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

Hypervitaminosis D is correlated with adverse dental implant outcomes: A retrospective case-control study

OBJECTIVES

To investigate vitamin-D levels effect on the survival/success and on marginal bone levels of dental implants.

METHODS

Patients with peri-implant disease and healthy control patients with functionally loaded dental implants were included in this retrospective case-control study. Forty patients with 201 implants were in the diseased-cohort, while thirty-three patients with 90 implants were in the control-cohort. Patient blood 25(OH)D levels were assessed through quantitative blood test. The correlation between abnormal 25(OH)D levels and disease status of each patient was assessed using Fisher's exact tests. The correlation of each implant's outcomes with vitamin-D status was assessed using Kaplan-Meier survival analysis and Mann-Whitney U tests.

RESULTS

Patients with blood 25(OH)D levels >70 ng/mL (hypervitaminosis-D) had a 21.1-fold increase in the risk of implant failure or severe peri-implant bone loss regarding patients with intermediate (>30, ≤70 ng/mL) levels. Kaplan-Meier survival analysis revealed that implants in the hypervitaminosis-D cohort had a survival probability of 73.7 % (95 % CI:56.5-84.5 %) at 19-years after surgery, compared to 95 % for implants in patients with intermediate 25(OH)D levels (95 % CI:88.3-97.9 %). Additionally, implants in the hypervitaminosis-D cohort lost bone faster than implants in the intermediate cohort. These results were specific to the patient cohort with elevated blood 25(OH)D levels and not observed in patients taking vitamin-D supplementation. The impact of hypervitaminosis-D was enriched for implants in the maxilla, and not as apparent for implants in the mandible.

CONCLUSIONS

Blood 25(OH)D levels >70 ng/mL were correlated with adverse implant outcomes, including implant failure and peri-implant bone loss, especially in the maxilla.

CLINICAL RELEVANCE

These results suggest that hypervitaminosis D may be a previously unidentified risk factor for dental implant complications and should be further investigated to elucidate the underlying mechanism.

[A e-Hypercalcemia]

INTRODUCTION

Hypercalcemia is a common biological abnormality. The etiologies are mainly represented by hyperparathyroidism and neoplastic causes. The other causes, including poisoning, are rare, but should not be neglected.

OBSERVATION

An 82-year-old female patient presented to the emergency room for repeated falls at home, confusion, drowsiness and digestive symptoms. The initial assessment showed hypercalcemia above 3mmol/L. The etiological exploration revealed a very high concentration of 25OH-vitamin D. After repeated interrogations, it appeared that the cause of this intoxication was the intake of a food supplement purchased on the internet, following a prescription from her dentist.

CONCLUSION

Intoxication due to a food supplement containing vitamin D is possible and potentially serious. Raising the awareness of patients and healthcare professionals is necessary in order to prevent this type of poisoning and/or to diagnose it as soon as possible.

EXPERIMENTAL CHOLECALCIFEROL SUPPLEMENTATION IN A HERD OF MANAGED ASIAN ELEPHANTS (ELEPHAS MAXIMUS)

Vitamin D supplementation may pose a significant health risk in species where levels of deficiency, sufficiency, and toxicity have not been clearly established, and species-specific research on vitamin D supplementation should be performed. This study documented the effect of vitamin D supplementation on serum vitamin D metabolites and other analytes of Ca homeostasis in Asian elephants (Elephas maximus). Six adult Asian elephants received PO supplementation with cholecalciferol at 300 IU/kg of body weight (BW) once a week for 24 wk. Serum was analyzed every 4 wk for 25-hydroxyvitamin D₂/D₃ [25(OH)D]; 24,25-dihydroxyvitamin D₂/D₃ [24,25(OH)₂D]; 1,25-dihydroxyvitamin D [1,25(OH)₂D]; parathyroid hormone (PTH); total Ca; ionized Ca (iCa); P; and Mg. After the supplement was discontinued, serum 25(OH)D₂/D₃ was measured every 4 wk until levels returned to baseline. At the start of the study, the average serum 25(OH)D₃ was nondetectable (<1.5 ng/ml). With cholecalciferol supplementation, 25(OH)D₃ increased at an average rate of 2.26 ng/ml per month and reached an average concentration of 12.9 ± 3.46 ng/ml at 24 wk. Both 24,25(OH)₂D₃ and 1,25(OH)₂D increased over time with supplementation from an average of <1.5 to 12.9 ng/ml and from 9.67 to 36.4 pg/ml, respectively. PTH, iCa, Ca, P, and Mg remained within reported normal ranges throughout supplementation. After the supplement was discontinued, serum 25(OH)D₃ demonstrated a slow decline to baseline, taking an average of 48 wk. Elephants demonstrated significant individual variation in response to supplementation and subsequent return to baseline. Supplementation of Asian elephants with a weekly dose of 300 IU/kg BW cholecalciferol for 24 wk appears to be effective and safe. Additional clinical studies would be necessary to investigate the safety of other routes of administration, dosages, and duration of vitamin D supplementation, as well as associated health benefits.

Prevalence of Iatrogenic Vitamin D Toxicity Among the Saudi Population of Vitamin D Users Due to Overcorrection

Background Despite abundant sunlight exposure, vitamin D deficiency remains a major challenge in Saudi Arabia. Meanwhile, the widespread use of vitamin D supplements has prompted concerns about toxicity, which although rare, can have severe health consequences. Objective The objective of this cross-sectional study was to analyze the prevalence and associated factors of iatrogenic vitamin D toxicity among the Saudi population of vitamin D users due to overcorrection. Methods An online questionnaire was used to collect data from 1,677 participants across all regions of Saudi Arabia. The questionnaire included responses on the prescription, duration of vitamin D intake, dosage, frequency, history of vitamin D toxicity, symptom onset, and duration. Results One thousand six hundred and seventy-seven responses were included across all regions of Saudi Arabia. A majority of participants were female (66.7%) and around half were aged 18-25 years. A history of vitamin D use was reported by 63.8% of participants, and 48% were still using vitamin D supplements. Most participants (79.3%) consulted a physician, and 84.8% had taken a vitamin D test before using the supplement. Commonly reported motives for taking vitamin D included vitamin D deficiency (72.1%), lack of sun exposure (26.1%), and hair loss (20.6%). Symptoms of overdose were reported by 6.6% of participants, with 3.3% having an overdose and 2.1% experiencing both overdose and symptoms. Conclusion This study showed that although a large portion of the Saudi population is taking vitamin D supplements, the prevalence of vitamin D toxicity is relatively low. However, this prevalence should not be ignored, and further research is needed to understand the factors contributing to vitamin D toxicity in order to minimize its occurrence.

Vitamin D Supplementation Does Not Influence SARS-CoV-2 Vaccine Efficacy or Immunogenicity: Sub-Studies Nested within the CORONAVIT Randomised Controlled Trial

Vitamin D deficiency has been reported to associate with the impaired development of antigen-specific responses following vaccination. We aimed to determine whether vitamin D supplements might boost the immunogenicity and efficacy of SARS-CoV-2 vaccination by conducting three sub-studies nested within the CORONAVIT randomised controlled trial, which investigated the effects of offering vitamin D supplements at a dose of 800 IU/day or 3200 IU/day vs. no offer on risk of acute respiratory infections in UK adults with circulating 25-hydroxyvitamin D concentrations <75 nmol/L. Sub-study 1 (n = 2808) investigated the effects of vitamin D supplementation on the risk of breakthrough SARS-CoV-2 infection following two doses of SARS-CoV-2 vaccine. Sub-study 2 (n = 1853) investigated the effects of vitamin D supplementation on titres of combined IgG, IgA and IgM (IgGAM) anti-Spike antibodies in eluates of dried blood spots collected after SARS-CoV-2 vaccination. Sub-study 3 (n = 100) investigated the effects of vitamin D supplementation on neutralising antibody and cellular responses in venous blood samples collected after SARS-CoV-2 vaccination. In total, 1945/2808 (69.3%) sub-study 1 participants received two doses of ChAdOx1 nCoV-19 (Oxford−AstraZeneca); the remainder received two doses of BNT162b2 (Pfizer). Mean follow-up 25(OH)D concentrations were significantly elevated in the 800 IU/day vs. no-offer group (82.5 vs. 53.6 nmol/L; mean difference 28.8 nmol/L, 95% CI 22.8−34.8) and in the 3200 IU/day vs. no offer group (105.4 vs. 53.6 nmol/L; mean difference 51.7 nmol/L, 45.1−58.4). Vitamin D supplementation did not influence the risk of breakthrough SARS-CoV-2 infection in vaccinated participants (800 IU/day vs. no offer: adjusted hazard ratio 1.28, 95% CI 0.89 to 1.84; 3200 IU/day vs. no offer: 1.17, 0.81 to 1.70). Neither did it influence IgGAM anti-Spike titres, neutralising antibody titres or IFN-γ concentrations in the supernatants of S peptide-stimulated whole blood. In conclusion, vitamin D replacement at a dose of 800 or 3200 IU/day effectively elevated 25(OH)D concentrations, but it did not influence the protective efficacy or immunogenicity of SARS-CoV-2 vaccination when given to adults who had a sub-optimal vitamin D status at baseline.

Effect of a test-and-treat approach to vitamin D supplementation on risk of all cause acute respiratory tract infection and covid-19: phase 3 randomised controlled trial (CORONAVIT)

OBJECTIVE

To determine the effect of population level implementation of a test-and-treat approach to correction of suboptimal vitamin D status (25-hydroxyvitamin D (25(OH)D) <75 nmol/L) on risk of all cause acute respiratory tract infection and covid 19.

DESIGN

Phase 3 open label randomised controlled trial.

SETTING

United Kingdom.

PARTICIPANTS

6200 people aged ≥16 years who were not taking vitamin D supplements at baseline.

INTERVENTIONS

Offer of a postal finger prick test of blood 25(OH)D concentration with provision of a six month supply of lower dose vitamin D (800 IU/day, n=1550) or higher dose vitamin D (3200 IU/day, n=1550) to those with blood 25(OH)D concentration <75 nmol/L, compared with no offer of testing or supplementation (n=3100). Follow-up was for six months.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of participants with at least one swab test or doctor confirmed acute respiratory tract infection of any cause. A secondary outcome was the proportion of participants with swab test confirmed covid-19. Logistic regression was used to calculate odds ratios and associated 95% confidence intervals. The primary analysis was conducted by intention to treat.

RESULTS

Of 3100 participants offered a vitamin D test, 2958 (95.4%) accepted and 2674 (86.3%) had 25(OH)D concentrations <75 nmol/L and received vitamin D supplements (n=1328 lower dose, n=1346 higher dose). Compared with 136/2949 (4.6%) participants in the no offer group, at least one acute respiratory tract infection of any cause occurred in 87/1515 (5.7%) in the lower dose group (odds ratio 1.26, 95% confidence interval 0.96 to 1.66) and 76/1515 (5.0%) in the higher dose group (1.09, 0.82 to 1.46). Compared with 78/2949 (2.6%) participants in the no offer group, 55/1515 (3.6%) developed covid-19 in the lower dose group (1.39, 0.98 to 1.97) and 45/1515 (3.0%) in the higher dose group (1.13, 0.78 to 1.63).

CONCLUSIONS

Among people aged 16 years and older with a high baseline prevalence of suboptimal vitamin D status, implementation of a population level test-and-treat approach to vitamin D supplementation was not associated with a reduction in risk of all cause acute respiratory tract infection or covid-19.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04579640.

Vitamin D replacement in children with acute wheeze: a dose-escalation study

Meta-analyses report protective effects of vitamin D supplementation against asthma exacerbations and acute respiratory infections in adults [1–3], but data relating to effects of vitamin D on risk of preschool wheeze and asthma attacks in childhood are more limited [4]. In preparation for a randomised controlled trial (RCT) of vitamin D in children with recurrent preschool wheeze or school-age asthma, we carried out a dose-escalation study to find the daily vitamin D₃ supplementation regimen that is most effective in elevating circulating 25-hydroxyvitamin D (25(OH)D) concentrations in these children. We hypothesised that daily oral vitamin D₃ supplementation of 1000 IU would be more effective than 400 IU (UK recommendation [5]) in elevating the circulating 25(OH)D concentration to ≥75 nmol·L⁻¹ at 3 months in vitamin-D-insufficient children with recurrent preschool wheeze or school-age asthma.

Vitamin D supplementation at the current UK recommended level (400 IU·day⁻¹) or enhanced supplementation (1000 IU·day⁻¹) failed to achieve adequate levels of vitamin D (>75 nmol·L⁻¹) in vitamin-D-insufficient children with acute wheezehttps://bit.ly/3J43Ouo

Practices of vitamin D supplementation leading to vitamin D toxicity: Experience from a Low-Middle Income Country

Introduction

The trend of prescribing VD preparations for nonspecific body aches and self-medication has increased significantly. The importance of vitamin D toxicity (VDT) has been underestimated and under recognized. This study was done to determine the frequency toxicity (>150 ng/ml) in subjects for 25-hydroxyvitamin D (25OHD) and evaluate the vitamin D (VD) supplements used by these subjects.

Methodology

This descriptive cross-sectional study was conducted at the Section of Chemical Pathology, Aga Khan University Hospital Karachi from April 2020 to March 2021. Subjects with 25OHD toxicity were contacted and information related to history of calcium and VD supplementation were collected. The statistical analysis was performed using the Microsoft Excel 2016.

Results

Over a year period 105398 subjects were tested for serum 25OHD, of which 0.34% (n = 364) subjects had 25OHD level of >150 ng/ml. After satisfying exclusion criteria 186 subjects (78 were <18 years of age and 108 were adults) were included in final analysis. All of these were using VD supplements and the main indications were delayed growth/short height (43.7%, n = 34) and aches or pains in (54.6%, n = 59) in pediatric and adult subjects respectively.

Most of the subjects were taking supplements orally (74.1%, n = 138). Commonly prescribed preparation in adults and pediatric was 200,000 IU (70.4%, n = 76) and 400 IU (35.9%, n = 28) respectively. Most subjects took supplements for 1–3 months (68.3%, n = 127). Stated total supplementation ranged from 20,000 IU to 3600,000 IU in pediatric subjects and 200,000 IU to 96,00,000 IU in adults.

Conclusions

Supplementation is a leading cause of potential toxic levels of 25OHD. The condition can be prevented by careful use of VD supplements and consistent monitoring.

•

Vitamin D toxicity is extremely rare; but it may happen at high doses. The use of vitamin D supplementation should be guarded and monitored.

•

In this study we observed that vitamin D toxicity (>150 ng/ml) was prevalent, present in 0.34% (n=364) subjects.

•

Main indications of supplementation were delayed growth in children and aches or pains in adults

The effect of hypervitaminosis D and intoxication on haematological parameters

BACKGROUND

This study aims to compare the haematological parameters of patients with very high and normal 25-hydroxyvitamin-D3 (25(OH)D3) levels.

METHODS

This study was designed as a retrospective cross-sectional study. The patients were divided into three groups according to their 25(OH)D3 levels: groups 1, 2 and 3 are patients with normal 25(OH)D3 levels (30-88 ng/mL), hypervitaminosis D (89-149 ng/mL) and vitamin D intoxication (>150 ng/mL), respectively. According to vitamin D levels, statistical analysis was performed by comparing the biochemical and haematological data between the groups.

RESULTS

This study evaluated 120 patients (40 patients) in three equal groups. A statistically significant difference was found between the three groups in haemoglobin (p = 0.03), haematocrit (p = 0.01), red blood cell levels (p = 0.03), leukocyte count (p < 0.001), neutrophil count (p < 0.001), lymphocyte count (p = 0.006), mean platelet volume (p = 0.04), and neutrophil/lymphocyte ratio (p = 0.03). In post hoc analysis, haemoglobin, haematocrit and RBC were significantly higher in group 1 than in group 3 (post hoc Tukey, p < 0.05). A statistically significant negative correlation was noted between 25(OH)D3 level and haemoglobin (r = -0.236), haemotocrit (r = -0.230), and red blood cell (r = -0.265) levels.

CONCLUSIONS

Vitamin D intoxication has been observed to affect haemoglobin, haematocrit, and RBC levels negatively. However, more studies are needed to clarify the effects and mechanisms of high vitamin D levels on the haematopoietic system.

Risk of hypercalcemia in patients with very high serum 25-OH vitamin D levels

OBJECTIVE

We aimed to evaluate the risk of hypercalcemia in patients with very high levels of 25-hydroxy vitamin D (25(OH)D).

METHODS

The distribution of patients who were screened for 25(OH)D in our hospital between January 2014 and December 2018 was evaluated and patients with serum concentrations of 25(OH)D >88 ng/mL were selected. Then, biochemical parameters of the cases with 25(OH)D >88 ng/mL were compared according to calcium status, vitamin D level (group 1, 88-100 ng/mL; group 2, 100-150 ng/mL, and group 3, >150 ng/mL), and gender.

RESULTS

A total of 282 932 patients who underwent 25(OH)D tests in our hospital were evaluated. A total of 1311 (0.5%) patients had very high 25(OH)D levels (>88 ng/mL). Four hundred and ninety-five patients who met our inclusion criteria and had complete data participated in the study. The median age was 58 years (interquartile range [IQR] = 41-71 years) and the median level of 25(OH)D was 104.6 mg/mL (IQR = 94.9-124.9 ng/mL). Most of the subjects (83.7%) with very high 25(OH)D levels were normocalcemic. A weak inverse correlation was observed between 25(OH)D level and intact parathyroid hormone (iPTH) level (r = -0.118, P = .01), but no correlation between 25(OH)D and calcium levels was observed. Alkaline phosphatase (ALP) levels were significantly higher in males (P = .032), and age and iPTH levels were higher in females (P < .001 and P = .004). ALP, phosphorus levels, and iPTH suppression rates were higher in hypercalcemic patients (P < .001, P < .001, and P < .001, respectively), while the iPTH level was significantly lower in hypercalcemic patients (P < .001) than in normocalcemic patients. Amongst the three groups with different 25(OH)D levels, no difference was found in levels of iPTH, calcium, phosphorus, ALP, or age.

CONCLUSION

Most patients with very high vitamin D levels were normocalcemic, but severe hypercalcemia was also observed. Vitamin D replacement therapy and follow-up should be performed according to clinical guideline recommendations.

Remote testing of vitamin D levels across the UK MS population-A case control study

Objective

The association between vitamin D deficiency and multiple sclerosis (MS) is well described. We set out to use remote sampling to ascertain vitamin D status and vitamin D supplementation in a cross-sectional study of people with MS across the UK.

Methods

People with MS and matched controls were recruited from across the UK. 1768 people with MS enrolled in the study; remote sampling kits were distributed to a subgroup. Dried blood spots (DBS) were used to assess serum 25(OH)D in people with MS and controls.

Results

1768 MS participants completed the questionnaire; 388 MS participants and 309 controls provided biological samples. Serum 25(OH)D was higher in MS than controls (median 71nmol/L vs 49nmol/L). A higher proportion of MS participants than controls supplemented (72% vs 26%, p<0.001); people with MS supplemented at higher vD doses than controls (median 1600 vs 600 IU/day, p<0.001). People with MS who did not supplement had lower serum 25(OH)D levels than non-supplementing controls (median 38 nmol/L vs 44 nmol/L). Participants engaged well with remote sampling.

Conclusions

The UK MS population have higher serum 25(OH)D than controls, mainly as a result of vitamin D supplementation. Remote sampling is a feasible way of carrying out large studies.

Population vitamin D supplementation in UK adults: too much of nothing?

Topics for DTB review articles are selected by DTB's editorial board to provide concise overviews of medicines and other treatments to help patients get the best care. Articles include a summary of key points and a brief overview for patients. Articles may also have a series of multiple choice CME questions.

Quality and use of unlicensed vitamin D preparations in primary care in England: Retrospective review of national prescription data and laboratory analysis

AIM

To evaluate the type (licensed vs unlicensed) and cost of preparations used to fulfil vitamin D prescriptions in England over time, and to compare measured vitamin D content of selected vitamin D preparations against labelled claim.

METHODS

Retrospective analysis of vitamin D prescription data in primary care in England (2008-2018). Laboratory analysis of 13 selected vitamin D preparations.

RESULTS

Alongside a rise in the number of oral licensed colecalciferol preparations from 0 to 27 between 2012 and 2018, the proportion of vitamin D prescriptions in which licensed vitamin D preparations were supplied increased from 11.8 to 54.2%. However, the use of unlicensed food supplements (dose strength 400-50 000 IU) remained high, accounting for 39.7% of vitamin D prescriptions in 2018. The two licensed preparations showed mean (±SD) vitamin D content of 90.9 ± 0.7% and 90.5 ± 3.9% of the labelled claimed amount, meeting the British Pharmacopeia specification for licensed medicines (90-125% of labelled claim). The 11 food supplements showed vitamin D content ranging from 41.2 ± 10.6% to 165.3 ± 17.8% of the labelled claim, with eight of the preparations failing to comply with the food supplement specification (80-150% of labelled claim).

CONCLUSIONS

Despite the increasing availability of quality assured licensed preparations, food supplements continued to be used interchangeably with licensed preparations to fulfil vitamin D prescriptions. Food supplements, manufactured under less stringent quality standards, showed wide variations between measured and declared vitamin D content, which could lead to the risk of under- and over-dosing.

Efficiency of Vitamin D Supplementation in Healthy Adults is Associated with Body Mass Index and Baseline Serum 25-Hydroxyvitamin D Level

Vitamin D (VitD) has a critical role in phosphorous-calcium metabolism as well as an important role in the immune system. In the human body, VitD is synthesized as cholecalciferol in the skin, but this process requires sunlight (UVB) radiation. Numerous reports showed high prevalence of VitD deficiency, particularly during the winter season, indicating the importance of VitD supplementation. Various factors can affect the absorption of VitD, including dosage and formulation. The primary study objective was to examine the efficiency of supplementation with three different formulations containing cholecalciferol in comparison with the control group. The secondary objective was to identify other factors affecting increase in serum 25-OH-VitD. A randomized controlled intervention study was conducted in Slovenia during wintertime (January- March) on 105 apparently healthy subjects (aged 18-65 years) with suboptimal VitD status (25-OH-VitD 30-50 nmol/L). Subjects were randomized into four groups: three treatment groups receiving (A) capsules with starch-adsorbed VitD, (B) oil-based Valens VitD oral spray, or (C) water-based Valens VitD oral spray and a control group (D) which did not receive supplemental VitD. Two months of supplementation with cholecalciferol (1000 IU; 25 µg daily) resulted in significant increase in serum 25-OH-VitD levels in comparison with control group (pooled Δc 32.8 nmol/L; 95% CI: 23.0, 42.5, p < 0.0001). While we did not observe any significant differences between the tested formulations, the efficiency of supplementation was associated with body mass index and baseline serum 25-OH-VitD level. Higher supplementation efficiency was observed in participants with normal body weight (BMI < 25) and in those with more pronounced VitD insufficiency. We also determined that tested dosage was not sufficient to achieve recommended 25-OH-VitD levels in all subjects.

Rate of change of circulating 25-hydroxyvitamin D following sublingual and capsular vitamin D preparations

BACKGROUND

Vitamin D is critical for skeletal health, and is increasingly associated with other pathologies encompassing gastrointestinal, immunological and psychological effects. A significant proportion of the population exhibits suboptimal levels of vitamin D, particularly in Northern latitudes in winter. Supplementation is advocated, but few data are available on achievable or typical rates of change. There has been considerable interest in the potential use of sublingual sprays for delivery of nutrient supplements, but data on efficacy remain sparse.

METHODS

A randomised, placebo-controlled, three-arm parallel design study was conducted in healthy volunteers (n = 75) to compare the rate of change of vitamin D status in response to vitamin D3 (3000 IU/day) supplementation in capsule and sublingual spray preparations over a 6-week period between January and April 2017. Blood 25(OH)D concentrations were measured after day 0, 3, 7, 14, 21 and 42 days of supplementation with 3000 IU per diem.

RESULTS

Baseline measurements show 25(OH)D deficiency (<30 nmol/l), insufficiency (31-46 nmol/l) and sufficiency (> 50 mmol/l) in 14.9, 44.6 and 40.5% of the participants, respectively. There was a significant elevation in blood concentrations of 25(OH)D in both of the treatment arms (capsule p = 0.003, spray p = 0.001) compared with control. The capsule and spray were equally efficacious. The rate of change ranged from 0.69 to 3.93 (capsule) and 0.64 to 3.34 (spray) nmol/L day with average change in blood 25(OH)D levels of 2 nmol/l/day. Rates followed a simple normal distribution in the study population (ks = 0.94 and 0.82 for capsule and spray, respectively). The data suggest that rates of change are higher in individuals with lower levels of 25(OH)D.

CONCLUSIONS

A sublingual vitamin D spray is an effective mode of delivery for supplementation in a healthy population. The data provide reference values and ranges for the rate of change of 25(OH)D for nutrikinetic analyses.

Vitamin D status and its management for achieving optimal health benefits in the elderly

INTRODUCTION

Vitamin D deficiency is common, world-wide, but vitamin D repletion throughout life, and into older age, has accepted health benefits for bone. Many mechanisms through which vitamin D also benefits soft tissues are understood, and clinical evidence of such benefits is now accumulating, especially following re-analyses of trial data, which are revealing previously missed health benefits with correction of deficiency.

AREAS COVERED

The sources of vitamin D, its activation, mechanistic effects; problems of trials of supplementation for reducing health risks, the benefits shown for mortality, cardiovascular disease, infection and cancer; the global problem of vitamin D deficiency; age-related reductions in vitamin D efficacy, and currently recommended intakes.

EXPERT COMMENTARY

High prevalence of vitamin D deficiency and insufficiency worldwide have proven ill-effects on health. Governmental efforts to improve population repletion by recommending minimal daily intakes does benefit some but is not effective at the population-level. However, food fortification with vitamin D3, already implemented in some countries, can solve this highly avoidable problem cost-effectively and is probably the best way to abolish vitamin D inadequacy, allowing public health benefits to emerge over time, thereby allowing future research on vitamin D to be directed at emerging issues on vitamin D.

Risks of the 'Sunshine pill' - a case of hypervitaminosis D

Vitamin D is a fat-soluble vitamin essential for calcium homeostasis and bone health. Vitamin D toxicity or hypervitaminosis D is extremely rare. We describe the case of a 73-year-old man who presented with life-threatening hypervitaminosis D and hypercalcaemia resulting from self-medicated doses of vitamin D supplements. This case, alongside other global case reports, highlights the potential dangers of unlicensed vitamin D replacement. We discuss the evidence for vitamin D replacement and remind readers of the current guidance on daily intake and supplementation.

The value and significance of 25(OH) and 1,25(OH) vitamin D serum levels in adult coeliac patients: A review of the literature

Within the wide spectrum of symptoms and alteration of systems that characterizes CeD, several studies indicate a low-level of vitamin D, therefore recent guidelines suggest its evaluation at the time of diagnosis. This review examines the data from existing studies in which vitamin D has been assessed in CeD patients. Our review indicates that most of the studies on vitamin D in adult CeD report a 25 (OH) vitamin D deficiency at diagnosis that disappears when the patient goes on a gluten-free diet, independently of any supplementation. Instead, when the calcitriol, the active 1,25 (OH) vitamin D form, was evaluated, it resulted in the normal range at the time of CeD diagnosis. A strict and lifelong gluten-free diet can help recover vitamin D level without any supplementation.

Dose-dependent effects of vitamin 1,25(OH)2D3 on oxidative stress and apoptosis

Background The purpose of this study is to examine the dose-dependent effects of vitamin 1,25(OH)2D3 on apoptosis and oxidative stress. Methods In this study, 50 male Balb/c mice were used as control and experiment groups. The mice were divided into 5 groups each consisting of 10 mice. Calcitriol was intraperitoneally administered as low dose, medium dose, medium-high dose and high dose vitamin D groups (at 0.5, 1, 5 and 10 μg/kg, respectively), for three times a week during 14 days. At the end of the study, annexin V was measured by enzyme-linked immunosorbent assay method, and total antioxidant capacity and total oxidant status values were measured by colorimetric method in serum. Hematoxylin eosin staining was performed in liver tissues and periodic acid schiff staining was performed in kidney tissues. Results While comparing the results of medium-high dose (5 μg/kg) and high dose (10 μg/kg) vitamin D administration to that of the control group, it was observed that serum antioxidant status and annexin V levels decreased and glomerular mesenchial matrix ratio increased in kidney (p<0.05). In addition to these findings, in the group receiving high dose vitamin D (10 μg/kg), it was observed that the damage to the liver increased together with the the oxidative stress index values (p<0.05). Conclusions As a result, this study was the first in the literature to report that use of high-dose vitamin D (10 μg/kg) results in oxidant effect, rather than being an antioxidant, and causes severe histopathological toxicity in the liver and kidney.

A review of the growing risk of vitamin D toxicity from inappropriate practice

Vitamin D is a particularly important sterol hormone, with evidence emerging of its beneficial effects well beyond bone. In consequence of this and increased global recognition of vitamin D deficiency in the general population, there has been a resurgence in treatment with vitamin D preparations. However, the increasing use of vitamin D treatments has also seen a substantial increase in the number of reports of vitamin D intoxication, with the majority (75%) of reports published since 2010. Many of these cases are a consequence of inappropriate prescribing, and the use of high-dose over-the-counter preparations or unlicensed preparations. This review highlights that the majority of cases were preventable and discusses the inappropriate use of poorly formulated, and unlicensed vitamin D preparations.