The change in plasma 25-hydroxyvitamin D did not differ between breast-fed infants that received a daily supplement of ergocalciferol or cholecalciferol for 3 months

The Relationship Between Vitamin D Intake and Serum 25-hydroxyvitamin D in Young Children: A Meta-Regression to Inform WHO/FAO Vitamin D Intake Recommendations

BACKGROUND

This work was commissioned by the World Health Organization and Food and Agriculture Organization to inform their update on the vitamin D requirements for children aged <4 y.

OBJECTIVES

The objective of this work was to undertake multilevel and multivariable dose-response modeling of serum 25-hydroxyvitamin D (25OHD) to total vitamin D intake in children aged <4 y with the goal of deriving updated vitamin D requirements for young children.

METHODS

Systematically identified randomized controlled trials among healthy children from 2 wk up to 3.9 y of age provided with daily vitamin D supplements or vitamin D-fortified foods were included. Linear and nonlinear random effects multilevel meta-regression models with and without covariates were fitted and compared. Interindividual variability was included by simulating the individual serum 25OHD responses. The percentage of individuals reaching set minimal and maximal serum 25OHD thresholds was calculated and used to derive vitamin D requirements.

RESULTS

A total of 31 trials with 186 data points from North America, Europe, Asia, and Australasia/Oceania, with latitudes ranging from 61°N to 38°S, and with participants of likely mostly light or medium skin pigmentation, were included. In 29 studies the children received vitamin D supplements and in 2 studies the children received vitamin D-fortified milk with or without supplements. The dose-response relationship between vitamin D intake and serum 25OHD was best fitted with the unadjusted quadratic model. Adding additional covariates, such as age, did not significantly improve the model. At a vitamin D intake of 10 μg/d, 97.3% of the individuals were predicted to achieve a minimal serum 25OHD threshold of 28 nmol/L. At a vitamin D intake of 35 μg/d, 1.4% of the individuals predicted to reach a maximal serum 25OHD threshold of 200 nmol/L.

CONCLUSIONS

In conclusion, this paper details the methodological steps taken to derive vitamin D requirements in children aged <4 y, including the addition of an interindividual variability component.

Scientific opinion on the tolerable upper intake level for vitamin D, including the derivation of a conversion factor for calcidiol monohydrate

Following two requests from the European Commission (EC), the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the revision of the tolerable upper intake level (UL) for vitamin D and to propose a conversion factor (CF) for calcidiol monohydrate into vitamin D3 for labelling purposes. Vitamin D refers to ergocalciferol (vitamin D2), cholecalciferol (vitamin D3), and calcidiol monohydrate. Systematic reviews of the literature were conducted to assess the relative bioavailability of calcidiol monohydrate versus vitamin D3 on serum 25(OH)D concentrations, and for priority adverse health effects of excess vitamin D intake, namely persistent hypercalcaemia/hypercalciuria and endpoints related to musculoskeletal health (i.e. falls, bone fractures, bone mass/density and indices thereof). Based on the available evidence, the Panel proposes a CF for calcidiol monohydrates of 2.5 for labelling purposes. Persistent hypercalciuria, which may be an earlier sign of excess vitamin D than persistent hypercalcaemia, is selected as the critical endpoint on which to base the UL for vitamin D. A lowest-observed-adverse-effect-level (LOAEL) of 250 μg/day is identified from two randomised controlled trials in humans, to which an uncertainty factor of 2.5 is applied to account for the absence of a no-observed-adverse-effect-level (NOAEL). A UL of 100 μg vitamin D equivalents (VDE)/day is established for adults (including pregnant and lactating women) and for adolescents aged 11-17 years, as there is no reason to believe that adolescents in the phase of rapid bone formation and growth have a lower tolerance for vitamin D compared to adults. For children aged 1-10 years, a UL of 50 μg VDE/day is established by considering their smaller body size. Based on available intake data, European populations are unlikely to exceed the UL, except for regular users of food supplements containing high doses of vitamin D.

The clinical relevance of native vitamin D in pediatric kidney disease

Hypovitaminosis D has been reported to be common in chronic kidney disease (CKD) as well as in proteinuric disorders. We reviewed available evidence to assess clinically relevant effects of low vitamin D status and native vitamin D (NVD) therapy, in pediatric renal diseases. Online medical databases were searched for articles related to vitamin D status, associations of hypovitaminosis D and effects of NVD therapy in kidney disease. Hypovitaminosis D was associated with worse skeletal, cardiovascular, inflammatory, and renal survival outcomes in CKD. Low serum 25 hydroxy-vitamin D (25[OH]D) levels correlated positively with glomerular filtration rate and negatively with serum parathyroid (PTH) levels. However, to date, evidence of benefit of NVD supplementation is restricted mainly to improvements in serum PTH, and biochemical 25[OH]D targets form the basis of clinical practice recommendations for NVD therapy. In nephrotic syndrome (NS) relapse, studies indicate loss of 25[OH]D along with vitamin D binding protein in urine, and serum total 25[OH]D levels are low. Preliminary evidence indicates that free 25[OH]D may be a better guide to the biologically active fraction. NVD therapy in NS does not show consistent results in improving skeletal outcomes and hypercalciuria has been reported when total 25[OH]D levels were considered as indication for therapy. NVD formulations should be regularised, and therapy monitored adequately to avoid adverse effects.

Effect of Vitamin D Supplementation on Bone Mass in Infants With 25-Hydroxyvitamin D Concentrations Less Than 50 nmol/L: A Prespecified Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

The dose of supplemental vitamin D needed in infants born with serum 25-hydroxyvitamin D (25[OH]D) concentrations less than 50 nmol/L (ie, 20 ng/mL) is unclear.

OBJECTIVE

To determine whether a higher dose (1000 IU vs 400 IU per day) is required in infants born with 25(OH)D concentrations less than 50 nmol/L for bone mineral accretion across infancy.

DESIGN, SETTING, AND PARTICIPANTS

In this prespecified secondary analysis of a double-blinded randomized clinical trial, conducted from March 2016 to March 2019 in a single center in Greater Montreal, Quebec, Canada, a consecutive sample of 139 healthy term singletons were recruited from 866 infants screened for vitamin D status at birth. Data were analyzed from June 2021 to November 2022.

INTERVENTIONS

Capillary blood was collected 24 to 36 hours after birth to measure serum total 25(OH)D concentrations. Infants with 25(OH)D concentrations less than 50 nmol/L were randomized to receive either 1000 IU or 400 IU per day of oral vitamin D3 supplementation from age 1 to 12 months. Infants with 25(OH)D concentrations of 50 nmol/L or greater formed a reference group.

MAIN OUTCOMES AND MEASURES

Measures at age 1, 3, 6, and 12 months were preplanned and included whole-body bone mineral content, lumbar spine bone mineral content, and bone mineral density using dual-energy x-ray absorptiometry, and serum 25(OH)D3 using liquid chromatography tandem mass spectrometry.

RESULTS

Of 139 included infants, 81 (58.3%) were male, and the median (IQR) gestational age at birth was 39.6 (38.9-40.6) weeks. A total of 49 infants were included in the 1000 IU per day group, 49 infants in the 400 IU per day group, and 41 in the reference group. Mean (SD) whole-body bone mineral content was not different between trial groups over time (1000 IU per day, 173.09 [2.36] g; 400 IU per day, 165.94 [66.08] g). Similarly, no differences were observed in lumbar spine bone mineral content or density. Mean (SD) serum 25(OH)D3 concentrations were significantly higher in the 1000 IU per day group from age 3 to 12 months (3 months, 115.2 [35.3] nmol/L; 6 months, 121.6 [34.4] nmol/L; 12 months, 99.6 [28.8] nmol/L) compared with the 400 IU per day trial group (3 months, 77.4 [23.3] nmol/L; 6 months, 85.1 [18.6] nmol/L; 12 months, 82.3 [14.3] nmol/L).

CONCLUSIONS AND RELEVANCE

In this study, a higher dose of vitamin D supplementation in infants born with 25(OH)D concentrations less than 50 nmol/L did not present advantages to bone mass in infancy. This study supports a standard dose of 400 IU per day of vitamin D supplementation for breastfed infants in Montreal.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02563015.

Vitamin D intakes and health outcomes in infants and preschool children: Summary of an evidence report

BACKGROUND

A systematic review was commissioned to support an international expert group charged to update the Food and Agriculture Organisation of the United Nations (FAO)/World Health Organisation (WHO)'s vitamin D intake recommendations for children aged 0-4 years.

MATERIALS AND METHODS

Multiple electronic databases were searched to capture studies published from database inception to the 2^nd week of June 2020 according to key questions formulated by the FAO/WHO. Relevant studies were summarised and synthesised by key questions and by health outcomes using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

The 146 included studies examined the effects of different vitamin D intake levels on a variety of health outcomes (e.g. infectious disease, growth, neurodevelopment, rickets, and bone mineral density), and on outcomes for setting vitamin D upper limits (e.g. hypercalcemia, hypercalciuria, and nephrocalcinosis). For most outcomes, the strength of evidence was low or very low. Evidence was rated moderate for the effect of daily vitamin D supplementation on raising serum 25(OH)D concentrations, and a random-effects meta-regression analysis of 28 randomised controlled trials (mostly in infants 0-12 months) showed that each 100 IU/d increase in vitamin D supplementation was associated with an average of 1.92 (95% CI 0.28, 3.56) nmol/L increase in achieved 25-hydroxy-vitaminn D (25[OH]D) concentration (n = 53 intervention arms; p = .022) with large residual heterogeneity (I² = 99.39%). Evidence was very low on two of the upper limit outcomes - hypercalcemia and hypercalciuria.

CONCLUSIONS

The evidence report provided the expert group with a foundation and core set of data to begin their work to set vitamin D nutrient reference values. To move the field forward, future studies should use standardised 25(OH)D assay measurements and should examine the relationship between long-term vitamin D status and health outcomes.Key MessagesResults of a large complex systematic review suggest the current totality of evidence from trials and prospective observational studies do not reach sufficient certainty level to support a causal relationship between vitamin D intake and asthma, wheeze, eczema, infectious diseases, or rickets (most trials reported no rickets) in generally healthy infants and young children.In this systematic review, the only body of evidence that reached a moderate level of certainty was regarding the effect of daily vitamin D supplementation (vitamin D₃ or D₂ supplements to infants/children) on increasing serum 25(OH)D concentrations. However, currently there is no consensus on the definitions of vitamin D status, e.g. deficiency, insufficiency, sufficiency and toxicity, based on serum 25(OH)D concentrations.This systematic review provided an international expert group a foundation and core set of data through intake-response modelling to help set vitamin D nutrient reference values for infants and children up to 4 years of age.

Vitamin D Status of Infants of Mothers with Gestational Diabetes: Status at Birth and a Randomized Controlled Trial of Vitamin D Supplementation across Infancy

BACKGROUND

Vitamin D status and requirements of infants of women with gestational diabetes mellitus (GDM) are unclear.

OBJECTIVES

The objectives were to assess vitamin D status in infants of mothers with GDM and compare vitamin D status in response to 400 vs. 1000 IU/d vitamin D supplementation in infants born with serum 25-hydroxyvitamin D [25(OH)D] <50 nmol/L.

METHODS

Women with GDM delivering full-term infants (n = 98; March 2017-2019, Montreal, Canada) were surveyed for demographic and lifestyle factors. Pregnancy history was obtained from medical records. Newborn serum 25(OH)D was measured (immunoassay) and categorized as <30 (deficient) or ≥40 nmol/L (adequate). Breastfed neonates (n = 16) with serum 25(OH)D <50 nmol/L at birth were randomly assigned to 400 or 1000 IU/d of supplemental cholecalciferol (vitamin D3), and serum 25(OH)D was measured at baseline (≤1 mo) and 3, 6, and 12 mo of age. Groups were compared using a linear mixed-effects model and Tukey-Kramer post hoc tests.

RESULTS

Mean newborn serum 25(OH)D was 46.4 (95% CI: 43.9, 49.9) nmol/L, with 15.3% (95% CI: 8.2%, 22.4%) <30 nmol/L and 61.2% (95% CI: 51.6%, 70.9%) ≥40 nmol/L. During the trial, most infants were breastfed to 3 mo (400 IU/d: 87.5%; 1000 IU/d: 75.0%). Mean (± SEM) infant serum 25(OH)D was higher in the 1000-IU/d group at 3 mo (79.9 ± 5.9 vs. 111.5 ± 15.2 nmol/L; P = 0.0263), and although not different at 6-12 mo, was maintained at >50 nmol/L.

CONCLUSIONS

Most infants of women with GDM had adequate vitamin D status in this study. In those born with serum 25(OH)D <50 nmol/L, vitamin D status was corrected by 3 mo of age in response to 400 or 1000 IU/d of supplemental vitamin D. Dietary guidance should continue to recommend that all women who could become pregnant take a multivitamin supplement and that breastfed infants receive 400 IU/d of supplemental vitamin D. This study and ancillary trial were registered at clinicaltrials.gov (https://www.

CLINICALTRIALS

gov/ct2/show/NCT02563015) as NCT02563015.

Yeast as a biological platform for vitamin D production: A promising alternative to help reduce vitamin D deficiency in humans

Vitamin D is an important human hormone, known primarily to be involved in the intestinal absorption of calcium and phosphate, but it is also involved in various non-skeletal processes (molecular, cellular, immune, and neuronal). One of the main health problems nowadays is the vitamin D deficiency of the human population due to lack of sun exposure, with estimates of one billion people worldwide with vitamin D deficiency, and the consequent need for clinical intervention (i.e., prescription of pharmacological vitamin D supplements). An alternative to reduce vitamin D deficiency is to produce good dietary sources of it, a scenario in which the yeast Saccharomyces cerevisiae seems to be a promising alternative. This review focuses on the potential use of yeast as a biological platform to produce vitamin D, summarizing both the biology aspects of vitamin D (synthesis, ecology and evolution, metabolism, and bioequivalence) and the work done to produce it in yeast (both for vitamin D₂ and for vitamin D₃ ), highlighting existing challenges and potential solutions. This article is protected by copyright. All rights reserved.

Maternal excess adiposity and serum 25-hydroxyvitamin D < 50 nmol/L are associated with elevated whole body fat mass in healthy breastfed neonates

BACKGROUND

Vitamin D status of pregnant women is associated with body composition of the offspring. The objective of this study was to assess whether the association between maternal vitamin D status and neonatal adiposity is modified by maternal adiposity preconception.

METHODS

Healthy mothers and their term appropriate weight for gestational age (AGA) infants (n = 142; 59% male, Greater Montreal, March 2016-2019) were studied at birth and 1 month postpartum (2-6 weeks). Newborn (24-36 h) serum was collected to measure total 25-hydroxyvitamin D [25(OH)D] (immunoassay); maternal pre-pregnancy BMI was obtained from the medical record. Anthropometry, body composition (dual-energy X-ray absorptiometry) and serum 25(OH)D were measured at 2-6 weeks postpartum in mothers and infants. Mothers were grouped into 4 categories based on their vitamin D status (sufficient 25(OH)D ≥ 50 nmol/L vs. at risk of being insufficient < 50 nmol/L) and pre-pregnancy BMI (< 25 vs. ≥25 kg/m2): insufficient-recommended weight (I-RW, n = 24); insufficient-overweight/obese (I-OW/O, n = 21); sufficient-recommended weight (S-RW, n = 69); and sufficient-overweight/obese (S-OW/O, n = 28). Partial correlation and linear fixed effects model were used while adjusting for covariates.

RESULTS

At birth, infant serum 25(OH)D mean concentrations were below 50 nmol/L, the cut-point for sufficiency, for both maternal pre-pregnancy BMI categories; 47.8 [95%CI: 43.8, 51.9] nmol/L if BMI < 25 kg/m2 and 38.1 [95%CI: 33.5, 42.7] nmol/L if BMI ≥25 kg/m2. Infant serum 25(OH)D concentrations at birth (r = 0.77; P < 0.0001) and 1 month (r = 0.59, P < 0.0001) were positively correlated with maternal postpartum serum 25(OH)D concentrations. Maternal serum 25(OH)D concentration was weakly correlated with maternal percent whole body fat mass (r = - 0.26, P = 0.002). Infants of mothers in I-OW/O had higher fat mass versus those of mothers in S-OW/O (914.0 [95%CI: 766.4, 1061.6] vs. 780.7 [95%CI: 659.3, 902.0] g; effect size [Hedges' g: 0.42]; P = 0.04 adjusting for covariates) with magnitude of difference of 220.4 g or ~ 28% difference.

CONCLUSIONS

Maternal and neonatal vitamin D status are positively correlated. In this study, maternal adiposity and serum 25(OH)D < 50 nmol/L are dual exposures for neonatal adiposity. These findings reinforce the importance of vitamin D supplementation early in infancy irrespective of vitamin D stores acquired in utero and maternal weight status.

Vitamin D prophylaxis in infancy

We looked at existing recommendations and supporting evidence on the effectiveness of vitamin D supplementation in infancy for reducing vitamin D deficiency and for preventing rickets and infections. We also looked at optimal dose of vitamin D and the age until which vitamin D supplementation is beneficial.We conducted a literature search up to the 17th of July 2019 by using key terms and manual search in selected sources. We summarized the recommendations and the strength of the recommendation when and as reported by the authors. We summarized the main findings of systematic reviews with the certainty of the evidence as reported.A daily dose of 400 international units of vitamin D in infants has shown to be effective for improving bone health and preventing rickets. Evidence is more robust in groups of infants and children at risk. Vitamin D supplementation is well tolerated, and not associated with toxicity. Higher doses have not shown to add benefit while it could potentially cause toxic blood levels and hypercalcemia. Adequate levels of vitamin D might not be achieved with lower daily doses. Universal vitamin D supplementation starting shortly after birth, regardless of the mode of feeding and until 12 months of age, is strongly recommended. Beyond 12 months of age vitamin D supplementation is recommended only in groups of children at risk.

Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health

BACKGROUND

Vitamin D deficiency is common worldwide, contributing to nutritional rickets and osteomalacia which have a major impact on health, growth, and development of infants, children and adolescents. Vitamin D levels are low in breast milk and exclusively breastfed infants are at risk of vitamin D insufficiency or deficiency.

OBJECTIVES

To determine the effect of vitamin D supplementation given to infants, or lactating mothers, on vitamin D deficiency, bone density and growth in healthy term breastfed infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to 29 May 2020 supplemented by searches of clinical trials databases, conference proceedings, and citations.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs in breastfeeding mother-infant pairs comparing vitamin D supplementation given to infants or lactating mothers compared to placebo or no intervention, or sunlight, or that compare vitamin D supplementation of infants to supplementation of mothers.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and independently extracted data. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included 19 studies with 2837 mother-infant pairs assessing vitamin D given to infants (nine studies), to lactating mothers (eight studies), and to infants versus lactating mothers (six studies). No studies compared vitamin D given to infants versus periods of infant sun exposure. Vitamin D supplementation given to infants: vitamin D at 400 IU/day may increase 25-OH vitamin D levels (MD 22.63 nmol/L, 95% CI 17.05 to 28.21; participants = 334; studies = 6; low-certainty) and may reduce the incidence of vitamin D insufficiency (25-OH vitamin D < 50 nmol/L) (RR 0.57, 95% CI 0.41 to 0.80; participants = 274; studies = 4; low-certainty). However, there was insufficient evidence to determine if vitamin D given to the infant reduces the risk of vitamin D deficiency (25-OH vitamin D < 30 nmol/L) up till six months of age (RR 0.41, 95% CI 0.16 to 1.05; participants = 122; studies = 2), affects bone mineral content (BMC), or the incidence of biochemical or radiological rickets (all very-low certainty). We are uncertain about adverse effects including hypercalcaemia. There were no studies of higher doses of infant vitamin D (> 400 IU/day) compared to placebo. Vitamin D supplementation given to lactating mothers: vitamin D supplementation given to lactating mothers may increase infant 25-OH vitamin D levels (MD 24.60 nmol/L, 95% CI 21.59 to 27.60; participants = 597; studies = 7; low-certainty), may reduce the incidences of vitamin D insufficiency (RR 0.47, 95% CI 0.39 to 0.57; participants = 512; studies = 5; low-certainty), vitamin D deficiency (RR 0.15, 95% CI 0.09 to 0.24; participants = 512; studies = 5; low-certainty) and biochemical rickets (RR 0.06, 95% CI 0.01 to 0.44; participants = 229; studies = 2; low-certainty). The two studies that reported biochemical rickets used maternal dosages of oral D3 60,000 IU/day for 10 days and oral D3 60,000 IU postpartum and at 6, 10, and 14 weeks. However, infant BMC was not reported and there was insufficient evidence to determine if maternal supplementation has an effect on radiological rickets (RR 0.76, 95% CI 0.18 to 3.31; participants = 536; studies = 3; very low-certainty). All studies of maternal supplementation enrolled populations at high risk of vitamin D deficiency. We are uncertain of the effects of maternal supplementation on infant growth and adverse effects including hypercalcaemia. Vitamin D supplementation given to infants compared with supplementation given to lactating mothers: infant vitamin D supplementation compared to lactating mother supplementation may increase infant 25-OH vitamin D levels (MD 14.35 nmol/L, 95% CI 9.64 to 19.06; participants = 269; studies = 4; low-certainty). Infant vitamin D supplementation may reduce the incidence of vitamin D insufficiency (RR 0.61, 95% CI 0.40 to 0.94; participants = 334; studies = 4) and may reduce vitamin D deficiency (RR 0.35, 95% CI 0.17 to 0.72; participants = 334; studies = 4) but the evidence is very uncertain. Infant BMC and radiological rickets were not reported and there was insufficient evidence to determine if maternal supplementation has an effect on infant biochemical rickets. All studies enrolled patient populations at high risk of vitamin D deficiency. Studies compared an infant dose of vitamin D 400 IU/day with varying maternal vitamin D doses from 400 IU/day to > 4000 IU/day. We are uncertain about adverse effects including hypercalcaemia.

AUTHORS' CONCLUSIONS

For breastfed infants, vitamin D supplementation 400 IU/day for up to six months increases 25-OH vitamin D levels and reduces vitamin D insufficiency, but there was insufficient evidence to assess its effect on vitamin D deficiency and bone health. For higher-risk infants who are breastfeeding, maternal vitamin D supplementation reduces vitamin D insufficiency and vitamin D deficiency, but there was insufficient evidence to determine an effect on bone health. In populations at higher risk of vitamin D deficiency, vitamin D supplementation of infants led to greater increases in infant 25-OH vitamin D levels, reductions in vitamin D insufficiency and vitamin D deficiency compared to supplementation of lactating mothers. However, the evidence is very uncertain for markers of bone health. Maternal higher dose supplementation (≥ 4000 IU/day) produced similar infant 25-OH vitamin D levels as infant supplementation of 400 IU/day. The certainty of evidence was graded as low to very low for all outcomes.

Effects of oral vitamin D supplementation on linear growth and other health outcomes among children under five years of age

BACKGROUND

Vitamin D is a secosteroid hormone that is important for its role in calcium homeostasis to maintain skeletal health. Linear growth faltering and stunting remain pervasive indicators of poor nutrition status among infants and children under five years of age around the world, and low vitamin D status has been linked to poor growth. However, existing evidence on the effects of vitamin D supplementation on linear growth and other health outcomes among infants and children under five years of age has not been systematically reviewed.

OBJECTIVES

To assess effects of oral vitamin D supplementation on linear growth and other health outcomes among infants and children under five years of age.

SEARCH METHODS

In December 2019, we searched CENTRAL, PubMed, Embase, 14 other electronic databases, and two trials registries. We also searched the reference lists of relevant publications for any relevant trials, and we contacted key organisations and authors to obtain information on relevant ongoing and unpublished trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs assessing the effects of oral vitamin D supplementation, with or without other micronutrients, compared to no intervention, placebo, a lower dose of vitamin D, or the same micronutrients alone (and not vitamin D) in infants and children under five years of age who lived in any country.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

Out of 75 studies (187 reports; 12,122 participants) included in the qualitative analysis, 64 studies (169 reports; 10,854 participants) contributed data on our outcomes of interest for meta-analysis. A majority of included studies were conducted in India, USA, and Canada. Two studies reported for-profit funding, two were categorised as receiving mixed funding (non-profit and for-profit), five reported that they received no funding, 26 did not disclose funding sources, and the remaining studies were funded by non-profit funding. Certainty of evidence varied between high and very low across outcomes (all measured at endpoint) for each comparison. Vitamin D supplementation versus placebo or no intervention (31 studies) Compared to placebo or no intervention, vitamin D supplementation (at doses 200 to 2000 IU daily; or up to 300,000 IU bolus at enrolment) may make little to no difference in linear growth (measured length/height in cm) among children under five years of age (mean difference (MD) 0.66, 95% confidence interval (CI) -0.37 to 1.68; 3 studies, 240 participants; low-certainty evidence); probably improves length/height-for-age z-score (L/HAZ) (MD 0.11, 95% CI 0.001 to 0.22; 1 study, 1258 participants; moderate-certainty evidence); and probably makes little to no difference in stunting (risk ratio (RR) 0.90, 95% CI 0.80 to 1.01; 1 study, 1247 participants; moderate-certainty evidence). In terms of adverse events, vitamin D supplementation results in little to no difference in developing hypercalciuria compared to placebo (RR 2.03, 95% CI 0.28 to 14.67; 2 studies, 68 participants; high-certainty evidence). It is uncertain whether vitamin D supplementation impacts the development of hypercalcaemia as the certainty of evidence was very low (RR 0.82, 95% CI 0.35 to 1.90; 2 studies, 367 participants). Vitamin D supplementation (higher dose) versus vitamin D (lower dose) (34 studies) Compared to a lower dose of vitamin D (100 to 1000 IU daily; or up to 300,000 IU bolus at enrolment), higher-dose vitamin D supplementation (200 to 6000 IU daily; or up to 600,000 IU bolus at enrolment) may have little to no effect on linear growth, but we are uncertain about this result (MD 1.00, 95% CI -2.22 to 0.21; 5 studies, 283 participants), and it may make little to no difference in L/HAZ (MD 0.40, 95% CI -0.06 to 0.86; 2 studies, 105 participants; low-certainty evidence). No studies evaluated stunting. As regards adverse events, higher-dose vitamin D supplementation may make little to no difference in developing hypercalciuria (RR 1.16, 95% CI 1.00 to 1.35; 6 studies, 554 participants; low-certainty evidence) or in hypercalcaemia (RR 1.39, 95% CI 0.89 to 2.18; 5 studies, 986 participants; low-certainty evidence) compared to lower-dose vitamin D supplementation. Vitamin D supplementation (higher dose) + micronutrient(s) versus vitamin D (lower dose) + micronutrient(s) (9 studies) Supplementation with a higher dose of vitamin D (400 to 2000 IU daily, or up to 300,000 IU bolus at enrolment) plus micronutrients, compared to a lower dose (200 to 2000 IU daily, or up to 90,000 IU bolus at enrolment) of vitamin D with the same micronutrients, probably makes little to no difference in linear growth (MD 0.60, 95% CI -3.33 to 4.53; 1 study, 25 participants; moderate-certainty evidence). No studies evaluated L/HAZ or stunting. In terms of adverse events, higher-dose vitamin D supplementation with micronutrients, compared to lower-dose vitamin D with the same micronutrients, may make little to no difference in developing hypercalciuria (RR 1.00, 95% CI 0.06 to 15.48; 1 study, 86 participants; low-certainty evidence) and probably makes little to no difference in developing hypercalcaemia (RR 1.00, 95% CI 0.90, 1.11; 2 studies, 126 participants; moderate-certainty evidence). Four studies measured hyperphosphataemia and three studies measured kidney stones, but they reported no occurrences and therefore were not included in the comparison for these outcomes.

AUTHORS' CONCLUSIONS

Evidence suggests that oral vitamin D supplementation may result in little to no difference in linear growth, stunting, hypercalciuria, or hypercalcaemia, compared to placebo or no intervention, but may result in a slight increase in length/height-for-age z-score (L/HAZ). Additionally, evidence suggests that compared to lower doses of vitamin D, with or without micronutrients, vitamin D supplementation may result in little to no difference in linear growth, L/HAZ, stunting, hypercalciuria, or hypercalcaemia. Small sample sizes, substantial heterogeneity in terms of population and intervention parameters, and high risk of bias across many of the included studies limit our ability to confirm with any certainty the effects of vitamin D on our outcomes. Larger, well-designed studies of long duration (several months to years) are recommended to confirm whether or not oral vitamin D supplementation may impact linear growth in children under five years of age, among both those who are healthy and those with underlying infectious or non-communicable health conditions.

25-Hydroxyvitamin D, Vitamin D Binding Protein, Bioavailable 25-Hydroxyvitamin D, and Body Composition in a Diverse Sample of Women Collegiate Indoor Athletes

Women athletes are at higher risk for bone diseases; yet, information on vitamin D status ((25(OH)D), vitamin D binding protein (VDBP), and bioavailable 25(OH)D is limited. Collegiate athletes (n = 36) from volleyball (WVB), basketball (WBB), and track and field (WTF) were measured for (25(OH)D), VDBP, and bioavailable 25(OH)D; body composition and bone mineral density (BMD); and skin pigmentation. Participants self-reported daily vitamin D intake and sun exposure. One-way analysis of variance analyzed mean differences in measures across sports. Linear regression examined relationships between 25(OH)D; VDBP; bioavailable 25(OH)D; and whole body, hip, and spine BMD. Participants' (mean ± SD, 19.4 ± 1.4 years, 172.75 ± 8.21 cm, 70.9 ± 13.2 kg, and 22.9 ± 4.1% body fat) overall mean 25(OH)D was 70.5 ± 32.25 nmol/L, and 28% of participants were deemed inadequate and 61% below thresholds identified as sufficient for athletes. Although WBB athletes consumed higher (p = 0.007) dietary vitamin D (760.9 ± 484.2 IU/d) than WVB (342.6 ± 257.8) and WTF (402.3 ± 376.4) athletes did, there were no differences across sport in serum 25(OH)D. WVB and WTF had higher bioavailable 25(OH)D than WBB. No relationships existed between vitamin D status and body composition. Vitamin D inadequacy was identified among 1/3 of women indoor sport athletes. Consistent monitoring of vitamin D status and diet are recommended to sustain athlete health and sport performance.

Infants' Vitamin D Nutritional Status in the First Year of Life in Northern Taiwan

Vitamin D deficiency (VDD) and insufficiency (VDI) are common among exclusively breastfeeding infants. However, epidemiological evidence for the prevalence of VDD in infants during their first year of life in Taiwan has never been found. This trial determined the prevalence of VDD and VDI and the association between dietary vitamin D and vitamin D nutritional status in Northern Taiwan. A cross-sectional study was conducted on infants who returned to well-baby examinations from October 2012 to January 2014 in three hospitals: Shin Kong Wu Ho-Su Memorial Hospital, Taipei Medical University Hospital, and Shuang Ho Hospital. The specific vitamin D cut-off concentrations for VDD, VDI, and VDS are 25(OH)D₃ levels ≤20, 21–29, and ≥30 (ng/mL). Overall, 481 infants’ parents completed a questionnaire comprising questions related to vitamin D nutritional status, including weekly time outdoors, breastfeeding status, anthropometric measurement, and assessment of dietary intake, including milk and complementary food. The results revealed that 197 (41%) and 212 (44%) of infants in their first year of life had VDI and VDD, respectively, by the Endocrine Society guidelines. Breastfed infants had a higher prevalence of VDI (86.1%) than did mixed-fed (51.9%) and formula-fed (38.5%) infants (p < 0.001). The prevalence of VDD was 55.4% in infants aged under six months but increased to 61.6% in infants aged over six months. Infants in the VDI and VDD groups had the same anthropometrics as those in the vitamin D sufficiency (VDS) group. Our results revealed that 25(OH)D₃ had a negative correlation with the intact parathyroid hormone (iPTH) when the serum 25(OH)D₃ level ≤20 ng/mL (r = −0.21, p = 0.001). The VDS group had a higher total vitamin D intake than did the VDI and VDD groups, which was mainly obtained from infant formula. Our data revealed that dietary vitamin D intake and birth season were major indicators in predicting VDD. Lower dietary vitamin D intake and born in winter and spring significantly increased the odds ratio (OR) for VDI by 1.15 (95% CI 1.09–1.20) and 2.02 (95% CI 1.10–3.70), respectively, and that for VDD by 1.23 (95% CI 1.16–1.31) and 2.37 (95% CI 1.35–4.17) without covariates adjustment, respectively. Furthermore, ORs for VDI and VDD significantly differed after adjustment for covariates. In conclusion, the prevalence of VDI and VDD were high in infants during the first year of life. Breastfeeding infants had difficulty in obtaining sufficient vitamin D from diet. In cases where the amount of sun exposure that is safe and sufficient to improve vitamin D status is unclear, breastfed infants aged below one year old are recommended to be supplemented with vitamin D.

The Effects of Cholecalciferol Supplementation on Vitamin D Status Among a Diverse Population of Collegiate Basketball Athletes: A Quasi-Experimental Trial

Vitamin D may play a role in performance and injury risk, yet the required supplementation dosage for collegiate athletes is unclear. The objective of this study was to define the dosage of vitamin D₃ supplementation required to beneficially affect serum 25-hydroxyvitamin D (25(OH)D) among a sample of collegiate basketball athletes. This was a quasi-experimental trial, participants were allocated to one of three groups of vitamin D₃ daily at the beginning of pre-season training and dependent upon their baseline vitamin D status as follows: insufficient (<75 nmol/L) to 10,000 IU, sufficient (75–125 nmol/L) to 5000 IU and optimal (>125 nmol/L) to no supplementation. Follow-up assessments were completed ~ 5 months later in post season. The majority (n = 13) were allocated to 10,000 IU vs. n = 5 to 5000 IU and n = 2 to no supplementation. The 10,000 IU group showed the greatest change (35.0 ± 27.0 nmol/L) vs. the 5000 IU group (−9.3 ± 9.6 nmol/L) and no supplementation group (−41.6 ± 11.7 nmol/L, p < 0.01). Only 1 participant reached optimal status in the 10,000 IU group. In conclusion, a daily dosage of 10,000 IU vitamin D₃ supplementation mitigated the high prevalence of vitamin D deficiency among collegiate basketball players but was insufficient for all to reach sufficient levels.

Vitamin D Status Differs by Sex, Sport-Season, and Skin Pigmentation among Elite Collegiate Basketball Players

Vitamin D plays a key role in bone health, musculoskeletal function, and sport performance. Collegiate athletes competing in indoor sports may be at greater risk of vitamin D deficiency due to limited outdoor time. Therefore, the purpose was to assess 25-hydroxyvitamin D (25(OH)D) concentrations among collegiate men and women basketball (MBB, WBB) athletes. National Collegiate Athletic Association Division I men (MBB, n = 11) and women (WBB, n = 9) were tested during the off-season (T1; July) and pre-season (T2; October). Measurements included serum 25(OH)D; skin pigmentation, bone mineral density, and daily sun exposure (self-reported). Paired t-tests determined changes in 25(OH)D by sport-season and sex. Pearson correlations examined relationships between outcome variables. MBB athletes (mean ± SD; 19.6 ± 1.3 years) showed a reduction in 25(OH)D (T1: 64.53 nmol·L⁻¹ ± 11.96) (T2: 56.11 nmol·L⁻¹ ± 7.90) (p = 0.001). WBB (20.1 ± 1.1 years) had no change in 25(OH)D (T1: 99.07 nmol·L⁻¹ ± 49.94. T2: 97.56 nmol·L⁻¹ ± 36.47, p = 0.848). A positive association between 25(OH)D and skin pigmentation was observed (r = 0.47, p = 0.038). 25(OH)D was inversely correlated with lean body mass (LBM), body mass (BM), and bone mineral density (BMD), while a positive association was seen between 25(OH)D and skin pigmentation. In summary, 25(OH)D insufficiency was prevalent amongst male collegiate basketball athletes, with 25(OH)D levels being lower in the pre-season (October) than the off-season (July). Furthermore, darker skin pigmentation significantly correlated with 25(OH)D, indicating that individuals with darker skin tones may be at a greater risk of insufficiency/deficiency. More research is needed to examine the relationships between 25(OH)D and bone health in athletes.

Effects of nutritional vitamin D supplementation on markers of bone and mineral metabolism in children with chronic kidney disease

Background

We investigated the effects of nutritional vitamin D supplementation on markers of bone and mineral metabolism, i.e. serum levels of fibroblast growth factor 23 (FGF23), Klotho, bone alkaline phosphatase (BAP) and sclerostin, in two cohorts with chronic kidney disease (CKD).

Methods

In all, 80 vitamin D-deficient children were selected: 40 with mild to moderate CKD from the ERGO study, a randomized trial of ergocalciferol supplementation [estimated glomerular filtration rate (eGFR) 55 mL/min/1.73 m2], and 40 with advanced CKD from the observational Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study (eGFR 24 mL/min/1.73 m2). In each study, vitamin D supplementation was started in 20 children and 20 matched children not receiving vitamin D served as controls. Measures were taken at baseline and after a median period of 8 months. Age- and gender-related standard deviation scores (SDSs) were calculated.

Results

Before vitamin D supplementation, children in the ERGO study had normal FGF23 (median 0.31 SDS) and BAP (-0.10 SDS) but decreased Klotho and sclerostin (-0.77 and -1.04 SDS, respectively), whereas 4C patients had increased FGF23 (3.87 SDS), BAP (0.78 SDS) and sclerostin (0.76 SDS) but normal Klotho (-0.27 SDS) levels. Vitamin D supplementation further increased FGF23 in 4C but not in ERGO patients. Serum Klotho and sclerostin normalized with vitamin D supplementation in ERGO but remained unchanged in 4C patients. BAP levels were unchanged in all patients. In the total cohort, significant effects of vitamin D supplementation were noted for Klotho at eGFR 40-70 mL/min/1.73 m2.

Conclusions

Vitamin D supplementation normalized Klotho and sclerostin in children with mild to moderate CKD but further increased FGF23 in advanced CKD.

Serum 25-hydroxyvitamin D response to vitamin D supplementation in infants: a systematic review and meta-analysis of clinical intervention trials

PURPOSE

For the prevention of nutritional rickets, 400 IU vitamin D daily and circulating 25-hydroxyvitamin D (25OHD) concentrations > 50 nmol/L are recommended, whereas the toxicity threshold is set at 250 nmol/L. We synthesized the evidence for the effect of vitamin D supplementation on incremental 25OHD in infants up to 1 year of age.

METHODS

We performed a systematic review and meta-analysis of intervention trials in several databases. A total of 87 records were identified for full-text review and 27 articles with 61 studies were included in the final analysis.

RESULTS

The selected 61 studies included 1828 participants. Nineteen cohorts had already mean baseline 25OHD levels ≥ 50 nmol/L. The weighted mean difference in 25OHD following vitamin D supplementation was + 49.4 nmol/L (95% CI 43.6-55.3 nmol/L; P < 0.001). The increment was dose-dependent (P = 0.002), was higher in full-term than in pre-term infants (P < 0.001), was higher in infants with baseline 25OHD < 50 nmol/L as compared to ≥ 50 nmol/L (P = 0.001), and was marginally influenced by the 25OHD test procedure (P = 0.080). Vitamin D₃ doses of 400 IU/day were sufficient to achieve 25OHD concentrations ≥ 50 nmol/L in most full-term infants. A 25OHD level of 250 nmol/L was not exceeded in ≥ 97.5% of infants at doses between 200 and 1200 IU/day, but potentially in ≥ 2.5% of infants at a dose of 1600 IU/day.

CONCLUSIONS

Vitamin D supplementation of 400 IU/day is sufficient for achieving 25OHD concentrations able to prevent nutritional rickets. A more personalized vitamin D dosing strategy would require 25OHD testing, but also assay standardization.

Vitamin-D2 treatment-associated decrease in 25(OH)D3 level is a reciprocal phenomenon: a randomized controlled trial

BACKGROUND

Vitamin-D2 (D2) treatment has been associated with a decrease in 25-hydroxy (25(OH)) vitamin-D3 (D3) level, suggesting that D3 treatment would be preferred to raise total 25(OH) vitamin-D (D) level. We postulated that D2 treatment-associated decrease in 25(OH)D3 level is related to the increase in 25(OH)D level rather than being D2-specific, and thus there would be a similar D3 treatment-associated decrease in 25(OH)D2 level.

METHODS

Fifty volunteers were block-randomized to 50,000 IU D2 or placebo orally once (study-1) and fifty volunteers received 50,000 IU D2 orally once and 4 days later block-randomized to 50,000 IU D3 or placebo orally once (study-2). Interventions were concealed from volunteers and research coordinators and blindly-administered. Serum 25(OH)D2 and 25(OH)D3 levels were blindly-determined at baseline and days 14, 28, 42, and 56, post-randomization by high performance liquid chromatography assay. Results of 97 participants were analyzed. Primary outcome measure was day-28 D2-associated change in 25(OH)D3 level in study-1 and D3-associated change in 25(OH)D2 level in study-2, adjusted for baseline levels.

RESULTS

Mean (95% confidence interval) difference between the active and placebo arms in the decrease in day-28 25(OH)D3 (study-1) and 25(OH)D2 (study-2) levels was 13.2 (9.7 to 16.6) and 9.8 (5.2 to 14.4) nmol/L, respectively. Corresponding differences at day-56 were 10.8 (6.8 to 14.8) and 1.7 (- 7.6 to 11.1) nmol/L, respectively. The difference between the placebo and active arms in area-under-the-curve at day-28 (AUC₂₈) and day-56 (AUC₅₆) were 262.3 (197.8 to 326.7) and 605.1 (446.3 to 784.0) for 25(OH)D3 (study-1) and 282.2 (111.2 to 453.3) and 431.2 (179.3 to 683.2) nmol.d/L for 25(OH)D2 (study-2), respectively. There were significant correlations between day-28 changes in 25(OH)D2 and 25(OH)D3 levels in study-1 (rho = - 0.79, p < 0.001) and study-2 (rho = - 0.36, p = 0.01), and between day-28 changes in 25(OH)D2 level and baseline 25(OH)D level in study-2 (rho = - 0.42, p = 0.003).

CONCLUSIONS

Compared to placebo, D3 treatment is associated with a decrease in 25(OH)D2 level similar in magnitude to D2-treatment associated decrease in 25(OH)D3 level; however, the D3-placebo difference in 25(OH)D2 level is shorter-lasting. Changes in 25(OH)D2 and 25(OH)D3 levels are correlated with each other and with baseline 25 (OH) D levels, suggesting a common regulatory mechanism.

TRIAL REGISTRATION

ClinicalTrial.gov identifier: NCT03035084 (registered January 27, 2017).

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.

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

ABM Clinical Protocol #29: Iron, Zinc, and Vitamin D Supplementation During Breastfeeding

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols, free from commercial interest or influence, for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Clinical practice recommendations for native vitamin D therapy in children with chronic kidney disease Stages 2-5 and on dialysis

Vitamin D deficiency is widely prevalent and often severe in children and adults with chronic kidney disease (CKD). Although native vitamin D {25-hydroxyvitamin D [25(OH)D]} is thought to have pleiotropic effects on many organ systems, its skeletal effects have been most widely studied. The 25(OH)D deficiency is causally linked with rickets and fractures in healthy children and those with CKD, contributing to the CKD-mineral and bone disorder (MBD) complex. There are few studies to provide evidence for vitamin D therapy or guidelines for its use in CKD. A core working group (WG) of the European Society for Paediatric Nephrology (ESPN) CKD-MBD and Dialysis WGs have developed recommendations for the evaluation, treatment and prevention of vitamin D deficiency in children with CKD. We present clinical practice recommendations for the use of ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3) in children with CKD Stages 2-5 and on dialysis. A parallel document addresses treatment recommendations for active vitamin D analogue therapy. The WG has performed an extensive literature review to include meta-analyses and randomized controlled trials in healthy children as well as children and adults with CKD, and prospective observational studies in children with CKD. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system has been used to develop and grade the recommendations. In the absence of applicable study data, the opinion of experts from the ESPN CKD-MBD and Dialysis WGs is provided, but clearly GRADE-ed as such and must be carefully considered by the treating physician, and adapted to individual patient needs as appropriate.

Vitamin D requirements in infancy: a systematic review

PURPOSE OF REVIEW

New evidence for recommendations for vitamin D supplementation in healthy infants based upon recent literature.

RECENT FINDINGS

Randomized controlled trials published since 2009 that related to vitamin D doses in infancy were reviewed. They do not provide any additional evidence that larger, more generous amounts of daily vitamin D beyond the customary recommended 400 IU daily dose, affect any significant outcome. Larger amounts may lead to serum 25 hydroxy vitamin D concentrations that have been reported to be potentially associated with adverse effects.

SUMMARY

There are still many unanswered questions left, in particular whether or not more 'generous' amounts of vitamin D in infancy may improve long-term health outcomes such as prevention of osteoporosis, allergies, or cancer.

Differential effects of vitamin D2 and D3 supplements on 25-hydroxyvitamin D level are dose, sex, and time dependent: a randomized controlled trial

BACKGROUND

Vitamin D (D) supplements are indispensable for its world-wide deficiency. Controversy continues on ergocalciferol (D2) and cholecalciferol (D3) relative potency as well as on dosing-schedule and sex role in raising 25-hydroxy D (25(OH)D) level, the best indicator of D status.

METHODS

We randomized 279 adults to daily D2, D3, D2/D3, or placebo; 2-weekly D2 or D3; or 4-weekly D2 or D3 (250,000 IU over/140 days). Randomization sequence, stratified by body-mass-index (BMI) and sex, was concealed from study coordinators and participants who were then blinded to capsules' content. D2, D3, 25(OH)D2, and 25(OH)D3 Serum levels were determined blindly on days 0,1,2,3,4,7,14, and 2-weekly thereafter by high performance liquid chromatography assay. The results of 269 participants were available for analysis. Primary endpoint was area-under-the-curve (AUC) of 25(OH)D (25(OH)D2 + 25(OH)D3) adjusted for sex, BMI, and baseline 25(OH)D level.

RESULTS

Mean(SD) age was 33.0(8.5) year, 41% were males, and 85% completed follow-up. Baseline 25(OH)D level was 39.8(11.9) and increased by 3.3(11.6) and 28.6(16.3) nmol/L, in the placebo and active-treatment groups, respectively. AUC from day 0 to 140 (AUC₁₄₀) of 25(OH)D was 40% (D3 daily) to 55% (D3 2-weekly) higher with active-treatment than placebo (p < 0.001). 25(OH)D2 AUC₁₄₀ was higher in daily than 2-weekly (17%, p = 0.006) and 4-weekly (20%, p = 0.001) D2-treated groups. 25(OH)D3 AUC₁₄₀ was lower in daily than 2-weekly (11%, p = 0.002) and 4-weekly D3-treated groups (10%, p = 0.008). In D2-treated groups, there was 16.4 nmol/L decrease in 25(OH)D3 level that correlated (p < 0.001) with 25(OH)D2 level increase (r = 0.48) and baseline 25(OH)D level (r = 0.58), in one participant with measurable baseline 25(OH)D2 level, D3 caused a similar decrease in 25(OH)D2 level, while in the D2/D3-treated group, 25(OH)D3 level didn't increase. Incremental AUC from day 0 to 7 (AUC₇) of D3 and 25(OH)D3 in D3-treated groups were 118-243% higher and 31-39% lower, respectively, than incremental AUC₇ of D2 and 25(OH)D2 in D2-treated groups. Incremental AUC₇ of D3 and 25(OH)D3 in D3-treated groups and D2 and 25(OH)D2 in D2-treated groups were higher in females than males (55, 13, 64, and 28%, respectively). Baseline 25(OH)D level predicted response to D2 and D3 (p < 0.001), whereas, BMI was significant predictor only for early response to D2.

CONCLUSIONS

Effects of D2 and D3 supplements on 25 (OH)D level may be dosing-schedule and sex-dependent. D2-associated reduction in 25(OH)D3 level may be related to total 25(OH)D level rather than being D2-specific. D2 may be 25-hydroxylated faster than D3.

TRIAL REGISTRATION

ClinicalTrial.gov identifier: NCT01170494 (registered July 25, 2010).

Efficacy of Internet-Based Self-Monitoring Interventions on Maternal and Neonatal Outcomes in Perinatal Diabetic Women: A Systematic Review and Meta-Analysis

Background

Self-monitoring using the Internet offers new opportunities to engage perinatal diabetic women in self-management to reduce maternal and neonatal complications.

Objective

This review aims to synthesize the best available evidence to evaluate the efficacy of Internet-based self-monitoring interventions in improving maternal and neonatal outcomes among perinatal diabetic women.

Methods

The review was conducted using Cochrane Central Register of Controlled Trials, PubMed, EMBASE, Cumulative Index to Nursing and Allied Health Literature, PsyINFO, Scopus, and ProQuest Dissertations and Theses to search for English-language research studies without any year limitation. A risk of bias table was used to assess methodological quality. Meta-analysis was performed with RevMan software. Cochran Q and I² tests were used to assess heterogeneity. The overall effect was assessed using z tests at P<.05. Of the 438 studies identified through electronic searches and reference lists, nine experimental studies from 10 publications were selected.

Results

Half of the selected studies showed low risk of bias and comprised 852 perinatal diabetic women in six countries. The meta-analysis revealed that Internet-based self-monitoring interventions significantly decreased the level of maternal glycated hemoglobin A1c (z=2.23, P=.03) compared to usual care among perinatal diabetic women at postintervention. Moreover, Internet-based self-monitoring interventions significantly decreased the cesarean delivery rate (z=2.23, P=.03) compared to usual care among the mixed group at postintervention.

Conclusions

This review shows neonatal or other maternal outcomes are similar between Internet-based self-monitoring interventions and usual diabetes care among perinatal diabetic women. The long-term effects of the intervention must be confirmed in future studies using randomized controlled trials and follow-up data.

High Prevalence of Vitamin D Deficiency in Native versus Migrant Mothers and Newborns in the North of Italy: A Call to Act with a Stronger Prevention Program

Background

Vitamin D status during pregnancy is related to neonatal vitamin D status. Vitamin D deficiency has been associated with an increased risk of rickets in children and osteomalacia in adults. Aim of this study was to investigate 25OHD levels in maternal serum and in neonatal blood spots in native and migrant populations living in Novara (North Italy, 45°N latitude).

Methods and Findings

We carried out a cross sectional study from April 1st 2012 to March 30th 2013, in a tertiary Care Center. Maternal blood samples after delivery and newborns' blood spots were analyzed for 25OHD levels in 533 pairs. Maternal country of origin, skin phototype, vitamin D dietary intake and supplementation during pregnancy were recorded. Multivariate regression analysis, showed a link between neonatal and maternal 25OHD levels (R-square:0.664). Severely deficient 25OHD values (<25 nmol/L) were found in 38% of Italian and in 76.2% of migrant’s newborns (p <0.0001), and in 18% of Italian and 48,4% of migrant mothers (p <0.0001) while 25OHD deficiency (≥25 and <50 nmol/L) was shown in 40.1% of Italian and 21.7% of migrant’s newborns (p <0.0001), and in 43.6% of Italian and 41.3% of migrant mothers (p <0.0001). Italian newborns and mothers had higher 25OHD levels (34.4±19.2 and 44.9±21.2nmol/L) than migrants (17.7±13.7 and 29.7±16.5nmol/L; p<0.0001). A linear decrease of 25OHD levels was found with increasing skin pigmentation (phototype I 42.1 ±18.2 vs phototype VI 17.9±10.1 nmol/l; p<0.0001). Vitamin D supplementation resulted in higher 25OHD values both in mothers and in their newborns (p<0.0001).

Conclusions

Vitamin D insufficiency in pregnancy and in newborns is frequent especially among migrants. A prevention program in Piedmont should urgently be considered and people identified as being at risk should be closely monitored. Vitamin D supplementation should be taken into account when considering a preventative health care policy.

Vitamin D in childhood and adolescence: an expert position statement

Vitamin D is a key hormone in the regulation of calcium and phosphorus metabolism and plays a pivotal role in bone health, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur. Great interest has been placed in recent years on vitamin D's extraskeletal actions. However, while recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious and autoimmune diseases, the actual impact of vitamin D status on the global health of children and adolescents, other than bone, remains a subject of debate. In the meantime, pediatricians still need to evaluate the determinants of vitamin D status and consider vitamin D supplementation in children and adolescents at risk of deficiency. This review is the result of an expert meeting that was held during the congress "Update on vitamin D and bone disease in childhood" convened in Pisa, Italy, in May 2013.

CONCLUSION

The collaboration of the international group of experts produced this "state of the art" review on vitamin D in childhood and adolescence. After dealing with vitamin D status and its determinants, the review outlines the current debate on vitamin D's health benefits, concluding with a practical approach to vitamin D supplementation during childhood and adolescence.

WHAT IS KNOWN

• Vitamin D deficiency is a worldwide health problem. • Vitamin D deficiency affects not only musculoskeletal health but also a potentially wide range of acute and chronic diseases. What is New: • We reviewed the literature focusing on randomized controlled trials of vitamin D supplementation during childhood and adolescence. • This review will help pediatricians to appreciate the clinical relevance of an adequate vitamin D status and it will provide a practical approach to vitamin D supplementation.

High vitamin D status before conception, but not during pregnancy, is inversely associated with maternal gestational diabetes mellitus in guinea pigs

BACKGROUND

Whether there is a dose-dependent effect of maternal dietary cholecalciferol during pregnancy on maternal glucose tolerance is unknown. In addition, circulating osteocalcin is increased by 1,25-dihydroxyvitamin D [1,25(OH)2D] and may improve glucose homeostasis.

OBJECTIVE

This study was designed to test whether dietary cholecalciferol during pregnancy dose-dependently affects maternal glucose tolerance and maternal and neonatal glucose concentrations in relation to plasma osteocalcin and body composition.

METHODS

Female guinea pigs (n = 45; 4 mo old) were randomly assigned to 5 doses of cholecalciferol (0, 0.25, 0.5, 1, or 2 IU/g diet) fed from mating to delivery. Plasma vitamin D metabolites, minerals, and osteocalcin, and blood glucose were measured before mating, at midgestation (day 42), and at day 2 postpartum in sows and in 2-d-old pups. At day 50 of pregnancy (early third trimester), a 3-h oral-glucose-tolerance test (OGTT) (2 g/kg) was conducted. Body composition was measured before mating and at day 2 postpartum in sows and in pups.

RESULTS

A positive dose-response to dietary cholecalciferol was observed for change in maternal plasma 25-hydroxyvitamin D [25(OH)D] through pregnancy (P < 0.0001), with 1,25(OH)2D increasing by 198% in the 1-IU/g group by midgestation vs. a reduction of 43.6% in the 0-IU/g group (P = 0.05). Twenty-four (54.5%) sows had gestational diabetes mellitus (GDM) on the basis of nonfed glucose and 39 (88.6%) had GDM on the basis of 2-h OGTT glucose concentrations. There were no group differences in maternal OGTT or changes in glucose, minerals, osteocalcin concentrations, and body composition. Pre-mating 25(OH)D was inversely related to 3-h area under the curve for blood glucose from the OGTT (r = -0.31, P = 0.05). In guinea pig pups, although both 25(OH)D (P < 0.0001) and 1,25(OH)2D (P < 0.0001) followed a dose-response to maternal diet, glucose, osteocalcin, minerals, and body composition were not altered.

CONCLUSIONS

Dietary vitamin D intake during pregnancy in guinea pigs does not affect the already high rate of GDM, whereas higher prepregnancy vitamin D status appears to be protective.

Bioavailability of vitamin D2 from enriched mushrooms in prediabetic adults: a randomized controlled trial

BACKGROUND/OBJECTIVES

Based on the growing evidence of risk reduction from fresh fruit and vegetable consumption and an inverse relationship between serum 25-hydroxyvitamin D (25OHD) and the risk of type 2 diabetes (T2D), we determined the benefits of regularly consuming vitamin D-enriched mushrooms in a prediabetic cohort. Exposing edible mushrooms to ultraviolet B (UVB) light increases vitamin D2 (D2) and raises serum 25OHD2 in healthy young adults; however, their benefit to deficient prediabetics and glucose metabolism remains untested.

SUBJECTS/METHODS

Forty-three prediabetic, D-deficient adults (25OHD≤20 ng/ml), BMI>25 were randomized to four groups consuming daily entrées containing 100 g fresh sliced cooked mushrooms prepared by a chef for 16 weeks. Two groups were fed UVB-treated mushrooms initially containing: 600 IU D2 or 4000 IU D2; each one also received one capsule of placebo daily. Two control groups were fed untreated mushrooms and D3 dietary supplements at two label doses: 600 IU D3 and 4000 IU D3. D2 and D3 content were analyzed in mushrooms, before and after cooking and in over-the-counter supplements.

RESULTS

After 16 weeks, both D2-UVB-mushroom entrée doses, which were significantly lower after cooking, produced modest or no increases in 25OHD2 or total 25OHD relative to the positive control subjects who actually consumed about 1242 and 7320 IU per day of D3 (higher than stated on the label).

CONCLUSIONS

Unanticipated D2 cooking loss from fresh UVB mushrooms and probable low absorption and/or hydroxylation may explain the smaller increase in 25OHD2 in our prediabetic overweight/obese cohort compared with past findings in younger, healthy subjects. Moreover, no dose or vitamin D source was associated with modifying T2D risk factors.

Rickets

Rickets, historically referred to as "the English disease", is common worldwide. Absence of phosphate at the growth plate and mineralising bone surfaces due to inadequate vitamin D supply either from sunlight exposure or diet is the main cause. Inherited disorders causing hypophosphataemia have shown the intricacies of phosphate metabolism. Present advice about the provision of vitamin D to young infants needs to be clarified; the existing guidance is fragmentary and contradictory, and will not help to eradicate the disease.