Intermittent high-dose vitamin D prophylaxis during infancy: effect on vitamin D metabolites, calcium, and phosphorus

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

BACKGROUND

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

METHODS

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

RESULTS

Of 67 randomized participants, one was withdrawn and seven received more than one dose of cholecalciferol before the protocol was amended to a single loading dose, leaving 59 participants in the primary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

CONCLUSIONS

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

TRIAL REGISTRATION

CLINICALTRIALS

gov NCT02452762 Registered 25/05/2015.

Acute Renal Failure Secondary to Inadvertent Propylene Glycol Overdose with Single-Day High-Dose Vitamin D (Stosstherapy)

Globally, there has been increasing attention paid to vitamin D deficiency and its treatment. Vitamin D stosstherapy with high-dose ergocalciferol in a single day is reemerging as a potential treatment option. We present an as yet unreported complication of acute renal injury due to propylene glycol toxicity in a 7-month infant treated with vitamin D stosstherapy. The product label for the vitamin D used for this patient states it is dissolved in propylene glycol (PG), but the amount is not listed on this or other US ergocalciferol liquid products that contain PG. Caution should be used when considering vitamin D stosstherapy with liquid ergocalciferol products available in the United States.

Update of the tolerable upper intake level for vitamin D for infants

Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to revise the tolerable upper intake level (UL) for vitamin D for infants (≤ 1 year) set in 2012. From its literature review, the Panel concluded that the available evidence on daily vitamin D intake and the risk of adverse health outcomes (hypercalciuria, hypercalcaemia, nephrocalcinosis and abnormal growth patterns) cannot be used alone for deriving the UL for infants. The Panel conducted a meta-regression analysis of collected data, to derive a dose-response relationship between daily supplemental intake of vitamin D and mean achieved serum 25(OH)D concentrations. Considering that a serum 25(OH)D concentration of 200 nmol/L or below is unlikely to pose a risk of adverse health outcomes in infants, the Panel estimated the percentage of infants reaching a concentration above this value at different intakes of vitamin D. Based on the overall evidence, the Panel kept the UL of 25 μg/day for infants aged up to 6 months and set a UL of 35 μg/day for infants 6-12 months. The Panel was also asked to advise on the safety of the consumption of infant formulae with an increased maximum vitamin D content of 3 μg/100 kcal (Commission Delegated Regulation (EU) 2016/127 repealing Directive 2006/141/EC in 2020). For infants aged up to 4 months, the intake assessment showed that the use of infant formulae containing vitamin D at 3 μg/100 kcal may lead some infants to receive an intake above the UL of 25 μg/day from formulae alone without considering vitamin D supplemental intake. For infants aged 4-12 months, the 95th percentile of vitamin D intake (high consumers) estimated from formulae and foods fortified or not with vitamin D does not exceed the ULs, without considering vitamin D supplemental intake.

Weekly regimen of vitamin D supplementation is more efficacious than stoss regimen for treatment of vitamin D deficiency in children with chronic liver diseases

There are no evidence-based recommendations on the ideal dose and regimen for supplementation of vitamin D in children with chronic liver disease (CLD). This study aimed to compare the safety and efficacy of weekly and stoss regimens for treatment of vitamin D deficiency in these children. Children between the ages of 1 to 18 years with CLD and hypovitaminosis D defined by 25-OH vitamin D (25(OH)D) < 30µg/l were included. They were randomized to receive either stoss regimen (600,000 IU on day 1) or weekly (60,000 IU weekly) regimen of vitamin D. The 25(OH)D levels at 3 and 6 months were compared in the two groups. A total of 210 suspected cases of CLD were assessed for eligibility. Of a total of 67 children satisfying the inclusion criteria, 33 and 34 were randomized to receive stoss and weekly regimen, respectively. Final analysis included 28 children in each group. Clinical rickets was seen in 25.4% of children with hypovitaminosis D. The rise in levels of 25(OH)D at 3 months was higher with weekly regimen (34.3 ± 30.7 µg/l) as compared to stoss regimen (17.2 ± 11.5 µg/l) (p = 0.009). Rise at 6 months as compared to baseline was significantly higher with weekly regimen (30.7 ± 24µg/l) as compared to stoss regimen (11 ± 8.4 µg/l) (p < 0.001). Normal levels of 25(OH)D at 6 months were achieved in 24/28 (85.7%) of those receiving weekly regimen and 9/28 (32.1%) of those receiving stoss regimen (p < 0.001). With stoss therapy, 25(OH)D increased at 3 months as compared to baseline but thereafter dropped significantly at 6 months (p = 0.008).

CONCLUSION

Weekly regimen of vitamin D supplementation is more effective than stoss regimen for treatment of hypovitaminosis D in children with CLD. Once normal levels are achieved, child should be shifted to 60,000 IU per month as maintenance dose. What is Known: • Vitamin D deficiency is more common and severe in children with chronic liver diseases. • Currently used doses fail to achieve normal vitamin D levels in these children. What is New? • Weekly regimen of 60,000 IU of vitamin D3 is the most effective regimen for treating vitamin D deficiency in children with CLD. • Children with CLD should further receive maintenance dose of 60,000 IU every month.

Randomised Controlled Trial Comparing Daily Versus Depot Vitamin D3 Therapy in 0-16-Year-Old Newly Settled Refugees in Western Australia Over a Period of 40 Weeks

Vitamin D deficiency is highly prevalent in newly settled refugees in Western Australia (WA). If adherence to daily vitamin D therapy is problematic, depot therapy is a therapeutic alternative. The aim of this study was to compare daily versus depot treatment and factors influencing the therapeutic outcome. Newly settled refugees (n = 151) with 25(OH)D levels less than 78 nmol/L were randomised to receive daily or depot vitamin D therapy with eight weekly interval follow up to 40 weeks. Biochemical and clinical parameters were collected at each visit. Generalized Linear Mixed Models (GLMM) examined the longitudinal changes over time controlling for confounders including age, gender, treatment arm, season, country of refuge/origin and sun exposure score. Participants were aged 5.5 months to 16.0 years (75 males, 83 females). Both treatment groups achieved vitamin D sufficiency. The daily treatment group had significantly higher 25(OH)D levels at each visit post baseline and a higher proportion of participants with levels above 50 nmol/L at all time points. Time, treatment group, calcium and sun exposure score were significant predictors of 25(OH)D serum levels. Depot vitamin D therapy is an alternative to daily treatment in this at-risk group of children and adolescents in whom treatment adherence is problematic.

Comparative analysis of nutritional guidelines for vitamin D

Vitamin D is essential for calcium and bone homeostasis. Humans are largely dependent on UVB-radiation-induced photosynthesis of vitamin D, as few foods contain vitamin D. However, the same radiation that produces vitamin D is also carcinogenic, albeit with a long lag time, and causes DNA damage. In view of the increasing life expectancy, avoiding excessive sun exposure is prudent. Several groups of people have a shortfall between their requirements for vitamin D and their combined endogenous synthesis and intake from natural foods, and therefore need vitamin D supplementation. Governments and scientific societies are regularly updating their recommendations for intake of vitamin D, especially for groups that should (infants) or prefer to (especially elderly individuals) avoid direct sunlight. An overview of such guidelines is presented in this Review. A fairly large consensus exists that all infants should receive 400 international units (IU) (10 μg) daily during their first year of life and that elderly individuals should have access to vitamin D supplementation (at recommended dosages varying from 400 IU to 800 IU daily in most governmental guidelines but at higher dosages in other guidelines). All guidelines unanimously agree that serum levels of 25-hydroxyvitamin D (25OHD) <25 nmol/l (10 ng/ml) should be avoided at all ages. Children and adults who have limited sun exposure should receive vitamin D supplementation, but the recommended doses vary widely (from 200 IU to 2,000 IU daily), in line with disagreement regarding the minimal desirable serum concentration of 25OHD (which varies from 25 nmol/l to >100 nmol/l).

Cross-sectional analysis of universal vitamin D supplementation in former East Germany during the first year of life

BACKGROUND

Universal vitamin D supplementation is controversial. Preventative examinations and public health initiatives in former East Germany that included vitamin D prophylaxis for children were regulated by official recommendations and guidelines. The aim of this study is to analyse the impact of a standardised nationwide guideline for universal supplementation with 400 International Units (IU) vitamin D3/day during the first year of life on clinical and biochemical parameters and the influence of surrounding factors.

METHODS

This is a cross-sectional analysis looking at data from a field study of 3481 term-born children during their first year of life that was conducted in 1989.

RESULTS

There were no significant clinical signs of rickets. 25 hydroxyvitamin D (25(OH)D) (mean and SEM, total analyses n=572) after birth (n=28) was 36(7) nmol/L, at 1 month 64(4) nmol/L (n=70, p<0.0001), 91(5) nmol/L at 3 months (n=95, p<0.0001), 65(8) nmol/L at 8 months (n=21, p=0.005) and ranged between 33 and 109 nmol/L until 12 months. Less than 0.2% of analyses revealed pathological levels for calcium or phosphate. Alkaline phosphatase (ALP) levels (n=690) were >1500 U/L (95th percentile) in 3.6%. Participants were on breastmilk or vitamin D-free formula, with solids added from 6 months of age. There were seasonal variations in 25(OH)D levels with a rise during spring and autumn. Thus this analysis is unique as sun exposure and supplementation can be considered as the only vitamin D sources.

CONCLUSIONS

We conclude that universal supplementation with 400 IU of vitamin D3 during the first year of life is safe and provides sufficient 25(OH)D levels in Germany.

Effect of intramuscular cholecalciferol megadose in children with nutritional rickets

BACKGROUND

The treatment practices for vitamin D deficiency rickets are highly variable. Though a single intramuscular (IM) megadose of vitamin D is economical, and ensures good compliance, it poses the risk of hypervitaminosis D. This observational study was conducted to assess the duration of effect and safety of single IM megadose of cholecalciferol in the treatment of vitamin D deficiency rickets.

METHODS

Children younger than 14 years with rickets were enrolled. Baseline investigations included radiograph of wrists and estimation of serum calcium, phosphate, alkaline phosphatase (ALP), 25(OH) vitamin D and parathormone (PTH) levels. All children received a single IM megadose of vitamin D3. Biochemical parameters were re-evaluated at 1.5, 3 and 6 months after the megadose and the values were compared to the baseline.

RESULTS

We enrolled 21 children, out of which nine remained under active follow-up till 6 months. Radiological evidence of rickets was present in all 21 children, 14 had hypocalcemia at the time of presentation. After IM cholecalciferol megadose, median 25 hydroxy vitamin D [25(OH)D] level remained significantly more than the baseline till 6 months after the megadose. At 1.5 months after the vitamin D megadose, three (30%) of the children were found to develop toxic levels of vitamin D (>150 ng/mL), although none had hypercalcemia or any clinical manifestation of vitamin D toxicity. At 3 months and 6 months after the megadose, 25(OH)D levels remained in the sufficient range (20-100 ng/mL) in seven out of the eight children who came for follow-up.

CONCLUSIONS

A single IM megadose of vitamin D may be effective in significantly increasing the 25(OH)D levels for at least 6 months in children with rickets, but elevation of 25(OH)D to toxic range raises concern regarding its safety.

Vitamin D Deficiency in Pediatric Critical Care

Vitamin D deficiency (VDD) is a well-established cause of pediatric bone and muscle disease. In addition, a role has been recognized for vitamin D in the health and stress response of other organs, including the cardiovascular, immune, and respiratory systems. As these organs are central to the development of and recovery from critical illness, VDD has been hypothesized to be a modifiable risk factor for ICU outcome. Over the past 5 years, a growing number of adult and pediatric critical care studies have investigated the prevalence of VDD and its association with illness severity and outcome. The adult studies have recently been synthesized in systematic reviews, with results that convincingly suggest the need for trials to determine whether optimization of vitamin D status improves outcome. In contrast, the pediatric ICU and related literature has not been similarly synthesized. The goal of this review is to describe vitamin D metabolism, known biological mechanisms, potential role in pathophysiology, and summarize the available pediatric intensive care unit (PICU) studies reporting on prevalence of VDD deficiency and its association with outcome. The problems with currently approved supplementation approaches and alternative strategies are discussed, including evidence from available RCTs in adult ICU. Altogether the results suggest that critically ill children are at risk for VDD, and that VDD appears to be associated with a worse clinical course. Clinical trials evaluating novel approaches to testing for and supplementing vitamin D require exploration.

A systematic review of pediatric clinical trials of high dose vitamin D

Background. Due to inadequate UV exposure, intake of small quantities of vitamin D is recommended to prevent musculoskeletal disease. Both basic science and observational literature strongly suggest that higher doses may benefit specific populations and have non-musculoskeletal roles. Evaluating the evidence surrounding high dose supplementation can be challenging given a relatively large and growing body of clinical trial evidence spanning time, geography, populations and dosing regimens. Study objectives were to identify and summarize the clinical trial literature, recognize areas with high quality evidence, and develop a resource database that makes the literature more immediately accessible to end users. Methods. Medline (1946 to January 2015), Embase (1974 to January 2015), and Cochrane databases (January 2015), were searched for trials. All pediatric (0-18 years) trials administering doses higher than 400 IU (<1 year) or 600 IU (≥1 year) were included. Data was extracted independently by two of the authors. An online searchable database of trials was developed containing relevant extracted information (http://www.cheori.org/en/pedvitaminddatabaseOverview). Sensitivity and utility were assessed by comparing the trials in the database with those from systematic reviews of vitamin D supplementation including children. Results. A total of 2,579 candidate papers were identified, yielding 169 trials having one or more arms meeting eligibility criteria. The publication rate has increased significantly from 1 per year (1970-1979) to 14 per year (2010-2015). Although 84% of the total trials focused on healthy children or known high risk populations (e.g., renal, prematurity), this proportion has declined in recent years due to the rise in trials evaluating populations and outcomes not directly related to the musculoskeletal actions of vitamin D (27% in 2010s). Beyond healthy children, the only pediatric populations with more than 50 participants from low risk of bias trials evaluating a clinically relevant outcome were prematurity and respiratory illness. Finally, we created and validated the online searchable database using 13 recent systematic reviews. Of the 38 high dose trials identified by the systematic review, 36 (94.7%) could be found within the database. When compared with the search strategy reported in each systematic review, use of the database reduced the number of full papers to assess for eligibility by 85.2% (±13.4%). Conclusion. The pediatric vitamin D field is highly active, with a significant increase in trials evaluating non-classical diseases and outcomes. Despite the large overall number there are few high quality trials of sufficient size to provide answers on clinical efficacy of high-dose vitamin D. An open access online searchable data should assist end users in the rapid and comprehensive identification and evaluation of trials relevant to their population or question of interest.

Prevention of vitamin D deficiency in children following cardiac surgery: study protocol for a randomized controlled trial

BACKGROUND

Vitamin D is a pleiotropic hormone important for the recovery of organ systems after critical illness. Recent observational studies have suggested that three out of every four children are vitamin D deficient following cardiac surgery, with inadequate preoperative intake and surgical losses playing important contributory roles. Observed associations between postoperative levels, cardiovascular dysfunction and clinical course suggest that perioperative optimization of vitamin D status could improve outcome. With this two-arm, parallel, double blind, randomized controlled trial (RCT), we aim to compare immediate postoperative vitamin D status in children requiring cardiopulmonary bypass for congenital heart disease who receive preoperative daily high dose vitamin D supplementation (high-dose arm) with those who receive usual intake (low-dose arm).

METHODS/DESIGN

Eligibility requirements include age (>36 weeks, <18 years) and a congenital heart defect requiring cardiopulmonary bypass surgical correction. Enrollment of 62 participants will take place at a single Canadian tertiary care center over a period of 2 years. Children randomized to the high-dose group will receive age-based dosing that was informed by the Institute of Medicine (IOM) daily tolerable upper intake level (<1 year old = 1,600 IU/day, >1 year old = 2,400 IU/day). Children in the low-dose arm will receive usual care based on IOM recommendations (<1 year old = 400 IU, >1 year old = 600 IU). The primary outcome measure is immediate postoperative vitamin D status, using blood 25(OH)D.

DISCUSSION

Maintaining adequate postoperative vitamin D levels following surgery could represent an effective therapy to speed recovery following CHD surgery. The proposed research project will determine whether preoperative supplementation with a dosing regimen based on the IOM recommended daily upper tolerable intake will prevent postoperative vitamin-D deficiency in the majority of children. The results will then be used to inform the design of a large international RCT exploring whether preoperative optimization of vitamin D status might improve short and long-term outcomes in this vulnerable population.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier--NCT01838447 Date of registration: 11 April 2013.

Rapid normalization of vitamin D levels: a meta-analysis

BACKGROUND

Vitamin D deficiency may represent a modifiable risk factor to improve outcome in severe illness. The efficacy of high-dose regimens in rapid normalization of vitamin D levels is uncertain.

METHODS

We conducted a systematic review of pediatric clinical trials administering high-dose vitamin D to evaluate 25-hydroxyvitamin D (25[OH]D) response and characteristics associated with final 25(OH)D levels by using Medline, Embase, and the Cochrane Central Register of Controlled Trials, including reference lists of systematic reviews and eligible publications. Uncontrolled and controlled trials reporting 25(OH)D levels after high-dose (≥1000 IU) ergocalciferol or cholecalciferol were selected. Two reviewers independently extracted and verified predefined data fields.

RESULTS

We identified 88 eligible full-text articles. Two of 6 studies that administered daily doses approximating the Institute of Medicine's Tolerable Upper Intake Level (1000-4000 IU) to vitamin D-deficient populations achieved group 25(OH)D levels >75 nmol/L within 1 month. Nine of 10 studies evaluating loading therapy (>50 000 IU) achieved group 25(OH)D levels >75 nmol/L. In meta-regression, baseline 25(OH)D, regimen type, dose, age, and time factors were associated with final 25(OH)D levels. Adverse event analysis identified increased hypercalcemia risk with doses >400 000 IU, but no increased hypercalcemia or hypercalciuria with loading doses <400 000 IU (or 10 000 IU/kg). Few studies in adolescents evaluated loading dose regimens >300 000 IU.

CONCLUSIONS

Rapid normalization of vitamin D levels is best achieved by using loading therapy that considers disease status, baseline 25(OH)D, and age (or weight). Loading doses >300 000 IU should be avoided until trials are conducted to better evaluate risk and benefit.

A Randomized controlled trial on safety and efficacy of single intramuscular versus staggered oral dose of 600 000IU Vitamin D in treatment of nutritional rickets

OBJECTIVE

Comparison of efficacy and safety of two different regimens of vitamin D-600 000 IU as a single intramuscular dose, and 60 000IU orally once a week for 10 weeks-in treatment of nutritional rickets.

METHODS

Children with nutritional rickets (age: 0.5-5 years, n = 61) were randomized to receive either 60 000IU vitamin D orally once a week for 10 weeks or 600 000IU single intramuscular injection. Serum calcium, phosphate, alkaline phosphatase, urinary calcium/creatinine ratio, serum 25 hydroxy vitamin D and radiological score were compared at 12-week follow-up.

RESULTS

No difference was found in efficacy of the two regimens on comparing biochemical and radiological parameters. Serum 25 hydroxy vitamin D >100 ng/ml was found in two children in the oral group and one child in the intramuscular group. No child developed hypercalcemia or hypercalciuria after starting treatment.

CONCLUSION

Staggered oral and one-time intramuscular administrations of 600 000IU vitamin D are equally effective and safe in treatment of nutritional rickets.

Vitamin D supplementation and risk of toxicity in pediatrics: a review of current literature

CONTEXT

Although vitamin D toxicity is rare in children, increased use of vitamin D formulations, re-examination of optimal vitamin D levels, and use of higher doses lend potential for an increased incidence of vitamin D toxicity.

EVIDENCE ACQUISITION

A PubMed search was conducted through May 2013 for cases of vitamin D intoxication and vitamin D trials in pediatrics. Safety data were collected and reviewed.

EVIDENCE SYNTHESIS

A small number of pediatric studies tested vitamin D doses at or above the currently recommended upper tolerable intake. In children and adolescents, vitamin D excess was rare and usually asymptomatic. Recent cases of intoxication relate to errors in manufacturing, formulation, or prescription; involve high total intake in the range of 240,000 to 4,500,000 IU; and present with severe hypercalcemia, hypercalciuria, or nephrocalcinosis. However, mild hypercalcemia and hypervitaminosis using currently recommended doses have been reported in infants with rickets.

CONCLUSIONS

Although rare, cases of vitamin D intoxication that present with dramatic life-threatening symptoms still occur in children. Moreover, recent studies in infants raise a potential need for monitoring vitamin D levels when doses at or above the currently recommended upper range are used. Further studies are needed to clarify these findings. The Drugs and Therapeutics Committee of the Pediatric Endocrine Society suggests obtaining serum 25-hydroxyvitamin D levels in infants and children who receive long-term vitamin D supplementation at or above the upper level intake that is currently recommended.

A review on vitamin d deficiency treatment in pediatric patients

Vitamin D is essential for calcium absorption and for maintaining bone health in the pediatric population. Vitamin D deficiency may develop from nutritional deficiencies, malabsorption, enzyme-inducing medications, and many other etiologies. It may present as hypocalcemia before bone demineralization at periods of increased growth velocity (infancy and adolescence) because the increased calcium demand of the body cannot be met. In children, inadequate concentrations of vitamin D may cause rickets and/or symptomatic hypocalcemia, such as seizures or tetany. In this review, we will discuss the pharmacology behind vitamin D supplementation, laboratory assessments of vitamin D status, current literature concerning vitamin D supplementation, and various supplementation options for the treatment of vitamin D deficiency in the pediatric population.

Vitamin D deficiency in surgical congenital heart disease: prevalence and relevance

Vitamin D is a pleiotropic hormone important for the proper functioning of multiple organ systems. An emerging body of adult and pediatric critical care literature strongly suggests that vitamin D deficiency contributes to secondary organ pathophysiology, prolongs ICU stay, and worsens outcome in critically ill populations. Recent clinical studies suggest that a significant number of children with congenital heart disease (CHD) have post-operative vitamin D deficiency which appears to be associated with greater cardiovascular dysfunction. Altogether the cumulative body of literature suggests that peri-operative optimization of vitamin D status has the potential to speed recovery and/or improve outcome. This review describes the epidemiological and basic science research linking vitamin D deficiency to post-operative organ dysfunction. Furthermore, the available supplementation approaches are reviewed in the context of prevention of post-operative vitamin D deficiency and avoidance of toxicity in the majority of CHD patients. Finally, knowledge gaps regarding vitamin D supplementation are identified and the next stages for research are outlined.

Vitamin D: still a topical matter in children and adolescents. A position paper by the Committee on Nutrition of the French Society of Paediatrics

The aims of the present position paper by the Committee on Nutrition of the French Society of Paediatrics were to summarize the recently published data on vitamin D in infants, children and adolescents, i.e., on metabolism, physiological effects, and requirements and to make recommendations on supplementation after careful review of the evidence. Scientific evidence indicates that calcium and vitamin D play key roles in bone health. The current evidence, limited to observational studies, however, does not support other benefits for vitamin D. More targeted research should continue, especially interventional studies. In the absence of any underlying risk of vitamin D deficiency, the recommendations are as follows: pregnant women: a single dose of 80,000 to 100,000 IU at the beginning of the 7th month of pregnancy; breastfed infants: 1000 to 1200 IU/day; children less than 18 months of age, receiving milk supplemented with vitamin D: an additional daily dose of 600 to 800 IU; children less than 18 months of age receiving milk not supplemented with vitamin D: daily dose of 1000 to 1200 IU; children from 18 months to 5 years of age: 2 doses of 80,000 to 100,000 IU every winter (November and February). In the presence of an underlying risk of vitamin D deficiency (dark skin; lack of exposure of the skin to ultraviolet B [UVB] radiation from sunshine in summer; skin disease responsible for decreased exposure of the skin to UVB radiation from sunshine in summer; wearing skin-covering clothes in summer; intestinal malabsorption or maldigestion; cholestasis; renal insufficiency; nephrotic syndrome; drugs [rifampicin; antiepileptic treatment: phenobarbital, phenytoin]; obesity; vegan diet), it may be justified to start vitamin D supplementation in winter in children 5 to 10 years of age as well as to maintain supplementation of vitamin D every 3 months all year long in children 1 to 10 years of age and in adolescents. In some pathological conditions, doses of vitamin D can be increased. If necessary, the determination of 25(OH) vitamin D serum concentration will help determine the level of vitamin D supplementation.

Randomized trial of fortified milk and supplements to raise 25-hydroxyvitamin D concentrations in schoolchildren in Mongolia

BACKGROUND

The optimal public health strategy for maintaining 25-hydroxyvitamin D [25(OH)D] concentrations in schoolchildren in Mongolia is unknown.

OBJECTIVE

The objective was to compare the effectiveness of different supplement and fortified milk regimens to increase 25(OH)D concentrations in Mongolian schoolchildren.

DESIGN

Twenty-one classrooms of 579 children aged 9-11 y were randomized to interventions with an equivalent content of vitamin D(3): 1) a one-time seasonal supplement of 13,700 IU, 2) 300 IU/d from supplements, 3) 300 IU/d from fortified ultra-high-temperature pasteurized milk from the United States, 4) 300 IU/d from fortified pasteurized Mongolian milk, or 5) unfortified pasteurized Mongolian milk (control).

RESULTS

In January, the mean (±SD) serum 25(OH)D concentration was 8 ± 4 ng/mL (20 ± 10 nmol/L), and 98% of the children had a concentration <20 ng/mL (50 nmol/L). In March, concentrations were 8 ± 4 ng/mL after unfortified milk, 20 ± 6 ng/mL after fortified Mongolian milk, 29 ± 10 ng/mL after fortified US milk, 21 ± 6 ng/mL after daily supplements, and 12 ± 4 ng/mL after seasonal supplements (each greater than unfortified milk, P < 0.01). Seasonal supplementation was less effective than was daily supplementation (P < 0.0001). Despite consuming daily supplements or fortified milk, 41% of the children still had concentrations <20 ng/mL (50 nmol/L). Children with lower baseline 25(OH)D concentrations experienced slightly larger 25(OH)D responses to intervention than did children with higher concentrations (P = 0.002).

CONCLUSIONS

In this population with extremely low vitamin D concentrations, delivery of 300 IU vitamin D/d via supplements or in fortified milk improved 25(OH)D concentrations but failed to raise concentrations uniformly to >20 ng/mL (50 nmol/L). The daily low-dose intervention was superior to the seasonal larger-dose intervention. Higher doses may be needed to prevent deficiency in schoolchildren in Mongolia and at other northern latitudes. This trial is registered at clinicaltrials.gov as NCT00886379.

The virtues of vitamin D--but how much is too much?

Vitamin D deficiency is common in healthy adults and children as well as in the chronic kidney disease (CKD) population. What was once a disease of malnourished children in the developing world has re-emerged and reached pandemic proportions. In parallel with this development, there is a growing awareness that vitamin D is not simply a 'calcaemic hormone' but plays an important role in the prevention of cardiovascular disease, infectious and auto-immune conditions, renoprotection, glycaemic control and prevention of some common cancers. Most tissues in the body have a vitamin D receptor and the enzymatic machinery to convert 'nutritional' 25-hydroxyvitamin D to the active form 1,25-dihydroxyvitamin D; it is estimated that 3% of the human genome is regulated by the vitamin D endocrine system. Although there are few well-conducted studies on the benefits of vitamin D therapy, an exuberant use of vitamin D is now seen in the general population and at all stages of CKD. There is emerging evidence that vitamin D may in fact have a therapeutic window, and at least from the effects on the cardiovascular system, more is not necessarily better. In this review, we discuss the role of nutritional vitamin D (ergocalciferol or cholecalciferol) supplementation in CKD patients, interpreting the clinical studies in the light of the vitamin D metabolic pathway and its pluripotent effects. While nutritional vitamin D compounds clearly have numerous beneficial effects, randomised controlled studies are required to determine the effectiveness and optimal dose at different stages of CKD, its concurrent use with activated vitamin D compounds and its safety profile.

[Administration of a single Winter oral dose of 200,000 IU of vitamin D3 in adolescents in Normandy: evaluation of the safety and vitamin D status obtained]

Adolescence, a period of growth and acquisition of bone mass, requires adequate calcium and vitamin D intake. This study was designed to assess the impact of a single loading dose of 200,000 IU of vitamin D(3) on the winter vitamin D status of healthy adolescents. Vitamin D status was assessed by 25-OH-D levels before, 3 weeks, and 3 months after this single dose, and safety was assessed by serum calcium and PTH and urinary calcium excretion in random samples from 27, 23, and 17 healthy adolescents derived from the same institution. The 25-OH-D peak value 2 weeks after the vitamin D supplement of 71-129 nmol/l (mean, 96 nmol/l), and a residual level at 3 months of 29-83 nmol/l (mean, 57 nmol/l) serum calcium and urinary calcium excretion expressed by the calcium/creatinine ratio were normal and stable at 2 weeks and 3 months, remaining less than 0.5 for the calcium/creatinine ratio. This simple measure, ensuring good compliance during adolescence, ensures optimal winter vitamin D status with no signs of overload.

Vitamin requirements for term infants: considerations for infant formulae

OBJECTIVE

To provide the informed health professional with an up to date evaluation of the current thinking regarding requirements for vitamins in infant feeds. ESTABLISHING CRITERIA FOR ADEQUACY: Vitamin adequacy in the neonate is currently defined in terms of circulating levels of a vitamin or of the activity of a vitamin dependent enzyme in the erythrocytes. Although these measurements have their value there is a need to develop biochemical, physiological or clinical markers of well defined specific function. For some vitamins there is a risk of deleterious effects of very high intakes: risk of toxicity needs to be taken into consideration when making recommendations for inclusion in infant formulae. BREAST MILK AS THE 'GOLD STANDARD': Breast milk concentrations of vitamins have been used as the criteria of adequate intake by neonates. This may not always be justified. Greater consideration needs to be given to differences in bioavailability of vitamins from breast milk compared with formula feeds, of the influence of season, and of stage of lactation, on the stated composition.

EXPERIMENTAL APPROACHES

Animal studies have provided limited information regarding effects of different levels of intakes on current status indices in the neonatal period. There are few reports of randomized controlled studies into the effects of different levels of vitamins and these rely heavily on biochemical criteria of adequacy.

RECENT DEVELOPMENTS

The inclusion of beta-carotene into formula feeds for premature babies is an issue of current interest. What is the justification for this? Are there potential benefits for the term infant? Riboflavin deficiency in the period around weaning may affect the normal structural and functional development of the gastrointestinal tract; some of these effects may be permanent. RESEARCH TO BE DONE: A greater understanding of the absorption and metabolism of vitamins during infancy is required in order to help establish dietary requirements. The relative bioavailability of vitamins in human milk and formulae needs to be investigated. Criteria for vitamin adequacy should be extended to include measures of function. Information regarding the conversion factor from tryptophan to niacin in infancy would allow us to set niacin requirements with greater confidence. There is a particular lack of information about concentrations of biotin and pantothenic acid in breast milk and the relative biochemical status of infants receiving breast milk and formulae. Benefits of including beta-carotene into infant formulae need to be evaluated. The role of individual micronutrients in the structural and functional development of the gastrointestinal tract should be explored.

Vitamin D, nervous system and aging

This is a mini-review of vitamin D(3), its active metabolites and their functioning in the central nervous system (CNS), especially in relation to nervous system pathologies and aging. The vitamin D(3) endocrine system consists of 3 active calcipherol hormones: calcidiol (25OHD(3)), 1alpha-calcitriol (1alpha,25(OH)2D(3)) and 24-calcitriol (24,25(OH)2D(3)). The impact of the calcipherol hormone system on aging, health and disease is discussed. Low serum calcidiol concentrations are associated with an increased risk of several chronic diseases including osteoporosis, cancer, diabetes, autoimmune disorders, hypertension, atherosclerosis and muscle weakness all of which can be considered aging-related diseases. The relationship of many of these diseases and aging-related changes in physiology show a U-shaped response curve to serum calcidiol concentrations. Clinical data suggest that vitamin D(3) insufficiency is associated with an increased risk of several CNS diseases, including multiple sclerosis, Alzheimer's and Parkinson's disease, seasonal affective disorder and schizophrenia. In line with this, recent animal and human studies suggest that vitamin D insufficiency is associated with abnormal development and functioning of the CNS. Overall, imbalances in the calcipherol system appear to cause abnormal function, including premature aging, of the CNS.

Treatment of hypovitaminosis D in infants and toddlers

CONTEXT

Hypovitaminosis D appears to be on the rise in young children, with implications for skeletal and overall health.

OBJECTIVE

The objective of the study was to compare the safety and efficacy of vitamin D2 daily, vitamin D2 weekly, and vitamin D3 daily, combined with supplemental calcium, in raising serum 25-hydroxyvitamin D [25(OH)D] and lowering PTH concentrations.

DESIGN

This was a 6-wk randomized controlled trial.

SETTING

The study was conducted at an urban pediatric clinic in Boston.

SUBJECTS

Forty otherwise healthy infants and toddlers with hypovitaminosis D [25(OH)D < 20 ng/ml] participated in the study.

INTERVENTIONS

Participants were assigned to one of three regimens: 2,000 IU oral vitamin D2 daily, 50,000 IU vitamin D2 weekly, or 2,000 IU vitamin D3 daily. Each was also prescribed elemental calcium (50 mg/kg.d). Infants received treatment for 6 wk.

MAIN OUTCOME MEASURES

Before and after treatment, serum measurements of 25(OH)D, PTH, calcium, and alkaline phosphatase were taken.

RESULTS

All treatments approximately tripled the 25(OH)D concentration. Preplanned comparisons were nonsignificant: daily vitamin D2 vs. weekly vitamin D2 (12% difference in effect, P = 0.66) and daily D2 vs. daily D3 (7%, P = 0.82). The mean serum calcium change was small and similar in the three groups. There was no significant difference in PTH suppression.

CONCLUSIONS

Short-term vitamin D2 2,000 IU daily, vitamin D2 50,000 IU weekly, or vitamin D3 2,000 IU daily yield equivalent outcomes in the treatment of hypovitaminosis D among young children. Therefore, pediatric providers can individualize the treatment regimen for a given patient to ensure compliance, given that no difference in efficacy or safety was noted among these three common treatment regimens.

Interventions for the prevention of nutritional rickets in term born children

BACKGROUND

Nutritional rickets is a disease of growing children leading to bone deformities, bone pain, convulsions or delayed motor development. Today, high-incidence of nutritional rickets is mainly found in low-income countries.

OBJECTIVES

To assess the effects of various interventions on the prevention of nutritional rickets in term born children.

SEARCH STRATEGY

Studies were obtained from computerised searches of The Cochrane Library, MEDLINE, EMBASE, LILACS and reference lists of relevant articles. We contacted authors of studies or reviews to obtain further studies.

SELECTION CRITERIA

Studies were included if they were randomised controlled clinical trials, controlled clinical trials or prospective cohort studies comparing any intervention for the prevention of nutritional rickets in term born children with placebo or no intervention. Minimum duration of the intervention was three months for children under 12 months or six months for children over 12 months.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed study quality. Authors of studies were contacted to obtain missing information.

MAIN RESULTS

Four studies enrolled approximately 1700 participants. Trials lasted between nine months to two years. Three studies were randomised controlled trials, two of which showed a cluster randomised design; one trial probably was a controlled trial with researcher controlled group assignment. In children up to three years of age in Turkey, Vitamin D compared to no intervention showed a relative risk of 0.04 (95% confidence interval (CI) 0 to 0.71). Despite a marked non-compliance, a Chinese trial in children up to three years of age comparing a combined intervention of supplementation of vitamin D, calcium and nutritional counseling showed a relative risk of 0.76 (95% CI 0.61 to 0.95) compared to no intervention. In two studies conducted in older children in China and in France no rickets occurred in both the intervention and control group.

AUTHORS' CONCLUSIONS

There a only few studies on the prevention of nutritional rickets in term born children. Until new data become available, it appears sound to offer preventive measures (vitamin D or calcium) to groups of high risk, like infants and toddlers; children living in Africa, Asia or the Middle East or migrated children from these regions into areas where rickets is not frequent. Due to a marked clinical heterogeneity and the scarcity of data, the main and adverse effects of preventive measures against nutritional rickets should be investigated in different countries, different age groups and in children of different ethnic origin.

Bones and beyond: an update on the role of vitamin D in child and adolescent health in Canada

Knowledge regarding the physiological role and dietary requirements of vitamin D has dramatically expanded over the past several decades. The “new” vitamin D is not only a mediator of calcium homeostasis, but also has important immunomodulatory, anti-microbial, and anti-proliferative actions. Amidst the growing interest in vitamin D as a mediator of many chronic diseases of adulthood such as cancer and type II diabetes, less attention has focused on the implications of the new understanding of vitamin D for child and adolescent health. This article reviews the definition of vitamin D insufficiency (VDI) as it applies to children and adolescents, the current vitamin D status of Canadian children and adolescents, pediatric conditions that may be related to VDI, and the evidence base for current dietary recommendations for vitamin D intake. Pharmacokinetic studies and epidemiologic research that incorporates clinical and functional outcomes are needed to clarify the role of vitamin D in growth and development and the specific dietary vitamin D requirements among Canadian children and adolescents.

Twice single doses of 100,000 IU of vitamin D in winter is adequate and safe for prevention of vitamin D deficiency in healthy children from Ushuaia, Tierra Del Fuego, Argentina

In order to improve vitamin D status of children from Ushuaia (55 degrees S), at the South of Argentina, double supplementation with 100.000 IU of vitamin D was administered at the beginning of winter (March 2004), and 3 months later during winter (June 2004). In 2004, serum 25-hydroxyvitamin D (25OHD) was measured before the first supplementation, a month after, and 3 months after receiving the second supplementation (March, April and September). We studied 18 healthy children from Ushuaia, age (mean+/-S.D.) 7.3+/-4.4 years old (range 1.2-14.6), seven girls and 11 boys. Before treatment, serum 25OHD was 29.3+/-5.9 ng/ml. It increased significantly 1 month after the first supplementation (April): 35.3+/-4.4 ng/ml (p<0.001), and decreased significantly 3 months after the second supplementation: 22.4+/-4.6 ng/ml (September (p<0.001). No child was neither deficient (<10 ng/ml) nor insufficient (10-15 ng/ml) of vitamin D. On April, a month after the first supplementation, no children had vitamin D intoxication levels (>50 ng/ml). These results disclosed that to prevent vitamin D deficiency for children at zones of risk at the south of our country, double supplementation of 100,000 IU of vitamin D during autumn and winter, would be adequate and safe.

Rickets and vitamin D deficiency in children and adolescents

This article discusses the pathogenesis, epidemiology, prevention, and treatment of nutritional rickets in children, highlighting the roles of exclusive breastfeeding and low dietary calcium intakes in its pathogenesis. The worldwide nature of the problem is described. Preventive strategies are discussed, and various treatment options are provided.

Vitamin D in preventive medicine: are we ignoring the evidence?

Vitamin D is metabolised by a hepatic 25-hydroxylase into 25-hydroxyvitamin D (25(OH)D) and by a renal 1alpha-hydroxylase into the vitamin D hormone calcitriol. Calcitriol receptors are present in more than thirty different tissues. Apart from the kidney, several tissues also possess the enzyme 1alpha-hydroxylase, which is able to use circulating 25(OH)D as a substrate. Serum levels of 25(OH)D are the best indicator to assess vitamin D deficiency, insufficiency, hypovitaminosis, adequacy, and toxicity. European children and young adults often have circulating 25(OH)D levels in the insufficiency range during wintertime. Elderly subjects have mean 25(OH)D levels in the insufficiency range throughout the year. In institutionalized subjects 25(OH)D levels are often in the deficiency range. There is now general agreement that a low vitamin D status is involved in the pathogenesis of osteoporosis. Moreover, vitamin D insufficiency can lead to a disturbed muscle function. Epidemiological data also indicate a low vitamin D status in tuberculosis, rheumatoid arthritis, multiple sclerosis, inflammatory bowel diseases, hypertension, and specific types of cancer. Some intervention trials have demonstrated that supplementation with vitamin D or its metabolites is able: (i) to reduce blood pressure in hypertensive patients; (ii) to improve blood glucose levels in diabetics; (iii) to improve symptoms of rheumatoid arthritis and multiple sclerosis. The oral dose necessary to achieve adequate serum 25(OH)D levels is probably much higher than the current recommendations of 5-15 microg/d.

Nutrient requirements for preterm infant formulas

Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.

Rapid and sensitive high-performance liquid chromatographic method for simultaneous determination of retinol, alpha-tocopherol, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in human plasma with photodiode-array ultraviolet detection

A new rapid and sensitive high-performance liquid chromatographic method using 0.5 ml of plasma has been developed for the simultaneous determination of retinol (vitamin A), alpha-tocopherol (vitamin E), 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3. The eluate was monitored with a photodiode-array detector with two fixed wavelengths (267 nm for vitamin D, 292 nm for alpha-tocopherol and retinol). For all compounds, including internal standards, the method provides extraction recoveries greater than 81%. Detection limits were equal to or lower than 1.5 microg/l for the 4 vitamins. Linearity of standards was excellent (r>0.999 in all cases). Intra-day and inter-day precision were generally acceptable; the intra-dayassay C.V. was 3/4 7.7 for all compounds and the inter-day-assay C.V. was <9.2% except for the lower concentrations of 25-hydroxyvitamin D3, 25-hydroxyvitamin D2 and alpha-tocopherol (10.8, 11.8 and 11.9, respectively). The important properties of the present method are its ease of use, its rapidity, since sample preparation was achieved in 15 min and all the compounds were eluted in less than 15 min, and its small sample volume required (=0.5 ml), which enables it to be used in pediatric practice.

[Vitamin D status in the adolescent: seasonal variations and effects of winter supplementation with vitamin D3]

BACKGROUND

Recently, 25 hydroxyvitamin D (25 OHD) blood concentrations measured in adolescents during or at the end of winter were found very low. A concomitant stimulation of parathyroid function was observed. The aim of the present study was to test the biological effects of a treatment with vitamin D3 during winter.

POPULATIONS AND METHODS

The effects of vitamin D3 supplementation (100,000 IU, twice, at the end of November and of January) were assessed in 24 male Caucasian adolescents (mean age +/- SD: 14 y 6 m +/- 9 m). They were pupils in a lad-jockeys training center located in the countryside near Chantilly (49 degrees northern latitude). Blood concentrations of 25 OHD, calcium and intact parathormone (PTH) were measured three times: before each oral intake of vitamin D3 and 2 months after the last intake (March). A group of 32 male adolescents (mean age +/- SD: 14 y 9 m +/- 6 m), pupils in the same center, receiving no vitamin D and sampled in November and in March, served as controls.

RESULTS

In March, mean concentrations of 25 OHD (8.36 +/- 2.73 micrograms/L) were very low in vitamin D-not supplemented adolescents since 34% had levels less than 6 micrograms/L. In March, PTH concentrations (40.5 +/- 12.2 ng/L) were significantly (P = 0.0001) higher than in November (28.8 +/- 9.9 ng/L). In boys receiving vitamin D3 25 OHD serum concentrations measured in January (17.5 +/- 3.2 micrograms/L) and in March (18.7 +/- 4.0 micrograms/L) remained at a level not very different from that measured in November (16.6 +/- 3.8 micrograms/L). During the same period, calcium and PTH concentrations (32.2 +/- 11.7 ng/L in November; 32.4 +/- 14.3 in January and 32.9 +/- 13.5 ng/L in March) remained at their basal level as well.

CONCLUSIONS

The observation that, after winter, a relatively large number of adolescents presented low concentrations of 25 OHD suggests that, during winter, usual dietary intakes and/or vitamin D stores are not sufficient to provide for their needs. Administration of two oral doses of 100,000 IU of vitamin D3 could maintain the vitamin D status at its initial level. The efficiency of such a prophylactic treatment is also assessed by its effect on parathyroid function.

Single-day therapy for nutritional vitamin D-deficiency rickets: a preferred method

A single-day large dose of vitamin D (stosstherapy) was given to 42 patients with nutritional vitamin D-deficiency rickets. Stosstherapy is safe and effective, obviates problems with compliance, and, by evoking a response in 4 to 7 days in nutritional rickets, becomes a valuable diagnostic aid for patients in whom initial findings do not clearly distinguish nutritional rickets from familial hypophosphatemic rickets.

Nephrocalcinosis, hypercalciuria and elevated serum levels of 1,25-dihydroxyvitamin D in children. Possible link to vitamin D toxicity

Ten children age 1 1/2 to 14 years, had bilateral nephrocalcinosis and hypercalciuria, but normal serum calcium (Ca) and phosphate (P) concentrations. Patients with hypercalciuria were divided into absorptive (n = 4) and renal (n = 6) subgroups, and in the latter four patients had a primary Ca-leak and two had a P-leak. All the children had received intermittent high dose vitamin D prophylaxis during infancy. At the time of investigation all had normal serum levels of 25-hydroxyvitamin D, yet all but one had elevated values of 1,25-(OH)2D. Although the hypercalciuria was indistinguishable from the various known forms of idiopathic hypercalciuria, the previous clinical course and the pattern of bone mineral homeostasis suggest that both clinical features, namely nephrocalcinosis and hypercalciuria were related to vitamin D toxicity through various pathogenetic pathways.