Vitamin D supplementation during pregnancy: double-blind, randomized clinical trial of safety and effectiveness

The effect of vitamin D deficiency during pregnancy on adverse birth outcomes in neonates: a systematic review and meta-analysis

Objective

To systematically evaluate the effect of vitamin D deficiency during pregnancy on neonatal adverse outcomes, such as preterm infants, low birth weight infants (LBWI), and small for gestational age (SGA) infants.

Methods

A comprehensive literature search was conducted across multiple databases including PubMed, Embase, Cochrane Library, SinoMed, Wanfang Data Knowledge Service Platform, China National Knowledge Internet (CNKI), and VIP Chinese Science and Technology Journal Database (VIP). Following predefined inclusion and exclusion criteria, two researchers independently screened, extracted data, and assessed the quality of the included studies. Meta-analysis was performed using RevMan 5.4 and Stata 14 software to synthesize the findings.

Results

This study incorporated 13 cohort studies from 8 different countries and regions, encompassing a total of 55,162 pregnant women, among whom 28,155 were identified as having vitamin D deficiency. The Newcastle-Ottawa Scale (NOS) score ranged from 7-9 points. Meta-analysis results indicated a higher incidence of LBWI (OR = 5.52, 95% CI = 1.31-23.22. P = 0.02) in the group of pregnant women with vitamin D deficiency compared to those with adequate levels. However, there was no statistically significant difference in the likelihood of premature birth (OR = 1.25, 95% CI = 0.78-1.99. P = 0.36) or SGA (OR = 1.47, 95% CI = 0.81-2.68. P = 0.21) among newborns born to mothers with vitamin D deficiency vs. those with sufficient levels of vitamin D. Subgroup analysis based on the timing of maternal blood collection revealed that there was no statistically significant association between vitamin D levels during pregnancy and the incidence of preterm birth across all stages of pregnancy. Furthermore, vitamin D deficiency throughout the entire pregnancy was associated with an increased incidence of neonatal LBWI, whereas vitamin D levels during the first, second, and third trimesters did not demonstrate statistically differences on LBWI. Neonates born to mothers with vitamin D deficiency throughout pregnancy were found to have a higher likelihood of developing SGA. However, there was no statistically significant association between vitamin D levels and the development of SGA during the first and second trimesters.

Conclusions

Adequate levels of vitamin D during pregnancy may decrease the incidence of LBWI, although further research is needed to determine its impact on the occurrence of preterm birth and SGA.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024535950, Identifier: (CRD42024535950).

A Study of Vitamin D Status and Its Influencing Factors among Pregnant Women in Szeged, Hungary: A Secondary Outcome of a Case-Control Study

Adequate vitamin D (VD) intake during pregnancy is needed for fetal development and maternal health maintenance. However, while there is no doubt regarding its importance, there is not a unified recommendation regarding adequate intake. The main aim of our study was to measure the VD serum level of studied women, together with its potential influencing factors: demographic (i.e., age, level of education, relationship status and type of residence), conception and pregnancy related factors. Results are based on secondary data analyses of a retrospective case-control study of 100 preterm and 200 term pregnancies, where case and control groups were analyzed together. Data collection was based on a self-administered questionnaire, health documentation, and maternal serum VD laboratory tests. VD intake was evaluated by diet and dietary supplement consumption. According to our results, 68.1% of women took some kind of prenatal vitamin, and only 25.9% of them knew about its VD content. Only 12.1% of included women reached the optimal, 75 nmol/L serum VD level. Higher maternal serum levels were associated with early pregnancy care visits (p = 0.001), assisted reproductive therapy (p = 0.028) and advice from gynecologists (p = 0.049). A correlation was found between VD intake and serum levels (p < 0.001). Despite the compulsory pregnancy counselling in Hungary, health consciousness, VD intake and serum levels remain below the recommendations. The role of healthcare professionals is crucial during pregnancy regarding micronutrients intake and the appropriate supplementation dose.

Post Hoc Analysis of National Institute of Child Health and Human Development Vitamin-D Pregnancy Cohort and The Role of Functional Vitamin-D Deficiency in Pregnancy

OBJECTIVE

 Our objective was to conduct a secondary, post hoc analysis of the National Institute of Child Health and Human Development (NICHD) vitamin D (vitD) pregnancy study by Hollis et al, which reported on the effect of vitD supplementation in pregnant women and determine the potential interaction between intact parathyroid hormone (iPTH) concentrations, vitD status, and various comorbidities associated with pregnancy. Women with low 25-hydroxy vitamin D (25(OH)D) concentrations and high iPTH concentrations during pregnancy, known as functional vitamin-D deficiency (FVDD), were more likely to acquire complications also affecting their neonates.

STUDY DESIGN

 This post hoc analysis of data collected from a diverse group of pregnant women participating in the NICHD vitD pregnancy study was applied to investigate the applicability of the concept of FVDD in pregnancy (Hemmingway, 2018) in identifying potential risks for certain comorbidities of pregnancy. This analysis defines FVDD as maternal serum 25(OH)D concentrations below 20 ng/mL and iPTH concentrations above 65 pg/mL creating a definitive ratio number, 0.308, to classify mothers as having FVDD prior to delivery (PTD). Statistical analyses were performed using SAS 9.4 (Cary, NC).

RESULTS

 In total, 281 women (85 African American, 115 Hispanic, and 81 Caucasian) with 25(OH)D and iPTH concentrations measured at monthly visits were included in this analysis. No statistically significant association was found between mothers classified as having FVDD at baseline or 1-month PTD and hypertensive disorders of pregnancy, infection, or admittance to the neonatal intensive care unit. When combining all comorbidities of pregnancy in this cohort, results showed those with FVDD at baseline, 24 weeks' gestation, and 1-month PTD were more likely to experience a comorbidity (p = 0.001; p = 0.001; p = 0.004, respectively). Those with FVDD 1-month PTD were 7.1 times (confidence interval [CI]: 1.71-29.81) more likely to have preterm birth (<37 weeks) than women without FVDD.

CONCLUSION

 Participants were more likely to have experienced preterm birth if they met the criteria for FVDD. This study supports the importance of FVDD during pregnancy.

KEY POINTS

· Functional vitamin D deficiency (FVDD) is defined as the ratio of 25(OH)D divided by iPTH concentration ≤0.308.. · At a minimum, it is recommended that vitamin D status be kept in the healthy range based on current recommendations for pregnant individuals.. · FVDD is a more sensitive predictor of pregnancy risk than 25(OH)D alone.. · FVDD identified those with greater risk of preterm birth in this cohort..

Bayesian modeling of spatially differentiated multivariate enamel defects of the children's primary maxillary central incisor teeth

BACKGROUND

The analysis of dental caries has been a major focus of recent work on modeling dental defect data. While a dental caries focus is of major importance in dental research, the examination of developmental defects which could also contribute at an early stage of dental caries formation, is also of potential interest. This paper proposes a set of methods which address the appearance of different combinations of defects across different tooth regions. In our modeling we assess the linkages between tooth region development and both the type of defect and associations with etiological predictors of the defects which could be influential at different times during the tooth crown development.

METHODS

We develop different hierarchical model formulations under the Bayesian paradigm to assess exposures during primary central incisor (PMCI) tooth development and PMCI defects. We evaluate the Bayesian hierarchical models under various simulation scenarios to compare their performance with both simulated dental defect data and real data from a motivating application.

RESULTS

The proposed model provides inference on identifying a subset of etiological predictors of an individual defect accounting for the correlation between tooth regions and on identifying a subset of etiological predictors for the joint effect of defects. Furthermore, the model provides inference on the correlation between the regions of the teeth as well as between the joint effect of the developmental enamel defects and dental caries. Simulation results show that the proposed model consistently yields steady inferences in identifying etiological biomarkers associated with the outcome of localized developmental enamel defects and dental caries under varying simulation scenarios as deemed by small mean square error (MSE) when comparing the simulation results to real application results.

CONCLUSION

We evaluate the proposed model under varying simulation scenarios to develop a model for multivariate dental defects and dental caries assuming a flexible covariance structure that can handle regional and joint effects. The proposed model shed new light on methods for capturing inclusive predictors in different multivariate joint models under the same covariance structure and provides a natural extension to a nested hierarchical model.

Effect of early vitamin D supplementation on the incidence of preeclampsia in primigravid women: a randomised clinical trial in Eastern Democratic Republic of the Congo

BACKGROUND

Previous studies have reported the association between maternal vitamin D deficiency and preeclampsia. However, the efficacy of vitamin D supplementation in reducing the occurrence of preeclampsia remains unclear. The objective of this study was to evaluate the effect of cholecalciferol supplementation on the incidence of preeclampsia in primigravid women and its related maternal and foetal outcomes.

METHODS

A single-blinded clinical trial was conducted in fourteen antenatal care health facilities in the North (Goma, Mwesso, Nyiragongo) and South Kivu (Bukavu-Panzi) provinces of the Democratic Republic of Congo from March 1, 2020, to June 30, 2021. A total of 1300 primigravid women not exceeding 16 weeks of gestation were randomised with a 1:1 ratio to either the supplemented (A) or control (B) group. Each pregnant woman (A) presenting for antenatal care received a single monthly dose of cholecalciferol (60,000 IU) orally for 6 months. The control group received no vitamin D supplementation or placebo. Serum 25(OH)D was measured at recruitment and at 34 weeks of gestation. Outcomes were assessed monthly until delivery.

RESULTS

The median maternal age was 21 years (14-40), while the median gestational age was 15 weeks (5.4-29.0). A significant reduction in the risk of preeclampsia [RR = 0.36 (0.19-0.69); p = 0.001] and preterm delivery [RR = 0.5 (0.32-0.78); p = 0.002] was observed in the intervention group. An RR of 0.43 [(0.27-0.67); p < 0.001] was found for low birth weight. The RR for caesarean section was 0.63 [(0.52-0.75); p < 0.001]. The APGAR score at the 5th minute (p = 0.021) and the size of the newborn were significantly higher in the supplemented group (p = 0.005).

CONCLUSION

A single monthly dose (60,000 IU) of vitamin D supplementation, started in earlypregnancy, significantly reduced the incidence of preeclampsia and its maternal and foetal complications.

TRIAL REGISTRATION

ISRCTN Register with ISRCTN46539495 on 17 November 2020.

Prenatal vitamin D supplementation to prevent childhood asthma: 15-year results from the Vitamin D Antenatal Asthma Reduction Trial (VDAART)

This article provides an overview of the findings obtained from the Vitamin D Antenatal Asthma Reduction Trial (VDAART) spanning a period of 15 years. The review covers various aspects, including the trial's rationale, study design, and initial intent-to-treat analyses, as well as an explanation of why those analyses did not achieve statistical significance. Additionally, the article delves into the post hoc results obtained from stratified intent-to-treat analyses based on maternal vitamin D baseline levels and genotype-stratified analyses. These results demonstrate a statistically significant reduction in asthma among offspring aged 3 and 6 years when comparing vitamin D supplementation (4400 IU/d) to the standard prenatal multivitamin with vitamin D (400 IU/d). Furthermore, these post hoc analyses found that vitamin D supplementation led to a decrease in total serum IgE levels and improved lung function in children compared to those whose mothers received a placebo alongside the standard prenatal multivitamin with vitamin D. Last, the article concludes with recommendations regarding the optimal dosing of vitamin D for pregnant women to prevent childhood asthma as well as suggestions for future trials in this field.

Molecular pathways in placental-fetal development and disruption

The first trimester of pregnancy ranks high in priority when minimizing harmful exposures, given the wide-ranging types of organogenesis occurring between 4- and 12-weeks' gestation. One way to quantify potential harm to the fetus in the first trimester is to measure a corollary effect on the placenta. Placental biomarkers are widely present in maternal circulation, cord blood, and placental tissue biopsied at birth or at the time of pregnancy termination. Here we evaluate ten diverse pathways involving molecules expressed in the first trimester human placenta based on their relevance to normal fetal development and to the hypothesis of placental-fetal endocrine disruption (perturbation in development that results in abnormal endocrine function in the offspring), namely: human chorionic gonadotropin (hCG), thyroid hormone regulation, peroxisome proliferator activated receptor protein gamma (PPARγ), leptin, transforming growth factor beta, epiregulin, growth differentiation factor 15, small nucleolar RNAs, serotonin, and vitamin D. Some of these are well-established as biomarkers of placental-fetal endocrine disruption, while others are not well studied and were selected based on discovery analyses of the placental transcriptome. A literature search on these biomarkers summarizes evidence of placenta-specific production and regulation of each biomarker, and their role in fetal reproductive tract, brain, and other specific domains of fetal development. In this review, we extend the theory of fetal programming to placental-fetal programming.

Implications of maternal vitamin D administration for the neonatal respiratory distress syndrome: A randomized clinical trial

BACKGROUND

Vitamin D deficiency has been suggested to be a risk factor for neonatal respiratory distress syndrome (RDS). This study aimed to evaluate the effect of 25 (OH) D administrations in pregnant women with findings of preterm labor on the incidence of RDS in their preterm neonates.

MATERIALS AND METHODS

A randomized controlled clinical trial was conducted on pregnant mothers with gestational age (GA) of less than 34 weeks at risk of preterm delivery. 175 subjects were randomly assigned into two groups, including intervention (intramuscular injection of 50,000 units of 25(OH) D during 72 hours before delivery) and control (no injections). Serum concentrations of 25(OH) D were measured shortly after birth in both mothers and neonates. Then, clinical and laboratory results of mothers and their offspring were recorded (in a checklist). Short-term outcomes and the need for respiratory support were also assessed. Data were analyzed by independent t-test, Mann-Whitney U test, Fisher's exact test, and chi-square test.

RESULTS

Even though gestational age, birth weight, delivery method, and serum vitamin D levels are consistent among both groups, 45% of neonates in the control group and 20% in the intervention group developed respiratory distress syndrome (P = 0.05). The mean 25(OH) D level in neonates was 17.7±10.5 and 19.29±9.94 ng/mL in the intervention and control groups, respectively (P > 0.05).

CONCLUSION

A single dose of 50,000 units of intramuscular 25(OH)D in pregnant women at risk of preterm labor can lower the risk of RDS in the infant.

Prospective cohort study of vitamin D deficiency in pregnancy: Prevalence and limited effectiveness of 1000 IU vitamin D supplementation

BACKGROUND

Vitamin D deficiency is highly prevalent worldwide among pregnant women. Although vitamin D supplementation is effective in improving vitamin D status, the safety and optimal dosing of vitamin D supplementation during pregnancy remain less well understood.

OBJECTIVE

This study aimed to investigate the prevalence of vitamin D deficiency among pregnant women and evaluate the effectiveness of vitamin D supplementation in improving vitamin D status during pregnancy.

DESIGN

This prospective cohort study assessed the impact of a 16-week daily vitamin D supplementation 1000 IU regimen on vitamin D status among pregnant women.

METHODS

A total of 365 pregnant women were recruited, and their baseline total circulating 25-hydroxy vitamin D concentrations were measured. Of these, 249 participants completed the study, which involved oral daily supplementation with 1000 IU of vitamin D and a repeat of total circulating 25-hydroxy vitamin D concentrations after 16 weeks.

RESULTS

The study found that 57.7% of the participants had vitamin D deficiency, consistent with the rates reported in other studies. However, vitamin D supplementation at a dose of 1000 IU had a small effect size and was not clinically significant. However, 67% of participants with vitamin D deficiency remained deficient; among participants initially with vitamin D insufficiency, 30% became deficient. Moreover, 26.5% of individuals with sufficient vitamin D status at 12 weeks showed insufficient levels by 28 weeks.

CONCLUSION

Vitamin D deficiency is widespread among pregnant women, and vitamin D supplementation at a daily dose of 1000 IU may not adequately address this problem. Although the study has limitations, its results align with previous research and may apply to other populations with a high prevalence of vitamin D deficiency during pregnancy. Further research is necessary to determine the most effective approach for addressing prenatal vitamin D deficiency.

"You are my sunshine, my only sunshine": maternal vitamin D status and supplementation in pregnancy and their effect on neonatal and childhood outcomes

Vitamin D (VD) plays a crucial role in regulating calcium homeostasis, while the wealth of its pleiotropic actions is gaining increasing research interest. Sufficient VD concentrations are of clinical relevance, particularly in the context of physiological alterations, such as those occurring during pregnancy when maternal VD is the sole source for the developing fetus. As a result, inadequate VD concentrations in pregnancy have been associated with perinatal complications and adverse neonatal outcomes, including preeclampsia, gestational diabetes mellitus, increased rates of cesarean section, low birth weight, small-for-gestational-age infants, poor immune and skeletal growth, allergies, and respiratory infections. Over the past few decades, several observational studies have underlined the important role of maternal VD in the neural, musculoskeletal, and psychomotor growth and bone health of the offspring. However, the complexity of the factors involved in regulating and assessing VD homeostasis, including race, sun exposure, dietary habits, and laboratory measurement techniques, makes the interpretation of relevant research findings challenging. The aim of this narrative review is to summarize the evidence on the importance of VD in maintaining optimal health during pregnancy, infancy, childhood, and adolescence.

A nutritional supplement during preconception and pregnancy increases human milk vitamin D but not B-vitamin concentrations

BACKGROUND & AIMS

Optimal maternal vitamin status during pregnancy and lactation is essential to support maternal and infant health. For instance, vitamin D3 is involved in infant bone development, and B-vitamins are involved in various metabolic processes, including energy production. Through a double-blind randomised controlled trial, we investigated the effects of maternal supplementation from preconception throughout pregnancy until birth on human milk (HM) concentrations of vitamin D3 and B-vitamins. In addition, we aimed to characterise longitudinal changes in milk concentrations of these vitamins.

METHODS

Both control and intervention supplements contained calcium, iodine, iron, β-carotene, and folic acid, while the intervention also contained zinc, vitamins B2, B6, B12, and D3, probiotics, and myo-inositol. HM samples were collected across 4 time points from 1 week to 3 months post-delivery from 158 mothers in Singapore, and 7 time points from 1 week to 12 months from 180 mothers in New Zealand. HM vitamin D was quantified using supercritical fluid chromatography and B-vitamins with mass spectrometry. Potential intervention effects on HM vitamins D3, B2, B6, and B9, as well as other B-vitamin (B1 and B3) concentrations were assessed using linear mixed models with a repeated measures design.

RESULTS

Over the first 3 months of lactation, HM 25-hydroxyvitamin D3 concentrations were 20% (95% CI 8%, 33%, P = 0.001) higher in the intervention group, with more marked effects in New Zealand. There were no observed intervention effects on HM concentrations of vitamins B1, B2, B3, B6, and B9. In New Zealand mothers, longitudinally, vitamin D3 concentrations gradually increased from early lactation up to 12 months, while vitamins B1 and B2 peaked at 6 weeks, B3 at 3 weeks, and B6 and B9 at 3 months.

CONCLUSIONS

Maternal supplementation during preconception and pregnancy increased HM vitamin D, but not B-vitamin concentrations in lactation. Further studies are required to examine the discrete benefits of vitamin D supplementation starting preconception vs during pregnancy, and to further characterise the effects of supplementation on later offspring health outcomes.

CLINICAL TRIAL REGISTRATION

Registered at ClinicalTrials.gov on the 16 July 2015 (identifier NCT02509988); Universal Trial Number U1111-1171-8056. This study was academic-led by the EpiGen Global Research Consortium.

How effective is public health policy in Scotland on vitamin D deficiency during pregnancy?

OBJECTIVE

To evaluate the uptake of universal vitamin D supplementation during pregnancy, its effectiveness in preventing vitamin D deficiency and the factors associated with these.

DESIGN

The regional public health organisation in Ayrshire, Scotland has a policy of universal provision of vitamin D supplements (10 µg/d) to all pregnant women for the duration of their pregnancy. Pregnant women in this area were recruited at their 12-week antenatal appointment. Blood samples were collected at the 12-week and 34-week appointments. To account for the seasonal variation, women were recruited in two cohorts: summer and winter. Telephone interviews were conducted at 34 weeks to assess the uptake of vitamin D supplements during pregnancy. Other variables were obtained from medical records.

SETTING

The study was conducted in the NHS Ayrshire and Arran Health Board in Scotland.

PARTICIPANTS

612 pregnant women (aged 15-44 years) living in Ayrshire (latitude 55°), Scotland.

RESULTS

Sixty-six percentage took supplementation as recommended. Consumption of supplementation was significantly associated with a higher median serum 25-hydroxyvitamin D concentrations at 34 weeks. Despite this at 34 weeks, 33 % of the summer cohort had insufficient or deficient vitamin D status, while 15 % of the winter cohort had insufficient or deficient status. In multivariable analysis, only adherence and season were independent predictors of vitamin D status.

CONCLUSIONS

While supplementation improved and maintained vitamin D status during pregnancy, it was not adequate to ensure all those insufficient at 12 weeks achieved sufficient status at the end of pregnancy.

Biological Pathways Associated with Vitamins in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is characterized by early-appearing social communication deficits, with genetic and environmental factors potentially playing a role in its etiology, which remains largely unknown. During pregnancy, certain deficiencies in critical nutrients are mainly associated with central nervous system impairment. The vitamin B9 (folate) is primarily related to one-carbon and methionine metabolism, participating in methyl donor generation. In addition, supplementation with folic acid (FA) is recommended by the World Health Organization (WHO) in the first three gestational months to prevent neural tube defects. Vitamin B12 is related to folate regeneration, converting it into an active form. Deficiencies in this vitamin have a negative impact on cognitive function and brain development since it is involved in myelin synthesis. Vitamin D is intimately associated with Ca2+ levels, acting in bone development and calcium-dependent signaling. This vitamin is associated with ASD at several levels since it has a relation with ASD genes and oxidative stress environment. This review carries the recent literature about the role of folate, vitamin B12, and vitamin D in ASD. In addition, we discuss the possible impact of nutrient deficiency or hypersupplementation during fetal development. On the other hand, we explore the biases of vitamin supplementation studies such as the loss of participants in retrospective studies, as well as multiple variants that are not considered in the conclusion, like dietary intake or auto-medication during pregnancy. In this regard, we aim to contribute to the discussion about the role of vitamins in ASD currency, but also in pregnancy and fetal development as well. Furthermore, stress during pregnancy can be an ASD predisposition, with cortisol as a regulator. In this view, we propose that cortisol is the bridge of susceptibility between vitamin disorders and ASD prevalence.

Vitamin D and preeclampsia: A systematic review and meta-analysis

Objectives

Preeclampsia is one of the most frequent pregnancy disorders, with a global incidence of 2%-8%. Serum 25-hydroxyvitamin D is an essential mineral for human health; some studies suggest link between 25-hydroxyvitamin D deficiency and preeclampsia, while others offer contradictory findings. Thus, the goal of this study is to evaluate the relationships between maternal 25- hydroxyvitamin D concentrations and the risk of preeclampsia. In addition to this, our study also evaluates the effects of 25- hydroxyvitamin D supplementation on the incidence of preeclampsia. Therefore, assessing 25- hydroxyvitamin D's potential as a possible intervention to lower the risk of preeclampsia.

Methods

The Medline database was queried from inception until July 2021 for randomized controlled trials and observational studies without any restrictions. The studies assessing the association between 25-hydroxyvitamin D deficiency and preeclampsia and the impact of 25-hydroxyvitamin D supplementation on the incidence of preeclampsia were incorporated. The results were reported using a random-effects meta-analysis and the Mantel-Haenszel odds ratio. A p-value of <0.05 was considered significant for the analysis.

Results

This analysis includes 34 papers, including 10 randomized controlled trials and 24 observational studies. According to our pooled analysis, 25-hydroxyvitamin D supplementation was significantly associated with a lower risk of preeclampsia in pregnant women (OR: 0.50; 95% CI: 0.40-0.63; p = 0.00001), while 25-hydroxyvitamin D deficiency was significantly associated with an increased risk of preeclampsia (OR: 4.30; 95 % CI: 2.57-7.18; p < 0.00001, OR: 1.71; 95 % Cl: 1.27-2.32; p = 0.0005, OR 1.61; 95 % Cl: 1.21-2.16; p = 0.001).

Conclusion

Results suggest that 25-hydroxyvitamin D has a significant relationship with preeclampsia as confirmed by the findings that low maternal 25-hydroxyvitamin D concentrations cause increased risk of preeclampsia while 25-hydroxyvitamin D supplementation reduces the incidence of preeclampsia. Our findings indicate that 25-hydroxyvitamin D supplementation can be used as a possible intervention strategy in preventing one of the most common causes of maternal mortality around the world, preeclampsia.

Predictors of Developmental Defects of Enamel in Primary Maxillary Central Incisors Using Bayesian Model Selection

INTRODUCTION

Localized non-inheritable developmental defects of tooth enamel (DDE) are classified as enamel hypoplasia (EH), opacity (OP), and post-eruptive breakdown (PEB) using the enamel defects index. To better understand the etiology of DDE, we assessed the linkages amongst exposome variables for these defects during the specific time duration for enamel mineralization of the human primary maxillary central incisor enamel crowns. In general, these two teeth develop between 13 and 14 weeks in utero and 3-4 weeks' postpartum of a full-term delivery, followed by tooth eruption at about 1 year of age.

METHODS

We utilized existing datasets for mother-child dyads that encompassed 12 weeks' gestation through birth and early infancy, and child DDE outcomes from digital images of the erupted primary maxillary central incisor teeth. We applied a Bayesian modeling paradigm to assess the important predictors of EH, OP, and PEB.

RESULTS

The results of Gibbs variable selection showed a key set of predictors: mother's prepregnancy body mass index (BMI); maternal serum concentrations of calcium and phosphorus at gestational week 28; child's gestational age; and both mother's and child's functional vitamin D deficiency (FVDD). In this sample of healthy mothers and children, significant predictors for OP included the child having a gestational period >36 weeks and FVDD at birth, and for PEB included a mother's prepregnancy BMI <21.5 and higher serum phosphorus concentration at week 28.

CONCLUSION

In conclusion, our methodology and results provide a roadmap for assessing timely biomarker measures of exposures during specific tooth development to better understand the etiology of DDE for future prevention.

The Impact of Vitamin D Deficiency on Infants' Health

Vitamin D is an essential nutrient that plays a vital role in bone health and musculoskeletal development. The aim of this narrative review is to present up-to-date information about the impact of vitamin D deficiency (VDD) on the health status of infants in their first year of life. Vitamin D is indispensable for skeletal growth and bone health, and emerging research suggests that it may also have significant roles in maternal and fetal health. VDD affects a large proportion of infants according to current guidelines. However, its prevalence varies depending on geographic location, skin pigmentation, and the time of year. Based on current guidelines for normal vitamin D levels and recommended daily intake, studies suggest that VDD is a global health issue with potentially significant implications for those at risk, especially infants. Our understanding of the role of vitamin D has improved significantly in the last few decades. Systematic reviews and meta-analyses investigating the effect of vitamin D on preterm birth, low birth weight, anthropometric parameters, and health outcomes such as infectious diseases in infants, have found conflicting or inconsistent results. It is important to encourage further research to fill in these knowledge gaps and develop national or global strategies that ease the burden of VDD, especially in groups at risk.

Vitamin D and Child Neurodevelopment-A Post Hoc Analysis

INTRODUCTION

Vitamin D (VitD) has been shown to impact neurodevelopment. Studies have shown that higher 25-hydroxy-vitamin D (25(OH)D) concentrations (the indicator of vitD status) may be associated with better neurodevelopmental outcomes, although current data are conflicting. This study examined the relationship between total circulating 25(OH)D concentrations and neurodevelopmental outcomes in 3-5-year-old (3-5 yo) children.

METHODS

In this study, pregnant women were randomized to receive 400 (standard dose), 2000, or 4000 IU vitD3/day. Offspring then underwent the Brigance Screen at 3-5 yo. The 25(OH)D concentration was measured at birth and 3-5 yo. Relationships between Brigance scores and 25(OH)D and Brigance scores and vitamin D binding protein (VDBP) genotype were examined.

RESULTS

Higher 25(OH)D at the time of testing was associated with better overall performance on neurodevelopmental testing as measured by the Brigance quotient (B = 0.208, p = 0.049). Scores were then broken down into sub-scores. Children born to mothers in the 2000 IU/day group scored higher on the Brigance language component of the assessment versus the standard dose group (B = 4.667, p = 0.044). The group of children who had the Gc1f-1s or Gc1f-2 genotypes scored higher on the Brigance academic component (B = 9.993, p < 0.001) and lower on the Brigance language component versus the 1f1f genotype (B = -9.313, p < 0.001). Children with the Gc1s-1s, Gc1s-2, or Gc2-2 genotypes also scored lower than the Gc1f-1f genotype (B = -6.757, p = 0.003).

CONCLUSION

These results suggest that higher 25(OH)D concentrations early in life and higher doses of maternal vitamin D supplementation during pregnancy may have a positive association with neurodevelopmental outcomes. This study also suggests that the VDBP genotype is associated with neurodevelopment and differentially affects various fields of neurodevelopment.

Does maternal vitamin D status influence placental weight or vascular and inflammatory pathology? Secondary analysis from the Kellogg Pregnancy Study

INTRODUCTION

Positive effects of vitamin D (vitD) supplementation on comorbidities of pregnancy (COP) have been explored; however, few studies have elucidated the pathophysiology behind the development of these COP and the potential relationship with derangements in placental development and morphology. Additionally, it is known that placentas weighing 10th-90th % for gestational age are associated with better outcomes. Therefore, the objective of this study was to assess the impact of resulting circulating serum 25(OH)D concentrations associated with intake of high or low doses of supplementary vitD on placental development and morphology in women who participated in a randomized double blind, placebo-controlled trial of vitD supplementation. We hypothesized that if maternal serum 25(OH)D concentration (vitD status marker) is insufficient/deficient, then placental weight and % for gestational age (GA) will be smaller and will correlate with increased vascular and inflammatory placental pathologic findings.

METHODS

The findings of the present study are a secondary analysis of data generated from a previously reported randomized controlled trial (RCT), the Kellogg Vitamin D Pregnancy Study. Pregnant women (n = 297) in this RCT (January 2013 - April 2018) were randomly assigned to 400 IU vs. 4400 IU vitD/day (10-14 weeks' gestational age) and followed to delivery. 132 placentas were analyzed by pathologists blinded to treatment, and the 2016 Amsterdam Consensus Criteria were used to categorize grouping/grading of placental pathology and weight. Total [25(OH)D] was measured using radioimmunoassay (ng/mL). Chi-square and Student's t-test were used to show the difference in maternal characteristics by treatment group and by placental weight. Chi-square analysis was used to determine differences between the percent pathology findings by treatment group. Students t-test was used to determine the differences in vitD status and the frequency of placental lesions. Association between [25(OH)D] area under the curve (AUC) and placental morphology were determined in a regression model that included maternal BMI ≥ 30 kg/m2, race/ethnicity, and vitD treatment group allocation. Data were analyzed using SAS v9.4 (Cary, NC) and statistical significance was indicated by p < 0.05.

RESULTS

The percent pathology findings by treatment group were not significantly different for each of the placental pathology categories as defined by the 2016 Amsterdam Consensus Criteria including placental weight. However, when using 25(OH)D as a biomarker for vitD status, linear regression model showed maternal serum [25(OH)D] AUC was significantly associated with greater placental weight (p = 0.023). Logistic regression models showed mothers with BMI ≥ 30 kg/m2 had larger placental weight (p = 0.046), and Hispanic and white/Caucasian mothers had greater placental weights than Black American mothers (p = 0.025). When placentas ≥ 90th % for GA, n = 7, were removed from the placental pool, Pearson correlation still showed a positive association between maternal serum 25(OH)D AUC and placental weight (p = 0.011). In a second linear regression model of placentas ≥ 90th % for GA (n = 7) vs. placentas < 90th % (n = 108), maternal serum 25(OH)D AUC was significantly greater in those placentas ≥ 90th % (p = 0.03); however, this was not associated with increased perinatal mortality. CONCLUSION FINDINGS: suggest increasing maternal serum [25(OH)D] via vitamin D supplementation during pregnancy did not adversely affect placental morphology; trends showed those in the treatment group had fewer placental lesions. Placental weight was found to be significantly associated with [25(OH)D] AUC, which represents maternal vitamin D status over the course of pregnancy; 7 placentas ≥ 90th % for GA were not associated with perinatal mortality.

Does antenatal cholecalciferol supplementation affect the mode or timing of delivery? Post hoc analyses of the MAVIDOS randomized controlled trial

BACKGROUND

Observational studies relating maternal 25-hydroxyvitamin D status to timing and mode of delivery have reported inconsistent results. We assessed the effect of antenatal cholecalciferol supplementation on the incidence of preterm birth, delivery mode and post-partum haemorrhage (PPH).

METHODS

MAVIDOS was a randomized, double-blind, placebo-controlled trial of 1000 IU/day cholecalciferol from 14 weeks' gestation until delivery. Gestational age, mode of delivery [categorized as spontaneous vaginal delivery (SVD), instrumental (including forceps and vacuum extraction) or Caesarean section] and PPH (>500 ml estimated blood loss) were determined from medical records.

RESULTS

A total of 965 women participated in the study until delivery. Gestation at birth and incidence of preterm birth (cholecalciferol 5.7%, placebo 4.5%, P = 0.43) were similar between the two treatment groups. SVD (versus instrumental or Caesarean delivery) was more likely in women randomized to cholecalciferol [Relative Risk (RR) 1.13, 95% confidence interval (CI) 1.02,1.25] due to lower instrumental (RR 0.68, 95%CI 0.51,0.91) but similar risk of Caesarean delivery (RR 0.94, 95%CI 0.74,1.19). PPH was less common in women randomized to cholecalciferol [32.1% compared with placebo (38.1%, P = 0.054) overall], but similar when stratified by delivery mode.

CONCLUSIONS

Antenatal cholecalciferol supplementation did not alter timing of birth or prevalence of preterm birth but demonstrated a possible effect on the likelihood of SVD.

Controlling Chronic Diseases and Acute Infections with Vitamin D Sufficiency

Apart from developmental disabilities, the prevalence of chronic diseases increases with age especially in those with co-morbidities: vitamin D deficiency plays a major role in it. Whether vitamin D deficiency initiates and/or aggravates chronic diseases or vice versa is unclear. It adversely affects all body systems but can be eliminated using proper doses of vitamin D supplementation and/or safe daily sun exposure. Maintaining the population serum 25(OH)D concentration above 40 ng/mL (i.e., sufficiency) ensures a sound immune system, minimizing symptomatic diseases and reducing infections and the prevalence of chronic diseases. This is the most cost-effective way to keep a population healthy and reduce healthcare costs. Vitamin D facilitates physiological functions, overcoming pathologies such as chronic inflammation and oxidative stress and maintaining broader immune functions. These are vital to overcoming chronic diseases and infections. Therefore, in addition to following essential public health and nutritional guidance, maintaining vitamin D sufficiency should be an integral part of better health, preventing acute and chronic diseases and minimize their complications. Those with severe vitamin D deficiency have the highest burdens of co-morbidities and are more vulnerable to developing complications and untimely deaths. Vitamin D adequacy improves innate and adaptive immune systems. It controls excessive inflammation and oxidative stress, generates antimicrobial peptides, and neutralizes antibodies via immune cells. Consequently, vitamin D sufficiency reduces infections and associated complications and deaths. Maintaining vitamin D sufficiency reduces chronic disease burden, illnesses, hospitalizations, and all-cause mortality. Vulnerable communities, such as ethnic minorities living in temperate countries, older people, those with co-morbidities, routine night workers, and institutionalized persons, have the highest prevalence of vitamin D deficiency-they would significantly benefit from vitamin D and targeted micronutrient supplementation. At least now, health departments, authorities, and health insurance companies should start assessing, prioritizing, and encouraging this economical, non-prescription, safe micronutrient to prevent and treat acute and chronic diseases. This approach will significantly reduce morbidity, mortality, and healthcare costs and ensure healthy aging.

Vitamin D Intake and Serum Levels in Pregnant and Postpartum Women

Maternal vitamin D deficiency, which is highly prevalent in pregnant women in Europe, is linked to adverse health effects for both the mother and child. The objective was to assess vitamin D status in pregnant women by evaluating their dietary and supplemental vitamin D intake, serum vitamin D levels, parathyroid hormone levels, and lifestyle factors. This cross-sectional study, with a total of 735 participants (145 pregnant and 590 up to the seventh day postpartum), took place in Latvia. Blood samples, a food frequency questionnaire, and medical documentation were used for data collection. The median serum vitamin D concentration was 34.0 ng/mL, with pregnant women having higher levels (42.9 ng/mL) than postpartum women (31.8 ng/mL). There was no association between vitamin D serum concentration and dietary intake of vitamin D (p > 0.05), whereas there was a significant correlation with use of vitamin D supplements (r = 0.41; p < 0.001 in pregnant women and r = 0.35; p < 0.001 in postpartum women). This study demonstrated that a minority of pregnant women (21.9%) had optimal serum vitamin D concentration (>45 ng/mL), and diet had no significant impact on vitamin D levels. Thus, our proposed recommendation for vitamin D intake during pregnancy was 63 mcg (2500 IU) year-round for optimal levels in pregnant women in Northeastern Europe.

Randomised controlled trial of perinatal vitamin D supplementation to prevent early-onset acute respiratory infections among Australian First Nations children: the 'D-Kids' study protocol

INTRODUCTION

Globally, acute respiratory infections (ARIs) are a leading cause of childhood morbidity and mortality. While ARI-related mortality is low in Australia, First Nations infants are hospitalised with ARIs up to nine times more often than their non-First Nations counterparts. The gap is widest in the Northern Territory (NT) where rates of both acute and chronic respiratory infection are among the highest reported in the world. Vitamin D deficiency is common among NT First Nations neonates and associated with an increased risk of ARI hospitalisation. We hypothesise that perinatal vitamin D supplementation will reduce the risk of ARI in the first year of life.

METHODS AND ANALYSIS

'D-Kids' is a parallel (1:1), double-blind (allocation concealed), randomised placebo-controlled trial conducted among NT First Nations mother-infant pairs. Pregnant women and their babies (n=314) receive either vitamin D or placebo. Women receive 14 000 IU/week or placebo from 28 to 34 weeks gestation until birth and babies receive 4200 IU/week or placebo from birth until age 4 months. The primary outcome is the incidence of ARI episodes receiving medical attention in the first year of life. Secondary outcomes include circulating vitamin D level and nasal pathogen prevalence. Tertiary outcomes include infant immune cell phenotypes and challenge responses. Blood, nasal swabs, breast milk and saliva are collected longitudinally across four study visits: enrolment, birth, infant age 4 and 12 months. The sample size provides 90% power to detect a 27.5% relative reduction in new ARI episodes between groups.

ETHICS AND DISSEMINATION

This trial is approved by the NT Human Research Ethics Committee (2018-3160). Study outcomes will be disseminated to participant families, communities, local policy-makers, the broader research and clinical community via written and oral reports, education workshops, peer-reviewed journals, national and international conferences.

TRIAL REGISTRATION NUMBER

ACTRN12618001174279.

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.

Pregnancy, Breastfeeding, and Vitamin D

Exclusive breastfeeding is considered the ideal food in the first six months of life; however, paradoxically, vitamin D content in human breast milk is clearly low and insufficient to obtain the recommended intake of 400 IU daily. This article summarizes the extraordinary metabolism of vitamin D during pregnancy and its content in human breast milk. The prevalence of hypovitaminosis D in pregnant women and/or nursing mothers and its potential maternal-fetal consequences are analyzed. The current guidelines for vitamin D supplementation in pregnant women, nursing mothers, and infants to prevent hypovitaminosis D in breastfed infants are detailed. Low vitamin D content in human breast milk is probably related to active changes in human lifestyle habits (reduced sunlight exposure).

Clinical Toxicology of Vitamin D in Pediatrics: A Review and Case Reports

Intoxication of vitamin D is not a common case in pediatrics. Vitamin D supplements are sold as OTC drugs; however, there is a lack of public education about the permissible limits of vitamin D intake which may lead to vitamin D toxicity (VDT). This review aims to give insights to readers or practitioners about the clinical toxicology of vitamin D in pediatrics, which includes the mechanism of VDT, case reports, and the management of vitamin D poisoning. VDT refers to serum 25(OH)D levels, particularly when the level exceeds 100 ng/mL (250 nmol/L) or is defined as hypervitaminosis D. Hypercalcemia is a common condition of vitamin D toxicity. Vitamin D and its metabolites in moderate levels can induce hypercalcemia, as indicated by the elevation of osteoclastic bone resorption, the presence of calcium in renal tubules, intestinal calcium intake (through increased production of calcium-binding protein in enterocytes), and the decrease of parathyroid hormone synthesis. VDT in pediatrics can be managed by discontinuing vitamin D intake; using activated charcoal, furosemide, prednisone, and calcitonin; rehydration using intravenous sodium chloride 0.9%; and dextrose fluid therapy. It is important for parents to be more careful when providing vitamin D to their children.

Vitamin D intake and determinants of vitamin D status during pregnancy in The Norwegian Mother, Father and Child Cohort Study

Background

Norwegian data on vitamin D status among pregnant women indicate a moderate to high prevalence of insufficient vitamin D status (25-hydroxyvitamin D (25OHD) concentrations ≤50  nmol/L). There is a lack of population-based research on vitamin D intake and determinants of 25OHD in pregnant women from northern latitudes. The aims of this study were (1) to evaluate total vitamin D intake from both diet and supplements, (2) to investigate determinants of vitamin D status, and (3) to investigate the predicted response in vitamin D status by total vitamin D intake, in pregnant Norwegian women.

Methods

In total, 2,960 pregnant women from The Norwegian Environmental Biobank, a sub-study within The Norwegian Mother, Father and Child Cohort Study (MoBa), were included. Total vitamin D intake was estimated from a food frequency questionnaire in gestational week 22. Concentrations of plasma 25OHD was analyzed by automated chemiluminescent microparticle immunoassay method in gestational week 18. Candidate determinant variables of 25OHD were chosen using stepwise backward selection and investigated using multivariable linear regression. Predicted 25OHD by total vitamin D intake, overall and stratified by season and pre-pregnancy BMI, was explored using restricted cubic splines in an adjusted linear regression.

Results

Overall, about 61% of the women had a total vitamin D intake below the recommended intake. The main contributors to total vitamin D intake were vitamin D supplements, fish, and fortified margarine. Higher 25OHD concentrations were associated with (in descending order of the beta estimates) summer season, use of solarium, higher vitamin D intake from supplements, origin from high income country, lower pre-pregnancy BMI, higher age, higher vitamin D intake from foods, no smoking during pregnancy, higher education and energy intake. During October-May, a vitamin D intake according to the recommended intake was predicted to reach sufficient 25OHD concentrations >50  nmoL/L.

Conclusion

The findings from this study highlight the importance of the vitamin D intake, as one of few modifiable determinants, to reach sufficient 25OHD concentrations during months when dermal synthesis of vitamin D is absent.

Recurrent Pregnancy Loss Etiology, Risk Factors, Diagnosis, and Management. Fresh Look into a Full Box

Recurrent pregnancy loss is a complex health challenge with no universally accepted definition. Inconsistency in definitions involves not only the number of spontaneous abortions (two or three) that are accepted for recurrent pregnancy loss but the types of pregnancy and gestational age at miscarriage. Due to the heterogeneity of definitions and criteria applied by international guidelines for recurrent pregnancy loss, the true incidence of recurrent miscarriage, which is reported to range from 1% to 5%, is difficult to estimate. Moreover, the exact etiology of recurrent pregnancy loss remains questionable; thus, it is considered a polyetiological and multifactorial condition with many modifiable and non-modifiable factors involved. Even after thoroughly evaluating recurrent pregnancy loss etiology and risk factors, up to 75% of cases remain unexplained. This review aimed to summarize and critically analyze accumulated knowledge on the etiology, risk factors, relevant diagnostic options, and management approach to recurrent pregnancy loss. The relevance of various factors and their proposed roles in recurrent pregnancy loss pathogenesis remains a matter of discussion. The diagnostic approach and the management largely depend on the etiology and risk factors taken into consideration by a healthcare professional as a cause of recurrent miscarriage for a particular woman or couple. Underestimation of social and health consequences of recurrent pregnancy loss leads to compromised reproductive health and psychological well-being of women after miscarriage. Studies on etiology and risk factors for recurrent pregnancy loss, especially idiopathic, should be continued. The existing international guidelines require updates to assist clinical practice.

Prevalence of 25-Hydroxyvitamin D (Vitamin D) Deficiency in a Group of Infertile Women from Baghdad City

Background

Infertility is a common issue affecting a large number of Iraqi women of reproductive age. The relationship between vitamin D deficiency and infertility has previously drawn the attention of gynecologists, and an increasing number of vitamin D testing has been requested.

Methods

120 women were enrolled in this study between April 2019 and April 2020. Patients were divided into two groups comprising sixty women complaining of infertility, with the other 60 women being fertile and enrolled as controls. All patients were assessed for vitamin D level.

Results

In the fertile study group, patients with deficient, insufficient, and sufficient level of vitamin were 28%, 23%, and 48%, respectively (these numbers were rounded to the nearest whole digit, as the numbers for the infertile group were given with that level of precision), whereas the infertile study group showed a statistically significant (p value = 0.002) distribution of vitamin levels with 50%, 35%, and 15% of women being deficient, insufficient, and sufficient, respectively.

Conclusions

Vitamin D is significantly deficient in infertile patients which suggests a possible, positive impact if vitamin D is considered in the management of female infertility. Further study with more participants is highly recommended.

Vitamin D in pregnancy (GRAVITD) - a randomised controlled trial identifying associations and mechanisms linking maternal Vitamin D deficiency to placental dysfunction and adverse pregnancy outcomes - study protocol

BACKGROUND

The prevalence of vitamin D deficiency is high among pregnant women. Vitamin D deficiency in pregnancy is associated with increased risk of adverse pregnancy outcomes especially complications related to placental dysfunction and insulin resistance. The objective of this study is to investigate if a higher dose of vitamin D supplementation in pregnancy reduces the prevalence of vitamin D deficiency and prevents adverse pregnancy outcome with special emphasize on preeclampsia, foetal growth restriction and gestational diabetes.

METHODS

GRAVITD is a double-blinded randomised trial with parallel groups where all pregnant women attending the free of charge national nuchal translucency scan programme in gestational week 10-14 at Randers Regional Hospital are invited to participate. Enrolment started in June 2020. Participants are randomised in a two armed randomization with a 1:1 allocation ratio into 1) control group - receives 10 µg of vitamin D or 2) intervention group - receives 90 µg of vitamin D. A total of 2000 pregnant women will be included. Maternal blood samples and questionnaires describing life-style habits are collected upon enrolment. For half of the participants blood samples and questionnaires will be repeated again in 3rd trimester. Blood samples will be analysed for 25-hydroxy-vitamin D using high-performance liquid chromatography coupled with tandem mass spectrometry. Upon delivery, placental tissue and umbilicalcord blood will be collected and information on maternal and fetal outcomes will be exstracted from medical records. The primary outcomes are serum levels of 25-hydroxy-vitamin D ≥ 75 nmol/L and the rate of preeclampsia, foetal growth restriction and gestational diabetes. Secondary outcome includes identification and impact on placental functions related to vitamin D. A tertiary outcome is to initiate a cohort of children born from mothers in the trial for future follow-up of the effects of vitamin D on childhood health.

DISCUSSION

Provided that this trial finds beneficial effects of a higher dose of vitamin D supplementation in pregnancies, official recommendations can be adjusted accordingly. This will provide a low-cost and easily implementable adjustment of prenatal care which can improve health for both mother and child during pregnancy and beyond.

TRIAL REGISTRATION

ClinicalTrial.gov: NCT04291313 . Registered February 17, 2020.

Association between vitamin D level in mother's serum and the level of vitamin D in the serum of pre-term infants

BACKGROUND

Vitamin D deficiency and insufficiency is common in mothers and infants. The present study was conducted with the aim of association between the level of vitamin D in the mother's serum and the level of vitamin D in the serum of preterm infants.

METHOD

The present descriptive - analytical study was performed on 140 mothers and preterm infants referred to the Kamali hospital in Alborz University of Medical Sciences. Sampling was done from available mothers after hospitalization for delivery and their infants during the first 72 hours after delivery. Information from mothers and infants were collected with researcher made check list, including age, type of delivery, number of pregnancies, vitamin D during this pregnancy, infants birth age, gender, and birth weight. Data analysis was performed using SPSS version 24 software.

RESULTS

The average age of mothers was 28 ± 5 years and the average age of infants at the time of birth was 30 ± 1 weeks. Forty two infants (67%) were boys and 23 infants (33%) were girls. The results showed a high rate of vitamin D insufficiency and deficiency in mother (44, 49%) and preterm infants (49, 38%). The results of the Pearson correlation test showed that there is a strong and significant relationship between the serum vitamin D level of mothers and preterm infants (P = 0.001). Logistic regression tests showed that mother's vitamin D level had an effect on the infant's vitamin D level.

CONCLUSION

Considering high rate of vitamin D deficiency and insufficiency and relationship between vitamin D in preterm infants serum and mothers, diagnostic screenings are recommended to investigate vitamin D disorders in pregnant mothers, which should be planned, implemented and followed up in the form of a therapeutic program to prevent the occurrence of complications caused by this disorder in the mother and infant.

Long-term supplementation with 3200 to 4000 IU of vitamin D daily and adverse events: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The upper tolerable intake level for vitamin D in the general population has been set at 4000 international units (IU) daily, but considerable uncertainty remains. We summarized reported harmful effects of a daily vitamin D supplement of 3200-4000 IU in trials lasting ≥ 6 months.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials in several databases and identified 22 trials reporting safety data. Parameters of calcium metabolism, falls, hospitalization, and mortality were assessed.

RESULTS

The selected trials comprised a total number of 12,952 participants. All trials used supplemental vitamin D₃. The relative risk (RR) of hypercalcemia in the vitamin D vs. control arm was 2.21 (95%CI: 1.26-3.87; 10 studies), with a vitamin D-induced frequency of hypercalcemia of 4 cases per 1000 individuals. Subgroup analysis in trials with > 100 and ≤ 100 study participants revealed an RR of 2.63 (95%CI: 1.30-5.30; 7 studies) and 0.80 (95%CI: 0.24-2.62; 3 studies), respectively (P_interaction = 0.06). Risks of falls and hospitalization were also significantly increased in the vitamin D arm with an RR of 1.25 (95%CI: 1.01-1.55; 4 studies) and 1.16 (95%CI: 1.01-1.33; 7 studies), respectively. Risks of hypercalciuria, kidney stones, and mortality did not differ significantly between study arms. Quality assessment revealed high risk of incomplete reporting of safety-related outcome data.

CONCLUSION

Supplemental vitamin D doses of 3200-4000 IU/d appear to increase the risk of hypercalcemia and some other adverse events in a small proportion of individuals, indicating that this dose is not completely safe. In future studies, rigorous reporting of safety-related outcomes is needed when using moderately high doses of vitamin D.

Influence of Vitamin D supplementation on reproductive outcomes of infertile patients: a systematic review and meta-analysis

BACKGROUND

Low vitamin D status has been associated with an increased risk for infertility. Recent evidence regarding the efficacy of vitamin D supplementation in improving reproductive outcomes is inconsistent. Therefore, this systematic review was conducted to investigate whether vitamin D supplementation could improve the reproductive outcomes of infertile patients and evaluate how the parameters of vitamin D supplementation affected the clinical pregnancy rate.

METHODS

We searched seven electronic databases (CNKI, Cqvip, Wanfang, PubMed, Medline, Embase, and Cochrane Library) up to March 2022. Randomized and cohort studies were collected to assess the reproductive outcomes difference between the intervention (vitamin D) vs. the control (placebo or none). Mantel-Haenszel random effects models were used. Effects were reported as odds ratio (OR) and their 95% confidence interval (CI). PROSPERO database registration number: CRD42022304018.

RESULTS

Twelve eligible studies (n = 2352) were included: 9 randomized controlled trials (RCTs, n = 1677) and 3 cohort studies (n = 675). Pooled results indicated that infertile women treated with vitamin D had a significantly increased clinical pregnancy rate compared with the control group (OR: 1.70, 95% CI: 1.24-2.34; I² = 63%, P = 0.001). However, the implantation, biochemical pregnancy, miscarriage, and multiple pregnancy rates had no significant difference (OR: 1.86, 95% CI: 1.00-3.47; I² = 85%, P = 0.05; OR: 1.49; 0.98-2.26; I² = 63%, P = 0.06; OR: 0.98, 95% CI: 0.63-1.53; I² = 0%, P = 0.94 and OR: 3.64, 95% CI: 0.58-11.98; I² = 68%, P = 0.21). The improvement of clinical pregnancy rate in the intervention group was influenced by the vitamin D level of patients, drug type, the total vitamin D dosage, the duration, administration frequency, and daily dosage of vitamin D supplementation. The infertile women (vitamin D level < 30 ng/mL) treated with the multicomponent drugs including vitamin D (10,000-50,000 IU or 50,000-500,000 IU), or got vitamin D 1000-10,000 IU daily, lasting for 30-60 days could achieve better pregnancy outcome.

CONCLUSION

To the best of our knowledge, this is the first meta-analysis systematically investigated that moderate daily dosing of vitamin D supplementation could improve the clinical pregnancy rate of infertile women and reported the effects of vitamin D supplementation parameters on pregnancy outcomes. A larger sample size and high-quality RCTs are necessary to optimize the parameters of vitamin D supplementation to help more infertile patients benefit from this therapy.

The Role of Maternal Vitamin D Deficiency in Offspring Obesity: A Narrative Review

Currently, vitamin D (VD) deficiency during pregnancy is widespread globally, causing unfavorable pregnancy outcomes for both mothers and infants for a longer time than expected, based on the Developmental Origins of Health and Disease (DOHaD) theory. As VD plays a key role in maintaining normal glucose and lipid metabolism, maternal VD deficiency may lead to obesity and other obesity-related diseases among offspring later in life. This review mainly focuses on the effect of maternal VD deficiency on offspring lipid metabolism, reviewing previous clinical and animal studies to determine the effects of maternal VD deficit on offspring obesity and potential mechanisms involved in the progression of offspring obesity. Emerging clinical evidence shows that a low VD level may lead to abnormal growth (either growth restriction or largeness for gestational age) and lipid and glucose metabolism disorders in offspring. Here, we also outline the link between maternal VD deficiency and life-long offspring effects, including the disorder of adipogenesis, the secretion of adipocytokines (including leptin, resistin, and adiponectin), activated systemic inflammation, increased oxidative reactions in adipose tissue, insulin resistance, and abnormal intestinal gut microbiota. Thus, there is an urgent need to take active steps to address maternal VD deficiency to relieve the global burden of obesity.

The effect of vitamin D supplementation on body composition in nursing mothers with overweight or obesity: a randomized double-blind placebo-controlled clinical trial

BACKGROUND

This study aimed to evaluate the effect of vitamin D3 supplementation on body composition and anthropometric measures of nursing mothers.

METHODS

In a double-blind, randomized clinical trial, 90 nursing mothers with overweight or obesity were randomized into three groups for 12 weeks: two groups of vitamin D3 supplementation (2000 IU/d (VD1), n = 32 and 4000 IU/d (VD2), n = 29) and placebo (PL) group (n = 29). The information on body composition was obtained using the body impedance analysis (BIA) method. Serum 25-Hydroxy vitamin D (25(OH) D), Intact Parathyroid Hormone (iPTH), calcium, and phosphorus were measured before and after the intervention. Data were analyzed based on the intention-to-treat (ITT) method. Two-way repeated measure ANOVA (mixed ANOVA) was applied to assess whether the mean changes in the results from baseline to 12 weeks differ in the three groups.

RESULTS

There was a significant increase in the serum 25(OH) D concentration in the VD2 group compared to VD1 and PL groups (mean change (MC), 12.3 ng/ml; 95% CI, 9.4/15.0, p-value < 0.001). In addition, fat mass (MC, - 4.3 kg; 95% CI, - 7.0/- 1.1, p-value < 0.007), fat mass index (MC, - 1.6; 95% CI, - 2.6/- 0.5, p-value < 0.006) and body fat percentage (MC, - 8.1; 95% CI, - 12.0/- 4.2, p-value < 0.007) reduced in VD2 group as compared with VD1 and PL groups.

CONCLUSION

The intake of 4000 IU/d vitamins D3 supplementation would elevate circulating 25(OH) D concentrations in nursing mothers with overweight or obesity and improve some indices of body composition.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials ( http://www.irct.ir : IRCT20140413017254N6) registered on 11-04-2018. The graphical abstract of this clinical trial, is a figure that explains the final results of the manuscript in a clear and attractive way.

Vitamin D Deficiency is Associated With Increased Plasminogen Activator Inhibitor 1/Plasminogen Activator Inhibitor 2 Ratio in Pregnancy

BACKGROUND

Vitamin D deficiency has recently been suggested as an independent risk factor for thrombosis. Notably, vitamin D deficiency is common in pregnant populations, whom already have an increased thrombotic risk. However, pregnant women are commonly excluded from studies investigating the hemostatic system, and knowledge on the impact of vitamin D on hemostasis in pregnancy is therefore limited.

METHODS

A cross-sectional study comparing the hemostatic profile of pregnant women (gestational week 12.9 ± 0.7) with vitamin D deficiency (≤50 nmol/L) (n = 70) and high adequate vitamin D status (≥100 nmol/L) (n = 59).

RESULTS

Vitamin D deficient women displayed increased plasminogen activator inhibitor 1 levels and an increased plasminogen activator inhibitor 1/plasminogen activator inhibitor 2 ratio, even after adjusting for factors with potential influence on hemostasis (body mass index, smoking and use of fish oil supplements).

CONCLUSIONS

Vitamin D deficiency is associated with increased plasminogen activator inhibitor 1/plasminogen activator inhibitor 2 ratio in pregnant women. As an increased plasminogen activator inhibitor 1/plasminogen activator inhibitor 2 ratio with high plasminogen activator inhibitor 1 levels may increase thrombotic risk and is associated with the development of pregnancy complications, further research is needed to determine the optimal vitamin D supplementation in pregnancy.

Sex-Specific Variations in Vitamin D and Vitamin D Binding Protein (Vdbp) and Flipped Pattern of their Association in Preeclamptic Women with Dyslipidemia

BACKGROUND

Women with preeclampsia frequently have disorders of calcium metabolism during their pregnancies, including hypocalciuria and low vitamin D levels. The link between fetal sex and vitamin D and vitamin D binding protein levels in pregnancy and preeclampsia is not clear.

AIM

Present study was designed to explore sex-specific variations in vitamin D and vitamin D binding protein levels in maternal and umbilical cord blood samples for age and gestation matched 20 primigravida normotensive and 20 primigravida with preeclampsia with a singleton pregnancy.

METHODS

Routine investigations, vitamin D binding protein (VDBP), and serum vitamin D in both maternal serum and cord blood were measured in both groups. Association between maternal and cord blood vitamin D levels was highly positive in both cases and control with babies of either sex.

RESULTS

This association exhibited sexual dimorphism between cord blood vitamin D and vitamin D binding protein (VDBP) suggesting that the occurrence of pregnancy complications differs according to fetal sex with a higher cardiovascular and metabolic load for the mother in the presence of a male fetus.

CONCLUSION

Vitamin D binding protein (VDBP) measurement along with vitamin D level should be advised in clinical practice for early detection and screening.

Effects of vitamin D on insulin resistance and fasting blood glucose in pregnant women with insufficient or deficient vitamin D: a randomized, placebo-controlled trial

BACKGROUND

Gestational diabetes is one of the most common metabolic disorders during pregnancy. Some studies have reported the effect of vitamin D deficiency on the incidence of this disorder. Therefore, the purpose of the present study was to determine the effect of vitamin D supplementation on fasting blood glucose (FBG) levels, fasting blood insulin (FBI) levels and insulin resistance index (HOMA-IR) (primary outcomes) and symptoms of depression, musculoskeletal pain, frequency of gestational diabetes and the frequency of abortion (secondary outcomes).

METHODS

In this triple-blind randomized controlled trial, 88 pregnant women at 8-10 weeks of pregnancy who had the vitamin D of less than 30 ng/ml were randomly assigned to the vitamin D group (n = 44) and control group (n = 44) using block randomization. The vitamin D group received 4,000 units of vitamin D tablets daily and the control group received placebo tablets for 18 weeks. Independent t-test, Mann-Whitney U and ANCOVA tests were used to analyze the data.

RESULTS

After the intervention, there was no statistically significant difference between the two groups in terms of FBG (P = 0.850), FBI (P = 0.353), HOMA-IR (P = 0.632), mean score of depressive symptoms (P = 0.505), frequency of gestational diabetes (P = 0.187) and frequency of abortion (P = 1.000) and there was only a difference in terms of serum vitamin D level (P = 0.016) and musculoskeletal pain including knee pain (P = 0.025), ankle pain (P < 0.001) and leg pain (P < 0.001).

CONCLUSION

Vitamin D could improve the musculoskeletal pain in pregnant women but couldn't decrease FBG, FBI, HOMA-IR, depression symptoms score, incidence of GDM and abortion.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials (IRCT): IRCT20120718010324N59. Date of registration: 4/11/2020. URL: https://en.irct.ir/user/trial/50973/view ; Date of first registration: 21/11/2020.

Effects of vitamin D supplementation during pregnancy on bone health and offspring growth: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Whether vitamin D supplementation during pregnancy is beneficial to bone health and offspring growth remains controversial. Moreover, there is no universal agreement regarding the appropriate dose and the time of commencement of vitamin D supplementation during pregnancy.

OBJECTIVE

We aimed to systematically review the effects of vitamin D supplementation during pregnancy on bone development and offspring growth.

METHODS

A literature search for randomized controlled trials (RCTs) was performed in 7 electronic databases to identify relevant studies about the effects of vitamin D supplementation during pregnancy on bone development and offspring growth from inception to May 22, 2022. A Cochrane Risk Assessment Tool was used for quality assessment. Vitamin D supplementation was compared with placebo or standard supplements. The effects are presented as the mean differences (MDs) with 95% CIs. The outcomes include bone mineral content (BMC), bone mineral density (BMD), bone area (BA), femur length (FL) and humeral length (HL); measurement indicators of growth, including length, weight and head circumference; and secondary outcome measures, including biochemical indicators of bone health, such as the serum 25(OH)D concentration. Additionally, subgroup analyses were carried out to evaluate the impact of different doses and different initiation times of supplementation with vitamin D.

RESULTS

Twenty-three studies with 5390 participants met our inclusion criteria. Vitamin D supplementation during pregnancy was associated with increased humeral length (HL) (MD 0.13, 95% CI 0.06, 0.21, I2 = 0, P = 0.0007) during the fetal period (third trimester). Vitamin D supplementation during pregnancy was associated with a significantly increased length at birth (MD 0.14, 95% CI 0.04, 0.24, I2 = 24%, P = 0.005) and was associated with a higher cord blood 25(OH)D concentration (MD 48.74, 95% CI 8.47, 89.01, I2 = 100%, P = 0.02). Additionally, subgroup analysis revealed that birth length was significantly higher in the vitamin D intervention groups of ≤1000 IU/day and ≥4001 IU/day compared with the control group. Prenatal (third trimester) vitamin D supplementation was associated with a significant increase in birth length, while prenatal (second trimester) vitamin D supplementation was associated with a significant increase in birth weight.

CONCLUSION

Vitamin D supplementation during pregnancy may be associated with increased humeral length (HL) in the uterus, increased body length at birth and higher cord blood 25(OH)D concentration. Evidence of its effect on long-term growth in children is lacking. Additional rigorous high-quality, long-term and larger randomized trials are required to more fully investigate the effects of vitamin D supplementation during pregnancy.

Individualized high dairy protein + walking program supports bone health in pregnancy: a randomized controlled trial

BACKGROUND

Pregnancy induces bone mineral mobilization, which may be further compromised if diet and physical activity are suboptimal.

OBJECTIVES

We aimed to determine the effects of a Nutrition + Exercise intervention during pregnancy on maternal calciotropic and bone biomarker profiles throughout pregnancy and the postpartum.

METHODS

In the Be Healthy in Pregnancy (BHIP) randomized controlled trial, 203 of 225 participants who consented to the bone health substudy were, randomly assigned at 12-17 weeks gestation to receive either usual care (control) or a structured and monitored Nutrition + Exercise plan (intervention) providing an individualized high dairy protein diet and a walking program throughout pregnancy. Maternal serum total procollagen type 1 N-terminal propeptide (P1NP; bone formation), C-terminal telopeptide of type I collagen (CTX; bone resorption), and insulin-like growth factor-1 (IGF-1) were measured by ELISA, and vitamin D metabolites by ultra-performance LC tandem MS at early and late pregnancy, 6 mo postpartum, and in cord blood.

RESULTS

In 187 participants completing all measures, significantly higher intakes were observed in the intervention than in the control group for total protein (P < 0.0001), protein intake from dairy foods (P < 0.0001), and calcium (P < 0.0001), whereas vitamin D intake was similar between treatment groups in both the second and third trimesters. The intervention group had significantly lower serum CTX at end of pregnancy (mean ± SD: 0.78 ± 0.31 ng/mL; n = 91 compared with 0.89 ± 0.33 ng/mL; n = 96, P = 0.034) and in cord serum (0.58 ± 0.13 ng/mL; n = 31 compared with 0.69 ± 0.18 ng/mL; n = 22, P < 0.025). Serum concentrations of P1NP rose significantly (P < 0.02) from early pregnancy to 6 mo postpartum for the intervention group only. Serum 25-hydroxyvitamin D status was >50 nmol/L for 97% of all participants.

CONCLUSIONS

Higher maternal dietary protein and calcium intakes than usual care in concert with normal vitamin D status minimized bone resorption and maintained bone formation and may protect bone health during pregnancy.This trial was registered at clinicaltrials.gov as NCT01689961.

Vitamin D3 Supplementation in Overweight/Obese Pregnant Women: No Effects on the Maternal or Fetal Lipid Profile and Body Fat Distribution-A Secondary Analysis of the Multicentric, Randomized, Controlled Vitamin D and Lifestyle for Gestational Diabetes Prevention Trial (DALI)

Vitamin D deficiency is a common finding in overweight/obese pregnant women and is associated with increased risk for adverse pregnancy outcome. Both maternal vitamin D deficiency and maternal obesity contribute to metabolic derangements in pregnancy. We aimed to assess the effects of vitamin D3 supplementation in pregnancy versus placebo on maternal and fetal lipids. Main inclusion criteria were: women <20 weeks’ gestation, BMI ≥ 29 kg/m2. Eligible women (n = 154) were randomized to receive vitamin D3 (1600 IU/day) or placebo. Assessments were performed <20, 24−28 and 35−37 weeks and at birth. Linear regression models were used to assess effects of vitamin D on maternal and cord blood lipids. In the vitamin D group significantly higher total 25-OHD and 25-OHD3 levels were found in maternal and cord blood compared with placebo. Adjusted regression models did not reveal any differences in triglycerides, LDL-C, HDL-C, free fatty acids, ketone bodies or leptin between groups. Neonatal sum of skinfolds was comparable between the two groups, but correlated positively with cord blood 25-OH-D3 (r = 0.34, p = 0.012). Vitamin D supplementation in pregnancy increases maternal and cord blood vitamin D significantly resulting in high rates of vitamin D sufficiency. Maternal and cord blood lipid parameters were unaffected by Vitamin D3 supplementation.

A bibliometric analysis of global research on vitamin D and reproductive health between 2012 and 2021: Learning from the past, planning for the future

Background

Vitamin D plays an invaluable role in reproductive health, but vitamin D insufficiency and deficiency are generally common among couples of childbearing age and pregnant women. This study aimed to evaluate the evolution, development trend, and research hotspot of publications on vitamin D and reproductive health.

Methods

The literature on vitamin D and reproductive health between 2012 and 2021 was retrieved from the Web of Science Core Collection (WoSCC). We used VOSviewer and CiteSpace to analyze publication years, countries, institutions, journals, highly cited authors and publications, and co-occurrence and citation bursts of keywords.

Results

A total of 1,828 articles and reviews on vitamin D and reproductive health published between 2012 and 2021 were identified. The annual publication outputs showed steady growth, with the most publications (272) and citations (7,097) in 2021. The United States contributed the most publications (458) and had the highest h-index (58). In terms of the number of publications and h-index, the journal named Nutrients ranked first. Nutrition dietetics, obstetrics gynecology, and endocrinology metabolism were three well-represented disciplines in research on vitamin D and reproductive health. Hollis BW, Wagner CL, and Litonjua AA were the top three most productive authors in this field during the last decade. Apart from vitamin D, the five keywords with the most frequent occurrence were vitamin D deficiency, pregnancy, risk, vitamin D supplementation, and 25-hydroxyvitamin D. Keyword citation burst analysis revealed that low birth weight, adipose tissue, marker, and embryo had a citation burst lasting until 2021.

Conclusion

In conclusion, vitamin D has received continuous attention in the field of reproductive health, and there appears to have a higher level of research in North America. Multidisciplinary intersection contributed to the in-depth exploration in this field. And the effect of maternal vitamin D levels on fetal lipid metabolism and the prediction of fertility by vitamin D-related markers might be hotspots for the research.

Developmental exposure to vitamin D deficiency and subsequent risk of schizophrenia

Over the last half century, a body of convergent evidence has accumulated linking disruption of early brain development with an increased risk of mental disorders, including schizophrenia. The orderly cascade of brain development may be disrupted by exposure to suboptimal concentrations of a range of biological substrates and micronutrients. We hypothesized that those exposed to vitamin D deficiency during early life, have an increased risk of neurodevelopmental disorders, including schizophrenia. The hypothesis was based on the link between an increased risk of schizophrenia in (a) those born in winter and spring, when vitamin D deficiency is more prevalent, and (b) the offspring of dark-skinned migrants living in cold climates, who have a markedly increased risk of vitamin D deficiency. In this review, we summarize evidence from analytic epidemiology related to this hypothesis. Two case-control studies based on Danish neonatal dried blood spots have found that neonatal vitamin deficiency is associated with an increased risk of schizophrenia. However, recent genetic analyses have also suggested that common variants linked to schizophrenia may lead to lower vitamin D concentrations (possibly mediated via reduced outdoor activity). We summarize limitations of the current evidence and outline suggestions that can guide future research. Based on currently available data, there is insufficient evidence to support public health recommendations related to this topic. However, we cannot reject the hypothesis that the provision of vitamin D supplementation to pregnant women and/or offspring in groups vulnerable to vitamin D deficiency may subsequently reduce the incidence of schizophrenia in the offspring.

Vitamin D-Related Risk Factors for Maternal Morbidity during Pregnancy: A Systematic Review

Vitamin D has well-defined classical functions related to metabolism and bone health but also has non-classical effects that may influence pregnancy. Maternal morbidity remains a significant health care concern worldwide, despite efforts to improve maternal health. Nutritional deficiencies of vitamin D during pregnancy are related to adverse pregnancy outcomes, but the evidence base is difficult to navigate. The primary purpose of this review is to map the evidence on the effects of deficiencies of vitamin D on pregnancy outcome and the dosage used in such studies. A systematic search was performed for studies on vitamin D status during pregnancy and maternal outcomes. A total of 50 studies came from PubMed, 15 studies came from Cochrane, and 150 studies came from Embase, for a total of 215 articles. After screening, 34 were identified as candidate studies for inclusion. Finally, 28 articles met the inclusion criteria, which originated from 15 countries. The studies included 14 original research studies and 13 review studies conducted between 2012 and 2021. This review was finally limited to the 14 original studies. This systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, and the quality and strength of the evidence was evaluated using the Navigation Guide Systematic Review Methodology (SING). We found evidence that supports the idea that supplementary vitamin D for pregnant women is important for reducing the risk of gestational diabetes, hypertension, preeclampsia, early labor, and other complications. The data retrieved from this review are consistent with the hypothesis that adequate vitamin D levels might contribute to a healthy pregnancy.

Adequate Dietary Intake and Vitamin D Supplementation: A Study of Their Relative Importance in Determining Serum Vitamin D and Ferritin Concentrations during Pregnancy

Vitamin D is essential for human health. However, it is not clear if vitamin D supplementation is necessary for all pregnant women. This study examines the relative importance of dietary patterns and vitamin D supplementation frequency in determining serum 25-hydroxyvitamin D (25(OH)D) and ferritin concentrations among pregnant women in Hong Kong, China. A total of 572 healthy women were recruited from antenatal clinics at 25–35 weeks pregnant. Participants completed an electronic version of the food frequency questionnaire and a web questionnaire on supplement use. Their blood samples were tested for serum 25(OH)D and ferritin. The associations of dietary patterns and vitamin D supplementation frequency with serum 25(OH)D and ferritin concentrations were analyzed using moderated hierarchical regression. Two dietary patterns were identified. The adequate dietary intake was characterized by the high probability of meeting recommended daily food group servings, whereas the inadequate dietary intake was characterized by inadequate consumption of vegetables, fruits, meat, fish, and eggs, or alternatives. The association between adequate dietary intake and serum ferritin concentrations was independent of vitamin D supplementation frequency (β = 0.05, p = 0.035), but dietary patterns interacted with vitamin D supplementation frequency to determine serum 25(OH)D concentrations (β = −13.22, p = 0.014). The current study presents evidence on the relative importance of dietary patterns and vitamin D supplementation in maintaining sufficient vitamin D and iron in pregnancy. Antenatal nutrition counselling services should be provided to pregnant women who show signs of inadequate dietary intake.

The Influence of Maternal Vitamin D Supplementation in Pregnancies Associated with Preeclampsia: A Case-Control Study

Preeclampsia is a pregnancy-specific illness that is hypothesized to occur due to vitamin D deficiency during pregnancy. Therefore, vitamin D supplementation in early pregnancy should be explored for preventing preeclampsia and promoting neonatal well-being. The present study follows a case-control analysis that aims to determine the effect of vitamin D supplements on reducing the probability of recurrent preeclampsia. We identified 59 patients for the control group without vitamin D supplementation during pregnancy, while 139 patients were included in the cases group of pregnant women with a history of preeclampsia who confirmed taking daily vitamin D supplements in either 2000 UI or 4000 UI until the 36th week of pregnancy. There were 61 (80.3%) patients with a normal serum vitamin D level measured at 32 weeks in the pregnant women who took a daily dose of 4000 UI vitamin D and 43 (68.3%) in those who took a 2000 UI dose of vitamin D, compared to just 32 (54.2%) in those who did not take vitamin D at all. Regarding the blood pressure of pregnant women measured at 32 weeks, it was observed that 20.3% were hypertensive in the no supplementation group, compared to only 11.1% and 6.6% in those who were taking vitamin D during pregnancy (p-value = 0.049). Serum vitamin D levels at 32 weeks were measured at an average value of 23.9 ng/mL, compared with 28.4 ng/mL in the group taking a 2000 UI daily dose and 33.6 in those who supplemented with 4000 UI daily (p-value < 0.001). Proteinuria was identified more often in the group at risk for preeclampsia who did not take vitamin D supplements, while systolic blood pressure (p-value = 0.036) as well as diastolic blood pressure (p-value = 0.012), were all identified to have significantly higher values in the pregnant women with a history of preeclampsia that did not take vitamin D during the current pregnancy. The significant risk factors for preeclampsia development in pregnant patients at risk are: insufficient vitamin D serum levels (<20 ng/mL), OR = 2.52; no vitamin D supplementation, OR = 1.46; more than two pregnancies, OR = 1.89; gestational diabetes mellitus, OR = 1.66; and cardiovascular comorbidities, OR = 2.18. These findings imply that vitamin D has a role in the preservation of placental function and, therefore, in the prevention of the development of late preeclampsia. Pregnant mothers who supplemented their diets with vitamin D were protected against preeclampsia recurrence. Vitamin D supplementation during pregnancy may aid in the prevention of gestational hypertension and preeclampsia.

Preconception vitamin D intake and obstetric outcomes in women using assisted reproductive technology: the Japan Environment and Children’s Study

Background

In reproductive medicine, vitamin D (VitD) is of particular interest because its deficiency has been linked to various infertility issues. Thus, preconception care, including appropriate VitD supplementation, is essential, especially in women using assisted reproductive technology (ART). Despite the therapeutic benefits of VitD, adverse events due to a high daily intake may influence obstetric outcomes. However, the effects of either low or high preconception VitD intake on obstetric outcomes, including the outcomes in women who used ART, remain unclear. Therefore, the aim of this study was to examine the association between pre-pregnancy daily VitD intake and obstetric outcomes in Japanese women, including those who conceived through ART.

Methods

Data were obtained from the Japan Environment and Children’s study database comprising 92,571 women recruited between January 2011 and March 2014 in Japan. Participants were categorized into five quintiles according to pre-pregnancy VitD intake (Q1 and Q5 had the lowest and highest VitD intake, respectively) and stratified according to the use of ART. Multiple logistic regression was performed to identify the effects of pre-pregnancy VitD intake on preterm birth (PTB), low-birth weight infant (LBW), and small for gestational age (SGA).

Results

Using Q3 (middle VitD intake) as a reference, our analysis revealed that Q5 (highest VitD intake) showed an increased risk of LBW < 1500 g (adjusted odds ratio [aOR]: 1.09, 95% confidence interval [CI]: 1.00–1.18) and SGA (aOR: 1.26, 95% CI: 1.14–1.39) among women who conceived without ART. Among women who conceived with ART, we found that Q5 (highest VitD intake) showed an increased risk of PTB at < 37 weeks (aOR: 2.05, 95% CI: 1.27–3.31).

Conclusion

The present study revealed that higher VitD intake before pregnancy may affect perinatal outcomes, particularly in women using ART. Our findings may facilitate personalized preconceptional counseling regarding VitD intake based on the method of conception, especially among women using ART.

Cholecalciferol supplementation and angiogenic markers in chronic kidney disease

Vitamin D plays an important role in proliferation and differentiation of cells and deficiency of vitamin D disturbs angiogenic balance. Previous studies in animal models have reported an association between serum levels of vitamin D and balance between pro- and anti-angiogenic factors. There is insufficient evidence about the effect of vitamin D on mediators of angiogenesis in patients with CKD. We investigated the effect of cholecalciferol supplementation on serum levels of angiogenic markers in non-diabetic patients with CKD stage 3–4. In this secondary analysis on stored samples of our previously published randomized, double-blind, placebo-controlled trial, stable patients of either sex, aged 18–70 years, with non-diabetic CKD stage 3–4 and vitamin D deficiency (serum 25-hydroxyvitamin D ≤20 ng/ml) were randomized to receive either two directly observed oral doses of cholecalciferol (300,000 IU) or matching placebo at baseline and 8 weeks. The primary outcome was change in brachial artery flow-mediated dilatation at 16 weeks. Changes in levels of serum angiogenesis markers (angiopoietin-1, angiopoietin-2, VEGF-A, VEGEF-R, and Tie-2) between groups over 16 weeks were compared. A total 120 patients were enrolled. Supplementation with cholecalciferol led to significant improvement in FMD. Serum 25(OH)D levels were similar in both groups at baseline (13.21±4.78 ng/ml and 13.40±4.42 ng/ml; p = 0.888). At 16 weeks, the serum 25(OH)D levels increased in the cholecalciferol group but not in the placebo group (between-group difference in mean change:23.40 ng/ml; 95% CI, 19.76 to 27.06; p<0.001). Serum levels of angiogenic markers were similar at baseline. At 16 weeks, angiopoietin-2 level decreased in cholecalciferol group (mean difference:-0.73 ng/ml, 95%CI, -1.25 to -0.20, p = 0.002) but not in placebo group (mean difference -0.46 ng/ml, 95%CI, -1.09 to 0.17, p = 0.154), however there was no between-group difference at 16 weeks (between-group difference in mean change: -0.27 ng/ml, 95%CI, -1.09 to 0.55, p = 0.624). Serum angiopoietin-1 level increased [mean change: 5.63 (0.51 to 10.75), p = 0.018] and VEGF-R level decreased [mean change: -87.16 (-131.89 to -42.44), p<0.001] in placebo group but did not show any change in cholecalciferol group. Our data shows the changes in Ang-1, Ang-2 and Ang-1/Ang-2 ratio after high dose oral cholecalciferol supplementation in patients with non-diabetic G3-4 CKD. The data suggests changes in circulating levels of angiogenic markers which needs to be confirmed through an adequately powered study.

Vitamin D: Before, during and after Pregnancy: Effect on Neonates and Children

A worldwide high prevalence of vitamin D (VD) deficiency has become of growing concern because of potential adverse effects on human health, including pregnant women and their offsprings. Beyond its classical function as a regulator of calcium and phosphate metabolism, together with its fundamental role in bone health in every stage of life, its deficiency has been associated to multiple adverse health effects. The classic effects of VD deficiency in pregnancy and neonates have been late hypocalcemia and nutritional rickets. Nevertheless, recent studies have linked VD to fertility and 25(OH)D with several clinical conditions in pregnancy: preeclampsia, gestational diabetes, higher incidence of cesarean section and preterm birth, while in infants, the clinical conditions are low birth weight, lower bone mass and possible relationship with the development of such diseases as bronchiolitis, asthma, type 1 diabetes, multiple sclerosis and autism included as VD non-classical actions. The supplementation with Vitamin D and achievement of optimal levels reduce maternal-fetal and newborn complications. Supplementation in children with VD deficiency reduces the risk of respiratory infections and possibly autoimmune diseases and autism. This review emphasizes the roles of Vitamin D deficiency and the consequences of intervention from preconception to infancy.