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

Convergent evidence linking neonatal vitamin D status and risk of neurodevelopmental disorders: a Danish case-cohort study

BACKGROUND

There is growing evidence linking neonatal vitamin D deficiency to an increased risk of schizophrenia, ADHD, and autism spectrum disorder (ASD). The aim of this study was to examine the association between two vitamin D biomarkers (25 hydroxyvitamin D [25(OH)D] and vitamin D-binding protein [DBP], and their related genetic correlates) and the risk of six mental disorders.

METHODS

We used a population-based, case-cohort sample of all individuals born in Denmark between 1981 and 2005. Using Danish health registers with follow-up to Dec 31, 2012, we identified individuals diagnosed with major depressive disorder, bipolar disorder, schizophrenia, ADHD, ASD, and anorexia nervosa based on ICD-10 criteria. Additionally, a random subcohort from the general population was selected. Based on neonatal dried blood spots, we measured concentrations of 25(OH)D and DBP. Our primary analyses were based on hazard ratios (HR) with 95% CI and absolute risks for the six mental disorders according to measured concentrations of 25(OH)D and DBP. As secondary analyses, we examined the association between genetic predictors of 25(OH)D and DBP, and the six mental disorders, and Mendelian randomisation analyses based on published summary statistics for 25(OH)D, DBP, and the six mental disorders. People with lived experience contributed to the development of the guiding hypothesis.

FINDINGS

We used the total population from the iPSYCH2012 design (n=88 764), which included individuals who developed the six mental disorders, major depressive disorder (n=24 240), bipolar disorder (n=1928), schizophrenia (n=3540), ADHD (n=18 726), ASD (n=16 146), anorexia nervosa (n=3643), and the randomly sampled subcohort (n=30 000). Among those who met a range of inclusion criteria (eg, measured 25[OH]D, DBP or genotype, and predominantly European ancestry), we measured 25(OH)D or DBP in 71 793 individuals (38 118 [53·1%] male and 33 675 [46·9%] female); 65 952 had 25(OH)D and 66 797 the DBP measurements. Significant inverse relationships were found between 25(OH)D and schizophrenia (HR 0·82, 95% CI 0·78-0·86), ASD (HR 0·93, 95% CI 0·90-0·96), and ADHD (HR 0·89, 95% CI 0·86-0·92). A significant inverse relationship was found between DBP and schizophrenia (HR 0·84, 95% CI 0·80-0·88). Based on polygenic risk scores, higher concentrations of 25(OH)D (adjusted for DBP) were significantly associated with a reduced risk of both ASD and schizophrenia. Analyses based on Mendelian randomisation provided support for a causal association between both lower 25(OH)D and DBP concentrations and an increased risk of ADHD.

INTERPRETATION

Convergent evidence finds that neonatal vitamin D status is associated with an altered risk of mental disorders. Our study supports the hypothesis that optimising neonatal vitamin D status might reduce the incidence of a range of neurodevelopmental disorders.

FUNDING

The Danish National Research Foundation.

Understanding autism: Causes, diagnosis, and advancing therapies

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition marked by difficulties in social communication, languages, and repetitive behaviors. Its rising prevalence has made it a critical global public health issue. ASD is believed to arise from a combination of genetic and environmental influences. While some gene mutations associated with ASD have been identified, most cases lack clear genetic explanations. Evidence increasingly points to early-life environmental factors as key contributors to ASD, including advanced parental age, maternal diabetes during pregnancy, infections, hormonal imbalances, certain medications, and exposure to air pollution. Currently, ASD diagnosis relies on behavioral assessments, but the absence of specific molecular biomarkers poses significant obstacles to early detection and targeted therapies. Encouragingly, research has identified potential biomarkers, such as neuroimaging classifiers, electroencephalography patterns, eye-tracking data, digital analytics, gene expression profiles, inflammatory and chemokine markers, proteomic and metabolomic profiles, and gut microbiota characteristics. Potential therapeutical strategies under investigation include digital therapies, non-invasive brain stimulation, antioxidants, oxytocin, AVPR1a antagonists, PPAR agonists, and mTOR inhibitors. This review explores ASD across five areas: epidemiological trends, genetic mechanisms, early-life environmental factors and their potential roles, diagnostic biomarkers, and therapeutic approaches.

Modifiable Nutritional Biomarkers in Autism Spectrum Disorder: A Systematic Review and Meta-Analysis of Vitamin D, B12, and Homocysteine Exposure Spanning Prenatal Development Through Late Adolescence

Autism Spectrum Disorder (ASD) has been associated with disruptions in one-carbon metabolism and vitamin D pathways. Nutritional exposures-particularly vitamin D, vitamin B12, and homocysteine-may influence neurodevelopmental outcomes. However, a comprehensive, lifespan-spanning synthesis of these modifiable nutritional biomarkers has not been conducted. This systematic review and stratified meta-analysis critically synthesized data on vitamin D, vitamin B12, and homocysteine to elucidate their relationships with ASD risk and symptomatology. Our central question was: How do levels of vitamin D, vitamin B12, and homocysteine-measured before and after birth-affect the risk, severity, and potential treatment outcomes for ASD? We conducted a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) compliant systematic review and stratified meta-analysis (2015-2025) of 35 studies (11 randomized controlled trials, 24 observational), examining prenatal, neonatal, and postnatal biomarker levels. Eligibility criteria were defined using the PICOS (Population, Intervention, Comparator, Outcome, and Study Design) framework to ensure scientific rigor and clinical relevance, including studies involving human participants aged 0-18 years with a formal Autism Spectrum Disorder (ASD) diagnosis or prenatal exposures potentially linked to later ASD onset, while excluding animal studies, adult-only ASD populations, and studies lacking ASD cohorts or biomarker data. The search strategy, developed according to PRISMA, and Cochrane best practices, encompassed five major databases (PubMed/MEDLINE, Cochrane Library, Google Scholar, ClinicalTrials.gov, and ProQuest) alongside manual searches of key references, grey literature, and clinical trial registries to ensure comprehensive retrieval of both published and unpublished studies. Study quality was assessed using version 2 of the Cochrane risk-of-bias tool for RCTs (RoB2) and the Newcastle-Ottawa Scale (NOS) for observational studies; certainty of evidence was graded via GRADE (Grading of Recommendations Assessment, Development and Evaluation). Random-effects meta-analyses were stratified by biomarker and study design. Heterogeneity, small-study effects, and publication bias were evaluated using Cochran's Q, I2, Egger's test, and trim-and-fill. Prenatal vitamin D deficiency was associated with approximately two-fold increased odds of Autism Spectrum Disorder (ASD) in offspring (pooled OR ≈ 2.0; p < 0.05), while excessively elevated maternal B12 concentrations, often co-occurring with folate excess, were similarly linked to increased ASD risk. Meta-analytic comparisons revealed significantly lower circulating vitamin D (SMD ≈ -1.0; p < 0.001) and B12 levels (SMD ≈ -0.7; p < 0.001), alongside elevated homocysteine (SMD ≈ 0.7; p < 0.001), in children with ASD versus neurotypical controls. Early-life vitamin D/B12 insufficiency and elevated homocysteine are important, modifiable correlates of ASD risk and severity. Adequate maternal and child nutritional status could have risk-reducing and symptom-mitigating effects, although causality remains to be confirmed. This evidence supports tailored nutritional interventions as a component of ASD risk reduction and management strategies, within the bounds of overall developmental healthcare. The article processing charges (APC) were supported by "Dunărea de Jos" University of Galati, Romania. No external funding was received for the execution of the research. The review was not prospectively registered in PROSPERO or any other systematic review registry.

Enhancing the Design of Nutrient Clinical Trials for Disease Prevention-A Focus on Vitamin D: A Systematic Review

OBJECTIVES

This systematic review (SR) highlights principles for nutrient clinical trials and explore the diverse physiological functions of vitamin D beyond its traditional role in the musculoskeletal system related to clinical study designs.

BACKGROUND

Thousands of published research articles have investigated the benefits of vitamin D (a nutrient example taken in this SR) beyond the musculoskeletal system, including the immune, pulmonary, and cardiovascular systems; pregnancy; autoimmune disorders; and cancer. They illustrated vitamin D's molecular mechanisms, interactions, and genomic and nongenomic actions.

METHODS

This SR was designed to identify shortcomings in clinical study designs, statistical methods, and data interpretation that led to inconsistent findings in vitamin D-related publications. SR also highlights examples and insights into avoiding study design errors in future clinical studies, including randomized controlled clinical trials (RCTs). The SR adheres to the latest PRISMA statement, guidelines, and the PICOS process.

RESULTS

Inappropriate or flawed study designs were frequent in clinical trials. Major failures discussed here include too short clinical study duration, inadequate or infrequent doses, insufficient statistical power, failure to measure baseline and achieved levels, and recruiting vitamin D-sufficient participants. These design errors have led to misleading interpretations. Thus, conclusions from such studies should not be generalized or used in guidelines, recommendations, or policymaking.

CONCLUSION

Adequately powered epidemiological studies and RCTs with sufficient vitamin D and duration in individuals with vitamin D deficiency reported favorable clinical outcomes, enriching the literature, enabling to understand its physiology and mechanisms. Proper study designs with rigorous methodologies and cautious interpretation of outcomes are crucial in advancing the nutrient field. The principles discussed apply not only to vitamin D, but also other micro-nutrients and nutraceutical research. Adhering to them enhances the credibility and reliability of clinical trials, SRs, and meta-analysis outcomes. The study emphasizes the importance of focused, hypothesis-driven, well-designed, statistically powered RCTs to explore the diverse benefits of nutrients, conducted in index nutrient deficient participants, and avoidance of study design errors. Findings from such studies should be incorporated into clinical practice, policymaking, and public health guidelines, improving the health of the nation and reducing healthcare costs.

Nested Randomized Controlled Trials in Large Databases: An Opportunity for Inflammatory Bowel Disease?

INTRODUCTION

Although randomized controlled trials (RCTs) are the gold standard for investigating the efficacy and safety of interventions, they present major operational challenges due to their complexity, time-consuming nature, and costs. To address some of these difficulties, RCTs nested in cohorts (RCTsNC) have been developed. The aim was to review the opportunities and challenges of RCTsNC in inflammatory bowel disease (IBD).

METHODS

A literature search was conducted using MEDLINE, Embase, Cochrane and Clinicaltrials.gov from inception until March 2024 to identify studies focusing on this topic.

RESULTS

RCTsNC is an emerging trial design, which has been successfully utilized across several medical disciplines but not IBD. It enables the use of longer-term longitudinal data for safety and efficacy assessment, and enhanced recruitment and follow up processes. Observational data for IBD, derived from research (cohort and case-control studies) and non-research sources (electronic health records and registries), provides access to comprehensive records for a large number of IBD patients, which could present an opportunity to enhance the performance of RCTsNC. Leveraging pre-existing cohorts and their organizational structures improves patient acceptance and is more economical compared to traditional randomized trials. It may permit researchers to address knowledge gaps in IBD (specific sub-populations, or the effect of environmental exposures on disease course). Limitations of RCTsNC include the risk of selection bias and constraints related to comparisons with placebo.

CONCLUSION

RCTsNC offers a promising opportunity for IBD research and provides an alternative study design given the challenges of conventional trial designs in the current IBD RCT landscape.

The Role of Nutrition, Oxidative Stress, and Trace Elements in the Pathophysiology of Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by deficits in social communication and interaction, alongside repetitive behaviors, and atypical sensory-motor patterns. The growing prevalence of ASD has driven substantial advancements in research aimed at understanding its etiology, preventing its onset, and mitigating its impact. This ongoing effort necessitates continuous updates to the body of knowledge and the identification of previously unexplored factors. The present study addresses this need by examining the roles of nutrition, oxidative stress, and trace elements in the pathophysiology of ASD. In this review, an overview is provided of the key dietary recommendations for individuals with ASD, including gluten-free and casein-free (GFCF) diets, ketogenic diets (KDs), and other nutritional interventions. Furthermore, it explores the involvement of oxidative stress in ASD and highlights the significance of trace elements in maintaining neuropsychiatric health. The impact of these factors on molecular and cellular mechanisms was discussed, alongside therapeutic strategies and their efficacy in managing ASD.

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.

Associating prenatal antibiotics exposure with attention deficit hyperactivity disorder symptoms in preschool children: The role of maternal vitamin D

BACKGROUND

The associations between prenatal antibiotics exposure and attention-deficit/hyperactivity disorder (ADHD) in preschoolers, and the role of maternal vitamin D in these associations, remain to be explored.

OBJECTIVES

To evaluate the relationships between multiple maternal urinary antibiotics levels and preschoolers' ADHD symptoms, and to identify the potential modifying effects of maternal vitamin D.

METHODS

Based on a prospective birth cohort, the present study included 2033 motherchild pairs. Maternal urine and serum samples were collected during all three trimesters to measure the urinary concentrations of 43 antibiotics (including two metabolites) and the serum vitamin D levels. The ADHD symptoms of preschoolers were assessed using the Diagnostic and Statistical Manual-oriented ADHD problems scale in the Achenbach Child Behavior Checklist. Multiple informant models in the form of logistic regression were conducted to investigate the associations between prenatal antibiotics exposure and preschooler ADHD symptoms, and these associations were stratified by child sex and maternal vitamin D status.

RESULTS

Compared with the lowest tertile concentrations, maternal exposure to the middle tertile concentrations of doxycycline and human antibiotics/preferred as human antibiotics (HAs/PHAs), and the highest tertile concentrations of doxycycline during the first trimester were associated with an increased risk of ADHD symptoms in children. An increased risk of ADHD symptoms was observed in girls exposed to the highest tertile levels of sulfamethazine during the second trimester. Furthermore, pregnant women with vitamin D deficiency have a greater risk of ADHD symptoms in their offspring after exposure to doxycycline in the first trimester.

CONCLUSIONS

Maternal exposure to doxycycline and HAs/PHAs during the first trimester increases the risk of ADHD symptoms in preschoolers. Mid-pregnancy sulfamethazine exposure increases the risk of ADHD symptoms in girls. Maternal vitamin D deficiency during pregnancy may exacerbate the adverse effects of doxycycline exposure on ADHD symptoms.

The metabolic role of vitamin D in children's neurodevelopment: a network study

Neurodevelopmental disorders are rapidly increasing in prevalence and have been linked to various environmental risk factors. Mounting evidence suggests a potential role of vitamin D in child neurodevelopment, though the causal mechanisms remain largely unknown. Here, we investigate how vitamin D deficiency affects children's communication development, particularly in relation to Autism Spectrum Disorder (ASD). We do so by developing an integrative network approach that combines metabolomic profiles, clinical traits, and neurodevelopmental data from a pediatric cohort. Our results show that low levels of vitamin D are associated with changes in the metabolic networks of tryptophan, linoleic, and fatty acid metabolism. These changes correlate with distinct ASD-related phenotypes, including delayed communication skills and respiratory dysfunctions. Additionally, our analysis suggests the kynurenine and serotonin sub-pathways may mediate the effect of vitamin D on early life communication development. Altogether, our findings provide metabolome-wide insights into the potential of vitamin D as a therapeutic option for ASD and other communication disorders.

Prevalence and Causes of Vitamin D Deficiency in a Cohort of Greek HIV-Infected Individuals: A Prospective, Single Center, Observational Study

BACKGROUND

Vitamin D deficiency and/or insufficiency (hypovitaminosis D) has been associated with several disorders including autoimmune diseases, like type 1 diabetes mellitus; cardiovascular diseases; neoplasms; obesity; insulin resistance, and type 2 diabetes mellitus. This problem is common in southern European countries, especially in elderly and institutionalized persons. In HIV-infected individuals, hypovitaminosis D has been correlated with various complications like tuberculosis, hyperparathyroidism, bone mass loss, premature atherosclerosis, and systemic arterial hypertension, deterioration of immune function, progression of the disease and overall mortality.

OBJECTIVE

The objective of this study was to examine the prevalence and causes of hypovitaminosis D in a cohort of Greek HIV-infected patients, as well as possible complications associated with it.

METHODS

All patients attending our HIV unit for a period of 5 months were included in this study. Vitamin D status, medical anamnes, and laboratory tests were obtained at baseline; patients were followed for 3 years and HIV-related complications were noted. No patient received vitamin D supplementation during the follow-up period.

RESULTS

Hypovitaminosis D was common, with 83.7% of the patients showing levels below 30 ng/dl and 55.4% below 20 ng/dl. After multivariable analysis, age and duration of treatment were the only significant factors for low vitamin D levels. During follow-up, 26 patients exhibited a total of 34 HIV-related complications, the most common being pneumonocystis jiroveci pneumonia (PCP). Hypovitaminosis D showed a positive correlation with overall complications, PCP as well as wasting syndrome.

CONCLUSION

Overall, our study shows that hypovitaminosis D is common in HIV-infected individuals and should probably be treated as soon as possible to protect these patients from serious HIVrelated complications like PCP or wasting syndrome.