Vitamin D toxicity, policy, and science

Adverse events from large dose vitamin D supplementation taken for one year or longer

In recent years, clinical trials increasingly have given large doses of vitamin D supplements to investigate possible health benefits beyond bone at high 25-hydroxyvitamin D levels. However, there are few publications on the safety of high-dose vitamin D given long term. The study objective was to investigate the cumulative relative risk (RR) of total adverse events, kidney stones, hypercalcemia and hypercalciuria from ≥2800 IU/d vitamin D₂ or D₃ supplementation, followed for one year or more in randomized controlled trials (RCTs). A systematic review was conducted in Medline Ovid, EMBASE and Cochrane in March 2018 to update results of studies published since a previous review in October 2015. RCTs were included if they gave vitamin D₂ or D₃ at ≥2800 IU/d for at least one year and reported on total adverse events or at least one calcium-related adverse event. There were a total of 32 studies that met the inclusion criteria. Of these, only 15 studies (3150 participants) reported one or more event of the outcomes of interest. Long-term high-dose vitamin D supplementation did not increase total adverse events compared to placebo in 1731 participants from 10 studies (RR = 1.05; 95% CI = 0.88, 1.24; p = 0.61), nor kidney stones in 1336 participants from 5 studies (RR = 1.26; 95% CI = 0.35, 4.58; p = 0.72). However, there was a trend for vitamin D to increase risk of hypercalcemia in 2598 participants from 10 studies (RR = 1.93; 95% CI = 1.00, 3.73; p = 0.05); while its effect on hypercalciuria in only 276 participants from 3 studies was inconclusive (RR = 1.93; 95% CI = 0.83, 4.46; p = 0.12). In conclusion, one year or longer supplementation with a large daily, weekly or monthly dose of vitamin D₂ /D₃ did not significantly increase a risk of total adverse events or kidney stones, although there was a trend towards increased hypercalcemia, and possibly for hypercalciuria.

Vitamin D and critical illness: what endocrinology can learn from intensive care and vice versa

The prevalence of vitamin D deficiency in intensive care units ranges typically between 40 and 70%. There are many reasons for being or becoming deficient in the ICU. Hepatic, parathyroid and renal dysfunction additionally increases the risk for developing vitamin D deficiency. Moreover, therapeutic interventions like fluid resuscitation, dialysis, surgery, extracorporeal membrane oxygenation, cardiopulmonary bypass and plasma exchange may significantly reduce vitamin D levels. Many observational studies have consistently shown an association between low vitamin D levels and poor clinical outcomes in critically ill adults and children, including excess mortality and morbidity such as acute kidney injury, acute respiratory failure, duration of mechanical ventilation and sepsis. It is biologically plausible that vitamin D deficiency is an important and modifiable contributor to poor prognosis during and after critical illness. Although vitamin D supplementation is inexpensive, simple and has an excellent safety profile, testing for and treating vitamin D deficiency is currently not routinely performed. Overall, less than 800 patients have been included in RCTs worldwide, but the available data suggest that high-dose vitamin D supplementation could be beneficial. Two large RCTs in Europe and the United States, together aiming to recruit >5000 patients, have started in 2017, and will greatly improve our knowledge in this field. This review aims to summarize current knowledge in this interdisciplinary topic and give an outlook on its highly dynamic future.

The Effect of Nordic Walking Training Combined with Vitamin D Supplementation on Postural Control and Muscle Strength in Elderly People-A Randomized Controlled Trial

Nordic Walking (NW) and Vitamin D concentration (Vit D) alone have been shown to contribute to the health and performance of elderly people. However, the interaction between these two factors has yet to be explored. In this study 42 women over 60 years of age (69.02 ± 5.56 years) were recruited and divided in two NW groups: a high-intensity interval training group (HI-NW) and a moderate-intensity continuous training group (MI-NW). Individuals from each group completed a 12-week NW training program (3 times a week/2 hours) combined with randomized Vitamin D supplementation (HD = high dose: 4000 IU/day or LD = low dose: 800 IU/day). Body composition, postural control, muscle strength and Vitamin D serum concentration were measured twice; before and after the intervention. To investigate the interaction between supplementation and training a mixed-design analysis of variance (ANOVA) was performed. The HI-NW group, regardless of supplementation dose, increased their Vit D and elbow torque performance. On the other hand, in the MI-NW group the same Vit D outcome was seen only with HD supplementation and was also associated with increased leg muscle mass. In conclusion, beneficial effects of both HI-NW and MI-NW training regimes were seen. The impact of the dose supplementation on Vit D and body composition was related to the type of NW training.

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.

Successful Treatment of Severe Atopic Dermatitis with Calcitriol and Paricalcitol in an 8-Year-Old Girl

Atopic dermatitis (AD) is a chronic inflammatory disease affecting children and adolescence. The traditional therapeutic options for AD, including emollients topically and immune modulatory agents systemically focusing on reducing skin inflammation and restoring the function of the epidermal barrier, are proven ineffective in many cases. Several studies have linked vitamin D supplementation with either a decreased risk to develop AD or a clinical improvement of the symptoms of AD patients. In this report, we present a girl with severe AD who under adequate supplementation with cholecalciferol was treated with calcitriol and subsequently with paricalcitol. She had significant improvement-almost healing of her skin lesions within 2 months, a result sustained for more than 3 years now. Because of hypercalciuria as a side effect from calcitriol therapy, treatment was continued with paricalcitol, a vitamin D analogue used in secondary hyperparathyroidism in chronic kidney disease. Calcitriol therapy may be considered as a safe and efficacious treatment option for patients with severe AD, particularly for those with refractory AD, under monitoring for possible side effects. Treatment with paricalcitol resolves hypercalciuria, is safe, and should be further investigated as an alternative treatment of atopic dermatitis and possibly other diseases of autoimmune origin.

Lactase persistence may explain the paradoxical findings of high vitamin D concentrations in Europeans living in areas of low UV-B irradiation

BACKGROUND/OBJECTIVES

Vitamin D has a critical role in skeletal health and maintaining serum calcium levels. Calcium is needed for a variety of cellular and metabolic processes in the body. Large amounts of vitamin D can be produced in the skin when exposed to UV-B radiation. It is therefore a paradox that in Europe, Caucasians living in higher latitude countries, such as Scandinavia and Iceland, have higher serum vitamin D compared with those living in lower latitude. In a recent study of adult-type lactase persistence (LP), it was shown that Caucasian of European descent, who carried the C-13910T LP allele, had higher levels of total serum 25-hydroxyvitamin D compared with those who were lactase non-persistent. This was attributed to higher consumption of dairy. We postulated that the distribution of the LP C-13910T allele in Caucasian populations may explain the vitamin D concentration pattern seen in Europe.

SUBJECTS/METHODS

Baseline mean total serum 25 hydroxyvitamin D concentration from a clinical trial of post-menopausal women with osteoporosis was correlated to published LP frequencies in European populations.

RESULTS

In multiple regression analysis, mean total serum 25 hydroxyvitamin D concentrations in both winter and summer were in turn correlated to LP phenotype frequency (winter: r² = 0.51, p < 0.05; summer: r² = 0.4, p < 0.05).

CONCLUSIONS

High frequency of LP in northern Europe may explain high mean total serum 25 hydroxyvitamin D concentrations despite low UV-B radiation exposure.

Vitamin D in Vascular Calcification: A Double-Edged Sword?

Vascular calcification (VC) as a manifestation of perturbed mineral balance, is associated with aging, diabetes and kidney dysfunction, as well as poorer patient outcomes. Due to the current limited understanding of the pathophysiology of vascular calcification, the development of effective preventative and therapeutic strategies remains a significant clinical challenge. Recent evidence suggests that traditional risk factors for cardiovascular disease, such as left ventricular hypertrophy and dyslipidaemia, fail to account for clinical observations of vascular calcification. Therefore, more complex underlying processes involving physiochemical changes to mineral balance, vascular remodelling and perturbed hormonal responses such as parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF-23) are likely to contribute to VC. In particular, VC resulting from modifications to calcium, phosphate and vitamin D homeostasis has been recently elucidated. Notably, deregulation of vitamin D metabolism, dietary calcium intake and renal mineral handling are associated with imbalances in systemic calcium and phosphate levels and endothelial cell dysfunction, which can modulate both bone and soft tissue calcification. This review addresses the current understanding of VC pathophysiology, with a focus on the pathogenic role of vitamin D that has provided new insights into the mechanisms of VC.

Vitamin D and the Skin: An Update for Dermatologists

Vitamin D plays a key role in skeletal and cardiovascular disorders, cancers, central nervous system diseases, reproductive diseases, infections, and autoimmune and dermatological disorders. The two main sources of vitamin D are sun exposure and oral intake, including vitamin D supplementation and dietary intake. Multiple factors are linked to vitamin D status, such as Fitzpatrick skin type, sex, body mass index, physical activity, alcohol intake, and vitamin D receptor polymorphisms. Patients with photosensitive disorders tend to avoid sun exposure, and this practice, along with photoprotection, can put this category of patients at risk for vitamin D deficiency. Maintaining a vitamin D serum concentration within normal levels is warranted in atopic dermatitis, psoriasis, vitiligo, polymorphous light eruption, mycosis fungoides, alopecia areata, systemic lupus erythematosus, and melanoma patients. The potential determinants of vitamin D status, as well as the benefits and risks of vitamin D (with a special focus on the skin), will be discussed in this article.

Vitamin D levels and risk for periodontal disease: A systematic review

OBJECTIVE

To evaluate the existing evidence supporting or refuting the following questions: (i) Do patients with lower vitamin D levels have higher risk for periodontal disease? (ii) Are periodontal treatment outcomes improved by the adjuvant supplementation of vitamin D or by elevated serum vitamin D levels?

MATERIAL AND METHODS

MEDLINE, SCOPUS, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched up to September 2017. Studies were included if they had measured serum vitamin D levels or vitamin D intake and any periodontal parameter.

RESULTS

Overall, 27 studies were included (13 cross-sectional studies, 6 case-control studies, 5 cohort studies, 2 randomized clinical trials and 1 case series study). Sixty-five percent of the cross-sectional studies reported significant associations between low vitamin D levels and poor periodontal parameters. None of the observational longitudinal studies found that periodontal disease progression could be attributed to lower vitamin D levels. No interventional studies that evaluated the use of vitamin D supplementation as a solely adjuvant to periodontal treatment was found. No meta-analysis was performed due to high variability across studies.

CONCLUSION

The data to support or refute the association between vitamin D levels and periodontal disease are inconclusive at the moment. More rigorously designed longitudinal studies with standardized definitions of periodontal disease and vitamin D are necessary.

Vitamin D, cod liver oil, sunshine, and phototherapy: Safe, effective and forgotten tools for treating and curing tuberculosis infections - A comprehensive review

Tuberculosis remains an epidemic throughout the world, with over 2 billion people, or more than one third of the world's population, infected with TB. In 2015, there were an estimated 10.4 million new cases of tuberculosis, and 1.8 million deaths, making TB one of the top ten causes of death worldwide. Approximately 95% of new TB cases occur in developing countries, where the costs of treatment force many patients and their families into poverty. The United Nations and the World Health Organization are working to end this global epidemic. Historically, cod liver oil in the 1840's, phototherapy in the 1890's, sunshine in the 1890's and 1930's, oral vitamin D in doses of 100,000-150,000 international units a day the 1940's, and injectable vitamin D in the 1940's were all shown to be able to safely treat tuberculosis. However, for reasons that are unclear, these treatments are no longer being used to treat tuberculosis. We will review several reports that documented the clinical efficacy of these seemingly disparate treatments in treating tuberculosis. Taken together, however, these reports show the consistent efficacy of vitamin D in treating tuberculosis infections, regardless of whether the vitamin D was produced in the skin from the effects of phototherapy or sunshine, taken orally as a pill or in cod-liver oil, or put into solution and injected directly into the body. We will discuss how vitamin D, through its action as a steroid hormone that regulates gene transcription in cells and tissues throughout the body, enables the body to eradicate TB by stimulating the formation of a natural antibiotic in white blood cells, the mechanism of which was discovered in 2006. We will speculate as to why vitamin D, cod liver oil, sunshine, and phototherapy are no longer being used to treat tuberculosis, in spite of their proven efficacy in safely treating this disease dating back to the early 1800's. In fact, in 1903 the Nobel Prize in Medicine or Physiology was awarded to a physician who was able to cure hundreds of cases of long-standing lupus vulgaris (cutaneous TB) with refracted light rays from an electric arc lamp. Vitamin D, cod liver oil, sunshine, and phototherapy have never been shown to lose their ability to safely eradicate tuberculosis infections, and deserve consideration to be re-examined as first-line treatments for tuberculosis. These treatments have the potential to help cost-effectively and safely end the global TB epidemic.

Association of serum 25-hydroxyvitamin D status with bone mineral density in 0-7 year old children

OBJECTIVE

To describe the status of serum 25-hydoxyvitamin D [25(OH)D] concentrations and identify the relationship between 25(OH)D and bone mineral density (BMD). In an effort to explore the appropriate definition of vitamin D (VD) deficiency in 0-7 year old children.

RESULTS

The median serum 25(OH)D concentrations was 62.9 nmol/L and 28.9% of the children had a low 25(OH)D (< 50 nmol/L). And a linear relation between 25(OH)D concentrations and BMD was surveyed (r = 0.144 , P < 0.001). After adjusting for the confounders, serum 25(OH)D was positively associated with BMD (β = 172.0, 95%CI = 142.8-201.2, P < 0.001), and low 25(OH)D (< 75 nmol/L) had a high stake for low BMD (OR = 1.424, 95%CI = 1.145-1.769, P = 0.001). Additionally, there was a nonlinear relation between 25(OH)D and low BMD, and a critical value for 25(OH)D of 75 nmol/L appeared for low BMD. The prevalence of low BMD was 14.1% in children with 25(OH)D ≥ 75 nmol/L, much lower than that of the concentrations between 50-75 nmol/L and < 50 nmol/L.

MATERIALS AND METHODS

A total of 4,846 children 0-7 years old were recruited in Jiangsu Province, China. BMD and serum 25(OH)D concentrations were determined by quantitative ultrasound and enzyme-linked immunosorbent assay, respectively. Linear regression and logistic regression analyses were used to assess the association of 25(OH)D concentrations with BMD.

CONCLUSIONS

Serum 25(OH)D concentrations was related with BMD and 25(OH)D concentrations < 75 nmol/L might be a more appropriate definition of VD deficiency in 0-7 year old children.

Rationale and Plan for Vitamin D Food Fortification: A Review and Guidance Paper

Vitamin D deficiency can lead to musculoskeletal diseases such as rickets and osteomalacia, but vitamin D supplementation may also prevent extraskeletal diseases such as respiratory tract infections, asthma exacerbations, pregnancy complications and premature deaths. Vitamin D has a unique metabolism as it is mainly obtained through synthesis in the skin under the influence of sunlight (i.e., ultraviolet-B radiation) whereas intake by nutrition traditionally plays a relatively minor role. Dietary guidelines for vitamin D are based on a consensus that serum 25-hydroxyvitamin D (25[OH]D) concentrations are used to assess vitamin D status, with the recommended target concentrations ranging from ≥25 to ≥50 nmol/L (≥10-≥20 ng/mL), corresponding to a daily vitamin D intake of 10 to 20 μg (400-800 international units). Most populations fail to meet these recommended dietary vitamin D requirements. In Europe, 25(OH)D concentrations <30 nmol/L (12 ng/mL) and <50 nmol/L (20 ng/mL) are present in 13.0 and 40.4% of the general population, respectively. This substantial gap between officially recommended dietary reference intakes for vitamin D and the high prevalence of vitamin D deficiency in the general population requires action from health authorities. Promotion of a healthier lifestyle with more outdoor activities and optimal nutrition are definitely warranted but will not erase vitamin D deficiency and must, in the case of sunlight exposure, be well balanced with regard to potential adverse effects such as skin cancer. Intake of vitamin D supplements is limited by relatively poor adherence (in particular in individuals with low-socioeconomic status) and potential for overdosing. Systematic vitamin D food fortification is, however, an effective approach to improve vitamin D status in the general population, and this has already been introduced by countries such as the US, Canada, India, and Finland. Recent advances in our knowledge on the safety of vitamin D treatment, the dose-response relationship of vitamin D intake and 25(OH)D levels, as well as data on the effectiveness of vitamin D fortification in countries such as Finland provide a solid basis to introduce and modify vitamin D food fortification in order to improve public health with this likewise cost-effective approach.

Is there a role for vitamin D in supporting cognitive function as we age?

Globally, an estimated 46 million people are currently living with dementia and this figure is projected to increase 3-fold by 2050, highlighting this major public health concern and its substantial associated healthcare costs. With pharmacological treatment yet to reach fruition, the emphasis on evidence-based preventative lifestyle strategies is becoming increasingly important and several modifiable lifestyle factors have been identified that may preserve cognitive health. These include good cardiovascular health, physical activity, low alcohol intake, smoking and a healthy diet, with growing interest in vitamin D. The aim of the present paper is to review the evidence supporting the potential roles of vitamin D in ageing and cognitive health in community-dwelling older adults. Furthermore, to describe the utility and challenges of cognitive assessments and outcomes when investigating vitamin D in this context. Evidence indicates that serum 25-hydroxyvitamin D (25(OH)D) may impact brain health. There is a biological plausibility from animal models that vitamin D may influence neurodegenerative disorders, through several mechanisms. Epidemiological evidence supports associations between low serum 25(OH)D concentrations and poorer cognitive performance in community-dwelling older populations, although an optimal 25(OH)D level for cognitive health could not be determined. The effect of raising 25(OH)D concentrations on cognitive function remains unclear, as there is a paucity of interventional evidence. At a minimum, it seems prudent to aim to prevent vitamin D deficiency in older adults, with other known common protective lifestyle factors, as a viable component of brain health strategies.

Vitamin D and systemic lupus erythematosus - The hype and the hope

Over the past 20years, much has been written about the potential role of vitamin D in on adverse health outcomes. In recent years, evidence has accumulated regarding the effect of vitamin D on the immune system, and its different cells. Some studies have noted lower vitamin D concentrations in patients with SLE. These epidemiological data still not answer the question: is vitamin D deficiency the cause or the effect? To answer this, we will discuss the association between vitamin D deficiency and SLE and review the evidence from interventional studies.

Results of daily oral dosing with up to 60,000 international units (iu) of vitamin D3 for 2 to 6 years in 3 adult males

In the 1930's and 1940's, vitamin D was reported to be an effective treatment for a number of diseases, including asthma, psoriasis, rheumatoid arthritis, rickets and tuberculosis. High doses were used, 60,000 to 300,000 IU a day for asthma, and 200,000 to 600,000 IU a day for rheumatoid arthritis. Toxicity from hypercalcemia occurred after prolonged oral dosing with these supraphysiologic doses. Assays for measuring vitamin D in the blood were not available, and blood levels of vitamin D associated with hypercalcemia were unknown. A 2011 report on vitamin D toxicity showed that hypercalcemia resolved when 25-hydroxyvitamin D (25OHD) blood levels dropped below 400ng/ml in 2 patients with blood levels ranging from 645ng/ml to 1220ng/ml after accidental ingestion of massive doses of vitamin D. We now know that vitamin D is made in the skin in amounts ranging up to 25,000 IU a day with exposure to UVB radiation. There is little data on the safety and blood levels of 25OHD and calcium after prolonged daily intake of amounts of vitamin D in this range. In this report, one subject took increasing daily doses of vitamin D3 for 6 years starting in April 2009: 6500 IU for 6 months; increasing to 10,000 IU for 13 months; 20,000 IU for 24 months; 40,000 IU for 12 months; 50,000 IU for 10 months, and 60,000 IU since October 2014. 25OHD blood levels were 28, 81, 204, 216, 225, 166, and 218ng/ml. Subject 2 began 10,000 IU in Nov 2011, increased to 20,000 IU in Feb 2014, 25,000 IU in June 2014, and 30,000 IU in Oct 2014, and then decreased to 20,000 IU in June 2015. 25OHD blood levels were 96.6, 161.1 and 106.9ng/ml. He reported marked clinical improvement in his asthma. Subject 3 started on daily 10,000 IU in Sept 2013, increasing to 20,000 IU on Nov 2013. 25OHD blood levels were 31.4, 102, 164, 148, and 143ng/ml. No one developed hypercalcemia or any adverse events. The major finding of this case series is prolonged daily dosing of vitamin D3 with doses of 10,000 to 60,000 IU was safely tolerated.

Vitamin D and Cardiovascular Disease: Controversy Unresolved

Vitamin D deficiency is typically caused by inadequate cutaneous synthesis secondary to decreased exposure to sunlight. Serum levels of 25-hydroxyvitamin D l <20 ng/ml are diagnostic of vitamin D deficiency. Vitamin D has various cardiovascular pleiotropic effects by activating its nuclear receptor in cardiomyocytes and vascular endothelial cells and by regulating the renin-angiotensin-aldosterone system, adiposity, energy expenditure, and pancreatic cell activity. In humans, vitamin D deficiency is associated with the following: vascular dysfunction; arterial stiffening; left ventricular hypertrophy; and worsened metrics of diabetes, hypertension, and hyperlipidemia. It is also linked with worse cardiovascular morbidity and mortality. However, meta-analyses of vitamin D supplementation trials have failed to show clear improvements in blood pressure, insulin sensitivity, or lipid parameters, thus suggesting that the link between vitamin D deficiency and cardiovascular disease may be an epiphenomenon. Ongoing larger randomized trials will clarify whether monitoring and supplementation of vitamin D play roles in cardiovascular protection.

Vitamin D levels in Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive congenital malformation syndrome caused by mutations in the 7-dehydrocholesterol reductase gene. This inborn error of cholesterol synthesis leads to elevated concentrations of 7-dehydrocholesterol (7-DHC). 7-DHC also serves as the precursor for vitamin D synthesis. Limited data is available on vitamin D levels in individuals with SLOS. Due to elevated concentrations of 7-DHC, we hypothesized that vitamin D status would be abnormal and possibly reach toxic levels in patients with SLOS. Through a retrospective analysis of medical records between 1998 and 2006, we assessed markers of vitamin D and calcium metabolism from 53 pediatric SLOS patients and 867 pediatric patients who were admitted to the NIH Clinical Center (NIHCC) during the same time period. SLOS patients had significantly higher levels of 25(OH)D (48.06 ± 19.53 ng/ml, p < 0.01) across all seasons in comparison to the NIHCC pediatric patients (30.51 ± 16.14 ng/ml). Controlling for season and age of blood draw, 25(OH)D levels were, on average, 15.96 ng/ml (95%CI 13.95-17.90) higher in SLOS patients. Although, mean calcium values for both patient cohorts never exceeded the normal clinical reference range (8.6-10.2 mg/dl), the levels were higher in the SLOS cohort (9.49 ± 0.56 mg/dl, p < 0.01) compared to the NIHCC patients (9.25 ± 0.68 mg/dl). Overall, in comparison to the control cohort, individuals with SLOS have significantly higher concentrations of 25(OH)D that may be explained by elevated concentrations of serum 7-DHC. Despite the elevated vitamin D levels, there was no laboratory or clinical evidence of vitamin D toxicity.

Direct and indirect risk associated with the use of dietary supplements among persons with dementia in a Norwegian memory clinic

BACKGROUND

The use of dietary supplements (DS) is common among persons with dementia. Direct risks associated with DS use include adverse events and DS-drug interactions. A direct risk is a risk caused by the treatment itself. Indirect risks are related to the treatment setting, such as the conditions of use, and not to the treatment itself. Because dementia symptoms may reduce a person's ability to cope with the administration of DS, the use of DS may pose a threat to safety as an indirect risk. The aim of this study was to describe the extent of DS use among persons with dementia in ambulatory care and to identify some relevant direct and indirect risks related to DS use.

METHODS

We conducted a survey among 151 persons with dementia attending an outpatient memory clinic in Northern Norway. Study measurements included: the participants' characteristics, cognitive functioning, functioning in the activities of daily living (ADL), and the use of DS and prescription drugs (PD). We assessed direct risks by evaluating potential DS-drug interactions and indirect risks by evaluating the conditions under which it was used.

RESULTS

Forty-six percent (n = 70) of the persons with dementia used DS. Ninety-seven percent (n = 147) used PD. We found potentially clinically relevant DS-drug interactions representing a direct risk in eight persons with dementia (11% of users). While only 36% (n = 26) of the participants received assistance with the administration of DS, 73% (n = 106) received assistance with the administration of PD. Persons with dementia living alone were at risk of not receiving assistance, as home care service seldom was involved in DS administration. Data indicated that assistance with DS administration was not provided for all persons with dementia in need, representing an indirect risk to these persons. Only one-third of the persons with dementia and half of the caregivers were aware of the general risks of adverse events and interactions associated with the use of DS.

CONCLUSIONS

Persons with dementia use DS frequently, yet DS use may be associated with direct and indirect risks to patient safety as potentially clinically relevant interactions were discovered and DS intake often was unsupervised.

Maternal vitamin D insufficiency and risk of adverse pregnancy and birth outcomes: A systematic review and meta-analysis of longitudinal studies

BACKGROUND

Three previous reviews on the association of vitamin D insufficiency in pregnancy with preterm birth (PTB) and stillbirth were limited in scope and deemed inconclusive. With important new evidence accumulating, there is the need to update the previous estimates and assess evidence on other clinically important outcomes such as spontaneous abortion and Apgar score. We conducted a systematic review and meta-analysis to evaluate the quality and strength of the available evidence on the relations between vitamin D nutritional status, and pregnancy and birth outcomes.

METHODS

PubMed and Scopus databases were searched from their inception to June, 2015 with no language restrictions imposed. Eighteen longitudinal studies satisfied the inclusion criteria. Random effects model was applied in computing the summary effect estimates and their corresponding 95% confidence intervals.

RESULTS

Serum 25(OH)D levels <75 nmol/l was associated with 83% (95% CI: 1.23, 2.74) and 13% (95% CI: 0.94, 1.36) increased risk of PTB measured at <32-34 weeks and <35-37 weeks, respectively. An inverse dose-response relation was observed for both PTB outcome. Serum 25(OH)D levels <75 nmol/l was also associated with 11% increased risk of spontaneous PTB (<35-37 weeks; RR = 1.11; 95% CI: 0.75, 1.65) with a dose-response relation also noted. Vitamin D insufficiency was not associated with risk of spontaneous abortion and stillbirth (RR of 1.04 [95% CI: 0.95, 1.13] and 1.02 [95% CI: 0.96, 1.09], respectively), as well as short gestational length (ES = -0.24, 95% CI: -0.69, 0.22), and low Apgar score.

CONCLUSIONS

We found vitamin D insufficiency to be associated with risk of PTB. Regarding spontaneous abortion and stillbirth, the available evidence suggest no association with low vitamin D levels. The evidence on vitamin D nutrition and Apgar score is conflicting and controversial. Overall, the experimental evidence uncovered was small and weak. Hence, the benefits of vitamin D supplementation during pregnancy should be further evaluated through rigorous intervention studies.

Pharmacokinetics and effects of demographic factors on blood 25(OH)D3 levels after a single orally administered high dose of vitamin D3

AIM

To examine the biological consequences and demographic factors that might affect the pharmacokinetics of vitamin D3 after a single high dose intervention in a young Chinese population with vitamin D insufficiency status.

METHODS

A total of 28 young subjects (25 to 35 years old) with vitamin D insufficiency status [serum 25(OH)D <30 ng/mL] was recruited in Shanghai, China. The subjects were orally administered a single high dose of vitamin D3 (300 000 IU). Baseline characteristics and blood samples were collected at d 0, 1, 2, 3, 7, 28, 56, 84 and 112 after the intervention. The blood biomarker levels were determined with standardized methods.

RESULTS

The intervention markedly increased the blood 25(OH)D3 levels within the first five days (mean T_max=5.1±2.1 d) and sustained an optimal circulating level of 25(OH)D3 (≥30 ng/mL) for 56 d. After the intervention, body weight and baseline 25(OH)D3 levels were significantly correlated with circulating 25(OH)D3 levels. No adverse events and no consistently significant changes in serum calcium, creatinine, glucose, parathyroid hormone, vitamin D binding protein, or the urinary calcium/reatinine ratio were observed. However, there was a significant increase in phosphorus after the vitamin D3 intervention. Total cholesterol and triglyceride levels were decreased at the end of the trial.

CONCLUSION

The pharmacokinetics of vitamin D after intervention were influenced by baseline 25(OH)D3 levels and the body weight of the subjects. The results suggest that a single high oral vitamin D3 intervention is safe and efficient for improving the vitamin D status of young Chinese people with vitamin D insufficiency.

Role of Vitamin D in Inflammatory Bowel Disease

Vitamin D is a secosteroid hormone that possesses immunomodulatory properties and has been demonstrated to potentially influence inflammatory bowel disease (IBD) pathogenesis and activity. Epidemiologic data have associated vitamin D deficiency with an increased risk of IBD, hospitalizations, surgery, and loss of response to biologic therapy. Conversely, IBD itself can lead to vitamin D deficiency. This bidirectional relationship between vitamin D and IBD suggests the need for monitoring and repletion of vitamin D, as needed, in the IBD patient. This review discusses the role of vitamin D in IBD and provides practical guidance on vitamin D repletion.

The effect of vitamin D on COPD exacerbation: a double blind randomized placebo-controlled parallel clinical trial

Background

To investigate the effect of supplementation of standard treatment (inhaled long-acting β2 agonists, anticholinergics and corticosteroids) with vitamin D on C reactive protein and pulmonary function tests in patients with COPD exacerbation.

Methods

Design: Randomized, single-center, double-blind, placebo-controlled parallel trial. One teaching hospital Participants: 135 patients in pulmonary ward with moderate to severe COPD and exacerbations.120 patients fulfilled the study protocol. Interventions: Patients were randomly divided into three groups receiving 7 day treatment with 0.25 μg calcitriol daily (n = 45), 50000 IU daily of vitamin D (n = 45) or placebo (n = 45). An independent nurse was responsible for allocation, preparation, and accounting of trial medications. Main Outcome measures: Maximal expiratory flow volume (FEV1) and forced volume capacity curves (FVC) and Modified Medical Research Council (MMRC) scale.

Results

Out of 135 patients who were recruited consecutively, 45 patients randomly were randomly assigned in three groups (balance blocked randomization.15 patients were dropped out due to non-compliance for second PFT. Intention to treat analysis was carried out for 120 participants. The difference between before and after treatment FEV1 and FEV1/FVC ratio had no significant difference between treatment groups and placebo. (P = 0.43, P = 0.51, respectively)but clinical improvement was significant in patients who received calcitriol. No side effects were reported.

Conclusions

Short term treatment with either calcitriol or 25(OH) ₂Vit D didn’t changed FEV1 or FVC in vitamin D sufficient patients with COPD exacerbation; nevertheless it can provide clinical benefit.

Trial registration

Trial registration: Iranian Registry of Clinical Trials no. IRCT138712271774N1. Registered 10 April 2011.

A Cross-sectional Examination of Vitamin D, Obesity, and Measures of Pain and Function in Middle-aged and Older Adults With Knee Osteoarthritis

OBJECTIVES

The prevalence of knee osteoarthritis (OA) is increasing with the aging population and is exacerbated by the growing numbers of obese older adults. Low levels of vitamin D, measured by serum 25-hydroxyvitamin D (25(OH)D), in older adults and obese individuals are correlated with several negative health conditions, including chronic pain. This cross-sectional study sought to examine the interactive influence of 25(OH)D levels and obesity on knee OA pain and functional performance measures.

METHODS

The sample consisted of 256 (63% female) racially diverse (55% black/African Americans) middle-aged and older adults (mean age 56.8 y). Blood was collected for analysis of 25(OH)D by high-performance liquid chromatography. Participants provided self-report regarding knee OA pain and underwent a lower extremity functional performance test.

RESULTS

Results demonstrated that obesity was associated with lower levels of 25(OH)D. Participants with adequate 25(OH)D levels reported significantly less knee OA pain compared with participants with deficient or insufficient levels, regardless of obesity status. Furthermore, there was a significant interaction between obesity and 25(OH)D levels for lower extremity functional performance, such that obese individuals with adequate 25(OH)D levels demonstrated better performance than those obese participants with deficient or insufficient 25(OH)D levels.

DISCUSSION

The mechanisms by which adequate 25(OH)D levels are associated with pain severity and improved function have not been completely elucidated. It may be that the pleiotropic role of biologically active 25(OH)D influences pain and pain processing through peripheral and central mechanisms. Alternatively, higher levels of pain may lead to reduced outdoor activity, which may contribute to both obesity and decreased vitamin D. Thus, investigating vitamin D status in obese and nonobese individuals with knee OA warrants further study.

The Effects of Vitamin D Supplementation on Pulmonary Function of Chronic Obstructive Pulmonary Disease Patients, before and after Clinical Trial

Vitamin D has several extra calcemic effects. Vitamin D deficiency is highly prevalent in chronic obstructive pulmonary disease (COPD) patients but little is known about it’s association with lung function. Objective: To investigate whether supplementation with vitamin D could improve pulmonary function in COPD patients. Design: Before and after, double center, clinical trial. Setting: Hazrat Rasoul University Hospital, Tehran, and Imam Khomaini University Hospital, Ahvaz, Iran. Participants: 24 patients with mild to very severe COPD. Intervention: Loading dose of 300,000–600,000 International Units (IU) of vitamin D, then 50000 IU weekly for 12 weeks. Measurements: The outcomes included forced expiratory volume in one second (FEV1), forced vital capacity (FVC), vital capacity (VC), forced expiratory flow between 25%–75% of forced vital capacity (FEF 25%–75%), exercise capacity according to the six minute walk test(6MWT) and the saturation of oxygen during exercise. Results: The mean FEV1 (p-value = 0.866), FVC (p-value = 0.475) and VC (p-value = 0.425) were not significantly different before and after intervention. FEF 25%–75% did not improve with this intervention (p-value = 0.555). The vitamin D supplementation did not have any significant effect on the exercise capacity (p-value=0.175) or the saturation of oxygen (p-value = 0.635). Conclusion: Pulmonary function and exercise capacity did not improve with vitamin D supplementation in COPD patients.

Optimal Vitamin D Supplementation Levels for Cardiovascular Disease Protection

First described in relation to musculoskeletal disease, there is accumulating data to suggest that vitamin D may play an important role in cardiovascular disease (CVD). In this review we aim to provide an overview of the role of vitamin D status as both a marker of and potentially causative agent of hypertension, coronary artery disease, heart failure, atrial fibrillation, stroke, and peripheral vascular disease. The role of vitamin D levels as a disease marker for all-cause mortality is also discussed. We review the current knowledge gathered from experimental studies, observational studies, randomised controlled trials, and subsequent systematic reviews in order to suggest the optimal vitamin D level for CVD protection.

The link between obesity and vitamin D in bariatric patients with omega-loop gastric bypass surgery - a vitamin D supplementation trial to compare the efficacy of postoperative cholecalciferol loading (LOAD): study protocol for a randomized controlled trial

Background

Beyond its classical role in calcium homoeostasis and bone metabolism, vitamin D deficiency has been found to be associated with several diseases, including diabetes, non-alcoholic fatty liver disease, and even obesity itself. Importantly, there are limited data on therapeutic strategies for vitamin D deficiency in bariatric patients, and the procedure-specific guidelines may not be sufficient. To improve long-term outcomes, nutritional screening and appropriate supplementation to prevent nutrient deficiencies are urgently needed. Therefore, the aim of this study is to examine effects and safety of a forced dosing regimen of vitamin D versus conventional dose supplementation on vitamin D levels and other parameters in bariatric patients.

Methods/Design

The study includes loading plus repeat dosing compared with repeated administration of vitamin D without a loading dose, according to guidelines, in a prospective, double-blind, randomized controlled trial. Up to a triple oral loading dose is given on day 1, then 2 and 4 weeks after surgery (100,000 IU dose each time), followed by an oral maintenance dose (3420 IU/day). The control group (n = 25) will receive placebo, followed by administration of a standard dose (3420 IU/day). We hypothesize that a significant increase in vitamin D levels will occur in patients in the treatment group (n = 25) by 24 weeks after surgery. Further measurements are aimed at evaluating changes in inflammation, bone turnover, insulin resistance, blood pressure, liver, mental health, and gut microbiota of patients undergoing omega-loop gastric bypass surgery. Furthermore, possible associations between concentrations of vitamin D, the involved enzymes, or vitamin D receptor in adipose and/or liver tissues will be determined.

Discussion

To our knowledge, this trial is the first of its kind with this type of vitamin D supplementation in bariatric patients. Its major strength is the design and implementation of evaluation of influencing factors such as liver function, bone health, inflammation, insulin resistance, blood pressure, symptoms of depression, or microbiota. This alternative vitamin D dosing regimen has the potential to be a safe, fast, evidence-based treatment of vitamin D deficiency in bariatric patients. Owing to the increasing number of bariatric patients, it is also of interest to elucidate the link between obesity and vitamin D.

Trial registration

ClinicalTrials.gov identifier: NCT02092376. Registered on 17 March 2014.

Investigating transdermal delivery of vitamin D3

Transdermal delivery of therapeutic amounts of vitamin D3 is proposed to overcome its variable oral bioavailability, especially for people who suffer from fat malabsorption. The main challenge for this delivery route is to overcome the barrier properties of skin, especially for very lipophilic compounds such as vitamin D3. In this study, the effect of different penetration enhancers, such as oleic acid, dodecylamine, ethanol, oleic acid in propylene glycol, isopropyl myristate, octyldodecanol, and oleyl alcohol in propylene glycol were evaluated in vitro for their effectiveness in delivering vitamin D3 through polyamide filter, polydimethylsiloxane membrane, and porcine skin. A diffusion cell was used to study the transdermal permeability of vitamin D3. Ointment formulations of vitamin D3 were prepared containing the most widely used penetration enhancers, oleic acid, and dodecylamine. The ointment containing oleic acid as chemical penetration enhancer did not improve delivery compared to control. On the other hand, the formulation containing dodecylamine as a penetration enhancer did improve the transdermal delivery of vitamin D3. However, statistical significance and an amount high enough for nutritional supplementation purposes were reached only when the skin was pretreated with 50% ethanol. In these conditions, the ointment delivered an amount of 760-ng vitamin D3 per cm(2) of skin. The research shows promise that transdermal delivery could be an effective administration route for vitamin D3 when ethanol and dodecylamine are used as penetration enhancers.

Excess 25-hydroxyvitamin D3 exacerbates tubulointerstitial injury in mice by modulating macrophage phenotype

Vitamin D hydroxylated at carbon 25 (25(OH)D) is generally recognized as a precursor of active vitamin D. Despite its low affinity for the vitamin D receptor (VDR), both deficient and excessive 25(OH)D levels are associated with poor clinical outcomes. Here we studied direct effects of 25(OH)D3 on the kidney using 25(OH)D-1α-hydroxylase (CYP27B1) knockout mice. The effects of 25(OH)D3 on unilateral ureteral obstruction were analyzed as proximal tubular cells and macrophages are two major cell types that take up 25(OH)D and contribute to the pathogenesis of kidney injury. Excess 25(OH)D3 in obstructed mice worsened oxidative stress and tubulointerstitial fibrosis, whereas moderate levels of 25(OH)D3 had no effects. The exacerbating effects of excess 25(OH)D3 were abolished in CYP27B1/VDR double-knockout mice and in macrophage-depleted CYP27B1 knockout mice. Excess 25(OH)D3 upregulated both M1 marker (TNF-α) and M2 marker (TGF-β1) levels of kidney-infiltrating macrophages. In vitro analyses verified that excess 25(OH)D3 directly upregulated TNF-α and TGF-β1 in cultured macrophages but not in tubular cells. TNF-α and 25(OH)D3 cooperatively induced oxidative stress by upregulating iNOS in tubular cells. Aggravated tubulointerstitial fibrosis in mice with excess 25(OH)D3 indicated that macrophage-derived TGF-β1 also had a key role in the pathogenesis of surplus 25(OH)D3. Thus, excess 25(OH)D3 worsens tubulointerstitial injury by modulating macrophage phenotype.

Changing Incidence of Serum 25-Hydroxyvitamin D Values Above 50 ng/mL: A 10-Year Population-Based Study

OBJECTIVE

To determine the incidence trend of 25-hydroxyvitamin D (25(OH)D) values above 50 ng/mL and associated toxicity.

PATIENTS AND METHODS

We conducted a retrospective population-based study in Olmsted County, Minnesota, in the 10-year period from January 1, 2002, through December 31, 2011, by using the Rochester Epidemiology Project. Individuals were eligible if they resided in Olmsted County during the study period and had a measured 25(OH)D value above 50 ng/mL. The date of the first 25(OH)D value above 50 ng/mL was considered the index date for incidence determination. Hypercalcemia, the primary vitamin D toxicity, was considered potentially associated with the 25(OH)D concentration if it was measured within 3 months of the 25(OH)D measurement, and such cases had a medical record review.

RESULTS

Of 20,308 total 25(OH)D measurements, 1714 (8.4%), 123 (0.6%), and 37 (0.2%) unique persons had 25(OH)D values above 50, 80 and above, and 100 ng/mL and above, respectively. The age- and sex-adjusted incidence of 25(OH)D values above 50 ng/mL increased from 9 to 233 cases per 100,000 person-years from 2002 to 2011 (P<.001), respectively, and was greatest in persons aged 65 years and older (P<.001) and in women (P<.001). Serum 25(OH)D values were not significantly related to serum calcium values (P=.20) or with the risk of hypercalcemia (P=.24). A medical record review identified 4 cases (0.2%) in whom 25(OH)D values above 50 ng/mL were temporally associated with hypercalcemia, but only 1 case had clinical toxicity associated with the highest observed 25(OH)D value of 364 ng/mL.

CONCLUSION

The incidence of 25(OH)D values above 50 ng/mL increased significantly between 2002 and 2011 without a corresponding increase in acute clinical toxicity.

Beneficial effects of calcitriol on hypertension, glucose intolerance, impairment of endothelium-dependent vascular relaxation, and visceral adiposity in fructose-fed hypertensive rats

Besides regulating calcium homeostasis, the effects of vitamin D on vascular tone and metabolic disturbances remain scarce in the literature despite an increase intake with high-fructose corn syrup worldwide. We investigated the effects of calcitriol, an active form of vitamin D, on vascular relaxation, glucose tolerance, and visceral fat pads in fructose-fed rats. Male Wistar-Kyoto rats were divided into 4 groups (n = 6 per group). Group Con: standard chow diet for 8 weeks; Group Fru: high-fructose diet (60% fructose) for 8 weeks; Group Fru-HVD: high-fructose diet as Group Fru, high-dose calcitriol treatment (20 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding; and Group Fru-LVD: high-fructose diet as Group Fru, low-dose calcitriol treatment (10 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding. Systolic blood pressure was measured twice a week by the tail-cuff method. Blood was examined for serum ionized calcium, phosphate, creatinine, glucose, triglycerides, and total cholesterol. Intra-peritoneal glucose intolerance test, aortic vascular reactivity, the weight of visceral fat pads, adipose size, and adipose angiotensin II levels were analyzed at the end of the study. The results showed that the fructose-fed rats significantly developed hypertension, impaired glucose tolerance, heavier weight and larger adipose size of visceral fat pads, and raised adipose angiotensin II expressions compared with the control rats. High- and low-dose calcitriol reduced modestly systolic blood pressure, increased endothelium-dependent aortic relaxation, ameliorated glucose intolerance, reduced the weight and adipose size of visceral fat pads, and lowered adipose angiotensin II expressions in the fructose-fed rats. However, high-dose calcitriol treatment mildly increased serum ionized calcium levels (1.44 ± 0.05 mmol/L). These results suggest a protective role of calcitriol treatment on endothelial function, glucose tolerance, and visceral adiposity in fructose-fed rats.

Vitamin D therapy in inflammatory bowel diseases: who, in what form, and how much?

BACKGROUND

The north–south geographical gradient of inflammatory bowel disease (IBD) prevalence, its epidemiology, the genetic association of vitamin D receptor polymorphisms, and results in animal models suggest that vitamin D plays an important role in the pathogenesis of IBD.

AIMS

The purpose of this review was to critically appraise the effectiveness and safety of vitamin D therapy in patients with IBD.

METHODS

MEDLINE, Scopus and Google Scholar were searched from inception to May 20, 2014 using the terms ‘Crohn’s disease’, ‘ulcerative colitis’ and ‘vitamin D’. Results: Vitamin D deficiency is common in patients with IBD. Limited clinical data suggest an association between low vitamin D concentration and increased disease activity in both ulcerative colitis (UC) and Crohn’s disease (CD). To date, only two small open label trials and one randomized controlled trial have shown a positive effect of vitamin D supplementation on disease activity in patients with CD; no effect has been shown for UC. An optimal vitamin D supplementation protocol for patients with IBD remains undetermined, but targeting serum 25-hydroxy vitamin D [25(OH)D] levels between 30 and 50 ng/mL appears safe and may have benefits for IBD disease activity. Depending on baseline vitamin D serum concentration, ileal involvement in CD, body mass index, and perhaps smoking status, daily vitamin D doses between 1800–10,000 international units/day are probably necessary.

CONCLUSION

Increasing preclinical and clinical evidence suggests a role for vitamin D deficiency in the development and severity of IBD. The possible therapeutic role of vitamin D in patients with IBD merits continued investigation.

High-dose vitamin D3 supplementation in children and young adults with HIV: a randomized, placebo-controlled trial

BACKGROUND

Suboptimal vitamin D status is prevalent in HIV-infected patients and associated with increased risk of disease severity and morbidity. We aimed to determine 12-month safety and efficacy of daily 7000 IU vitamin D3 (vitD3) versus placebo to sustain increased serum 25-hydroxyvitamin D (25(OH)D) and improve immune status in HIV-infected subjects.

METHODS

This was a double-blind trial of perinatally acquired HIV (PHIV)-infected subjects or behaviorally acquired HIV (BHIV)-infected subjects (5.0-24.9 years). Safety, 25(OH)D-related parameters and immune status were assessed at baseline, 3, 6 and 12 months.

RESULTS

Fifty-eight subjects enrolled (67% male, 85% African American and 64% BHIV) and 50 completed with no safety concerns. In unadjusted analyses, there were no differences between randomization groups at baseline; at 3, 6 and 12 months, 25(OH)D was higher with supplementation than baseline and higher than with placebo (P < 0.05). In adjusted mixed models, in the supplementation group, the fixed effect of 25(OH)D was higher (P < 0.001). Percentage of naive T-helper cells (Th naive%) were significantly (P < 0.01) and T-helper cells (CD4%) marginally (P < 0.10) increased with supplementation in those taking highly active antiretroviral therapy (HAART), and RNA viral load was reduced (P ≤ 0.05). In exploratory linear models, change in 25(OH)D predicted RNA viral load at 3 and 12 months and CD4% at 3 months (P < 0.05).

CONCLUSIONS

Daily 7000 IU vitD3 for 12 months was safe in HIV-infected subjects and effective in increasing 25(OH)D. Supplementation improved some clinically important HIV immune markers in subjects on HAART. Adjunct therapy with high-dose, daily vitD3 for HIV-infected subjects and for those on/off HAART requires further investigation.

[Native vitamin D in dialysis patients]

Chronic kidney disease is frequent and usually responsible of mineral and bone disorder. These abnormalities lead to increased morbidity and mortality. To become active, native vitamin D needs a first hydroxylation in the liver, and a second one in the kidney. Next to its action on bone metabolism, vitamin D also possesses pleiotropic actions on cardiovascular, immune and neurological systems as well as antineoplastic activities. End-stage renal disease (ESRD) is also associated with a decrease in vitamin D activity by mechanisms including the increase of plasma phosphate concentration, secretion of FGF-23 and decrease in 1α-hydroxylase activity. The prevalence of 25 hydroxy-vitamin D deficiency depends on the chosen cut-off value to define this lack. Currently it is well established that a patient has to be substituted when 25 hydroxy-vitamin D level is under 30 ng/mL. The use and monitoring of 1.25 hydroxy-vitamin D is still not recommended in routine practice. The goals of vitamin D treatment in case of ESRD are to substitute the deficiency and to prevent or treat hyperparathyroidism. Interest of native vitamin D in first intention is now well demonstrated. This review article describes the vitamin D metabolism and physiology and also the treatment for vitamin D deficiency in ESRD population.

VITamin D supplementation in renAL transplant recipients (VITALE): a prospective, multicentre, double-blind, randomized trial of vitamin D estimating the benefit and safety of vitamin D3 treatment at a dose of 100,000 UI compared with a dose of 12,000 UI in renal transplant recipients: study protocol for a double-blind, randomized, controlled trial

Background

In addition to their effects on bone health, high doses of cholecalciferol may have beneficial non-classic effects including the reduction of incidence of type 2 diabetes mellitus, cardiovascular disease, and cancer. These pleiotropic effects have been documented in observational and experimental studies or in small intervention trials. Vitamin D insufficiency is a frequent finding in renal transplant recipients (RTRs), and this population is at risk of the previously cited complications.

Methods/design

The VITALE study is a prospective, multicentre, double-blind, randomized, controlled trial with two parallel groups that will include a total of 640 RTRs. RTRs with vitamin D insufficiency, defined as circulating 25-hydroxyvitamin D levels of less than 30 ng/ml (or 75 nmol/l), will be randomized between 12 and 48 months after transplantation to blinded groups to receive vitamin D₃ (cholecalciferol) either at high or low dose (respectively, 100,000 UI or 12,000 UI every 2 weeks for 2 months then monthly for 22 months) with a follow-up of 2 years. The primary objective of the study is to evaluate the benefit/risk ratio of high-dose versus low-dose cholecalciferol on a composite endpoint consisting of de novo diabetes mellitus; major cardiovascular events; de novo cancer; and patient death. Secondary endpoints will include blood pressure (BP) control; echocardiography findings; the incidences of infection and acute rejection episodes; renal allograft function using estimated glomerular filtration rate; proteinuria; graft survival; bone mineral density; the incidence of fractures; and biological relevant parameters of mineral metabolism.

Discussion

We previously reported that the intensive cholecalciferol treatment (100 000 IU every 2 weeks for 2 months) was safe in RTR. Using a pharmacokinetic approach, we showed that cholecalciferol 100,000 IU monthly should maintain serum 25-hydroxyvitamin D at above 30 ng/ml but below 80 ng/ml after renal transplantation. Taken together, these results are reassuring regarding the safety of the cholecalciferol doses that will be used in the VITALE study. Analysis of data collected during the VITALE study will demonstrate whether high or low-dose cholecalciferol is beneficial in RTRs with vitamin D insufficiency.

Trial registration

ClinicalTrials.gov Identifier: NCT01431430.

Electronic supplementary material

The online version of this article (doi:10.1186/1745-6215-15-430) contains supplementary material, which is available to authorized users.

Pharmacokinetics and safety issues of an accidental overdose of 2,000,000 IU of vitamin D3 in two nursing home patients: a case report

Background

Administration of intermittent high doses of vitamin D₃ is increasingly used as a strategy for rapid normalization of low 25-hydroxyvitamin D (25(OH)D) blood concentrations in patients with vitamin D deficiency. Here, we describe the pharmacokinetics of an accidental single oral overdose of 2,000,000 IU of vitamin D₃ in two elderly nursing home patients and discuss safety issues.

Case presentation

Two patients, a Caucasian 90-year old man and a 95-year old woman, were monitored from 1 h up to 3 months after intake for clinical as well as biochemical signs of vitamin D intoxication. Blood vitamin D₃ concentrations showed a prompt increase with the highest peak area already hours after the dose, followed by a rapid decrease to undetectable levels after day 14. Peak blood 25(OH)D₃ concentrations were observed 8 days after intake (527 and 422 nmol/L, respectively (ref: 50–200 nmol/L)). Remarkably, plasma calcium levels increased only slightly up to 2.68 and 2.73 mmol/L, respectively (ref: 2.20–2.65 mmol/L) between 1 and 14 days after intake, whereas phosphate and creatinine levels remained within the reference range. No adverse clinical symptoms were noted.

Conclusion

A single massive oral dose of 2,000,000 IU of vitamin D₃ does not cause clinically apparent toxicity requiring hospitalization, with only slightly elevated plasma calcium levels in the first 2 weeks. Toxicity in the long term cannot be excluded as annual doses of 500,000 IU of vitamin D₃ for several years have shown an increase in the risk of fractures. This means that plasma calcium levels may not be a sensitive measure of vitamin D toxicity in the long term in the case of a single high overdose. To prevent a similar error in the future, the use of multiple-dose bottles need to be replaced by smaller single-unit dose formulations.

Importance of vitamin D and vitamin D levels status in Puerto Ricans

There is growing and compelling evidence demonstrating the extra-skeletal role of vitamin D and the importance of maintaining adequate levels of this nutrient. Currently, there is very limited information available on the vitamin D status in children and adults in underserved groups, including Puerto Ricans. We assessed the vitamin D status of 4,090 Puerto Ricans living in six geographical regions in the island. Only 31.5% of the studied population had sufficient vitamin D levels (>30 ng/ml). The 18-39 year age group and the females showed inadequate (&lt;30 ng/ml) levels of vitamin D (76.9% and 69.8%, respectively). Participants aged 60 or older showed the highest mean values of serum 25(OH)D (28.8 ng/ml) and the highest percentage (37.1%) of sufficient levels (>30 ng/ml). Future studies are certainly warranted to understand the prevalence of vitamin D deficiency and influencing factors (including obesity) in Puerto Ricans.

Effects of high doses of cholecalciferol in normal subjects: a randomized double-blinded, placebo-controlled trial

BACKGROUND

Vitamin D repletion with high doses of vitamin D is often recommended to patients and healthy subjects. The safety, especially concerning changes in urinary calcium excretion is of great importance.

METHODS

In a double-blinded, placebo-controlled study in 40 healthy volunteers, we examined the changes in mineral metabolism during supplementation with 3000 IU of oral cholecalciferol daily during 4 months.

RESULTS

Both 25(OH)vitamin D and 1,25(OH)2vitamin D increased significantly in the active treated group as compared to the placebo group (186% versus 14% (P<0.001) and 28% versus -8% (P<0.001)). No change was observed in urinary calcium excretion in the active group compared to the placebo group (P = 0.891). Fibroblast growth factor 23 increased significantly by 10% (P<0.018) in the active group. However, there was no difference in changes in FGF23 between treatment groups (P = 0.457).

CONCLUSION

High dose cholecalciferol significantly increases 25(OH)vitamin D and 1,25(OH)2vitamin D levels compared to placebo. No changes in urinary calcium excretion or other measured components of the mineral metabolism were found between groups.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00952562.

The trials and tribulations of vitamin D: time for the 'sunshine' vitamin to come in out of the cold - or just more broken promises?

We are presently faced with the competing notions of modern life being a 'state of vitamin D depletion', implying a widespread need to supplement with vitamin D, or, the opposite view, which is that the present evidence can only support at best selective targeted vitamin D intervention. This is important as there is evidence that over the last 40-50 years there were downwards global trends in serum 25(OH)D concentrations, while individual consumption of vitamin D as supplements rose. For this reason and many others, a large population-based interventional study, the VITAL trial, was designed to try to establish the health value of vitamin D supplementation. VITAL is a huge primary prevention trial looking at the effects of vitamin D repletion in preventing cancer and cardiovascular disease in a fundamentally healthy population. This may seem an unusual approach given that what we mostly know about vitamin D is that is has some effects on the skeleton. This review looks to explore current knowledge about vitamin D in health and disease, and at how this is now undergoing significant reappraisal and revision. We will carefully critique the VITAL study design to see if it will allow for the construction of the detailed portfolio of clinical evidence so urgently needed to allow us better to understand role of vitamin D supplementation in health and disease.

Vitamin D supplementation: when and how?

The multiple effects of vitamin D on skeletal and extra-skeletal tissues increased the attention of scientists and public to the possible relationship between hypovitaminosis D and a variety of acute and chronic diseases. However, several points are still largely debated. In particular, the definition of optimal vitamin D status [as assessed by the circulating levels of 25-hydroxyvitamin D (25(OH)D)] remains controversial, and experts still disagree about several related outcomes: how to estimate the prevalence of vitamin D deficiency, when to start treatment, how to reach optimal 25(OH)D levels, which type of vitamin is preferable for supplementation, which dosing strategy is the better option. In this context, a matter of major debate is represented by the measurement of circulating level of 25(OH)D, whose determination is affected by the lack of standardization and by several technical problems. It has been recently hypothesized that free and bio-available, rather than total 25(OH)D, mostly determine its biological action. However, further evaluation of directly measured free 25(OH)D levels is needed, in order to establish its role in research and clinical practice. Finally, it is not yet defined if a threshold of optimal vitamin D status for reducing the risk of extra-skeletal diseases exists. Actually, it is plausible that the desired 25(OH)D level may vary widely, depending on the health outcome in question. However, this topic is uncertain, partly due to the lack of randomized controlled trials assessing the effect of vitamin D supplementation on extra-skeletal end-points.

HDX reveals unique fragment ligands for the vitamin D receptor

Modulation of the vitamin D receptor (VDR) with a ligand has the potential to be useful for the oral treatment of osteoporosis. One component of our lead generation strategy to identify synthetic ligands for VDR included a fragment based drug design approach. Screening of ligands in a VDR fluorescence polarization assay and a RXR/VDR conformation sensing assay resulted in the identification of multiple fragment hits (lean >0.30). These fragment scaffolds were subsequently evaluated for interaction with the VDR ligand binding domain using hydrogen-deuterium exchange (HDX) mass spectrometry. Significant protection of H/D exchange was observed for some fragments in helixes 3, 7, and 8 of the ligand binding domain, regions which are similar to those seen for the natural hormone VD3. The fragments appear to mimic the A-ring of VD3 thereby providing viable starting points for synthetic expansion.

Evidence for a U-shaped relationship between prehospital vitamin D status and mortality: a cohort study

OBJECTIVE

The objective of the study was to examine the association between prehospital serum 25-hydroxyvitamin D [25(OH)D]and the risk of mortality after hospital admission.

DESIGN

We performed a retrospective cohort study of adults hospitalized for acute care between 1993 and 2011.

SETTING

The study was conducted at two Boston teaching hospitals.

PATIENTS

A total of 24,094 adult inpatients participated in the study.

INTERVENTION

There was no intervention.

MEASUREMENTS

All patients had serum 25(OH)D measured before hospitalization. The exposure of interest was 25(OH)D categorized as less than 10 ng/mL, 10-19.9 ng/mL, 20-29.9 ng/mL, 30-49.9 ng/mL, 50-59.9 ng/mL, 60-69.9 ng/mL, and 70 ng/mL or greater. The main outcome measure was 90-day mortality. Adjusted odds ratios (ORs) were estimated by multivariable logistic regression with inclusion of potential confounders.

RESULTS

After adjustment for age, gender, race (white vs nonwhite), patient type (surgical vs medical), season of 25(OH)D draw, and the Deyo-Charlson index, patients with 25(OH)D levels less than 30 ng/mL or 60 ng/mL or greater had higher odds of 90-day mortality compared with patients with levels of 30-49.9 ng/mL [adjusted OR (95% confidence interval) for 25(OH)D <10 ng/mL, 10-19.9 ng/mL, 20-29.9 ng/mL, 50-59.9 ng/mL, 60-69.9 ng/mL, and ≥70 ng/mL was 2.01 (1.68-2.40), 1.89 (1.64-2.18), 1.34 (1.16-1.56), 0.94 (0.69-1.26), 1.52 (1.03-2.25), and 1.69 (1.09-2.61), respectively, compared with patients with 25(OH)D levels 30-49.9 ng/mL].

LIMITATIONS

A causal relationship between either low or high 25(OH)D levels and increased mortality can not necessarily be inferred from this observational study.

CONCLUSIONS

Analysis of 24 094 adult patients showed that 25(OH)D levels less than 20 ng/mL and 60 ng/mL or greater before hospitalization were associated with an increased odds of 90-day mortality. Although previous reports have suggested an association between low vitamin D status and mortality, these data raise the issue of potential harm from high serum 25(OH)D levels, provide a rationale for an upper limit to supplementation, and emphasize the need for caution in the use of extremely high doses of vitamin D among patients.

Vitamin D supplementation does not improve human skeletal muscle contractile properties in insufficient young males

PURPOSE

Vitamin D may be a regulator of skeletal muscle function, although human trials investigating this hypothesis are limited to predominantly elderly populations. We aimed to assess the effect of oral vitamin D3 in healthy young males upon skeletal muscle function.

METHODS

Participants (n = 29) received an oral dose of 10,000 IU day(-1) vitamin D3 (VITD) or a visually identical placebo (PLB) for 3 months. Serum 25[OH]D and intact parathyroid hormone (iPTH) were measured at baseline and at week 4, 8 and 12. Muscle function was assessed in n = 22 participants by isokinetic dynamometry and percutaneous isometric electromyostimulation at baseline and at week 6 and 12.

RESULTS

Baseline mean total serum 25[OH]D was 40 ± 17 and 41 ± 20 nmol L(-1) for PLB and VITD, respectively. VITD showed a significant improvement in total 25[OH]D at week 4 (150 ± 31 nmol L(-1)) that remained elevated throughout the trial (P < 0.005). Contrastingly, PLB showed a significant decrease in 25[OH]D at week 12 (25 ± 15 nmol L(-1)) compared with baseline. Despite marked increases in total serum 25[OH]D in VITD and a decrease in PLB, there were no significant changes in any of the muscle function outcome measures at week 6 or 12 for either group (P > 0.05).

CONCLUSIONS

Elevating total serum 25[OH]D to concentrations > 120 nmol L(-1) has no effect on skeletal muscle function. We postulate that skeletal muscle function is only perturbed in conditions of severe deficiency (<12.5 nmol L(-1)).

DO IT Trial: vitamin D Outcomes and Interventions in Toddlers - a TARGet Kids! randomized controlled trial

BACKGROUND

Vitamin D levels are alarmingly low (<75 nmol/L) in 65-70% of North American children older than 1 year. An increased risk of viral upper respiratory tract infections (URTI), asthma-related hospitalizations and use of anti-inflammatory medication have all been linked with low vitamin D. No study has determined whether wintertime vitamin D supplementation can reduce the risk of URTI and asthma exacerbations, two of the most common and costly illnesses of early childhood. The objectives of this study are: 1) to compare the effect of 'high dose' (2000 IU/day) vs. 'standard dose' (400 IU/day) vitamin D supplementation in achieving reductions in laboratory confirmed URTI and asthma exacerbations during the winter in preschool-aged Canadian children; and 2) to assess the effect of 'high dose' vitamin D supplementation on vitamin D serum levels and specific viruses that cause URTI.

METHODS/DESIGN

This study is a pragmatic randomized controlled trial. Over 4 successive winters we will recruit 750 healthy children 1-5 years of age. Participating physicians are part of a primary healthcare research network called TARGet Kids!. Children will be randomized to the 'standard dose' or 'high dose' oral supplemental vitamin D for a minimum of 4 months (200 children per group). Parents will obtain a nasal swab from their child with each URTI, report the number of asthma exacerbations and complete symptom checklists. Unscheduled physician visits for URTIs and asthma exacerbations will be recorded. By May, a blood sample will be drawn to determine vitamin D serum levels. The primary analysis will be a comparison of URTI rate between study groups using a Poisson regression model. Secondary analyses will compare vitamin D serum levels, asthma exacerbations and the frequency of specific viral agents between groups.

DISCUSSION

Identifying whether vitamin D supplementation of preschoolers can reduce wintertime viral URTIs and asthma exacerbations and what dose is optimal may reduce population wide morbidity and associated health care and societal costs. This information will assist in determining practice and health policy recommendations related to vitamin D supplementation in healthy Canadian preschoolers.