Critique of the considerations for establishing the tolerable upper intake level for vitamin D: critical need for revision upwards

Meta-Analysis of European Clinical Trials Characterizing the Healthy-Adult Serum 25-hydroxyvitamin D Response to Vitamin D Supplementation

To obtain reliable data that allow health authorities to re-evaluate recommendations for oral vitamin D uptake, we conducted a meta-analysis to investigate the impact of supplementation on serum 25-hydroxyvitamin D (25(OH)D) levels in healthy adults in Europe. Of the publications identified (n = 4005) in our literature search (PUBMED, through 2 January 2022), 49 primary studies (7320 subjects, 73 study arms) were eligible for inclusion in our meta-analysis. The risk of bias was assessed using the Cochrane RoB tool based on seven categories, according to which each study is rated using three grades, and overall was rated as rather low. The median duration of intervention was 136.78 days (range, 1088 days); the mean weighted baseline 25(OH)D concentration and mean age were 33.01 vs. 33.84 nmol/L and 46.8 vs. 44.8 years in the vitamin D and placebo groups, respectively. Using random-effects models, 25(OH)D levels were increased by 36.28 nmol/L (95% CI 31.97-40.59) in the vitamin D group compared to the placebo, with a relative serum increment of 1.77 nmol/L per 2.5 μg of vitamin D daily. Notably, the relative serum 25(OH)D increment was affected by various factors, including the dosage and baseline serum 25(OH)D concentration, decreasing with increasing vitamin D doses and with increasing baseline serum levels. We estimate that supplementation in all healthy adults in Europe with appr. 25 μg of vitamin D (1000 IU) daily would raise serum 25(OH)D levels in 95% of the population to ≥50 nmol/L. Our work provides health authorities with reliable data that can help to re-evaluate recommendations for oral vitamin D supplementation.

A phase II dose evaluation pilot feasibility randomized controlled trial of cholecalciferol in critically ill children with vitamin D deficiency (VITdAL-PICU study)

BACKGROUND

Vitamin D deficiency (VDD) is highly prevalent in the pediatric intensive care unit (ICU) and associated with worse clinical course. Trials in adult ICU demonstrate rapid restoration of vitamin D status using an enteral loading dose is safe and may improve outcomes. There have been no published trials of rapid normalization of VDD in the pediatric ICU.

METHODS

We conducted a multicenter placebo-controlled phase II pilot feasibility randomized clinical trial from 2016 to 2017. We randomized 67 critically ill children with VDD from ICUs in Canada, Chile and Austria using a 2:1 randomization ratio to receive a loading dose of enteral cholecalciferol (10,000 IU/kg, maximum of 400,000 IU) or placebo. Participants, care givers, and outcomes assessors were blinded. The primary objective was to determine whether the loading dose normalized vitamin D status (25(OH)D > 75 nmol/L). Secondary objectives were to evaluate for adverse events and assess the feasibility of a phase III trial.

RESULTS

Of 67 randomized participants, one was withdrawn and seven received more than one dose of cholecalciferol before the protocol was amended to a single loading dose, leaving 59 participants in the primary analyses (40 treatment, 19 placebo). Thirty-one/38 (81.6%) participants in the treatment arm achieved a plasma 25(OH)D concentration > 75 nmol/L versus 1/18 (5.6%) the placebo arm. The mean 25(OH)D concentration in the treatment arm was 125.9 nmol/L (SD 63.4). There was no evidence of vitamin D toxicity and no major drug or safety protocol violations. The accrual rate was 3.4 patients/month, supporting feasibility of a larger trial. A day 7 blood sample was collected for 84% of patients. A survey administered to 40 participating families showed that health-related quality of life (HRQL) was the most important outcome for families for the main trial (30, 75%).

CONCLUSIONS

A single 10,000 IU/kg dose can rapidly and safely normalize plasma 25(OH)D concentrations in critically ill children with VDD, but with significant variability in 25(OH)D concentrations. We established that a phase III multicentre trial is feasible. Using an outcome collected after hospital discharge (HRQL) will require strategies to minimize loss-to-follow-up.

TRIAL REGISTRATION

CLINICALTRIALS

gov NCT02452762 Registered 25/05/2015.

Effect of Vitamin D Supplementation on Primary Dysmenorrhea: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Dysmenorrhea causes pain and inconvenience during menstruation. In addition to medication, natural compounds are widely used to relieve various types of pain. In this study, we aimed to assess the effects of vitamin D (vit. D) supplementation in relieving the symptoms of primary dysmenorrhea. A comprehensive systematic database search of randomized controlled trials (RCTs) was performed. Oral forms of vit. D supplementation were included and compared with a placebo or standard care. The degree of dysmenorrhea pain was measured with a visual analogue scale or numerical rating scale. Outcomes were compared using the standardized mean difference (SMD) and 95% confidence intervals (CIs) in a meta-analysis. RCTs were assessed using the Cochrane risk-of-bias v2 (RoB 2) tool. The meta-analysis included 8 randomized controlled trials involving 695 participants. The results of the quantitative analysis showed a significantly lower degree of pain in the vit. D versus placebo in those with dysmenorrhea (SMD: -1.404, 95% CI: -2.078 to -0.731). The results of subgroup analysis revealed that pain lessened when the average weekly dose of vit. D was over 50,000 IU, in which dysmenorrhea was relieved regardless of whether vit. D was administered for more or less than 70 days and in any dose interval. The results revealed that vit. D treatment substantially reduced the pain level in the primary dysmenorrhea population. We concluded that vit. D supplementation is an alternative treatment for relieving the pain symptoms of dysmenorrhea.

Vitamin D supplementation is associated with slower epigenetic aging

Adverse effects of low vitamin D level on mortality and morbidity are controversially discussed. Especially older people are at risk for vitamin D deficiency and therefore exposed to its potentially harmful consequences. A way of measuring differences in the biological age is through DNA methylation age (DNAm age) and its deviation from chronological age, DNAm age acceleration (DNAmAA). We previously reported on an association between vitamin D deficiency and higher 7-CpG DNAmAA in participants of the Berlin Aging Study II (BASE-II). In this study, we employ a quasi-interventional study design to assess the relationship between DNAmAA of five epigenetic clocks and vitamin D supplementation. Longitudinal data were available for 1,036 participants of BASE-II that were reexamined on average 7.4 years later in the GendAge study (mean age at follow-up: 75.6 years, SD = 3.8 years, age range: 64.9–94.1 years, 51.9% female). DNAmAA was estimated with the 7-CpG clock, Horvath’s clock, Hannum’s clock, PhenoAge, and GrimAge. Methylation data were obtained through methylation-sensitive single nucleotide primer extension (MS-SNuPE) or Illumina’s Infinium “MethylationEPIC” array. Vitamin D–deficient participants who chose to start vitamin D supplementation after baseline examination showed a 2.6-year lower 7-CpG DNAmAA (p = 0.011) and 1.3-year lower Horvath DNAmAA (p = 0.042) compared to untreated and vitamin D–deficient participants. DNAmAA did not statistically differ between participants with successfully treated vitamin D deficiency and healthy controls (p > 0.16). Therefore, we conclude that intake of vitamin D supplement is associated with lower DNAmAA in participants with vitamin D deficiency.

Rays of immunity: Role of sunshine vitamin in management of COVID-19 infection and associated comorbidities

The catastrophic pandemic engendered due to the Novel coronavirus (COVID-19) outbreak which causes severe clinical afflictions on the respiratory system has severely high morbidity and mortality rates. The requirement of novel compounds is at utmost importance due to lack of targeted drug molecule to treat the afflictions and restrict the viral infection and for the usage of prophylactic treatment to avoid the spread of the infection is of utmost importance. Vitamin D is one such naturally available multifunctional molecule, which plays an eminent role in the immune system and instigation of numerous cellular pathways further promoting health benefits and enhancing the human quality of life. This article reviews the current standpoint scenario and future prevalence of vitamin D supplementation in the management of covid-19 patients. Novel findings of Vitamin D suggest that along with regulation of cell growth, neuroprotective and mood-stabilizing effects, it regulates the immune response also modulate cytokine Interleukin-6 (IL-6) by inducing progesterone-induced blocking factor (PIBF), given the IL-6 levels are considerably high in COVID-19 patients which increases the further complications. Vitamin D also have its effect on angiotensin converting enzyme (ACEII) inhibitor through which the COVID-19 virus makes cell entry. Numerous research data elucidate the play of Vitamin D, in complications of COVID-19 including the most common comorbid conditions, neurological manifestations and immunological aspects makes it an ideal molecule for adjuvant therapy. Including Vitamin D as add-on therapy in the management of COVID-19 might aid the arrest of infection and helps fight this arduous epidemic.

Effects of high- vs low-dose native vitamin D on albuminuria and the renin-angiotensin-aldosterone system: a randomized pilot study

BACKGROUND

Residual albuminuria is associated with an increased risk of progression to ESKD. We tested whether a supplementation with native vitamin D could reduce albuminuria in stable CKD patients under maximal renin-angiotensin system (RAS) blockade.

METHODS

We conducted a randomized controlled study of high (cholecalciferol 100 000 UI per 10 days over 1 month) vs low-dose (ergocalciferol 400 UI/days over 1 month) supplementation with native vitamin D on urinary albumin/creatinine ratio, blood pressure and the RAS over 1 month in stable CKD patients with albuminuria and maximum tolerated RAS blockade.

RESULTS

We included 31 patients, 21 in the high dose group and 10 in the low dose group. In contrast with a low dose, high dose vitamin D normalized plasma 25(OH)D, decreased iPTH but slightly increased plasma phosphate. High dose vitamin D decreased geometric mean UACR from 99.8 mg/mmol (CI 95% 60.4-165.1) to 84.7 mg/mmol (CI 95% 51.7-138.8, p = 0.046). In the low dose group, the change in geometric mean UACR was not significant. Blood pressure, urinary 24 h aldosterone and peaks and AUC of active renin concentrations after acute stimulation by a single dose of 100 mg captopril were unaffected by the supplementation in native vitamin D, irrespective of the dose. Native vitamin D supplementation was well tolerated.

CONCLUSIONS

We found a small (- 15%) but significant decrease in albuminuria after high dose vitamin D supplementation. We found no effect of vitamin D repletion on blood pressure and the systemic RAS, concordant with recent clinical studies.

Vitamin D Sources, Metabolism, and Deficiency: Available Compounds and Guidelines for Its Treatment

Studies on vitamin/hormone D deficiency have received a vast amount of attention in recent years, particularly concerning recommendations, guidelines, and treatments. Moreover, vitamin D’s role as a hormone has been confirmed in various enzymatic, metabolic, physiological, and pathophysiological processes related to many organs and systems in the human body. This growing interest is mostly due to the evidence that modest-to-severe vitamin D deficiency is widely prevalent around the world. There is broad agreement that optimal vitamin D status is necessary for bones, muscles, and one’s general health, as well as for the efficacy of antiresorptive and anabolic bone-forming treatments. Food supplementation with vitamin D, or the use of vitamin D supplements, are current strategies to improve vitamin D levels and treat deficiency. This article reviews consolidated and emerging concepts about vitamin D/hormone D metabolism, food sources, deficiency, as well as the different vitamin D supplements available, and current recommendations on the proper use of these compounds.

Vitamin D in dysphagic patients who have undergone endoscopic gastrostomy for long-term enteral feeding

OBJECTIVE

Vitamin D plays a major role in biological processes. Its deficiency is associated with increased morbidity and mortality. Patients who have undergone endoscopic gastrostomy (PEG) present with protein-energy malnutrition, and may be at risk for Vitamin D deficiency, due to their age, less sunlight exposure and lower dietary intake. We aimed to determine the prevalence of hypovitaminosis D in PEG-patients, its change under PEG-feeding, and its relationship with serum proteins and risk factors for Vitamin D deficiency.

METHODS

This was a prospective observational study, over 4 weeks, after gastrostomy. Data were collected at the initial PEG procedure (T0), and after 4 weeks (T1). Initial evaluation included age, gender, underlying disorder, NRS-2002, BMI, serum albumin, transferrin and Vitamin D. At T1 we assessed Vit. D, albumin, and transferrin. Vitamin D was performed with Electrochemiluminescence through Elecsys 2010 assay. Patients were fed with blended homemade meals.

RESULTS

200 patients (118 males), 22-92 years of age, were studied. There were initial low values for Vit. D (181), albumin (96), transferrin (121), and BMI (124). A correlation was found between Vit. D and serum albumin (r=0.49, p=0.005) but not with transferrin (r=0.26, p=0.195). At T1 the subgroup who had Vit. D levels assessed (n=48) was part of the initial study group maintained low levels of Vitamin D despite nutritional intervention.

CONCLUSION

We recommend systematic Vitamin D supplementation of PEG fed patients using homemade meals or at least screening for hypovitaminosis D as a routine part of their care.

Reassessing vitamin D supplementation in preterm infants: a prospective study and review of the literature

Objectives Recommendations for vitamin D (VitD) intake and target serum levels of 25(OH)D in preterm infants are diverse. We hypothesized that preterm infants with low birth weight (BW) have low dietary intake of VitD and therefore should be supplemented with higher amounts of VitD. Methods Infants with BW < 2 kg were supplemented with 600 units of VitD a day during the first 2-6 weeks of life, whereas infants with BW>2 kg continued with the routine supplementation of 400 units of VitD daily. Serum levels of 25(OH)D, calcium, phosphorous, alkaline phosphatase (AP) and parathyroid hormone (PTH) were assessed 24 h after birth and before discharge. The total daily intake of vitD was calculated in each infant. Results Sixty-two infants were enrolled, 49 with BW < 2 kg. After birth, only 24% had sufficient levels of 25(OH)D, whereas before discharge 45 of 54 infants (83%) available for analysis reached sufficient levels of 25(OH)D. All 54 infants demonstrated significant elevation in serum levels of calcium, phosphorous, AP and significant reduction in PTH levels. The total daily intake of VitD was lower than recommended (800-1000 IU/d) in 16 of 45 infants with BW < 2 kg (36%) and in all nine infants with BW>2 kg. Nevertheless, only 2 of 25 infants with insufficient intake of VitD demonstrated insufficient levels of serum 25(OH)D. No case of vitamin D excess was recorded. Conclusions Increased supplementation of VitD (600 IU/d) for premature newborns with BW < 2 kg is effective in increasing both total daily intake of VitD and serum levels of 25(OH)D.

Influence of combined vitamin D3 supplementation and resistance exercise training on musculoskeletal health in older men and women (EXVITD): protocol for a randomised controlled trial

INTRODUCTION

Sarcopenia is a progressive loss in muscle mass, strength and function, the adverse consequences of which are severe, affecting quality of life and placing an increasing burden on social and healthcare systems. Vitamin D status is known to be associated with markers of sarcopenia, namely muscle mass, strength and function. Also, resistance exercise training (RET) is currently the only proven intervention to treat sarcopenia. However, very little data exist on the influence of combining the two interventions of vitamin D supplementation and resistance exercise training, although a recent systematic review provides tentative support for the current study's hypothesis that the combined intervention may further improve musculoskeletal function above exercise training alone. The aim of the present study is to determine whether vitamin D3 supplementation is any more effective in improving musculoskeletal function when combined with RET compared with exercise training alone in older adults.

METHODS AND ANALYSIS

This double-blinded randomised placebo-controlled trial will recruit a target of 127 eligible men and women aged ≥65 years living independently or in sheltered housing within the Birmingham area to two groups: (1) 6 months RET and placebo or (2) 6 months RET and 800 IU/d vitamin D3. Measures of muscle power (Nottingham Power Rig), body composition (dual energy X-ray absorptiometry), muscle function (short physical performance battery, timed up and go), falls and fractures as events will be assessed. Assessments will take place at baseline and postintervention, with intermittent monitoring of bone turnover, calcium and vitamin D. The primary outcome will be lower limb extensor power output. Analyses of within-group changes and between-group differences in outcome measures are planned.

ETHICS AND DISSEMINATION

The EXVITD study has ethical approval granted by the Black Country National Health Service Research Ethics Committee (14/WM/1220). Results of this trial will be submitted for publication in peer-reviewed journals and presented at conferences. The study is being conducted according to the principles of the Declaration of Helsinki.Trial registration numberNCT02467153; Post-results.

Vitamin D: A Micronutrient Regulating Genes

BACKGROUND

At sufficient sun exposure, humans can synthesize vitamin D3 endogenously in their skin, but today's lifestyle makes the secosteroid a true vitamin that needs to be taken up by diet or supplementation with pills. The vitamin D3 metabolite 1α,25-dihydroxyvitamin D3 acts as a nuclear hormone activating the transcription factor vitamin D receptor (VDR).

METHODS

This review discusses the biological effects of micronutrient vitamin D ranging from calcium homeostasis and bone formation to the modulation of innate and adaptive immunity.

RESULTS

Since normal human diet is sufficient in vitamin D, the need for efficient vitamin D3 synthesis in the skin acts as an evolutionary driver for its lightening during the migration out of Africa towards North. Via activating the VDR, vitamin D has direct effects on the epigenome and the expression of more than 1000 genes in most human tissues and cell types.

CONCLUSIONS

The pleiotropic action of vitamin D in health and disease prevention is explained through complex gene regulatory events of the transcription factor VDR.

Trying to identify who may benefit most from future vitamin D intervention trials: a post hoc analysis from the VITDAL-ICU study excluding the early deaths

Background

Vitamin D supplementation has shown promise for reducing mortality in the intensive care setting. As a steroid prohormone with pleiotropic effects, there may be a lag between administration and observing clinical benefit. This secondary analysis of the VITdAL-ICU study sought to explore whether the effect size of vitamin D on mortality was different when study participants who died or were discharged early were excluded.

Methods

The VITdAL-ICU study was a randomized, placebo-controlled trial in critically ill adults who received placebo or 540,000 IU cholecalciferol followed by monthly supplementation. The effect of vitamin D on 28-day mortality was evaluated after exclusion of participants who died or were discharged within 7 days from study drug administration, according to vitamin D concentrations on day 3, using a bivariate analysis adjusted for confounders and in a stepwise multiple analysis.

Results

Of 475 study participants, 65 died or were discharged within the first 7 days. In the remaining 410 patients, vitamin D supplementation was associated with a reduction in 28-day mortality [OR 0.58 (95% CI 0.35–0.97) p value = 0.035]. The effect on mortality was not significant after adjusting for age, severity scores, female gender, chronic liver and kidney disease, COPD, diagnosis of the tumor, mechanical ventilation, and vasopressors at enrollment (all p > 0.05). In a multiple model, the mortality reduction by vitamin D supplementation did not remain independently significant [OR 0.61 (95% CI 0.35–1.05) p = 0.075].

Vitamin D metabolite response, in the treatment group, demonstrated that survivors at 28 days, had higher levels of 25-hydroxyvitamin D (34.4 vs 25.4 ng/ml, p = 0.010) and 1,25-dihydroxyvitamin D (107.6 vs 70.3 pg/ml, p = 0.049) on day 3. The increase of plasma metabolites after vitamin D oral supplementation, independent of the baseline value, was associated with lower odds of death [OR 0.48 (95% CI 0.27–0.87) p value = 0.016].

Conclusions

High-dose vitamin D3 supplementation was associated with a reduction of 28-day mortality in a mixed population of critically ill adults with vitamin D deficiency when excluding patients who died or were discharged within 7 days after study inclusion. However, this survival benefit was not independently confirmed when adjusted for other factors strongly associated with mortality.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2472-z) contains supplementary material, which is available to authorized users.

Obesity attenuates serum 25-hydroxyvitamin D response to cholecalciferol therapy in critically ill patients

OBJECTIVES

The presence of obesity may confound cholecalciferol dosing in vitamin D-deficient patients owing to potentially decreased bioavailability. The aim of this retrospective study was to evaluate cholecalciferol therapy in vitamin D-deficient, critically ill trauma patients with and without obesity.

METHODS

Adult patients with severe traumatic injuries who had a serum 25-hydroxyvitamin D (25-OH vit D) <50nmol/L were prescribed 10 000 IU of liquid cholecalciferol daily. Efficacy was defined as achievement of a 25-OH vit D of 75 to 200nmol/L. Safety was evaluated by the presence of hypercalcemia (serum ionized calcium >1.32 mmol/L). Fifty-three patients (18 obese, 35 non-obese) were identified for study.

RESULTS

Despite similar baseline concentrations (36 ± 7 versus 37 ± 7 nmol/L; P = NS), 25-OH vit D response was attenuated for those with obesity after 1 and 2 wk of cholecalciferol therapy (51 ± 18 versus 66 ± 27nmol/L, P < 0.01; 68 ± 19 versus 92 ± 25nmol/L, P < 0.01, respectively). Patients with obesity also tended to experience less hypercalcemia (22% versus 49% of patients, respectively) post-cholecalciferol therapy.

CONCLUSION

Obesity alters the response to cholecalciferol therapy in critically ill patients with severe traumatic injuries.

Does vitamin D play a role in autoimmune endocrine disorders? A proof of concept

In the last few years, more attention has been given to the "non-calcemic" effect of vitamin D. Several observational studies and meta-analyses demonstrated an association between circulating levels of vitamin D and outcome of many common diseases, including endocrine diseases, chronic diseases, cancer progression, and autoimmune diseases. In particular, cells of the immune system (B cells, T cells, and antigen presenting cells), due to the expression of 1α-hydroxylase (CYP27B1), are able to synthesize the active metabolite of vitamin D, which shows immunomodulatory properties. Moreover, the expression of the vitamin D receptor (VDR) in these cells suggests a local action of vitamin D in the immune response. These findings are supported by the correlation between the polymorphisms of the VDR or the CYP27B1 gene and the pathogenesis of several autoimmune diseases. Currently, the optimal plasma 25-hydroxyvitamin D concentration that is necessary to prevent or treat autoimmune diseases is still under debate. However, experimental studies in humans have suggested beneficial effects of vitamin D supplementation in reducing the severity of disease activity. In this review, we summarize the evidence regarding the role of vitamin D in the pathogenesis of autoimmune endocrine diseases, including type 1 diabetes mellitus, Addison's disease, Hashimoto's thyroiditis, Graves' disease and autoimmune polyendocrine syndromes. Furthermore, we discuss the supplementation with vitamin D to prevent or treat autoimmune diseases.

The Effect of Improved Serum 25-Hydroxyvitamin D Status on Glycemic Control in Diabetic Patients: A Meta-Analysis

BACKGROUND

Type 2 diabetes is a global health concern, with an increased prevalence and high cost of treatment.

OBJECTIVE

The aim of this systematic review and meta-analysis was to determine the effect of vitamin D supplementation and improved vitamin D status on glycemia and insulin resistance in type 2 diabetic patients.

DATA SOURCE

We searched PUBMED/Medline, Cumulative Index to Nursing and Allied Health, and Cochrane Library (until January 2017).

STUDY SELECTION

Prospective clinical trials were selected evaluating the impact of vitamin D supplementation on glycosylated hemoglobin (HbA1c), serum fasting plasma glucose (FPG), and homeostatic model assessment of insulin resistance (HOMA-IR) in diabetic patients.

DATA EXTRACTION AND SYNTHESIS

We used a random-effects model to synthesize quantitative data, followed by a leave-one-out method for sensitivity analysis. The systematic review registration was CRD42017059555. From a total of 844 entries identified via literature search, 24 controlled trials (1528 individuals diagnosed with type 2 diabetes) were included. The meta-analysis indicated a significant reduction in HbA1c [mean difference: -0.30%; 95% confidence interval (CI): -0.45 to -0.15, P < 0.001], FPG [mean difference: -4.9 mg/dL (-0.27 mmol/L); 95% CI: -8.1 to -1.6 (-0.45 to -0.09 mmol/L), P = 0.003], and HOMA-IR (mean difference: -0.66; 95% CI: -1.06 to -0.26, P = 0.001) following vitamin D supplementation and significant increase in serum 25-hydroxyvitamin D levels [overall increase of 17 ± 2.4 ng/mL (42 ± 6 nmol/L)].

CONCLUSIONS

Vitamin D supplementation, a minimum dose of 100 µg/d (4000 IU/d), may significantly reduce serum FPG, HbA1c, and HOMA-IR index, and helps to control glycemic response and improve insulin sensitivity in type 2 diabetic patients.

Self-administration of vitamin D supplements in the general public may be associated with high 25-hydroxyvitamin D concentrations

Introduction Our dried blood spot vitamin D testing service enables members of the public to assess their vitamin D status. Vitamin D has become popular with the media and the general public. We noticed that our direct access service had a higher rate of high to toxic 25-hydroxyvitamin D levels compared with our GP population and we wanted to know why. Methods Between January 2013 and September 2015 we contacted all direct access users who had 25-hydroxyvitamin D >220 nmol/L measured using LC/MS/MS. We investigated the amount, type and length of supplementation used and whether or not users were medically supervised. Results A total of 372 service users had 25-hydroxyvitamin D concentrations >220 nmol/L. Of 14,806 direct access samples received, 372 (2.5%) were from users with 25-hydroxyvitamin D concentrations ranging from 221 to 1235 nmol/L. Only 0.06% of GP patients had results >220 nmol/L over the same time frame. There were 361 direct access users regularly supplementing, taking between 1000 to 120,000 IU/day. Two users took bolus doses of 300,000 and 900,000 IU. Only 23 users taking supplements (6.4%) were under medical supervision. There were 28 users with levels >500 nmol/L, but only one was under medical supervision. The internet was the main source of supplements (74%). Conclusions The proportion of high to toxic concentrations of vitamin D was higher in direct access users than in the GP population. Many people were taking more than the Institute of Medicine's recommendation of 10,000 IU/day, yet only a few were being medically supervised. Clinicians should be aware that patients may be self-administering very high concentrations of vitamin D, especially when investigating unexplained hypercalcaemia.

Hypovitaminosis D in bariatric surgery: A systematic review of observational studies

BACKGROUND

Obesity is a public health problem that carries global and substantial social and economic burden. Relative to non-surgical interventions, bariatric surgery has the most substantial and lasting impact on weight loss. However, it leads to a number of nutritional deficiencies requiring long term supplementation.

OBJECTIVES

The aims of this paper are to review 25-hydroxyvitamin D [25(OH)D] status pre and post bariatric surgery, describe the dose response of vitamin D supplementation, and assess the effect of the surgical procedure on 25(OH)D level following supplementation.

METHODS

We searched Medline, PubMed, the Cochrane Library and EMBASE, for relevant observational studies published in English, from 2000 to April 2015. The identified references were reviewed, in duplicate and independently, by two reviewers.

RESULTS

We identified 51 eligible observational studies assessing 25(OH)D status pre and/or post bariatric surgery. Mean pre-surgery 25(OH)D level was below 30ng/ml in 29 studies, and 17 of these studies showed mean 25(OH)D levels ≤20ng/ml. Mean 25(OH)D levels remained below 30ng/ml following bariatric surgery, despite various vitamin D replacement regimens, with only few exceptions. The increase in post-operative 25(OH)D levels tended to parallel increments in vitamin D supplementation dose but varied widely across studies. An increase in 25(OH)D level by 9-13ng/ml was achieved when vitamin D deficiency was corrected using vitamin D replacement doses of 1100-7100IU/day, in addition to the usual maintenance equivalent daily dose of 400-2000IU (total equivalent daily dose 1500-9100IU). There was no difference in mean 25(OH)D level following supplementation between malabsorptive/combination procedures and restrictive procedures.

CONCLUSION

Hypovitaminosisis D persists in obese patients undergoing bariatric surgery, despite various vitamin D supplementation regimens. Further research is needed to determine the optimal vitamin D dose to reach desirable 25(OH)D levels in this population, and to demonstrate whether this dose varies according to the surgical procedure.

Vitamin D, phosphate, and vasculotoxicity

Vascular calcification is a complex process that results in the ectopic deposition of calcium-phosphate hydroxyapatite. Medial and intimal vascular calcification is frequently present in patients with diabetes mellitus and chronic kidney disease (CKD), and markedly increases the morbidity and mortality of these patients. Increased serum levels of calcium and phosphate, along with the use of active vitamin D metabolites, are commonly implicated in the evolvement of vascular wall mineralization in CKD patients. Because CKD patients have lower serum levels of vitamin D, they are routinely prescribed vitamin D supplements that exert a dualistic role that is both healthful and harmful in these patients, perhaps protecting bone health, but at the expense of promoting vascular pathology. This review briefly explains how reducing the phosphate burden in CKD patients could minimize vitamin-D-associated vascular wall calcification.

Vitamin D deficiency remains prevalent despite increased laboratory testing in New South Wales, Australia

INTRODUCTION

The aim of the present study was to assess the prevalence of vitamin D deficiency and toxicity, the frequency of 25-hydroxyvitamin D (25[OH]D) testing, and 25(OH)D variations with respect to patient gender, patient age and season in New South Wales, Australia.

METHODS

A retrospective analysis of pathology records was performed to ascertain patient age, patient gender, sample collection date, plasma or serum 25(OH)D levels, calcium and parathyroid hormone (PTH) levels, and test numbers between 2001 and 2010. Linear regression with Bonferroni correction was used to calculate and compare age-adjusted mean 25(OH)D levels. Relationships of 25(OH)D with PTH and calcium were tested using Spearman's rank correlation.

RESULTS

25(OH)D testing increased by 730% over the ten-year study period. In 2010, many men (33%) and women (40%) were, to some degree, vitamin D deficient (≤ 50 nmol/L). Vitamin D toxicity was rare, with only one instance noted. 25(OH)D levels correlated positively with calcium and negatively with PTH levels. 25(OH)D levels decreased with age. In 2010, 25(OH)D levels were highest in February and lowest in September/October. Cyclical variation was observed for 25(OH)D levels between 2006 and 2010.

CONCLUSION

We found that vitamin D deficiency was prevalent in both men and women, with a higher prevalence in the latter, despite the substantial increased demand for 25(OH)D testing in our population over the decade. Vitamin D deficiency was associated with elevated PTH levels. Vitamin D toxicity was rare and only observed once during our study period. 25(OH)D levels decreased with age and varied with season, with the highest levels observed in late summer and the lowest in early spring.

Dose-response effect of ergocalciferol therapy on serum 25-hydroxyvitamin D concentration during critical illness

OBJECTIVE

The aim of this study was to evaluate the dose-response relationship between ergocalciferol therapy and serum 25-hydroxyvitamin D concentrations in enterally fed, critically ill patients with traumatic injuries.

METHODS

A retrospective cohort of critically ill patients with traumatic injuries and vitamin D deficiency (25-OH vitamin D <50 nmol/L) were given either 50 000 IU of liquid ergocalciferol weekly, twice weekly, or three times weekly while in the intensive care unit (ICU). Serum 25-OH vitamin D and ionized calcium concentrations were monitored weekly. Ergocalciferol therapy was stopped when the serum 25-OH vitamin D was >75 nmol/L, if the patient experienced hypercalcemia (ionized calcium >1.34 mmol/L), when the patient was discharged from the ICU, or if enteral nutrition was discontinued.

RESULTS

Sixty-five patients (16, 18, and 31 per dosage group) were examined. One (6%), two (11%), and eight (26%) patients achieved normal 25-OH vitamin D concentrations after 2 to 4 wk of ergocalciferol therapy for each dosage group, respectively (P < 0.001). Serum 25-OH vitamin D concentrations improved from 36 ± 6, 40 ± 7, and 37 ± 6 nmol/L to 50 ± 15, 54 ± 21, and 62 ± 17 nmol/L, respectively, after 2 wk of ergocalciferol therapy (P < 0.001) Two (13%), one (6%), and seven (23%) patients developed hypercalcemia for each dosage group, respectively (P = NS).

CONCLUSIONS

Ergocalciferol therapy improved baseline serum 25-OH vitamin D concentrations but was inadequate for consistently achieving normal serum concentrations of 25-OH vitamin D during critical illness. The trend in increasing appearance of mild hypercalcemia for the highest dosage group is concerning.

Emphasizing the health benefits of vitamin D for those with neurodevelopmental disorders and intellectual disabilities

People with neurodevelopmental disorders and intellectual disabilities have much greater health care needs. Mainly staying indoors, such people generally have low 25-hydroxyvitamin D (25(OH)D) concentrations. The Vitamin D Task Force of the American Academy of Developmental Medicine and Dentistry (AADMD) reviewed the evidence of 25(OH)D concentrations that benefit the health of persons with developmental disabilities. Maintaining recommended optimal serum 25(OH)D concentrations year long will benefit skeletal development in infants, children, and adolescents, and benefit musculoskeletal health and neuromuscular coordination in adult patients, and decrease risk of falls. Maintaining optimal concentrations decreases risks and severities of autoimmune diseases, cardiovascular disease, many types of cancer, dementia, types 1 and 2 diabetes mellitus, and respiratory tract infections. Other benefits include improved dental and oral health and improved physical performance. The Task Force recommends that 25(OH)D concentrations for optimal health to be in the range of 75 to 125 nmol/L, which can be achieved using between 800 and 4000 IU/day vitamin D3 and sensible exposure to solar UVB radiation. The paper also discusses the potential risks of higher 25(OH)D concentrations, the evidence from and limitations of randomized controlled trials, and the recommendations by various groups and agencies.

Optimal vitamin D levels in Crohn's disease: a review

Vitamin D deficiency is common among patients with Crohn's disease. Serum 25-hydroxyvitamin D (25(OH)D) is the best measure of an individual's vitamin D status and current cut-off ranges for sufficiency are debatable. Several factors contribute to vitamin D deficiency in Crohn's disease. These include inadequate exposure to sunlight, inadequate dietary intake, impaired conversion of vitamin D to its active metabolite, increased catabolism, increased excretion and genetic variants in vitamin D hydroxylation and transport. The effects of low 25(OH)D on outcomes other than bone health are understudied in Crohn's disease. The aim of the present review is to discuss the potential roles of vitamin D and the possible levels required to achieve them. Emerging evidence suggests that vitamin D may have roles in innate and adaptive immunity, in the immune-pathogenesis of Crohn's disease, prevention of Crohn's disease-related hospitalisations and surgery, in reducing disease severity and in colon cancer prevention. The present literature appears to suggest that 25(OH)D concentrations of ≥75 nmol/l may be required for non-skeletal effects; however, further research on optimal levels is required.

Vitamin D: An overview of vitamin D status and intake in Europe

In recent years, there have been reports suggesting a high prevalence of low vitamin D intakes and vitamin D deficiency or inadequate vitamin D status in Europe. Coupled with growing concern about the health risks associated with low vitamin D status, this has resulted in increased interest in the topic of vitamin D from healthcare professionals, the media and the public. Adequate vitamin D status has a key role in skeletal health. Prevention of the well-described vitamin D deficiency disorders of rickets and osteomalacia are clearly important, but there may also be an implication of low vitamin D status in bone loss, muscle weakness and falls and fragility fractures in older people, and these are highly significant public health issues in terms of morbidity, quality of life and costs to health services in Europe. Although there is no agreement on optimal plasma levels of vitamin D, it is apparent that blood 25-hydroxyvitamin D [25(OH)D] levels are often below recommended ranges for the general population and are particularly low in some subgroups of the population, such as those in institutions or who are housebound and non-Western immigrants. Reported estimates of vitamin D status within different European countries show large variation. However, comparison of studies across Europe is limited by their use of different methodologies. The prevalence of vitamin D deficiency [often defined as plasma 25(OH)D <25 nmol/l] may be more common in populations with a higher proportion of at-risk groups, and/or that have low consumption of foods rich in vitamin D (naturally rich or fortified) and low use of vitamin D supplements. The definition of an adequate or optimal vitamin D status is key in determining recommendations for a vitamin D intake that will enable satisfactory status to be maintained all year round, including the winter months. In most European countries, there seems to be a shortfall in achieving current vitamin D recommendations. An exception is Finland, where dietary survey data indicate that recent national policies that include fortification and supplementation, coupled with a high habitual intake of oil-rich fish, have resulted in an increase in vitamin D intakes, but this may not be a suitable strategy for all European populations. The ongoing standardisation of measurements in vitamin D research will facilitate a stronger evidence base on which policies can be determined. These policies may include promotion of dietary recommendations, food fortification, vitamin D supplementation and judicious sun exposure, but should take into account national, cultural and dietary habits. For European nations with supplementation policies, it is important that relevant parties ensure satisfactory uptake of these particularly in the most vulnerable groups of the population.

The importance of body weight for the dose response relationship of oral vitamin D supplementation and serum 25-hydroxyvitamin D in healthy volunteers

Unlike vitamin D recommendations by the Institute of Medicine, the Clinical Practice Guidelines by the Endocrine Society acknowledge body weight differentials and recommend obese subjects be given two to three times more vitamin D to satisfy their body's vitamin D requirement. However, the Endocrine Society also acknowledges that there are no good studies that clearly justify this. In this study we examined the combined effect of vitamin D supplementation and body weight on serum 25-hydroxyvitamin (25(OH)D) and serum calcium in healthy volunteers. We analyzed 22,214 recordings of vitamin D supplement use and serum 25(OH)D from 17,614 healthy adult volunteers participating in a preventive health program. This program encourages the use of vitamin D supplementation and monitors its use and serum 25(OH)D and serum calcium levels. Participants reported vitamin D supplementation ranging from 0 to 55,000 IU per day and had serum 25(OH)D levels ranging from 10.1 to 394 nmol/L. The dose response relationship between vitamin D supplementation and serum 25(OH)D followed an exponential curve. On average, serum 25(OH)D increased by 12.0 nmol/L per 1,000 IU in the supplementation interval of 0 to 1,000 IU per day and by 1.1 nmol/L per 1,000 IU in the supplementation interval of 15,000 to 20,000 IU per day. BMI, relative to absolute body weight, was found to be the better determinant of 25(OH)D. Relative to normal weight subjects, obese and overweight participants had serum 25(OH)D that were on average 19.8 nmol/L and 8.0 nmol/L lower, respectively (P<0.001). We did not observe any increase in the risk for hypercalcemia with increasing vitamin D supplementation. We recommend vitamin D supplementation be 2 to 3 times higher for obese subjects and 1.5 times higher for overweight subjects relative to normal weight subjects. This observational study provides body weight specific recommendations to achieve 25(OH)D targets.

Effects of vitamin D on patients with fibromyalgia syndrome: a randomized placebo-controlled trial

The role of calcifediol in the perception of chronic pain is a widely discussed subject. Low serum levels of calcifediol are especially common in patients with severe pain and fibromyalgia syndrome (FMS). We lack evidence of the role of vitamin D supplementation in these patients. To our knowledge, no randomized controlled trial has been published on the subject. Thirty women with FMS according to the 1990 and 2010 American College of Rheumatology criteria, with serum calcifediol levels <32ng/mL (80nmol/L), were randomized to treatment group (TG) or control group (CG). The goal was to achieve serum calcifediol levels between 32 and 48ng/mL for 20weeks via oral supplementation with cholecalciferol. The CG received placebo medication. Re-evaluation was performed in both groups after a further 24weeks without cholecalciferol supplementation. The main hypothesis was that high levels of serum calcifediol should result in a reduction of pain (visual analog scale score). Additional variables were evaluated using the Short Form Health Survey 36, the Hospital Anxiety and Depression Scale, the Fibromyalgia Impact Questionnaire, and the Somatization subscale of Symptom Checklist-90-Revised. A marked reduction in pain was noted over the treatment period in TG: a 2 (groups)×4 (time points) variance analysis showed a significant group effect in visual analog scale scores. This also was correlated with scores on the physical role functioning scale of the Short Form Health Survey 36. Optimization of calcifediol levels in FMS had a positive effect on the perception of pain. This economical therapy with a low side effect profile may well be considered in patients with FMS. However, further studies with larger patient numbers are needed to prove the hypothesis.

"Vitamin D supplementation and bone health in adults with diabetic nephropathy: the protocol for a randomized controlled trial"

BACKGROUND

Suboptimal vitamin D status is highly prevalent in Northern communities, particularly in those patients with chronic diseases such as diabetes and chronic renal disease. Emerging literature suggests that adherence to daily vitamin D supplementation may be an important factor influencing vitamin D status and overall bone health, but compliance with therapies for bone health is a major challenge. It is unknown what level of vitamin D supplementation will ameliorate or improve suboptimal vitamin D status in patients with diabetic nephropathy or contribute to improved bone health, particularly for those living in northern climates.

METHODS/DESIGN

The study purpose was to examine two different strategies of vitamin D3 supplementation; daily dosing of 2000 IU per day verses monthly dosing of 40,000 IU per month on markers of vitamin D status, bone health and to examine whether adherence, quality of life and patient satisfaction with the supplementation strategy differs between the two vitamin D strategies in adults diagnosed with diabetic nephropathy.

DISCUSSION

The need for RCTs assessing higher doses of vitamin D3 supplementation at varying frequencies of administration and its impact on bone health in adults with diabetes and chronic kidney disease are needed.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01476501.

Vitamin D and systemic lupus erythematosus: state of the art

Systemic lupus erythematosus (SLE) is a systemic inflammatory disease associated with genetic, environmental, hormonal, and immunological factors. One of these factors is vitamin D deficiency. Vitamin D plays many roles in the immune system. Several studies have suggested a potential role in the development of autoimmune diseases. SLE patients have low serum levels of vitamin D, which increase the possibility of an association between vitamin deficiency and disease onset and evolution. This review of the literature presents an analysis of the aspects related to the immunoregulatory effects of vitamin D and its importance for SLE, as well as the recommendations for vitamin D supplementation in these patients.

Vitamin D: deficiency, sufficiency and toxicity

The plethora of vitamin D studies over the recent years highlight the pleomorphic effects of vitamin D outside its conventional role in calcium and bone homeostasis. Vitamin D deficiency, though common and known, still faces several challenges among the medical community in terms of proper diagnosis and correction. In this review, the different levels of vitamin D and its clinical implications are highlighted. Recommendations and consensuses for the appropriate dose and duration for each vitamin D status are also emphasized.

Dose-related effects of vitamin D on immune responses in patients with clinically isolated syndrome and healthy control participants: study protocol for an exploratory randomized double- blind placebo-controlled trial

Background

There is increasing evidence linking vitamin D deficiency to both susceptibility to, and severity of, multiple sclerosis (MS). Patients with the clinically isolated syndrome represent the initial presentation of a demyelinating disorder, and those with asymptomatic lesions on magnetic resonance imaging (MRI) are at risk of progression to clinically definite MS. The aims of this study are to examine the immunologic effects of vitamin D in both healthy individuals and in patients with clinically isolated syndrome, and in the latter group the effects on disease progression assessed by MRI and clinical measures.

Methods/Design

This is a single-center double-blind randomized placebo-controlled clinical trial. The primary endpoint is the immunologic effects of two doses of vitamin D compared with placebo over 24 weeks in both healthy control participants and patients presenting with the clinically isolated syndrome. Healthy control participants (n = 39) and patients with clinically isolated syndrome (n = 45) will be randomized to one of three arms, namely 1) vitamin D 5,000 IU daily, 2) vitamin D 10,000 IU daily, or 3) placebo, and followed up for 24 weeks. In both patients and healthy control participants, the primary outcome will be immunologic measures of the frequency of CD4 T-cell subsets and cytokine responses in peripheral blood mononuclear cells, assessed at baseline, and after 16 and 24 weeks of treatment. Secondary endpoints, in the patients with clinically isolated syndrome, will be relapse activity, and the number of new T2 lesions and gadolinium-enhancing lesions assessed by MRI in the two vitamin D-treated groups compared with the placebo-treated group over the 24 weeks of the study.

Trial registration

EU Clinical Trials Register: EudraCT: 2012-000635-68. ClinicalTrials.gov identifier: NCT01728922

Comparison between daily supplementation doses of 200 versus 400 IU of vitamin D in infants

The daily supplementation of vitamin D is mandatory for infants. However, there are still conflicting opinions about the exact daily dose. Thus, we aimed to evaluate a daily supplementation dose of 200 IU is sufficient and compared the supplementation doses of 200 and 400 IU per day. One hundred and sixty-nine infants were randomly assigned to two groups (group 1, 200 IU/day; group 2, 400 IU/day) and there were 75 infants in group 1 and 64 were in group 2 with a total number of 139. The median levels of 25-hydroxyvitamin D3 were significantly increased in group 2 at the age of 4 months (group 1, 39.60 mcg/L; group 2, 56.55 mcg/L; p < 0.0001). We clearly demonstrated that at the age of 4 months, none of the infants on the group 2 had a serum level of 25-hydroxyvitamin D3 less than 30 mcg/L. However, 21.3% of the infants in group 1 had a level below 30 mcg/L. Thus, in order to avoid vitamin D deficiency and rickets, we recommend supplementation dose of vitamin D at 400 IU/day as a safe and effective dose.

Vitamin D and immune function

Vitamin D metabolizing enzymes and vitamin D receptors are present in many cell types including various immune cells such as antigen-presenting-cells, T cells, B cells and monocytes. In vitro data show that, in addition to modulating innate immune cells, vitamin D also promotes a more tolerogenic immunological status. In vivo data from animals and from human vitamin D supplementation studies have shown beneficial effects of vitamin D on immune function, in particular in the context of autoimmunity. In this review, currently available data are summarized to give an overview of the effects of vitamin D on the immune system in general and on the regulation of inflammatory responses, as well as regulatory mechanisms connected to autoimmune diseases particularly in type 1 diabetes mellitus.

Measurement of vitamin D

There are many different methods to choose for vitamin D analysis. While immunoassays are available commercially and readily automated, specificity for 25-hydroxyvitamin D2 and D3 is variable. Chemical assays such as HPLC and LC-MS/MS have greater specificity and are capable of detecting 25-hydroxyvitamin D2 and D3 separately, but are more complex and require method development. Currently LC-MS/MS is considered the method of choice for 25-hydroxyvitamin D analysis and the methods given here are for LC-MS/MS analysis of serum, plasma and dried whole blood for the separate quantitation of 25-hydroxyvitamin D2 and D3. In addition to highlighting potential interferences, the many non-analytical factors that influence vitamin D measurement are also discussed.

Vitamin D and Major Chronic Illness

OBJECTIVE

To review the current literature regarding vitamin D insufficiency and supplementation in major illnesses.

DESIGN AND METHODS

We reviewed Pubmed-indexed, English language manuscripts from January, 2003 to June, 2012 using search terms related to vitamin D, all-cause mortality, cardiovascular disease, pulmonary disease, diabetes mellitus, and cancer.

OUTCOME MEASURES

Incidence of disease, risk ratios associated with 25-hydroxyvitamin D [25(OH)D] levels, and/or vitamin D supplementation schedules were documented.

RESULTS

Although 25(OH)D levels ≥20 ng/mL were often associated with improved health outcomes, evidence suggests that 25(OH)D levels ≥30 ng/mL may confer additional health benefits.

CONCLUSIONS

Based on the available evidence, vitamin D supplementation to restore 25(OH)D levels within a range of 30-50 ng/mL is reasonable in order to optimize potential benefits and minimize potential risks. This, of course, should be considered in the context of individual patient needs and co-morbidities.

Vitamin D status and bone density in steroid-treated children with glomerulopathies: effect of cholecalciferol and calcium supplementation

PURPOSE

The aim of this study was to assess vitamin D status and bone density in steroid-treated children with glomerulopathies and to evaluate the effect of prophylactic vitamin D and calcium supplementation.

MATERIAL AND METHODS

Retrospective analysis was performed on 55 children aged 4-18 yrs with glomerulopathies. The following data were analyzed: antropometrical parameters, bone densitometries, parathormone, 25-hydroxyvitamin D (25-OHD), urinary calcium excretion and medications received for prevention of low bone mass.

RESULTS

A significant number of children (38%) had decreased spinal bone mineral density (BMD z-score < -2.0) and the majority of them (89%) had hypovitaminosis D (25-OHD < 30 ng/ml), 75% were vitamin D insufficient (25-OHD < 20 ng/ml) and 16% were vitamin D deficient (25-OHD < 10 ng/ml). The mean serum 25-OHD concentration was comparable to that of controls (19.32 ± 12.87 vs. 15.05 ± 8.52 ng/ml). Nearly all patients (82%) were receiving preparations of calcium and/or vitamin D to improve bone health. Patients on cholecalciferol had higher mean concentration of 25-OHD compared to those who were not receiving it (p=0.027) and to the controls (p=0.047). In 23 children on vitamin D and calcium supplementation for an average 6-month time, we observed an increase in the mean BMD values (p=0.004), however, mean BMD z-score and 25-OHD concentrations did not significantly change over time.

CONCLUSIONS

Vitamin D and bone density deficits are remarkably common in steroid-treated children with glomerulopathies, despite vitamin D and calcium repletion. In order to enhance the effectiveness of vitamin D supplementation for improvement of bone density, we suggest regular assessment of serum concentration of 25-OHD that can guide subsequent dose adjustment of vitamin D.

A prospective randomized controlled trial of the effects of vitamin D supplementation on cardiovascular disease risk

Vitamin D (VitD) supplementation has been advocated for cardiovascular risk reduction; however, supporting data are sparse. The objective of this study was to determine whether VitD supplementation reduces cardiovascular risk. Subjects in this prospective, randomized, double-blind, placebo-controlled trial of post-menopausal women with serum 25-hydroxyvitamin D concentrations >10 and <60 ng/mL were randomized to Vitamin D3 2500 IU or placebo, daily for 4 months. Primary endpoints were changes in brachial artery flow-mediated vasodilation (FMD), carotid-femoral pulse wave velocity (PWV), and aortic augmentation index (AIx). The 114 subjects were mean (standard deviation) 63.9 (3.0) years old with a 25-hydroxyvitamin D level of 31.3 (10.6) ng/mL. Low VitD (<30 ng/mL) was present in 47% and was associated with higher body-mass index, systolic blood pressure, glucose, CRP, and lower FMD (all p<0.05). After 4 months, 25-hydroxyvitamin D levels increased by 15.7 (9.3) ng/mL on vitamin D3 vs. −0.2 (6.1) ng/mL on placebo (p<0.001). There were no significant differences between groups in changes in FMD (0.3 [3.4] vs. 0.3 [2.6] %, p = 0.77), PWV (0.00 [1.06] vs. 0.05 [0.92] m/s, p = 0.65), AIx (2.7 [6.3] vs. 0.9 [5.6] %, p = 0.10), or CRP (0.3 [1.9] vs. 0.3 [4.2] mg/L, p = 0.97). Multivariable models showed no significant interactions between treatment group and low VitD status (<30 ng/mL) for changes in FMD (p = 0.65), PWV (p = 0.93), AIx (p = 0.97), or CRP (p = 0.26).In conclusion, VitD supplementation did not improve endothelial function, arterial stiffness, or inflammation. These observations do not support use of VitD supplementation to reduce cardiovascular disease risk.

Vitamin D and the critically ill patient

PURPOSE OF REVIEW

To summarize the current knowledge on vitamin D with a special focus on critically ill patients.

RECENT FINDINGS

Vitamin D deficiency is associated with adverse health outcomes including increased risk of cardiovascular disease, morbidity and mortality in the general population. In critically ill patients, the pleiotropic effects of vitamin D including its role in immune function are of great interest.

SUMMARY

To date, it is not clear whether vitamin D deficiency is a surrogate marker for increased morbidity or whether treatment with sufficiently large doses of vitamin D may improve patient outcome in an intensive care setting.

Vitamin D deficiency in pregnant women and their neonates in spring time in western Turkey

Although Turkey is located in a sunny region, vitamin D deficiency is still a serious health problem in pregnant women and their infants, especially among the low socio-economic status Turkish population. This study was carried out in order to measure serum 25-hydroxyvitamin D3 [25(OH)D] concentrations of the pregnant women in the last trimester and in their neonates at delivery and to determine the factors associated with maternal serum 25(OH)D concentrations. Among the patients visiting the Ege Obstetrics and Gynecology Hospital in the period March to May 2008, 258 healthy pregnant women ≥37 weeks of gestation were included in this study. The information on different characteristics such as the number of pregnancies and births, nutritional status, vitamin and mineral support during gestation, educational status, clothing style and the economic level of the family was collected from women. Blood samples from the mothers and umbilical cord of the newborns were taken to measure 25(OH)D. The mean 25(OH)D concentrations of the mothers and their infants were 11.5 ± 5.4 ng/mL and 11.5 ± 6.8 ng/mL, respectively. We found a strong positive correlation between maternal serum and umbilical cord blood 25(OH)D concentrations (r = 0.651, P < 0.001). The concentration of 25(OH)D was ≤20 ng/mL in 233 mothers (90.3%) and ≤10 ng/mL in 130 mothers (50.4%). Maternal serum 25(OH)D concentrations related strongly to factors such as uncovered dressing style, sufficient consumption of dairy products and multivitamin use during gestation (P < 0.05). About half (52.7%) of these women had a covered dressing style. 25(OH)D concentrations of these covered dressing mothers and their infants were 9.7 ± 5.1 ng/mL and 9.7 ± 5.6 ng/mL, respectively, which were significantly lower compared with those of uncovered mothers and their babies (P < 0.001). This study showed that, despite a sunny environment, vitamin D deficiency and insufficiency are highly prevalent among the mothers and their neonates. This is generally due to the life style and nutritional status of the mothers. These findings suggest that much more effective vitamin D prophylaxis programmes should be implemented for pregnant women as well as for their babies.

The effect of high-dose vitamin D on bone mineral density and bone turnover markers in postmenopausal women with low bone mass--a randomized controlled 1-year trial

Vitamin D is widely used in osteoporosis treatment, although the optimal dose is not known. This 1-year clinical study among 297 women aged 50-80 years old showed that a vitamin D(3) dose of 6,500 IU/day was not better than the standard dose of 800 IU/day in improving bone mineral density (BMD) in the hip and spine.

INTRODUCTION

The purpose of this study was to determine whether a high dose of vitamin D(3) was better than the standard dose in improving BMD and reducing bone turnover in postmenopausal women with reduced bone mass.

METHODS

The study was a 1-year randomized double-blind controlled trial comparing high-dose vitamin D(3) with the standard dose. Postmenopausal women (n = 297) with a BMD T-score ≤ -2.0 in either lumbar spine (L2-4) or total hip were included and randomized to 6,500 IU vitamin D(3)/day (20,000 IU twice per week + 800 IU/day) or 800 IU vitamin D(3)/day (placebo twice per week + 800 IU/day). Both groups were given 1,000 mg elemental calcium/day. The primary endpoint was a change in BMD in total hip and lumbar spine (L2-4).

RESULTS

After 1 year, serum 25-hydroxyvitamin D (25(OH)D) increased [mean (SD)] from 71 (23) to 185 (34) nmol/l and from 71 (22) to 89 (17) nmol/l in the high- and standard-dose vitamin D groups, respectively. BMD at all measurement sites was unchanged or slightly improved with no significant differences between the groups. Although bone turnover was reduced in both groups, the more pronounced reduction in serum levels of the bone formation marker P1NP in the standard-dose group may indicate that this treatment was more efficient. Adverse events did not differ between the groups.

CONCLUSIONS

One year treatment with 6,500 IU vitamin D(3)/day was not better than 800 IU/day regarding BMD in vitamin D-replete postmenopausal women with reduced bone mass and was less efficient in reducing bone turnover.

Vitamin D deficiency is associated with mortality in the medical intensive care unit

Introduction

The incidence of vitamin D deficiency in critically ill patients has been reported to range from as low as 17% to as high as 79%. Data regarding the relationship between 25-hydroxyvitamin D levels and outcomes in the medical intensive care unit are sparse. The goal of the study was to evaluate the prevalence of 25-hydroxyvitamin D deficiency in the medical intensive care unit and its relationship with outcomes.

Method

This was a retrospective study in a medical intensive care unit (MICU) at an inner city community hospital. The study period was between October 2009 and February 2010.

Results

Of the 932 patients admitted during the study period, 25-hydroxyvitamin D vitamin D (25(OH)D) levels were available in 523 (53%); 86 of them were excluded from the study due to readmission to the intensive care unit. Deficiency was defined as 0 to 19.9 ng/dL 25(OH)D levels, insufficiency as 20 to 29.9 ng/dL, and normal levels as ≥30 ng/dL. Of the 437 patients studied, 25(OH)D deficiency was identified in 340 (77.8%), insufficiency in 74 (16.9%), and normal levels in 23 (5.3%) patients. Patients with 25(OH)D deficiency/insufficiency were younger (P = 0.015), were male (P = 0.001), and had kidney disease (P = 0.017) and lower total serum calcium levels (P = 0.003). Hospital mortality was higher in patients with 25(OH)D deficiency (P = 0.01). No differences in ventilator days or length of stay in the MICU were evident among the three groups. Analysis by multiple logistic regression demonstrated that acute physiology and chronic health evaluation (APACHE) IV score ((odds ratio (OR) 1.036; 95% confidence interval (CI) 1.024-1.048, P < 0.0001), ventilator requirement (OR 7.7; 95% CI 4.3-13.98, P < 0.0001), 25(OH) D levels(OR 0.942; 95% CI 0.942-0.904, P < 0.0005) and 25(OH) D deficiency (OR 8.7; 95% CI 1.03-72.8, P < 0.0469) showed statistical significance. There was no association between 25(OH)]D insufficiency and hospital mortality. The mean 25(OH)D level of survivors (27.9 ± 9.7 ng/dL) was higher than for non-survivors (9.7 ± 4.7 ng/dL; P < 0.0001).

Conclusions

The study results demonstrate an association between 25(OH)D deficiency and hospital mortality in MICU patients. A randomized prospective study to evaluate the effect of vitamin D replacement therapy on mortality is warranted.

Vitamin D, cognitive dysfunction and dementia in older adults

The physiologically active form of vitamin D, 1,25-dihydroxyvitamin D(3), is a fat-soluble steroid hormone with a well established role in skeletal health. A growing body of evidence suggests low vitamin D levels also play a role in the pathogenesis of a wide range of non-skeletal, age-associated diseases including cancer, heart disease, type 2 diabetes mellitus and stroke. Low levels of serum 25-hydroxyvitamin D [25(OH)D], a stable marker of vitamin D status, are also associated with increased odds of prevalent cognitive dysfunction, Alzheimer's disease and all-cause dementia in a number of studies, raising the possibility that vitamin D plays a role in the aetiology of cognitive dysfunction and dementia. To date, the majority of human studies reporting associations between vitamin D and cognition or dementia have been cross-sectional or case-control designs that do not permit us to exclude the possibility that such associations are a result of disease progression rather than being causal. Animal and in vitro experiments have identified a number of neuroprotective mechanisms that might link vitamin D status to cognitive dysfunction and dementia, including vasoprotection and amyloid phagocytosis and clearance, but the clinical relevance of these mechanisms in humans is not currently clear. Two recent, large, prospective studies go some way to establish the temporal relationship with cognitive decline. The relative risk of cognitive decline was 60% higher (relative risk = 1.6, 95% CI 1.2, 2.0) in elderly Italian adults with severely deficient 25(OH)D levels (<25 nmol/L) when compared with those with sufficient levels (≥75 nmol/L). Similarly, the odds of cognitive decline were 41% higher (odds ratio = 1.4, 95% CI 0.9, 2.2) when elderly US men in the lowest quartile (≤49.7 nmol/L) were compared with those in the highest quartile (≥74.4 nmol/L). To our knowledge, no prospective studies have examined the association between 25(OH)D levels and incident dementia or neuroimaging abnormalities. The possible therapeutic benefits of vitamin D have attracted considerable interest as over 1 billion people worldwide are thought to have insufficient 25(OH)D levels and these levels can be increased using inexpensive and well tolerated dietary supplements. However, no large randomized controlled trials have yet examined the effect of vitamin D supplements on cognitive decline or incident dementia. Further studies are urgently needed to establish which mechanisms have clinical relevance in human populations and whether vitamin D supplements are effective at minimizing cognitive decline or preventing dementia.

Short-term effects of high-dose oral vitamin D3 in critically ill vitamin D deficient patients: a randomized, double-blind, placebo-controlled pilot study

Introduction

Vitamin D deficiency is encountered frequently in critically ill patients and might be harmful. Current nutrition guidelines recommend very low vitamin D doses. The objective of this trial was to evaluate the safety and efficacy of a single oral high-dose vitamin D3 supplementation in an intensive care setting over a one-week observation period.

Methods

This was a randomized, double-blind, placebo-controlled pilot study in a medical ICU at a tertiary care university center in Graz, Austria. Twenty-five patients (mean age 62 ± 16yrs) with vitamin D deficiency [25-hydroxyvitamin D (25(OH)D) ≤20 ng/ml] and an expected stay in the ICU >48 hours were included and randomly received either 540,000 IU (corresponding to 13.5 mg) of cholecalciferol (VITD) dissolved in 45 ml herbal oil or matched placebo (PBO) orally or via feeding tube.

Results

The mean serum 25(OH)D increase in the intervention group was 25 ng/ml (range 1-47 ng/ml). The highest 25(OH)D level reached was 64 ng/ml, while two patients showed a small (7 ng/ml) or no response (1 ng/ml). Hypercalcemia or hypercalciuria did not occur in any patient. From day 0 to day 7, total serum calcium levels increased by 0.10 (PBO) and 0.15 mmol/L (VITD; P < 0.05 for both), while ionized calcium levels increased by 0.11 (PBO) and 0.05 mmol/L (VITD; P < 0.05 for both). Parathyroid hormone levels decreased by 19 and 28 pg/ml (PBO and VITD, ns) over the seven days, while 1,25(OH)D showed a transient significant increase in the VITD group only.

Conclusions

This pilot study shows that a single oral ultra-high dose of cholecalciferol corrects vitamin D deficiency within 2 days in most patients without causing adverse effects like hypercalcemia or hypercalciuria. Further research is needed to confirm our results and establish whether vitamin D supplementation can affect the clinical outcome of vitamin D deficient critically ill patients.

EudraCT Number

2009-012080-34

German Clinical Trials Register (DRKS)

DRKS00000750