High maternal vitamin D levels in early pregnancy may protect against behavioral difficulties at preschool age: the Rhea mother-child cohort, Crete, Greece

Neurodevelopmental Outcomes in the Offspring of Women with Vitamin D Deficiency and Women Who Received Vitamin D Supplementation During Pregnancy

Vitamin D is an essential nutrient, involved in various biological processes including calcium homeostasis, bone health, immune function, and brain development. Vitamin D from the mother crosses the placenta during pregnancy, directly impacting the neurodevelopment of the fetus. Vitamin D insufficiency is a substantial global health problem, influencing almost 47.9% of individuals, with especially high predominance rates among pregnant women. Background/Objectives: Preclinical studies suggest that maternal vitamin D deficiency results in significant alterations in the development of the offspring's brain. Nonetheless, randomized clinical trials in humans have produced conflicting results on the beneficial effect of high-dose vitamin D supplementation during pregnancy on neurodevelopmental outcomes. This review aims to evaluate the association of maternal prenatal vitamin D levels and vitamin D supplementation during pregnancy with offspring neurodevelopment. Methods: This study thoroughly reviewed the literature and searched throughout PubMed, ScienceDirect, Cochrane Library, and Google Scholar, adhering to PRISMA guidelines. Studies assessing maternal vitamin D levels, supplementation, and offspring neurodevelopmental outcomes were included based on predefined eligibility criteria. Results: Among 9686 screened studies, only 20 met the inclusion criteria, representing 18,283 mother-child pairs. A small, non-significant trend suggested a positive association between higher maternal vitamin D levels and offspring cognitive, language, motor, and social-emotional development. The strongest associations were observed in cognitive performance and language acquisition, though inconsistencies emerged across studies. Cord blood vitamin D levels showed no consistent effects on neurodevelopment. Maternal vitamin D supplementation during pregnancy demonstrated no reliable benefits for offspring neurodevelopment, with results varying by study design and participant characteristics. Conclusions: Large-scale, multicenter randomized trials, with standardized neurodevelopmental assessments at multiple ages are needed to define the effects of vitamin D deficiency and supplementation during pregnancy on offspring neurodevelopmental outcomes. Future research should investigate the confounding factors contributing to inconsistencies, including supplementation protocols, genetic variations, and assessment methodologies. Clarifying these aspects will enhance the understanding of maternal vitamin D's role in fetal neurodevelopment and aid in refining prenatal supplementation guidelines.

Vitamin D status in pregnancy and cord blood is associated with symptoms of attention-deficit hyperactivity disorder at age 5 years: Results from Odense Child Cohort

BACKGROUND

Vitamin D status in pregnancy may affect offspring neurodevelopment.

OBJECTIVE

The objective was to investigate the association between serum 25-hydroxyvitamin D in cord blood and pregnancy and symptoms of attention-deficit hyperactivity disorder in 5-year-old offspring.

METHOD

In Odense Child Cohort, Denmark, 944 mother-child pairs had data on pregnancy or cord serum 25-hydroxyvitamin D and parent-rated attention-deficit hyperactivity disorder symptom score by Child Behavior Checklist for ages 1.5-5 years. Adjusted multiple linear regression and two-stage exposure analyses were performed for serum 25-hydroxyvitamin D associations to the attention-deficit hyperactivity disorder symptom score.

RESULTS

The mean (standard deviation) serum 25-hydroxyvitamin D in cord blood was 48.0 (21.8) nmol/L; early pregnancy was 65.5 (20.2) nmol/L and late pregnancy was 79.3 (25.7) nmol/L. The median (interquartile range) age of child at examination was 5.2 (5.1-5.4) years and median (interquartile range) attention-deficit hyperactivity disorder symptom score was 2 (0-3) points. In adjusted analyses, serum 25-hydroxyvitamin D of <25 nmol/L and <32 nmol/L in cord blood and <25 nmol/L in early pregnancy was associated with 0.9 [95% confidence interval: 0.4, 1.3], 0.5 [0.1, 0.9] and 2.1 [0.8, 3.4] points higher attention-deficit hyperactivity disorder symptom score vs reference. In the two-stage exposure analysis, attention-deficit hyperactivity disorder symptom score decreased by 0.4 points per 25 nmol/L increase in serum 25-hydroxyvitamin D. Moreover, serum 25-hydroxyvitamin D of <25 nmol/L in early pregnancy and cord was associated with a five-fold and a two-fold risk of attention-deficit hyperactivity disorder symptom score ⩾90th percentile, adjusted odds ratio [95% confidence interval] = 4.9 [1.3, 19.0] and 2.2 [1.2, 3.9].

CONCLUSION

In this cohort, serum 25-hydroxyvitamin D <25 nmol/L in cord blood and early pregnancy were risk factors for higher attention-deficit hyperactivity disorder symptom score in 5-year-old children, suggesting a protective effect of vitamin D on attention-deficit hyperactivity disorder traits at preschool age.

Preconceptional micronutrient adequacy among women in Greece: a prospective epidemiological study

INTRODUCTION

The importance of micronutrient intake during the preconceptional and early pregnancy period for both maternal and fetal outcomes is well-known, however, relevant data are not available for Greek pregnant women. The aim of the present study is to delineate the nutritional status preceding conception among a representative cohort of Greek pregnant women.

METHODS

This was a prospective study of pregnant women from routine care, recruited at 11+0-13+6 gestational weeks, between December 2020 and October 2022, at the 3rd Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Greece. Eligible participants for the study included healthy pregnant women aged 20 years or older, possessing a proficient understanding of the Greek language, and not engaged in specific nutritional programs. A validated Food Frequency Questionnaire was applied to gather information regarding nutritional habits in the last 6 months prior to conception. The consumption of nutrients was compared to the reference intake levels suggested by the European Food Safety Authority. Further analyses between different participants' subgroups were performed.

RESULTS

Overall, 1100 pregnant women (mean age: 32.4 ± 4.9 years) were enrolled. Almost all examined micronutrients' intake was significantly different from dietary reference values. Furthermore, nutrient adequacy ratio was below 60% in 6 out of 22 micronutrients examined, and Mean Adequacy Ratio was 93%. However, Mean Adequacy Ratio is characterized by extreme variance between the examined values. Iodine, folic acid, potassium, and vitamin D intake levels were significantly lower than the recommended intake levels (p < .001 for all), while vitamin K and niacin (p < .001 for both) were consumed in great extent. Sodium median intake, without calculating extra salt addition also exceeded the reference value levels (p = .03). Notably, magnesium intake exceeded the upper safety limits in 12.4% of the sample.

CONCLUSION

Potential inadequacies in important micronutrients for uneventful pregnancy outcomes have been revealed.. Special attention is needed for magnesium to balance possible toxicity with evident benefits.

Preconception and prenatal vitamin D associations with positive behavioral health in Black children

BACKGROUND

Low levels of vitamin D during pregnancy are associated with offspring behavioral problems but little is known about pre-pregnancy influences. Additionally, Black American individuals are underrepresented in studies, limiting translational impact. We tested independent and interactive effects of preconception and prenatal vitamin D in Black women in relation to positive behavioral and emotional outcomes in early childhood.

METHODS

Black-identifying participants (N = 156) enrolled in the longitudinal Pittsburgh Girls Study (PGS) provided venous blood samples before and during pregnancy to measure 25-hydroxyvitamin D (25[OH]D) levels. Participants completed questionnaires assessing sociodemographic factors, depression severity and life stress, and later reported on child behavioral and emotional problems and prosocial behavior between 2 and 4 years.

RESULTS

Mean serum 25(OH)D concentrations were 15.5 ng/ml (s.d. = 7.7) before pregnancy and 18.0 ng/ml (s.d. = 9.2) during pregnancy; below the sufficiency threshold according to commonly used dietary guidelines. After adjusting for covariates, prenatal 25(OH)D was negatively related to behavior problems and positively related to prosocial behavior in children, although the association attenuated for behavior problems after accounting for preconception 25(OH)D, which may reflect patterns of stability. Maternal 25(OH)D was unrelated to child emotional problems, and no synergistic effects of 25(OH)D timing were observed for any child outcome.

CONCLUSIONS

Findings have relevance for Black women living in the northeast U.S. Results suggest specific associations between maternal vitamin D and positive behaviors in early childhood, regardless of sufficiency levels and suggest potential opportunities for early interventions to support healthy child development.

High-dose vitamin D3 supplementation in pregnancy and risk of neurodevelopmental disorders in the children at age 10: A randomized clinical trial

BACKGROUND

Vitamin D deficiency in pregnancy may increase the risk of autism and attention deficit hyperactivity disorder (ADHD).

OBJECTIVE

The objective of this study was to estimate the effect of vitamin D3 supplementation in pregnancy on risk of autism and ADHD.

DESIGN

This randomized clinical trial was part of the COpenhagen Prospective Study on Neuro-PSYCHiatric Development (COPYCH) project nested within the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010) cohort comprising a population-based sample of 700 healthy mother-child pairs enrolled at week 24 of pregnancy. Maternal 25-hydroxy-vitamin D (25(OH)D) was measured at inclusion and 623 mothers were randomized 1:1 to either high-dose (2800 IU/d) or standard dose (400 IU/d) vitamin D3 until 1 wk postpartum (315 received high-dose, 308 standard dose). At age 10, diagnoses and symptom load of autism and ADHD, respectively, were established using the Kiddie-Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version.

RESULTS

The psychopathologic evaluation was completed by 591 children aged 10 y, and 16 children (2.7%) were diagnosed with autism and 65 (11.0%) with ADHD. Hereof, 496 children participated in the vitamin D3 trial (246 received high-dose, 250 standard dose). Of these, 12 children (2.4%) were diagnosed with autism and 58 (11.7%) with ADHD. Higher maternal preintervention 25(OH)D levels were associated with a decreased risk of autism [odd ratio (OR) per 10 nmol/L: 0.76 (0.59,0.97); P = 0.034], lower autistic symptom load [β per 10 nmol/L: -0.03 (-0.05,0.00); P = 0.024), and decreased risk of ADHD diagnosis (OR per 10 nmol/L: 0.88 (0.78,0.99); P = 0.033]. High-dose vitamin D3 supplementation was not associated with risk of autism or ADHD.

CONCLUSIONS

Higher maternal preintervention 25(OH)D was associated with a decreased risk of autism, lower autistic symptom load, and decreased risk of ADHD diagnosis, but high-dose vitamin D3 supplementation in pregnancy had no effect on risk of autism and ADHD. This trial was registered at clinicaltrials.gov as NCT00856947.

Maternal vitamin D status and attention deficit hyperactivity disorder (ADHD), an under diagnosed risk factor; A review

Vitamin D is important to mediate several brain processes such as proliferation, apoptosis, and neurotransmission in early stages of life. Vitamin D deficiency during critical periods of development can lead to persistent brain alterations. Vitamin D homeostasis during pregnancy is affected by two factors which includes an increase in mother’s calcitriol levels and an increase in mother’s Vitamin D Binding protein concentrations. Attention deficient hyperactivity disorder (ADHD) is an outcome of a complicated interaction between genetic, environmental, and developmental traits, and genetic factors cover about 80% of the cases. The efficiency of the immune system can be altered by a deficiency of Vitamin D in maternal body and maternal stress during gestation such as perinatal depression. Studies have proved that during gestation if there is a deficiency of vitamin D in maternal body, it can influence the brain development of the fetus and can also alter the synthesis of the brain-derived neurotropic factor. The current manuscript has been compiled to elaborate different factors which are associated with ADHD particularly focusing on the relationship of vitamin D deficiency in mothers. References material was selected from NCBI (PUBMED), Science direct, Google scholar, Publons etc. Using the terms ADHD, Vitamin D and Maternal nutritional status. Although, controversial relationship was found between the deficiency of Vitamin D level in pregnant women and development of ADHD in children but more controlled trials are required for future direction as well as to rule out other associated causes.

"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.

CYP24A1 is associated with fetal mummification in pigs

Mummified piglets are among the leading causes of fertility loss and severely hamper reproductive performance in pigs. However, the contributions of genomic variation to the emergence of mummified piglets (MUM) have rarely been studied. This study aims to (1) elucidate the genetic architecture of MUM in sows of parity 1 - 3 using a single-step genome-wide association study (ssGWAS). The ssGWAS involved genotyping-by-sequencing of Large White and Landrace pig breeds. (2) Explore the biological role of the candidate genes at the cellular level. A total of 185 and 48 genome-wide significant SNPs are associated with MUM in Large White and Landrace pigs, explaining 0.01-36.52% genetic variance for different significant loci, respectively. All the significant SNPs are parity-specific, and the numerous, consecutive significant loci likely generated the nine significant peaks in different parities. Multiple candidate genes (including CYP24A1, FBXO30, and ARHGEF28) are associated with fetal congenital and maternal diseases. Collectively, CYP24A1 regulation contributes to steady-state levels of embryo development genes. CYP24A1 is involved in reproduction and, immune and gestational disorders. Thus, it is associated with known newborn death traits and MUM in Large White sows. Altogether, these results improve the current understanding of the genetic architecture of MUM and expand the knowledge on genetic variations for selecting against mummified piglets in pig breeding.

Maternal vitamin D deficiency in early pregnancy and perinatal and long-term outcomes

Background

Vitamin D deficiency is common in pregnant women. Some studies have linked vitamin D deficiency to obstetric complications such as gestational hypertension, gestational diabetes, and preterm birth. Therefore, the objective of this study is to investigate the potential impact of vitamin D deficiency during pregnancy on both perinatal and long-term outcomes.

Methods

In this retrospective study, conducted between 2017 and 2021, we analyzed the data of 1079 singleton pregnant women with no medical or surgical complications prior to pregnancy. We evaluated obstetric and perinatal outcomes, as well as neurodevelopmental outcomes using Bayley-III tests, Gross Motor Function Measure, or chart review.

Results

The maternal serum vitamin D level in the first trimester was 18.2 ± 9.0 ng/mL. Vitamin D deficiency (<20 ng/mL) was found in 308 (62.0%) women in the first trimester, of which 288 women (26.7%) were in the very deficient group (<10 ng/mL). There were no differences in maternal age, body mass index, and previous preterm birth between the group with vitamin D < 10 ng/mL and ≥10 ng/mL group. There were also no differences in the rates of gestational hypertension, gestational diabetes, and preterm birth between the two groups, except for the rate of preterm birth before 37 weeks of gestation, which was significantly higher in the very deficient group (adjusted odds ratios [aOR] = 7.78, 95%CI [2.23-27.12], p = 0.001). In the very deficient group, the risk of developmental delay was also higher (aOR = 4.28, 95%CI [1.40-13.05], p = 0.011).

Conclusions

This is the first study to analyze the effects of maternal vitamin D deficiency during pregnancy on both long-term developmental outcomes and perinatal prognosis. Vitamin D deficiency, defined as a level lower than 10 ng/mL in the first trimester, may increase the risk of preterm birth and developmental delay in children.

Maternal and neonatal blood vitamin D status and neurodevelopment at 24 months of age: a prospective birth cohort study

BACKGROUND

This study aimed to explore the relationship of 25-hydroxyvitamin D [25(OH)D] in three trimesters and at birth with neurodevelopment at 24 months of age.

METHODS

From 2013 to 2016, pregnant women from the Shanghai Birth Cohort in China were recruited for the study. Altogether, 649 mother-infant pairs were included. Serum 25(OH)D was measured with mass spectrometry in three trimesters, and cord blood was divided into deficiency (< 20 and < 12 ng/mL, respectively), insufficiency (20-30 and 12-20 ng/mL, respectively), and sufficiency (≥ 30 and ≥ 20 ng/mL, respectively). Bayley-III scale was used to assess cognitive, language, motor, social-emotional, and adaptive behavior development at 24 months of age. The Bayley-III scores were grouped into quartiles, and scores within the lowest quartile were defined as suboptimal development.

RESULTS

After adjusting for confounding factors, cord blood 25(OH)D in the sufficient group was positively correlated with cognitive [β = 11.43, 95% confidence interval (CI) = 5.65-17.22], language (β = 6.01, 95% CI = 1.67-10.3), and motor scores (β = 6.43, 95% CI = 1.73-11.1); cord blood 25(OH)D in the insufficient group was also positively correlated with cognitive scores (β = 9.42, 95% CI = 3.74-15.11). Additionally, sufficient vitamin D status in the four periods and persistent 25(OH)D ≥ 30 ng/mL throughout pregnancy were associated with a lower risk of suboptimal cognitive development in adjusted models, although the effects were attenuated after applying the false discovery rate adjustment.

CONCLUSIONS

Cord blood 25(OH)D ≥ 12 ng/mL has a significant positive association with cognitive, language, and motor development at 24 months of age. Sufficient vitamin D status in pregnancy might be a protective factor for suboptimal neurocognition development at 24 months of age.

Nutritional factors associated with aggression

Although the vast majority of patients in forensic psychiatry are treated using pharmacological agents, clinical and ethical concerns about their use have led to the consideration of alternative strategies to reduce aggression that is common in forensic psychiatric settings. One non-invasive and benign biologically-based treatment approach involves nutrition. This article provides a mini-review of the recent evidence on four salient nutritional factors associated with aggressive behavior, namely omega-3 fatty acids, vitamin D, magnesium, and zinc. The current evidence base indicates that lower omega-3 levels are associated with increased aggression. Although research on vitamin D and zinc in relation to aggressive behavior is more limited, there is initial evidence that they are negatively associated with aggression in healthy participants and in psychiatric samples. The relationship between magnesium and aggression varies depending on how magnesium is assessed. Findings from experimental trials reveal that nutritional intervention in the form of omega-3 supplementation has the potential to serve as an effective mode of treatment, with effects that can last beyond the intervention period. There is also support for the utility of nutrition to improve our understanding of how social processes are linked to aggression. In light of the nascent, but promising findings on the role of nutritional factors on aggressive behavior, directions for future research are discussed.

Greater Gestational Vitamin D Status is Associated with Reduced Childhood Behavioral Problems in the Environmental Influences on Child Health Outcomes Program

BACKGROUND

Vitamin D deficiency is common in pregnancy. Vitamin D plays an important role in the developing brain, and deficiency may impair childhood behavioral development.

OBJECTIVES

This study examined the relationship between gestational 25(OH)D concentrations and childhood behavior in the Environmental influences on Child Health Outcomes (ECHO) Program.

METHODS

Mother-child dyads from ECHO cohorts with data available on prenatal (first trimester through delivery) or cord blood 25(OH)D and childhood behavioral outcomes were included. Behavior was assessed using the Strengths and Difficulties Questionnaire or the Child Behavior Checklist, and data were harmonized using a crosswalk conversion. Linear mixed-effects models examined associations of 25(OH)D with total, internalizing, and externalizing problem scores while adjusting for important confounders, including age, sex, and socioeconomic and lifestyle factors. The effect modification by maternal race was also assessed.

RESULTS

Early (1.5-5 y) and middle childhood (6-13 y) outcomes were examined in 1688 and 1480 dyads, respectively. Approximately 45% were vitamin D deficient [25(OH)D < 20 ng/mL], with Black women overrepresented in this group. In fully adjusted models, 25(OH)D concentrations in prenatal or cord blood were negatively associated with externalizing behavior T-scores in middle childhood [-0.73 (95% CI: -1.36, -0.10) per 10 ng/mL increase in gestational 25(OH)D]. We found no evidence of effect modification by race. In a sensitivity analysis restricted to those with 25(OH)D assessed in prenatal maternal samples, 25(OH)D was negatively associated with externalizing and total behavioral problems in early childhood.

CONCLUSIONS

This study confirmed a high prevalence of vitamin D deficiency in pregnancy, particularly among Black women, and revealed evidence of an association between lower gestational 25(OH)D and childhood behavioral problems. Associations were more apparent in analyses restricted to prenatal rather than cord blood samples. Interventions to correct vitamin D deficiency during pregnancy should be explored as a strategy to improve childhood behavioral outcomes.

Maternal Vitamin D Levels during Pregnancy and Offspring Psychiatric Outcomes: A Systematic Review

Prenatal exposure to vitamin D may play a significant role in human brain development and function. Previous epidemiological studies investigating the associations between maternal vitamin D status and offspring developmental and psychiatric outcomes in humans have been inconclusive. We aimed to systematically assess the results of previously published studies that examined the associations between maternal vitamin D levels, measured as circulating 25(OH)D levels in pregnancy or at birth, and offspring neuropsychiatric and psychiatric outcomes. Systematic searches were conducted using MEDLINE, Embase, PsychINFO and Web of Science for studies published by 10 August 2022. We included human observational studies that examined associations between prenatal or perinatal vitamin D levels and offspring neuropsychiatric and psychiatric outcomes and were published in English in peer-reviewed journals. Of the 3729 studies identified, 66 studies were screened for full texts and 29 studies published between 2003 and 2022 were included in the final review. There was a small amount of evidence for the association between prenatal vitamin D deficiency and autism spectrum disorder. When studies with larger sample sizes and stricter definitions of vitamin D deficiency were considered, positive associations were also found for attention-deficit/hyperactivity disorder and schizophrenia. Future studies with larger sample sizes, longer follow-up periods and prenatal vitamin D assessed at multiple time points are needed.

The role of nutrients in human neurodevelopment and their potential to prevent neurodevelopmental adversity

Nutritional deficits or excesses affect a huge proportion of pregnant women worldwide. Maternal nutrition has a significant influence on the fetal environment and can dramatically impact fetal brain development. This paper reviews current nutritional supplements that can be used to optimise fetal neurodevelopment and prevent neurodevelopmental morbidities, including folate, iodine, vitamin B12, iron, and vitamin D. Interestingly, while correcting nutritional deficits can prevent neurodevelopmental adversity, overcorrecting them can in some cases be detrimental, so care needs to be taken when recommending supplementation in pregnancy. The potential benefits of using nutrition to prevent neurodiversity is shown by promising nutraceuticals, sulforaphane and creatine, both currently under investigation. They have the potential to promote improved neurodevelopmental outcomes through mitigation of pathological processes, including hypoxia, inflammation, and oxidative stress. Neurodevelopment is a complex process and whilst the role of micronutrients and macronutrients on the developing fetal brain is not completely understood, this review highlights the key findings thus far.

Circulating levels of maternal vitamin D and risk of ADHD in offspring: results from the Vitamin D Antenatal Asthma Reduction Trial

BACKGROUND

Low levels of circulating 25-hydroxy-vitamin D [25(OH)D] have been shown to associate with prevalent attention-deficit/hyperactivity disorder (ADHD), but few studies have examined the association between 25(OH)D during fetal development and risk of childhood ADHD.

METHODS

Maternal plasma 25(OH)D was measured at 10-18 and 32-38 weeks of gestation, with sufficiency defined as 25(OH)D ≥ 30 ng/ml. Offspring ADHD status between ages 6-9 years was measured by parent report of clinical ADHD diagnosis among 680 mother-child pairs from the Vitamin D Antenatal Asthma Reduction Trial. Association between maternal 25(OH)D and child ADHD was assessed using logistic regression, adjusting for maternal age, race and ethnicity. Effect modification by offspring sex was also assessed.

RESULTS

No associations between maternal 25(OH)D at 10-18 weeks of gestation and offspring ADHD were observed. In the third trimester, we observed associations between maternal vitamin D sufficiency and offspring ADHD [odds ratio (OR) 0.47, 95% confidence interval (CI) 0.26-0.84], in addition to maternal 25(OH)D sufficiency category, comparing the deficient (OR 0.34, 95% CI 0.12-0.94), insufficient (OR 0.41, 95% CI 0.15-1.10) and sufficient (OR 0.20, 95% CI 0.08-0.54) categories against highly deficient 25(OH)D, respectively. Stratified analyses revealed a protective association for sufficient maternal 25(OH)D and child ADHD among males (OR 0.47, 95% CI 0.23-0.94); the synergy index for additive effect modification of risk was 1.78 (95% CI 0.62-5.08).

CONCLUSIONS

Higher levels of maternal vitamin D in the third trimester are associated with lower risk of ADHD in offspring, with modest evidence for a stronger effect among male offspring. However, larger studies will be necessary to confirm these findings.

Comparison of Vitamin D, Neurofeedback, and Neurofeedback Combined with Vitamin D Supplementation in Children with Attention-Deficit/Hyperactivity Disorder

BACKGROUND

Nowadays, some treatments such as neurofeedback and Vitamin D Supplementation are of great importance in the treatment of attention-deficit/hyperactivity disorder (ADHD). To determine the efficacy of the combined treatment, the present trial was conducted to investigate the effectiveness of each one of them with combined neurofeedback and vitamin D supplementation in the reduction of ADHD symptom in children suffering from this disorder.

METHODS

In this study from March 2020 to June 2020, we enrolled a total of 120 patients (6-15 years old) who were referred to the Mehr psychiatric hospital (affiliated to Lorestan University of Medical Sciences). Patients were then randomly categorized into three experimental groups and one control group. The first, the second, and the third experimental groups consumed vitamin D pearl, neurofeedback combined with vitamin D, and neurofeedback for 12 weeks, respectively. The control group was given no treatment. Vitamin D serum level was evaluated at baseline, 4, 8, and 12 weeks in all participants. For data collection, the Parent Attention-Deficit/Hyperactivity Disorder Rating Scale-IV (ADHD-RS-IV) was applied. The obtained information was analyzed using repeated measure variance analysis.

RESULTS

The mean scores were significantly different across the groups. Repeated measure variance analysis showed that the mean score was lower in the combined group in comparison with the other three groups (P<0.05).

CONCLUSION

Combined treatment could be considered as more effective compared to separate treatments. In addition, in this study, by applying the combined intervention, the duration of treatment decreased significantly.

Prenatal maternal and cord blood vitamin D concentrations and negative affectivity in infancy

Higher maternal vitamin D concentration during pregnancy is associated with better child mental health. Negative affectivity, an early-emerging temperamental trait, indicates an increased risk of psychopathology. We investigated if maternal early/mid-pregnancy 25-hydroxyvitamin D (25(OH)D) and neonatal cord blood 25(OH)D concentrations are associated with Negative affectivity in infancy. We studied term-born infants from the vitamin D Intervention in Infants study (VIDI, n = 777, follow-up rate 80%, Finland), and the Generation R Study (n = 1505, follow-up rate 40%, Netherlands). We measured maternal serum 25(OH)D at 6-27 weeks (VIDI) or 18-25 weeks (Generation R) of pregnancy, and cord blood 25(OH)D at birth (both cohorts). Caregivers rated infant Negative affectivity at 11.7 months (VIDI) or 6.5 months (Generation R) using the Revised Infant Behavior Questionnaire. Using linear regression, we tested associations between 25(OH)D and Negative affectivity adjusted for infant age, sex, season of 25(OH)D measurement, maternal age, education, smoking, and body-mass-index. Per 10 nmol/l increase in maternal early/mid-pregnancy 25(OH)D, infant Negative affectivity decreased by 0.02 standard deviations (95% confidence interval [CI] - 0.06, - 0.004) in VIDI, and 0.03 standard deviations (95% CI - 0.03, - 0.01) in Generation R. Cord blood 25(OH)D was associated with Negative affectivity in Generation R (- 0.03, 95% CI - 0.05, - 0.01), but not VIDI (0.00, 95% CI - 0.02, 0.02). Lower maternal 25(OH)D concentrations were consistently associated with higher infant Negative affectivity, while associations between cord blood 25(OH)D concentrations and Negative affectivity were less clear. Maternal vitamin D status during early- and mid-pregnancy may be linked with early-emerging differences in offspring behavior.

Dr. Sucksdorff et al. Reply

We thank Trivedi et al. for their letter¹ raising valuable questions regarding a clinical viewpoint on the observed association between maternal vitamin D levels in early pregnancy and offspring risk of attention-deficit/hyperactivity disorder (ADHD) in our study.² We are happy that our research has raised discussion and are grateful for the opportunity to reply.

Vitamin D supplementation during pregnancy: an overview

PURPOSE OF REVIEW

Examine recent evidence of randomized controlled trials and meta-analyses regarding the effect of maternal vitamin D status and supplementation over obstetrical and offspring outcomes.

RECENT FINDINGS

Maternal serum 25-hydroxyvitamin [25(OH)D] progressively declines during pregnancy because of fetal physiological demands and adjustments. Vitamin D supplementation during pregnancy in women with low vitamin D status may improve fetal growth and reduce the risks for small-for-gestational-age, preeclampsia, preterm birth, and gestational diabetes. Mothers with sufficient vitamin D levels have offsprings with less enamel defects and less attention deficit and hyperactive disorders and autism. All pregnant women should be supplemented with 600 IU/day of vitamin D3. We discuss evidence indicating that higher vitamin D doses (1000-4000 IU/day) may be convenient to achieve better maternal and infant outcomes. Low maternal vitamin D status during pregnancy may be associated in infants with a higher risk for lower bone mineral content, enamel defects and attention deficit hyperactive disorder.

SUMMARY

Recent evidence from vitamin D intervention studies and meta-analyses of a large number of studies support vitamin D supplementation during pregnancy to improve maternal, fetal and, immediate and later offspring health.

Third trimester maternal vitamin D and early childhood socioemotional development

BACKGROUND

Whether maternal vitamin D affects offspring socioemotional development in early childhood has been underexplored.

OBJECTIVES

This study examined associations between maternal vitamin D during in the 3rd trimester and offspring socioemotional development between 30 and 59 months.

METHODS

Data from 87 maternal-offspring pairs enrolled in the National Children's Study were used. Total plasma maternal vitamin D (25-hydroxyergocalciferol + 25-hydroxycholecalciferol) was measured between 28 and 35 gestational weeks and categorised as quartiles (Q). Multivariable regression models, adjusting for maternal race/ethnicity, education, and prepregnancy body mass index (BMI [kg/m² ]), were used to estimate the association between vitamin D and offspring scores on the Brief Infant-Toddler Social and Emotional Assessment (BITSEA).

RESULTS

The mean (standard deviation) vitamin D concentration was 86.5 (27.8) nmol/L. The median (range) BITSEA problem score was 6.0 (0.0-30.0), and competence score was 19.0 (7.0-22.0). Maternal vitamin D was inversely related to offspring problem scores. Compared to offspring of women with 25(OH)D in Q1, offspring problem scores were -4.80 (95% confidence interval [CI] -8.29, -1.33) units lower for Q2 vs Q1, -5.64 (95% CI -9.60, -1.68) units lower for Q3 vs Q1, and -4.70 (95% CI -8.59, -0.82) units lower for Q4 vs Q1. Vitamin D was not associated with offspring competence score.

CONCLUSIONS

Higher maternal vitamin D was associated with lower offspring behaviour problems and not associated with socioemotional competence. These data indicate the association of maternal vitamin D and offspring development may be dependent on the specific developmental component being investigated.

Uptake of Vitamins D2, D3, D4, D5, D6, and D7 Solubilized in Mixed Micelles by Human Intestinal Cells, Caco-2, an Enhancing Effect of Lysophosphatidylcholine on the Cellular Uptake, and Estimation of Vitamins D' Biological Activities

Vitamins D have various biological activities, as well as intestinal calcium absorption. There has been recent concern about insufficient vitamin D intake. In addition to vitamins D₂ and D₃, there are lesser-known vitamins D₄–D₇. We synthesized vitamins D₅–D₇, which are not commercially available, and then evaluated and compared the mixed micelles-solubilized vitamins D uptake by Caco-2 cells. Except for vitamin D₅, the uptake amounts of vitamins D₄–D₇ by differentiated Caco-2 cells were similar to those of vitamins D₂ and D₃. The facilitative diffusion rate in the ezetimibe inhibited pathway was approximately 20% for each vitamin D type, suggesting that they would pass through the pathway at a similar rate. Lysophosphatidylcholine enhanced each vitamin D uptake by approximately 2.5-fold. Lysophosphatidylcholine showed an enhancing effect on vitamin D uptake by reducing the intercellular barrier formation of Caco-2 cells by reducing cellular cholesterol, suggesting that increasing the uptakes of vitamins D and/or co-ingesting them with lysophosphatidylcholine, would improve vitamin D insufficiency. The various biological activities in the activated form of vitamins D₄–D₇ were estimated by Prediction of Activity Spectra for Substances (PASS) online simulation. These may have some biological activities, supporting the potential as nutritional components.

Maternal Vitamin D Levels and the Risk of Offspring Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Recent evidence has highlighted the importance of vitamin D in the development of the central nervous system. Some studies have shown an association between maternal vitamin D deficiency during pregnancy and offspring attention-deficit/hyperactivity disorder (ADHD) symptoms based on parent or teacher ratings. There are no previous studies on early pregnancy 25-hydroxyvitamin D [25(OH)D] levels and the risk of diagnosed offspring ADHD. Our aim was to examine maternal 25(OH)D levels in early pregnancy and offspring ADHD.

METHOD

In this nationwide population-based case-control study, 1,067 ADHD cases (born between 1998 and 1999 and diagnosed according to the International Classification of Diseases) and 1,067 matched controls were identified from Finnish registers. Maternal 25(OH)D levels were measured using quantitative immunoassay from maternal sera, collected during the first trimester and archived in the national biobank. Conditional logistic regression was used to examine the association between maternal 25(OH)D and offspring ADHD.

RESULTS

There was a significant association between decreasing log-transformed maternal 25(OH)D levels and offspring ADHD both in the unadjusted analyses (odds ratio 1.65; 95% CI 1.33-2.05; p < .001) and in the analyses adjusting for maternal socioeconomic status and age (odds ratio 1.45; 95% CI 1.15-1.81; p = .002). Analyses by quintiles of maternal 25(OH)D levels in the lowest versus highest quintile revealed an adjusted odds ratio for offspring ADHD of 1.53 (95% CI 1.11-2.12; p = .010).

CONCLUSION

This study demonstrated an association between low maternal 25(OH)D during pregnancy and an elevated risk for offspring ADHD. If replicated in independent samples, this finding may have significant public health implications.

High-Dose Vitamin D Supplementation in Pregnancy and Neurodevelopment in Childhood: A Prespecified Secondary Analysis of a Randomized Clinical Trial

Importance

Observational studies have reported an association between high maternal vitamin D levels and improved neurodevelopment in offspring, but no randomized clinical trial (RCT) has investigated these observations.

Objective

To determine whether high-dose vitamin D supplementation during pregnancy improves offspring neurodevelopment from birth to age 6 years.

Design, Setting, and Participants

This prespecified secondary analysis of a double-blinded, placebo-controlled RCT of high-dose vitamin D3 supplementation vs standard dose during the third trimester of pregnancy was conducted in the unselected prospective mother-child birth cohort at a single-center research unit in Denmark as part of the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC-2010). Participants included pregnant women; women with vitamin D intake greater than 600 IU/d or an endocrine, heart, or kidney disorder, and those who did not speak Danish fluently were excluded. Neurodevelopmental assessments for offspring of these women were performed at ages 0 to 6 years. Children born prematurely (gestational week <37), with low birth weight (<2500 g), or with a neurological disease affecting neurodevelopment were excluded. Data were analyzed from August 2019 to February 2020.

Interventions

High-dose (ie, 2800 IU/d) vs standard dose (ie, 400 IU/d) vitamin D3 supplementation from pregnancy week 24 until 1 week after birth.

Main Outcomes and Measures

The primary outcome of interest was cognitive development assessed at 2.5 years using the Bayley Scales of Infant and Toddler Development. Other neurodevelopmental outcomes included age of motor milestone achievement (Denver Developmental Index and World Health Organization milestone registration), language development (MacArthur-Bates Communicative Development Inventories), general neurodevelopment at age 3 years (Ages and Stages Questionnaire), and emotional and behavioral problems at age 6 years (Strengths and Difficulties Questionnaire).

Results

Among 623 women randomized, 315 were randomized to high-dose vitamin D3 and 308 were randomized to standard dose placebo. A total of 551 children were evaluated from birth to age 6 years, (282 [51.2%] boys; 528 [95.8%] White), with 277 children in the high-dose vitamin D3 group and 274 children in the standard dose group. There was no effect of the high-dose compared with standard dose of vitamin D3 supplementation during pregnancy on offspring achievement of motor milestones (β = 0.08 [95% CI, -0.26 to 0.43]; P = .64), cognitive development (score difference: 0.34 [95% CI, -1.32 to 1.99]; P = .70), general neurodevelopment (median [IQR] communication score: 50 [50-55] vs 50 [50-55]; P = .62), or emotional and behavioral problems (odds ratio, 0.76 [95% CI, 0.53 to 1.09]; P = .14). There was no effect on language development expressed by the word production at 1 year (median [IQR], 2 [0-6] words vs 3 [1-6] words; P = .16), although a decreased word production was apparent at 2 years in children in the high-dose vitamin D3 group (median [IQR], 232 [113-346] words vs 253 [149-382.5] words; P = .02).

Conclusions and Relevance

In this prespecified secondary analysis of an RCT, maternal high-dose vitamin D3 supplementation during the third trimester of pregnancy did not improve neurodevelopmental outcomes in the offspring during the first 6 years of life. These findings contribute essential information clarifying the effects of prenatal exposure to vitamin D on neurodevelopment in childhood.

Trial Registration

ClinicalTrials.gov Identifier: NCT00856947.

Maternal Plasma 25-Hydroxyvitamin D during Gestation Is Positively Associated with Neurocognitive Development in Offspring at Age 4-6 Years

BACKGROUND

Vitamin D is critical to embryonic neuronal differentiation and other developmental processes that may affect future neurocognitive function. However, observational studies have found inconsistent associations between gestational vitamin D and neurocognitive outcomes.

OBJECTIVES

We examined the association of gestational 25-hydroxyvitamin D [25(OH)D] with children's IQ at 4-6 y, and explored whether associations differed by race.

METHODS

This study used data from the CANDLE (Conditions Affecting Neurocognitive Development and Learning in Early Childhood) cohort. Between 2006 and 2011, CANDLE recruited 1503 women in their second trimester of healthy singleton pregnancies. Inclusion criteria for this analysis were gestation of ≥34 wk and availability of 25(OH)D and IQ data. Associations between second-trimester 25(OH)D plasma concentration and Stanford-Binet IQ scores in offspring at 4-6 y were examined using multivariable linear regression; interaction terms were used to explore possible effect modification by race.

RESULTS

Mean ± SD 25(OH)D concentration among 1019 eligible dyads was 21.6 ± 8.4 ng/mL, measured at a mean ± SD gestational age of 23.0 ± 3.0 wk. Vitamin D deficiency [25(OH)D < 20 ng/mL] was observed in 45.6%. Maternal 25(OH)D differed by race with a mean ± SD of 19.8 ± 7.2 ng/mL in Blacks sand 25.9 ± 9.3 ng/mL in Whites ( P  < 0.001). In adjusted models a 10-ng/mL increase in 25(OH)D was associated with a 1.17-point higher Full Scale IQ (95% CI: 0.27, 2.06 points), a 1.17-point higher Verbal IQ (95% CI: 0.19, 2.15 points), and a 1.03-point higher Nonverbal IQ (95% CI: 0.10, 1.95 points). We observed no evidence of effect modification by race.

CONCLUSIONS

Second-trimester maternal 25(OH)D was positively associated with IQ at 4-6 y, suggesting that gestational vitamin D status may be an important predictor of neurocognitive development. These findings may help inform prenatal nutrition recommendations and may be especially relevant for Black and other dark-skinned women at high risk of vitamin D deficiency.

Neurodevelopmental effects of prenatal vitamin D in humans: systematic review and meta-analysis

Diverse studies have investigated the impact of prenatal exposure to vitamin D levels on brain development; however, evidence in humans has never been systematically reviewed. This article summarized evidence of the association between 25-hydroxyvitamin D [25(OH)D] levels in maternal blood in pregnancy or newborn blood at birth and neurodevelopmental outcomes, including cognition, psychomotor performance, language development, behavioral difficulties, attention deficit and hyperactivity disorder (ADHD), and autistic traits. PubMed, Web of Science and SCOPUS databases were systematically searched for epidemiologic studies published through May 2018 using keywords. Random-effects meta-analyses were conducted. Of 260 identified articles, 25 were included in the present review. Comparing the highest vs. the lowest category of prenatal 25(OH)D levels, the pooled beta coefficients were 0.95 (95% CI -0.03, 1.93; p = 0.05) for cognition, and 0.88 (95% CI -0.18, 1.93; p = 0.10) for psychomotor development. The pooled relative risk for ADHD was 0.72 (95% CI, 0.59, 0.89; p = 0.002), and the pooled odds ratio for autism-related traits was 0.42 (95% CI, 0.25, 0.71; p = 0.001). There was little evidence for protective effects of high prenatal 25(OH)D for language development and behavior difficulties. This meta-analysis provides supporting evidence that increased prenatal exposure to 25(OH)D levels is associated with improved cognitive development and reduced risk of ADHD and autism-related traits later in life. Associations represent a potentially high public health burden given the current prevalence of vitamin D deficiency and insufficiency among childbearing aging and pregnant women.

Gut instincts: vitamin D/vitamin D receptor and microbiome in neurodevelopment disorders

The gut microbiome regulates a relationship with the brain known as the gut–microbiota–brain (GMB) axis. This interaction is influenced by immune cells, microbial metabolites and neurotransmitters. Recent findings show gut dysbiosis is prevalent in autism spectrum disorder (ASD) as well as attention deficit hyperactivity disorder (ADHD). There are previously established negative correlations among vitamin D, vitamin D receptor (VDR) levels and severity of ASD as well as ADHD. Both vitamin D and VDR are known to regulate homeostasis in the brain and the intestinal microbiome. This review summarizes the growing relationship between vitamin D/VDR signalling and the GMB axis in ASD and ADHD. We focus on current publications and summarize the progress of GMB in neurodevelopmental disorders, describe effects and mechanisms of vitamin D/VDR in regulating the microbiome and synoptically highlight the potential applications of targeting vitamin D/VDR signalling in neurodevelopment disorders.

Effects of vitamin D deficiency on neurobehavioural outcomes in children: a systematic review

Introduction: Vitamin D plays an important role in brain development in experimental studies; however, the effect of vitamin D deficiency on child development remains inadequately characterized. We aimed to estimate the effects of vitamin D deficiency on neurobehavioural outcomes in children up to 18 years of age. Methods: We searched PubMed, EMBASE, PsycINFO, Scopus, Cochrane Library, Web of Science and Open Grey for published studies up to 10th January 2020. We included all studies that assessed the effects of maternal or child vitamin D status or vitamin D supplementation on neurobehavioural outcomes in children. Study findings were synthesized qualitatively as the high level of heterogeneity in study populations and methodologies precluded a quantitative meta-analysis. Results: Our search identified 5,633 studies, of which 31 studies with 31,375 participants from 18 countries were included in the systematic review. Of the studies identified, one was a randomised controlled trial (RCT) of vitamin D supplementation in children, while 30 were observational. The RCT (n=55) reported a beneficial effect of supplementation with lower doses compared to higher doses of vitamin D on motor development. Twelve mother-child studies (n=17,136) and five studies in children (n=1,091) reported an association between low maternal or child 25-hydroxyvitamin D levels and impaired neurobehavioural outcomes in children, while 15 mother-child studies (n=20,778) and eight studies in children (n=7,496) reported no association. Conclusions: Although animal studies point to an effect of vitamin D deficiency on brain development, there are few studies on the effects of vitamin D deficiency on neurobehavioural outcomes in children and their findings are inconsistent. There is a need for well-conducted, adequately powered studies to further determine these effects in children. Registration: PROSPERO ID CRD42018087619; registered on 15 February 2018.

Effects of vitamin D deficiency on neurobehavioural outcomes in children: a systematic review

Introduction: Vitamin D plays an important role in brain development in experimental studies; however, the effect of vitamin D deficiency on child development remains inadequately characterized. We aimed to estimate the effects of vitamin D deficiency on neurobehavioural outcomes in children up to 18 years of age. Methods: We searched PubMed, EMBASE, PsycINFO, Scopus, Cochrane Library, Web of Science and Open Grey for published studies up to 10th January 2020. We included all studies that assessed the effects of maternal or child vitamin D status or vitamin D supplementation on neurobehavioural outcomes in children. Study findings were synthesized qualitatively as the high level of heterogeneity in study populations and methodologies precluded a quantitative meta-analysis. Results: Our search identified 5,633 studies, of which 32 studies with 31,445 participants from 18 countries were included in the systematic review. Of the studies identified, two were randomized controlled trials (RCTs) of vitamin D supplementation in children, while 30 were observational. One RCT (n=55) reported a beneficial effect of supplementation with lower doses compared to higher doses of vitamin D on motor development while the other RCT (n=70) found no beneficial effect of vitamin D supplementation on cognition in extremely preterm infants. Twelve mother-child studies (n=17,136) and five studies in children (n=1,091) reported an association between low maternal or child 25-hydroxyvitamin D levels and impaired neurobehavioural outcomes in children, while 15 mother-child studies (n=20,778) and eight studies in children (n=7,496) reported no association. Conclusions: Although animal studies point to an effect of vitamin D deficiency on brain development, there are few studies on the effects of vitamin D deficiency on neurobehavioural outcomes in children and their findings are inconsistent. There is a need for well-conducted, adequately powered studies to further determine these effects in children. Registration: PROSPERO ID CRD42018087619; registered on 15 February 2018.

Vitamin D Deficiency in Middle Childhood Is Related to Behavior Problems in Adolescence

BACKGROUND

Vitamin D deficiency (VDD) is associated with depression and schizophrenia in adults. The effect of VDD in childhood on behavioral development is unknown.

OBJECTIVES

We aimed to study the associations of VDD and vitamin D binding protein (DBP) in middle childhood with behavior problems in adolescence.

METHODS

We quantified plasma total 25-hydroxyvitamin D [25(OH)D] and DBP in 273 schoolchildren aged 5-12 y at recruitment into a cohort study in Bogota, Colombia. Externalizing and internalizing behavior problems were assessed after a median 6-y follow-up by parental report [Child Behavior Checklist (CBCL)] and self-report [Youth Self-Report (YSR)]. We estimated mean problem score differences with 95% CIs between exposure categories using multivariable linear regression. We also compared the prevalence of clinical behavior problems (score >63) between exposure groups. We assessed whether the associations between DBP and behavior problems were mediated through VDD.

RESULTS

Mean ± SD CBCL and YSR externalizing problems scores were 56.5 ± 9.3 and 53.2 ± 9.5, respectively. Internalizing problems scores averaged 57.1 ± 9.8 and 53.7 ± 9.8, respectively. VDD [25(OH)D <50 nmol/L] prevalence was 10.3%. VDD was associated with an adjusted 6.0 (95% CI: 3.0, 9.0) and 3.4 (95% CI: 0.1, 6.6) units higher CBCL and YSR externalizing problems scores, respectively, and an adjusted 3.6 (95% CI: 0.3, 6.9) units higher CBCL internalizing problems scores. The prevalence of clinical total externalizing problems was 1.8 (95% CI: 1.1, 3.1) times higher in children with VDD than that in children without VDD. DBP concentration below the population median was related to higher YSR aggressive behavior and anxious/depressed subscale scores and to higher prevalence of clinical total externalizing problems. The associations between DBP and behavior problems were not mediated through VDD.

CONCLUSIONS

VDD and low DBP in middle childhood are related to behavior problems in adolescence.

Maternal circulating Vitamin D3 levels during pregnancy and behaviour across childhood

Vitamin D deficiency during critical periods of development could lead to persistent brain alterations. We aimed to assess the association between maternal vitamin D₃, the major circulatory form of vitamin D, at pregnancy and neurodevelopmental outcomes during childhood, namely: behavioural problems, Attention Deficit and Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) symptoms, and social competence. This study included 2,107 mother-child pairs of a Spanish population-based birth cohort. Maternal plasma vitamin D₃ was measured in pregnancy. The outcomes were measured through questionnaires at 5, 8, 14, and 18 years old. We ran multivariate regression models adjusted for potential confounding variables. We found that per each 10 ng/mL increment of maternal vitamin D₃, children obtained higher social competence scores (coefficient = 0.77; 95% CI = 0.19, 1.35) at 5 years old. However, we observed null associations between maternal vitamin D₃ and total behavioural problems and ADHD and ASD symptoms in children from 5 to 18 years old. Further studies carried out in countries where the population is exposed to lower vitamin D levels are needed.

Neonatal vitamin D levels and cognitive ability in young adulthood

PURPOSE

Intelligence has a strong influence on life capability, and thus, identifying early modifiable risk factors related to cognitive ability is of major public health interest. During pregnancy, vitamin D is transported from the mother to the fetus through the placenta in the form of 25-hydroxyvitamin D (25(OH)D). Levels of 25(OH)D have in some studies been associated with childhood neurodevelopment; however, results from all studies are not in agreement. We investigated if neonatal 25(OH)D₃ concentrations were associated with Børge Priens IQ test score (BPP) in young adulthood.

METHODS

In this nested cohort study, 25(OH)D₃ concentrations were measured in dried blood spots from 818 newborns. We followed the children for their IQ BPP test scores in the Danish Conscription Register, which holds information on test results from the BPP test on individuals who have been recruited for Danish mandatory military draft board examination. Using general linear models, we investigated the crude and adjusted relationship between quintiles of 25(OH)D₃ concentrations and BPP IQ test results.

RESULTS

The study population consisted of 95.8% men, with a mean age of 19.4 years. The median and range of the neonatal 25(OH)D₃ levels were 26.2 nmol/L (0-104.7 nmol/L). The overall Wald test did not show an association between neonatal 25(OH)D₃ levels and BPP IQ scores (p = 0.23); however, individuals within the 3rd (BPP IQ = 101.0, 98.0-103.9) and 4th (BPP IQ = 101.2, 99.1-104.3) quintiles had slightly higher BPP IQ scores than individuals from the first quintile (BPP IQ = 97.6, 94.6-100.6).

CONCLUSIONS

Our results support the hypothesis that individuals with the lowest levels of neonatal vitamin D might have slightly lower BPP. However, more studies are needed with larger study populations to confirm our results.

Association between high levels of inflammatory markers and cognitive outcomes at 4 years of age: The Rhea mother-child cohort study, Crete, Greece

There is growing evidence associating inflammatory markers in complex, higher order neurological functions, such as cognition and memory. We examined whether high levels of various inflammatory markers are associated with cognitive outcomes at 4 years of age in a mother-child cohort in Crete, Greece (Rhea study). We included 642 children in this cross-sectional study. Levels of several inflammatory markers (IFN-γ, IL-1β, IL-6, IL-8, IL-17α, IL-10, MIP-1α, TNF-α and the ratios of IL-6 to IL-10 and TNF-α to IL-10) were determined in child serum via immunoassay. Neurodevelopment at 4 years was assessed by means of the McCarthy Scales of Children's Abilities. Multivariate linear regression analyses were used to estimate the associations between the exposures and outcomes of interest after adjustment for various confounders. Our results indicate that children with high TNF-α concentrations (≥90th percentile) in serum demonstrated decreased scores in memory (adjusted β = -4.0; 95% CI: -7.7, -0.2), working memory (adjusted β = -4.0; 95% CI: -8.0, -0.1) as well as in memory span scale (adjusted β = -4.0; 95% CI: -7.9, -0.1). We also found that children with high IFN-γ serum levels showed lower scores in memory span scale (adjusted β = -3.4; 95% CI: -7.3, -0.4). Children with elevated TNF-α/IL-10 ratio demonstrated decreased quantitative (adjusted β = -4.3; 95% CI: -8.2, -0.4), motor (adjusted β = -3.5; 95% CI: -7.5, -0.5), executive function (adjusted β = -4.8; 95% CI: -8.5, -1.1), general cognitive (adjusted β = -3.6; 95% CI: -7.3, -0.1), memory (adjusted β = -3.8; 95% CI: -7.6, -0), working memory (adjusted β = -3.5; 95% CI: -7.5, -0.5) and memory span scores (adjusted β = -5.3; 95% CI: -9.1, -1.4) The findings suggest that high levels of TNF-α may contribute to reduced memory performance at preschool age.

Child Health: Is It Really Assisted Reproductive Technology that We Need to Be Concerned About?

Concerns remain about the health of children conceived by infertility treatment. Studies to date have predominantly not identified substantial long-term health effects after accounting for plurality, which is reassuring given the increasing numbers of children conceived by infertility treatment worldwide. However, as technological advances in treatment arise, ongoing studies remain critical for monitoring health effects. To study whether the techniques used in infertility treatment cause health differences, however, remains challenging due to identification of an appropriate comparison group, heterogeneous treatment, and confounding by the underlying causes of infertility. In fact, the factors that are associated with underlying infertility, including parental obesity and other specific male and female factors, may be important independent factors to consider. This review will summarize key methodological considerations in studying children conceived by infertility treatment including the evidence of associations between underlying infertility factors and child health.

Vitamin D and health in the Mediterranean countries

Vitamin D, traditionally well known for its role in maintaining optimal health through its contribution to calcium metabolism and skeletal health, has received increased attention over the past two decades, with considerable focus being placed on its nonskeletal benefits. This paper is a narrative review of the nonskeletal health benefits of vitamin D, of particular interest to inhabitants of Mediterranean countries, namely, autism, cancer, cardiovascular disease, chronic obstructive pulmonary disease, dental caries, diabetes mellitus, erectile dysfunction, hypertension, metabolic syndrome, respiratory tract infections, all-cause mortality, and pregnancy and birth outcomes, because of the relatively high incidence and/or prevalence of these disorders in this region. Currently, the best evidence is coming out of observational studies related to serum 25-hydroxyvitamin D [25(OH)D] concentrations. Vitamin D clinical trials have generally been poorly designed and conducted, usually being based on vitamin D dose rather than 25(OH)D concentration. The optimal 25(OH)D concentration is above 75 nmol/l (30 ng/ml), with even better health outcomes in the range of 100-150 nmol/l. Achieving these concentrations with vitamin D₃ supplements will require 1000-4000 IU/day of vitamin D₃. Sensible sun exposure should also be encouraged. Countries should also consider fortifying grain and dairy products with vitamin D₃.

Vitamin D levels in children and adolescents with attention-deficit hyperactivity disorder (ADHD): a meta-analysis

The aim of this article was to assess the differences in serum 25(OH)D levels between children and adolescents with attention-deficit/hyperactivity disorder (ADHD) and healthy controls. We used the PubMed (1966-2017), Scopus (2004-2017), ClinicalTrials.gov (2008-2017), Cochrane Central Register of Controlled Trials CENTRAL (2000-2017), and Google Scholar (2004-2017) databases. Statistical meta-analysis was performed with RevMan 5.3. Εight studies were finally included in the present meta-analysis with a total number of 11,324 children. Among them, 2655 were diagnosed with ADHD, while the remaining 8669 were recruited as healthy controls. All eight trials reported significantly lower serum concentrations of 25(OH)D in patients diagnosed with ADHD compared to healthy controls. The pooled data showed that there was a significant difference between the ADHD group and the control group (SMD = - 0.73, 95% CI [- 1.00, - 0.46]). The systematic review and meta-analysis of observational studies demonstrated an inverse association between serum 25(OH)D and young patients with ADHD. Large cohort studies are required to investigate whether vitamin D-deficient infants are more likely to develop ADHD in the future. Also, whether children with ADHD should be supplemented with higher doses of vitamin D3 remains to be confirmed through long-term controlled clinical trials.

Vitamin D and vitamin D receptor levels in children with attention-deficit/hyperactivity disorder

OBJECTIVE

In this study, we aimed to evaluate vitamin D and vitamin D receptor levels in children with attention-deficit/hyperactivity disorder (ADHD).

PATIENTS AND METHODS

In this cross-sectional study, a total of 80 children including 40 ADHD patients (aged 6-12 years; 28 males and 12 females) and 40 age-, sex-, and season of blood collection-matched controls (aged 6-12 years; 25 males and 15 females) were enrolled. Serum vitamin D and vitamin D receptor levels and calcium, phosphorus, and alkaline phosphatase were measured. The vitamin D receptor levels in the serum were measured using the quantitative sandwich enzyme immunoassay technique.

RESULTS

Serum vitamin D and vitamin D receptor levels were found to be significantly lower in children with ADHD compared to healthy controls. No significant differences were found in serum calcium, phosphorus, and alkaline phosphatase levels. No significant differences were found among the ADHD subtypes in terms of serum vitamin D, vitamin D receptor, calcium, phosphorus and alkaline phosphatase levels.

CONCLUSION

This study suggests that children with ADHD have lower levels of vitamin D and vitamin D receptor. According to the authors' knowledge, this is the first study to describe vitamin D receptor levels in ADHD.