This study has investigated the anticonvulsant effect of paricalcitol in convulsions induced by pentylenetetrazole (PTZ). 36 male Sprague-Dawley rats were divided randomly into two groups: 18 for EEG recording (PTZ 35 mg/kg) and 18 for behavioral studies (PTZ 70 mg/kg). Forty-five minutes before the PTZ injection, both groups of rats were given 5 and 10 μg/kg of paricalcitol i.p., respectively. Racine convulsion scores, first myoclonic jerk time, spike percentages, and antioxidant status were evaluated in the groups. Our results showed that the Racine's Convulsion Scale (RCS) score significantly dropped in the paricalcitol-treated group, analysis of the first myoclonic jerk (FMJ) latencies demonstrated a significantly longer latency in the paricalcitol-applied group, and spike percentages at EEG recordings significantly decreased with paricalcitol. Moreover, MDA levels were lower and SOD activity were higher in the 5 μg/kg paricalcitol group compared to the saline group; these results were more prominent in 10 μg/kg paricalcitol group. Our study has demonstrated that paricalcitol has protective effects on PTZ-induced convulsions. Based on the SOD and MDA levels in our study, these effects may result from the antioxidant characteristics of paricalcitol.

Could both vitamin D and geomagnetic activity impact serum levels of soluble cell adhesion molecules in young men?

Vitamin D might have a role in diminishing endothelial dysfunction (ED). The initial aim was to test the hypothesis of reciprocity between levels of 25-hydroxyvitamin D (25(OH)D) and levels of soluble endothelial cell adhesion molecules (CAMs) that could serve as biomarkers of ED. Randomly selected men of age 20-39 were examined at February or March (cold season) and reexamined at August or September (warm season). Some lifestyle and anthropometrical data were recorded. Laboratory measurements, including those for serum levels of soluble CAMs-sICAM-1, sVCAM-1, sE-selectin and sP-selectin-were also performed. As some of the results were rather unexpected, indices of geomagnetic activity (GMA), obtained from the online database, were included in further analysis as a confounder. In 2012-2013, 130 men were examined in cold season, and 125 of them were reexamined in warm season. 25(OH)D levels were found to be significantly negatively associated with sVCAM-1 levels (β = -0.15, p = 0.043 in warm season; β = -0.19, p = 0.007 for changes). Levels of sVCAM-1 and sICAM-1 from the same seasons were notably different between years and have changed in an opposite manner. Soluble P-selectin levels were higher at warm season in both years. GMA was positively associated with sVCAM-1 (β = 0.17, p = 0.039 in cold season; β = 0.22, p = 0.002 for changes) and negatively with sICAM-1 (β = -0.30. p < 0.001 in cold season) levels. Vitamin D might play a role in diminishing sVCAM-1 levels. Levels of sVCAM-1 and sICAM-1 were associated with the GMA; this implies a need for further research.

Maternal and cord blood vitamin D status and childhood infection and allergic disease: a systematic review

CONTEXT

It is unclear how in utero vitamin D deficiency affects the extraskeletal health of children, despite the known risks for adverse pregnancy/birth outcomes.

OBJECTIVE

This systematic review seeks to assess the effect of in utero vitamin D exposure on childhood allergy and infection outcomes using the PRISMA guidelines.

DATA SOURCES

MEDLINE, Cochrane Library, and Web of Science databases were searched.

STUDY SELECTION

Literature published through April 2015 was searched for studies reporting on the association between maternal pregnancy or cord blood vitamin D status and childhood allergy and infection.

DATA EXTRACTION

Of 4175 articles identified, 43 studies met the inclusion criteria. They examined a wide variety of outcomes, using many different vitamin D cutoff values in their analyses.

DATA SYNTHESIS

For most outcomes, results were inconsistent, although there appeared to be a protective effect between higher in utero vitamin D status and childhood lower respiratory tract infection (5 of 10 studies).

CONCLUSIONS

More research is needed on childhood allergy and infection outcomes, and future studies should standardize outcome reporting, especially with regard to cutoff values for vitamin D concentrations. Evidence of a protective association between in utero vitamin D exposure and lower respiratory tract infection was found, while the other outcomes were either understudied or showed inconsistent results.PROSPERO registration no. CRD42013006156.

Systematic review and meta-analysis: Prevalence and possible causes of vitamin D deficiency and insufficiency in pediatric cancer patients

BACKGROUND AND AIMS

Vitamin D inadequacy is now an internationally recognized health problem and pediatric cancer patients may be at even higher risk than healthy children. We aimed to evaluate primary research to establish the prevalence of vitamin D inadequacy and to explore its possible causes in pediatric cancer patients.

METHODS

Electronic databases were searched (no restriction-Aug 2013) with no language restrictions and keywords related to cancer and vitamin D. We included studies of patients aged <18 years, diagnosed with and treated for cancer and reporting plasma vitamin D status. Evidence was critically appraised employing the CASP tool. Meta-analysis was performed when appropriate.

RESULTS

We included 19 studies, which were mainly of moderate-quality and heterogeneous in the definitions of vitamin D deficiency and insufficiency. The median (range) prevalence of vitamin D deficiency was 14% (0-61.5%) and insufficiency 23% (0-83%). Finally, a significant effect of younger age with vitamin D inadequacy was shown (effect size: -0.132; 95%CI -0.203, -0.060).

CONCLUSION

There is a possibility of a high prevalence of vitamin D inadequacy in pediatric cancer patients, especially older children, urging the need for high-quality population-based longitudinal studies using standard definitions.

Vitamin D Status Is Negatively Correlated with Insulin Resistance in Chinese Type 2 Diabetes

Objectives. Vitamin D deficiency plays a role in insulin resistance and the pathogenesis of type 2 diabetes mellitus. Little information is available about the association between vitamin D status and insulin resistance in the Chinese population. Currently, vitamin D status is evaluated by the concentrations of serum 25-hydroxyvitamin D [25(OH)D]. This study explores the relationship between insulin resistance and serum 25-hydroxyvitamin D concentrations in Chinese patients with type 2 diabetes mellitus. Subjects and Methods. This study included 117 patients with type 2 diabetes. The following variables were measured: 25-hydroxyvitamin D [25(OH)D], glycosylated hemoglobin A1c (HbA1c), fasting blood glucose (FBS), fasting blood insulin (FINS), fasting blood C-peptide, serum creatinine (SCr), glomerular filtration rate (eGFR), body mass index (BMI), and homeostatic model estimates of insulin resistance (HOMA-IR). Results. The cases were divided into three groups: Group 1 (G1) with 25(OH)D ≤ 20 ng/mL [≤50 nmol/L], Group 2 (G2) with 25(OH)D values from 20 ng/mL [50 nmol/L] to 30 ng/mL [75 nmol/L], and Group 3 (G3) with 25(OH)D ≥ 30 ng/mL [≥75 nmol/L], with 52.6%, 26.3%, and 21.1% of subjects in Groups 1-3, respectively. There was a negative correlation between 25(OH)D and HOMA-IR (β = -0.314, p = 0.001) adjusted by age, BMI, and eGFR. Conclusion. Better vitamin D status may be protective of glucose homeostasis since 25(OH)D was negatively associated with insulin resistance in Chinese patients with type 2 diabetes.

The vitamin D status and its effects on life quality among the elderly in Jinan, China

A challenge for researchers is that vitamin D has many functions in the body, and vitamin D status across the world is not optimistic. There was little data regarding insufficient vitamin D status and its adverse effect on health of elderly Chinese people. So we selected 686 subjects (310 men and 376 women) aged 60-89 years to explore the correlation between vitamin D status and their life quality in a community-based osteoporosis prevention study at Qianfoshan Hospital of Shandong University from 2009 to 2010. All subjects were divided into three groups: vitamin D adequacy [serum 25(OH)D ≧ 75 nmol/L], hypovitaminosis D (50-74.9 nmol/L), and vitamin D insufficiency (<50 nmol/L). Participants were requested to complete SF-36 health survey. The regression models were used to evaluate respectively the association between 25(OH)D levels and parameters of SF-36. As a result, serum 25(OH)D levels were 58.60 nmol/L in male [95% confidence interval (95% CI): 56.7-60.5 nmol/L] and 54.17 nmol/L in female (95% CI: 52.8-55.8 nmol/L). Vitamin D adequacy was in 19.4% of male and 14.4% of female. With aging, proportions of insufficient vitamin D increased significantly in male (P=0.004), and in female (P<0.001). The elderly with hypovitaminosis D got lower scores than that with vitamin D adequacy (almost P<0.01). Regression analysis showed that vitamin D appeared a positive association with parameters of SF-36 (almost P<0.001). In conclusion, vitamin D status in the elderly was severely inadequate, which decreased their life quality and cause adverse effect on their health.

Vitamin D and Age-Related Health Outcomes: Movement, Mood, and Memory

It has long been recognized that vitamin D plays an important role in calcium homeostasis and musculoskeletal health. More recent evidence supports a role of vitamin D in physical and cognitive function and depressive symptoms through direct effects on skeletal muscle and the brain as well as indirectly through its reported roles in chronic conditions such as cardiovascular disease and diabetes, conditions that frequently lead to declines in physical and cognitive function and depressed mood. The purpose of this review is to summarize the prospective cohort and randomized controlled trial evidence for vitamin D on physical and cognitive function and depressed mood in older adults. Results from both prospective cohort studies and randomized controlled trials of vitamin D supplementation are mixed. Thus, controversy remains over the optimal vitamin D concentration for physical and cognitive function and depressed mood and whether vitamin D supplementation is beneficial for these outcomes.

Recommendations of the Brazilian Society of Endocrinology and Metabology (SBEM) for the diagnosis and treatment of hypovitaminosis D

OBJECTIVE

The objective is to present an update on the diagnosis and treatment of hypovitaminosis D, based on the most recent scientific evidence.

MATERIALS AND METHODS

The Department of Bone and Mineral Metabolism of the Brazilian Society of Endocrinology and Metabology (SBEM) was invited to generate a document following the rules of the Brazilian Medical Association (AMB) Guidelines Program. Data search was performed using PubMed, Lilacs and SciELO and the evidence was classified in recommendation levels, according to the scientific strength and study type.

CONCLUSION

A scientific update regarding hypovitaminosis D was presented to serve as the basis for the diagnosis and treatment of this condition in Brazil.

High prevalence of vitamin D insufficiency in community-dwelling postmenopausal Polish women

Introduction

Inadequate vitamin D level is associated with altered bone turnover and bone loss, which increases the fracture risk.

Aim

To assess the seasonal prevalence of inadequate (insufficient or deficient) serum vitamin D levels in community-dwelling postmenopausal Polish women screened for osteoporosis.

Material and methods

A cross-sectional observational study based on the regional urban non-institutionalized sample (n = 107) of postmenopausal Caucasian women in the age range of 51-83 years, not taking any medication and free from any condition likely to affect vitamin D status or calcium/bone metabolism. The outcome measures were the mean 25-OH vitamin D level across all the seasons and the percentage of vitamin D deficiency and insufficiency and defined as < 20 ng/dl (50 nmol/l) and 20-30 ng/dl (50-75 nmol/l), respectively.

Results

No statistically significant difference has been found in the mean vitamin D level, regardless of the season (p = 0.4). The prevalence of vitamin D deficiency and insufficiency were in spring 54% and 32%, in summer 46% and 46%, in autumn 67% and 27%, and in winter 61% and 22%, respectively.

Conclusions

Vitamin D inadequacy is common in a sample of Polish community-dwelling postmenopausal women regardless of the season.

Vitamin D deficiency in pregnant women of ethnic minority: a potential contributor to preeclampsia

OBJECTIVE

We investigated risk for comorbidities and preeclampsia at low vitamin D levels in ethnic minorities.

STUDY DESIGN

Umbilical cord vitamin D (25(OH)D) concentration was determined in urban minorities: 80.9% African American and 17% Hispanic mothers-baby pairs. To identify the correlation between vitamin D levels and high-risk comorbidities which result in preeclampsia, multivariate logistic regression analyses were performed.

RESULT

Below the Institute of Medicine threshold of 25(OH)D for pregnant women (25 ng ml⁻¹), obesity (P=0.055) and pregestational diabetes (odds ratio (OR)=2.056) were observed. The study median was 16 ng ml⁻¹ (<25th percentile), at which gestational hypertension (P=0.042), chronic hypertension (OR=4.842) and pregestational diabetes (OR=3.45) became relevant. The risk for preeclampsia increased 12-fold with gestational hypertension (P=0.003) and 14-fold with combined chronic and gestational hypertension (P=0.001).

CONCLUSION

Pregnant women of ethnic minority had lower median vitamin D levels which may contribute to a potential risk for preeclampsia.

Effect of vitamin D therapy in addition to amitriptyline on migraine attacks in pediatric patients

The purpose of this study was to investigate the effect of supplementary vitamin D therapy in addition to amitriptyline on the frequency of migraine attacks in pediatric migraine patients. Fifty-three children 8-16 years of age and diagnosed with migraine following the International Headache Society 2005 definition, which includes childhood criteria, were enrolled. Patients were classified into four groups on the basis of their 25-hydroxyvitamin D [25(OH)D] levels. Group 1 had normal 25(OH)D levels and received amitriptyline therapy alone; group 2 had normal 25(OH)D levels and received vitamin D supplementation (400 IU/day) plus amitriptyline; group 3 had mildly deficient 25(OH)D levels and received amitriptyline plus vitamin D (800 IU/day); and group 4 had severely deficient 25(OH)D levels and was given amitriptyline plus vitamin D (5000 IU/day). All groups were monitored for 6 months, and the number of migraine attacks before and during treatment was determined. Calcium, phosphorus alkaline phosphatase, parathormone, and 25(OH)D levels were also determined before and during treatment. Results were compared between the groups. Data obtained from the groups were analyzed using one-way analysis of variance. The number of pretreatment attacks in groups 1 to 4 was 7±0.12, 6.8±0.2, 7.3±0.4, and 7.2±0.3 for 6 months, respectively (all P>0.05). The number of attacks during treatment was 3±0.25, 1.76±0.37 (P<0.05), 2.14±0.29 (P<0.05), and 1.15±0.15 (P<0.05), respectively. No statistically significant differences in calcium, phosphorus, alkaline phosphatase, or parathormone levels were observed (P>0.05). Vitamin D given in addition to anti-migraine treatment reduced the number of migraine attacks.

North-South gradients of melanomas and non-melanomas: A role of vitamin D?

Incidence rates of skin cancer increase with decreasing latitude in Norway, as in many other countries with white populations. The latitudinal trends of the incidence rates of skin cancer were studied and compared with data for vitamin D-induced by UV and for vitamin D intake. The north-south gradient for CMM incidence rates on sun exposed skin is much smaller than those for BCC and SCC, and that for BCC is smaller than that for SCC. This indicates that SCC and BCC are mainly due to solar UVB, while UVA may play a significant role for CMM and a smaller role for BCC, since the north-south gradient of annual UVB fluences is larger than that of UVA fluences. However, there is an inverse latitudinal gradient of skin cancer in central Europe. This is probably due to a gradient of skin color, since white skin is an important determinant of increased risk of skin cancer. The role of vitamin D for skin cancer risk is difficult to evaluate, since serum levels of 25-hydroxyvitamin D, as well as vitamin D intakes, are widely different from country to country. Still, epidemiological evidence indicates a role: for melanomas arising on non-sun exposed body localizations (uveal melanomas, melanomas arising in the vulva and perianal/anorectal regions) there appears to be no latitudinal gradient, or, a negative gradient, i.e., increasing rates with decreasing latitude as would be expected if UV-generated vitamin D plays a protective role. Both skin cancer risk and vitamin D photosynthesis decrease with increasing skin darkness.

Prevalence of vitamin D insufficiency among community dwelling elderly in Dakahlia as a representative of rural areas in Egypt

BACKGROUND

Vitamin D has a basic role in bone growth and metabolism and has been noticed for its important role in many diseases.

OBJECTIVES

To detect the prevalence of vitamin D insufficiency among the elderly in Dakahlia.

METHODOLOGY

A cross-sectional study was conducted on 176 elderly patients (60 years and older) recruited from Meet Abbad-Nabaroh-Dakahlia, Egypt. The level of 25 hydroxy vitamin D (25OHD) was measured. A normal level of vitamin D is defined as a 25OHD concentration ≥30 ng/mL. Vitamin D insufficiency is defined as a 25OHD concentration of 20-29 ng/mL. Vitamin D deficiency is defined as a 25OHD level <20 ng/mL.

RESULTS

There were no cases of vitamin D deficiency among the studied population. The prevalence of vitamin D insufficiency (25OHD level of 20-29 ng/mL) among the elderly in Dakahlia was 26 %. Prevalence of vitamin D insufficiency was (37.9 %) in males and (15.3 %) in females.

CONCLUSION

There was a low prevalence of vitamin D insufficiency in an elderly rural population and a higher prevalence of vitamin D insufficiency among males than females.