Neonatal vitamin D status is not associated with later risk of type 1 diabetes: results from two large Danish population-based studies

Insights in Nutrition to Optimize Type 1 Diabetes Therapy

Nutrition is an essential part of therapy for type 1 diabetes and is constantly evolving, offering growing opportunities to prevent this disease, slow down its evolution, and mitigate it. An attempt was made to bring together the current state of knowledge. In the path from the preclinical phase of the disease to its clinical onset, there is a phase known as the "honeymoon period" or partial remission, where different possible dietary options for combatting this disease have been presented. The most commonly used dietary models were compared, and the most frequent co-existing pathologies, such as overweight, non-alcoholic fatty liver disease, dyslipidemia, celiac disease, and metabolic instability, were addressed from their nutritional and dietary perspectives to provide clinicians with an updated framework of knowledge and support researchers in further investigations into the topic. Finally, a glimpse into the possible interplay between nutrition and the gut microbiome, food security, and ultra-processed food is provided. It is hoped that clinicians treating people with type 1 diabetes will be provided with further opportunities for the daily management of their patients through personalized nutrition.

Parental history of psychiatric disorders and risk of type 1 diabetes in the offspring

OBJECTIVE

To examine risk of type 1 diabetes mellitus (T1DM) in the offspring of parents with a psychiatric history at the birth of the child, which would suggest potential shared familial or environmental risk factors between T1DM and psychiatric disorders.

METHODS

We established a cohort including all children born in Sweden in 1997-2016, and their parents. Children were followed up from birth until 31 Dec 2017, using national registers. Relative risk for T1DM was estimated by incidence rate ratios (RR) with 95% confidence intervals (CI), calculated from Poisson regression. We examined psychiatric subtypes, T1DM risk within subgroups and in relation to the timing of exposure.

RESULTS

The study cohort included 1,497,949 children. During follow-up, 7,794 cases of T1DM were identified. Children of mothers with psychiatric disorders at delivery had a higher risk of T1DM (RR 1.10 [95%CI 1.01-1.20]). Psychiatric diagnoses in fathers or assigned after delivery was not associated with increased T1DM risk. The observed association disappeared after adjusting for T1DM in parents; however, remained significant in female offspring. Maternal eating disorder (RR 1.53 [1.17-2.00]) and obsessive-compulsive disorder (RR 1.62 [1.02-2.58]) were associated with offspring T1DM, independent of parental T1DM.

CONCLUSION

Our results do not support a strong genetic link between psychiatric conditions and T1DM. However, the risks of offspring T1DM were increased in subgroups of female offspring and in offspring of mothers with a history of eating disorder or obsessive-compulsive disorder, independent of heredity for T1DM, which may warrant further investigation in future studies.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Vitamin D and ω-3 Polyunsaturated Fatty Acids towards a Personalized Nutrition of Youth Diabetes: A Narrative Lecture

After the discovery of insulin, nutrition has become central in the management of diabetes in order to limit glycemic rise after meals, optimize metabolic control, and prevent complications. Over the past one hundred years, international scientific societies have consecutively refined nutritional needs and optimized food intake for the treatment of diabetes. In particular, over the past century, nutrition applied with pumps for the administration of insulin and continuous glucose monitoring have allowed substantial advancement in the treatment of type 1 diabetes mellitus. The role of some substances, such as vitamin D and n-3 polyunsaturated fatty acids, have been proposed without univocal conclusions, individually or in combination, or in the diet, to improve the nutrition of type 1 and type 2 diabetes. This second condition, which is highly associated with overweight, should be prevented from childhood onwards. Personalized nutrition could bypass the problem, reaching a scientific conclusion on the individual subject. This article focuses on childhood and adolescent diabetes, aims to provide a narrative summary of nutrition over the past century, and promotes the concept of personalized nutrition to pediatricians and pediatric diabetologists as a possible tool for the treatment of type 1 diabetes and the prevention of type 2 diabetes.

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 Deficiency as a Possible Cause of Type 1 Diabetes in Children and Adolescents up to 15 Years Old: A Systematic Review

OBJECTIVE: To evaluate vitamin D ((25OH)D levels) deficiency as a possible cause in the development of DT1 in children and adolescents aged 0-15. METHODS: We searched PubMed/ Medline, EBSCO, and Cochrane Library to identify potentially eligible articles that examine whether low serum 25(OH)D levels are associated with subsequent development of DT1. All type of research designs, including randomized and non-randomized controlled trials, prospective and retrospective cohort studies, case- control and cross-sectional studies with subjects aged ≤15 years old were consider for inclusion. RESULTS: Seven original studies met the entry criteria. Most of these studies found up to 50% lower levels of vitamin D in children with DT1 compared to control group and a significant positive association between vitamin D levels and of the risk of developing DT1. Results of quality assessment demonstrated moderate to high quality of all the studies included. CONCLUSIONS: Vitamin D deficiency may be a possible cause in the development of DT1 in the early years of life and particularly in children with genetic predisposition, whilst the deficiency of vitamin D is a very common occurrence in patients with DT1. Further long-term studies on children are required to determine the role of vitamin D on DT1.

A method to correct for the influence of bovine serum albumin-associated vitamin D metabolites in protein extracts from neonatal dried blood spots

Objective

We developed an assay to measure the concentration of 25 hydroxyvitamin D₂ and D₃ in protein extracts derived from stored neonatal dried blood spots. During this study, we postulated that these samples had been contaminated with exogenous vitamin D metabolites because of the addition of bovine serum albumin (BSA) as part of an extraction step undertaken 7 years earlier. The aim of the current study was to develop methods in order to adjust for this contamination.

Results

We identified between-plate variations in 25 hydroxyvitamin D₂ and D₃ concentrations which suggested the presence of three different BSA batches. Based on repeat extraction (without the addition of BSA) and testing of 395 samples, we developed models to correct for the exogenous 25 hydroxyvitamin D₂ and D_3. The regression models were Diff_25OHD3 = − 8.2 + 1.8* Diff_25OHD2 for low contamination, Diff_25OHD3 = 23.8 + 1.7* Diff_25OHD2 for middle contamination, and Diff_25OHD3 = 14.3 + 3.0* Diff_25OHD2 for high contamination. After these corrections, the three subsamples had comparable distributions within the expected range for both 25 hydroxyvitamin D₂ and D₃.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06077-1.

Vitamin D Concentrations at Birth and the Risk of Rheumatoid Arthritis in Early Adulthood: A Danish Population-Based Case-Cohort Study

Background: Low vitamin D in pregnancy may impair the development of the fetal immune system and influence the risk of later development of rheumatoid arthritis (RA) in the offspring. The aim was to examine whether lower 25-hydroxyvitamin D3 (25(OH)D) concentrations at birth were associated with the risk of developing RA in early adulthood. Methods: This case-cohort study obtained data from Danish registers and biobanks. Cases included all individuals born during 1981−1996 and recorded in the Danish National Patient Register with a diagnosis of RA with age >18 years at first admission. The random comparison consisted of a subset of Danish children. Vitamin D concentrations were measured in newborn dried blood. In total, 805 RA cases and 2416 individuals from the subcohort were included in the final analysis. Weighted Cox regression was used to calculate hazard ratio (HR). Results: The median (interquartile rage (IQR)) 25(OH)D concentrations among cases were 24.9 nmol/L (IQR:15.4;36.9) and 23.9 nmol/L (IQR:13.6;36.4) among the subcohort. There was no indication of a lower risk of RA among individuals in the highest vitamin D quintile compared with the lowest (HRadj.:1.21 (0.90;1.63)). Conclusion: The risk of RA in early adulthood was not associated with vitamin D concentrations at birth.

Immunoreactive Trypsinogen and Free Carnitine Changes on Newborn Screening after Birth in Patients Who Develop Type 1 Diabetes

Are free carnitine concentrations on newborn screening (NBS) 48–72 h after birth lower in patients who develop type 1 diabetes than in controls? A retrospective case-control study of patients with type 1 diabetes was conducted. NBS results of patients from a Sydney hospital were compared against matched controls from the same hospital (1:5). Multiple imputation was performed for estimating missing data (gestational age) using gender and birthweight. Conditional logistic regression was used to control for confounding and to generate parameter estimates (α = 0.05). The Hommel approach was used for post-hoc analyses. Results are reported as medians and interquartile ranges. A total of 159 patients were eligible (80 females). Antibodies were detectable in 86. Median age at diagnosis was 8 years. Free carnitine concentrations were lower in patients than controls (25.50 µmol/L;18.98–33.61 vs. 27.26; 21.22–34.86 respectively) (p = 0.018). Immunoreactive trypsinogen was higher in this group (20.24 µg/L;16.15–29–52 vs. 18.71; 13.96–26.92) (p = 0.045), which did not persist in the post-hoc analysis. Carnitine levels are lower and immunoreactive trypsinogen might be higher, within 2–3 days of birth and years before development of type 1 diabetes as compared to controls, although the differences were well within reference ranges and provide insight into the pathogenesis into neonatal onset of type 1 diabetes development rather than use as a diagnostic tool. Given trypsinogen’s use for evaluation of new-onset type 1 diabetes, larger studies are warranted.

Higher ultraviolet radiation during early life is associated with lower risk of childhood type 1 diabetes among boys

Population-level ecological studies show type 1 diabetes incidence is inversely correlated with ambient ultraviolet radiation (UVR) levels. We conducted a nested case-control study using administrative datasets to test this association at the individual level. Cases (n = 1819) were children born in Western Australia (WA) from 1980-2014, diagnosed with type 1 diabetes at ≤ 16 years. Controls (n = 27,259) were randomly selected from all live births in WA, matched to cases by sex and date of birth. Total ambient erythemal ultraviolet radiation (UVR) doses for each trimester of pregnancy and first year of life were estimated for each individual, using daily NASA satellite data that were date- and geographically-specific. Conditional logistic regression tested the association between UVR dose and case-control status. Type 1 diabetes risk was 42% lower in boys of mothers with third-trimester UVR dose in the highest (compared to the lowest) quartile (p = 0.04). Higher UVR in the first year of life was associated with lower type 1 diabetes risk among boys (p = 0.01). UVR dose was not associated with type 1 diabetes risk in girls. Higher UVR in late pregnancy and early life appear to interact with sex-specific factors to lower type 1 diabetes risk among boys in Western Australia.

Vitamin D concentrations from neonatal dried blood spots and the risk of early-onset type 2 diabetes in the Danish D-tect case-cohort study

AIMS/HYPOTHESIS

The aim of this study was to examine the influence of neonatal vitamin D concentration on the development of early-onset type 2 diabetes in a large population sample.

METHODS

We conducted a case-cohort study utilising data from the Danish biobank and registers. Neonatal vitamin D was assessed measuring 25-hydroxyvitamin D₃ [25(OH)D₃] concentrations on the dried blood spot samples from the Biological Specimen Bank for Neonatal Screening. Cases of type 2 diabetes (n = 731) were retrieved from the Danish National Patient Register for all individuals born in Denmark between 1 May 1981 and 31 December 1992. The sub-cohort (n = 1765) was randomly selected from all children born in the same period. We used a weighted Cox proportional hazard model assessing the hazard of first type 2 diabetes diagnoses by quintiles of 25(OH)D₃ and restricted cubic spline.

RESULTS

The median 25(OH)D₃ concentration (IQR) among cases was 21.3 nmol/l (13.3-34.1) and 23.9 nmol/l (13.7-35.7) in the sub-cohort. There was no indication of a potential lower risk of early-onset type 2 diabetes among individuals in the higher quintile of vitamin D concentration compared with the lowest (HR_crude 0.97 [95% CI 0.71, 1.33] p = 0.85; HR_adjusted 1.29 [95% CI 0.92, 1.83] p = 0.14).

CONCLUSIONS/INTERPRETATION

The results of this study do not support the hypothesis that higher neonatal vitamin D concentrations are associated with a lower risk of early-onset type 2 diabetes in adulthood.

Vitamin D and Calcium in Children 0-36 Months: A Scoping Review of Health Outcomes

METHODS

Updated literature searches were conducted across 5 electronic databases to identify all randomized controlled trials, cohort studies, nested case-control or case-cohort studies, and systematic reviews published after the 2009 U.S. Agency for Healthcare Research and Quality's (AHRQ) evidence report, Vitamin D and Calcium: a Systematic Review of Health Outcomes. In total, 65 studies were summarized and analyzed in the present review.

RESULTS

There was a steady increasing trend in the number of publications reporting outcomes related to skeletal health, growth, and infectious disease from 2008 to 2019, although the number of published vitamin D studies was much larger than calcium studies.

CONCLUSIONS

The data presented in this review can facilitate assessment of the variety of outcomes and the amount of potentially useful literature available for each outcome. The results of this scoping review can be used to guide the undertaking of the subsequent systematic reviews.

Vitamin D levels and risk of type 1 diabetes: A Mendelian randomization study

BACKGROUND

Vitamin D deficiency has been associated with type 1 diabetes in observational studies, but evidence from randomized controlled trials (RCTs) is lacking. The aim of this study was to test whether genetically decreased vitamin D levels are causally associated with type 1 diabetes using Mendelian randomization (MR).

METHODS AND FINDINGS

For our two-sample MR study, we selected as instruments single nucleotide polymorphisms (SNPs) that are strongly associated with 25-hydroxyvitamin D (25OHD) levels in a large vitamin D genome-wide association study (GWAS) on 443,734 Europeans and obtained their corresponding effect estimates on type 1 diabetes risk from a large meta-analysis of 12 type 1 diabetes GWAS studies (Ntot = 24,063, 9,358 cases, and 15,705 controls). In addition to the main analysis using inverse variance weighted MR, we applied 3 additional methods to control for pleiotropy (MR-Egger, weighted median, and mode-based estimate) and compared the respective MR estimates. We also undertook sensitivity analyses excluding SNPs with potential pleiotropic effects. We identified 69 lead independent common SNPs to be genome-wide significant for 25OHD, explaining 3.1% of the variance in 25OHD levels. MR analyses suggested that a 1 standard deviation (SD) decrease in standardized natural log-transformed 25OHD (corresponding to a 29-nmol/l change in 25OHD levels in vitamin D-insufficient individuals) was not associated with an increase in type 1 diabetes risk (inverse-variance weighted (IVW) MR odds ratio (OR) = 1.09, 95% CI: 0.86 to 1.40, p = 0.48). We obtained similar results using the 3 pleiotropy robust MR methods and in sensitivity analyses excluding SNPs associated with serum lipid levels, body composition, blood traits, and type 2 diabetes. Our findings indicate that decreased vitamin D levels did not have a substantial impact on risk of type 1 diabetes in the populations studied. Study limitations include an inability to exclude the existence of smaller associations and a lack of evidence from non-European populations.

CONCLUSIONS

Our findings suggest that 25OHD levels are unlikely to have a large effect on risk of type 1 diabetes, but larger MR studies or RCTs are needed to investigate small effects.

Maternal and Cord Blood 25-Hydroxyvitamin D3 Are Associated with Increased Cord Blood and Naive and Activated Regulatory T Cells: The Barwon Infant Study

Vitamin D has shown immune-modulatory effects but mostly in in vitro and animal studies. Regulatory T cells (Treg) are important for a balanced immune system. The relationship between vitamin D on the number of circulating neonatal Treg is unclear. We sought to investigate the association between maternal and neonatal vitamin D metabolites and cord blood (CB) Treg subsets. In a cohort of Australian infants (n = 1074), recruited using an unselected antenatal sampling frame, 158 mother-infant pairs had data on the following: 1) 25-hydroxyvitamin D₃ (25(OH)D₃) measures in both maternal peripheral blood (28- to 32-wk gestation) and infant CB; 2) proportions (percentage of CD4⁺ T cells) of CB Treg subsets (CD4⁺CD45RA⁺ FOXP3^low naive Treg, and CD4⁺CD45RA^- FOXP3^high activated Treg [aTreg]); and 3) possible confounders, including maternal personal UV radiation. Multiple regression analyses were used. The median 25(OH)D₃ was 85.4 and 50.7 nmol/l for maternal and CB samples, respectively. Higher maternal 25(OH)D₃ levels were associated with increased CB naive Treg (relative adjusted mean difference [AMD] per 25 nmol/l increase: 5%; 95% confidence interval [CI]: 1-9%), and aTreg (AMD per 25 nmol/l increase: 17%; 95% CI: 6-28%). Furthermore, a positive association between CB 25(OH)D₃ levels and CB aTreg (AMD per 25 nmol/l increase: 29%; 95% CI: 13-48%) was also evident. These results persisted after adjustment for other factors such as maternal personal UV radiation and season of birth. 25(OH)D_3, may play a role in the adaptive neonatal immune system via induction of FOXP3⁺ Tregs. Further studies of immune priming actions of antenatal 25(OH)D₃ are warranted.

Vitamin D and Immune Regulation: Antibacterial, Antiviral, Anti-Inflammatory

Regulation of immune function continues to be one of the most well-recognized extraskeletal actions of vitamin D. This stemmed initially from the discovery that antigen presenting cells such as macrophages could actively metabolize precursor 25-hydroxyvitamin D (25D) to active 1,25-dihydroxyvitamin D (1,25D). Parallel observation that activated cells from the immune system expressed the intracellular vitamin D receptor (VDR) for 1,25D suggested a potential role for vitamin D as a localized endogenous modulator of immune function. Subsequent studies have expanded our understanding of how vitamin D exerts effects on both the innate and adaptive arms of the immune system. At an innate level, intracrine synthesis of 1,25D by macrophages and dendritic cells stimulates expression of antimicrobial proteins such as cathelicidin, as well as lowering intracellular iron concentrations via suppression of hepcidin. By potently enhancing autophagy, 1,25D may also play an important role in combatting intracellular pathogens such as M. tuberculosis and viral infections. Local synthesis of 1,25D by macrophages and dendritic cells also appears to play a pivotal role in mediating T-cell responses to vitamin D, leading to suppression of inflammatory T helper (Th)1 and Th17 cells, and concomitant induction of immunotolerogenic T-regulatory responses. The aim of this review is to provide an update on our current understanding of these prominent immune actions of vitamin D, as well as highlighting new, less well-recognized immune effects of vitamin D. The review also aims to place this mechanistic basis for the link between vitamin D and immunity with studies in vivo that have explored a role for vitamin D supplementation as a strategy for improved immune health. This has gained prominence in recent months with the global coronavirus disease 2019 health crisis and highlights important new objectives for future studies of vitamin D and immune function. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A dose-response meta-analysis between serum concentration of 25-hydroxy vitamin D and risk of type 1 diabetes mellitus

It remains debatable whether vitamin D plays any role as a risk factor for type 1 diabetes mellitus (T1DM). We have summarized the effect of circulating 25-hydroxy vitamin D [25(OH)D] concentration on the risk of developing T1DM via a dose-response meta-analysis. We undertook a database search on PubMed, Embase, and Cochrane Library from inception to January 2020. A meta-analysis based on random-effects model was applied. Subgroup analysis and meta-regression were performed to inspect the source of heterogeneity. Dose-response data were examined using the generalized least squares trend estimation method. This study was registered with the PROSPERO (ID: CRD42020166174). In total, 16 studies including 10,605 participants (3913 case patients) were included. The pooled odds ratios (OR) and 95% confidence intervals (95% CI) for the highest versus the lowest 25(OH)D concentration was 0.39 (0.27, 0.57), with a high heterogeneity (I² = 76.7%, P < 0.001). Meta-regression analysis identified latitude (P = 0.02), adjustment for gender (P = 0.001), and 25(OH)D stratification (P < 0.001) as sources of heterogeneity. Furthermore, the nonlinear dose-response analysis determined the OR (95% CI) of T1DM to be 0.91 (0.90, 0.93) per 10 nmol/L increase in the 25(OH)D concentration. A 'U'-shaped association was found between serum 25(OH)D concentration and risk of T1DM. The present study highlights the significant inverse association between the circulating 25(OH)D concentration and the risk of T1DM.

Newborn Screening Samples for Diabetes Research: An Underused Resource

Inborn errors of metabolism and diabetes share common derangements in analytes of metabolic networks that are tested for in newborn screening, usually performed 48-72 h after birth. There is limited research examining the metabolic imprint of diabetes on newborn screening results. This paper aims to demonstrate the links between diabetes, biochemical genetics and newborn screening in investigating disease pathophysiology in diabetes, provide possible reasons for the lack of research in diabetes in newborn screening and offer recommendations on potential research areas. We performed a systematic search of the available literature from 1 April 1998 to 31 December 2018 involving newborn screening and diabetes using OVID, MEDLINE, Cochrane and the PROSPERO register, utilizing a modified extraction tool adapted from Cochrane. Eight studies were included after screening 1312 records. Five studies reanalyzed dried blood spots (DBS) on filter paper cards, and three studies utilized pre-existing results. The results of these studies and how they relate to cord blood studies, the use of cord blood versus newborn screening dried blood spots as a sample and considerations on newborn screening and diabetes research is further discussed. The timing of sampling of newborn screening allows insight into neonatal physiology in a catabolic state with minimal maternal and placental influence. This, combined with the wide coverage of newborn screening worldwide, may aid in our understanding of the origins of diabetes.

Vitamin D effects and endocrine diseases

A lack of vitamin D has been linked to autoimmune diseases including type 1 diabetes, autoimmune thyroiditis and to obesity. The prevalence of vitamin D deficiency is higher in diabetic or obese children and patients with thyroiditis compared to healthy controls. Moreover, low vitamin D values seem to be associated with major complications and poor glycemic control, in particular in obese children. Supplementation with vitamin D, which has immune-regulatory properties, may support our therapies and improve the outcomes in different diseases. Although some studies suggest a possible role of vitamin D in the etiology of autoimmune diseases and obesity, data on supplementation benefits are inconclusive and further studies are needed. In this paper, we focus on the current evidence regarding vitamin D function in endocrine diseases and possible benefits of its supplementation in pediatric age.

Neonatal vitamin D status and risk of childhood epilepsy

OBJECTIVE

Epilepsy is a nervous system abnormality that may be caused by unknown exposures during fetal development. Studies have shown neuroprotective effects of early exposure to vitamin D in other neurological disorders, and seasonal variation in birth of children with epilepsy. We aimed to investigate if neonatal 25(OH)D₃ was associated with risk of childhood epilepsy.

METHODS

This case-cohort study compared neonatal 25(OH)D₃ levels from children with epilepsy (n = 403) and a random selected cohort of controls (n = 1163), assessing the hazard of first epilepsy diagnosis between 1 and 4 years of age from a weighted Cox proportional hazard model. Analyses were adjusted for parental education, maternal age, maternal epilepsy, maternal ethnicity, and gestational age, and additionally for season of birth and smoking during pregnancy.

RESULTS

The mean (standard deviation [SD]) of neonatal 25(OH)D₃ levels were 30.8(19.6) nmol/L among cases and 28.5(19.4) nmol/L among the cohort. The hazard ratio (HR) of epilepsy was in a dose-response pattern higher among children from the highest neonatal 25(OH)D₃ quintiles (P-trend = .004). Results were unchanged after including season of birth in the analysis, where a significantly higher HR of epilepsy was observed among children in the two highest quintiles compared to children in the lowest quintile (Q4: HR_adj  1.62, 95% CI 1.07-2.47 and Q5: HR_adj  1.86, 95% CI 1.21-2.86).

SIGNIFICANCE

In this study, the risk of childhood epilepsy increased with neonatal 25(OH)D₃ categories in a dose-response pattern, suggesting an association between a high neonatal 25(OH)D₃ and the risk of childhood epilepsy. Considering that adjusting for season of birth strengthened the results, we conclude that maternal intake of vitamin D, and not vitamin D from sun exposure, was the vitamin D source associated with epilepsy. Although we cannot, in the present study, control for compounds in the diet like pollutants or heavy metals, which may correlate with dietary vitamin D, future studies investigating fetal origin of epilepsy should focus on compounds correlating with vitamin D.

Vitamin D's Effect on Immune Function

Ever since its discovery by Windhaus, the importance of the active metabolite of vitamin D (1,25-dihydroxyvitamin D₃; 1,25-(OH)2D₃) has been ever expanding. In this review, the attention is shifted towards the importance of the extra-skeletal effects of vitamin D, with special emphasis on the immune system. The first hint of the significant role of vitamin D on the immune system was made by the discovery of the presence of the vitamin D receptor on almost all cells of the immune system. In vitro, the overwhelming effect of supra-physiological doses of vitamin D on the individual components of the immune system is very clear. Despite these promising pre-clinical results, the translation of the in vitro observations to solid clinical effects has mostly failed. Nevertheless, the evidence of a link between vitamin D deficiency and adverse outcomes is overwhelming and clearly points towards avoidance of vitamin D deficiency especially in early life.

Serum 25-hydroxyvitamin D concentration in childhood and risk of islet autoimmunity and type 1 diabetes: the TRIGR nested case-control ancillary study

AIMS/HYPOTHESIS

Our aim was to study the association between serum 25-hydroxyvitamin D (25OHD) concentration and islet autoimmunity and type 1 diabetes in children with an increased genetic risk of type 1 diabetes.

METHODS

Serum samples for 25OHD measurements were obtained in the Trial to Reduce IDDM in the Genetically at Risk (TRIGR) ancillary study (Divia) from children in 15 countries. Case children (n = 244) were defined as having positivity for at least two out of four diabetes-associated autoantibodies measured at any one sample. For each case child, two control children were selected matched for country and date of birth (±1 year) (n = 488). Of the case children, 144 developed type 1 diabetes. Serum 25OHD was measured repeatedly in infancy and childhood and was compared according to age at the first seroconversion (at 6, 12 and 18 months prior to and at seroconversion) and calendar age (0, 6, 12 and 18 months).

RESULTS

In children with islet autoimmunity, mean serum 25OHD concentration was lower 18 months prior to the age of first seroconversion of the case children compared with the control children (57.7 vs 64.8 nmol/l, p = 0.007). In children with type 1 diabetes (n = 144), mean serum 25OHD concentration was lower 18 months prior to the age of the first seroconversion (58.0 vs 65.0 nmol/l, p = 0.018) and at the calendar age of 12 months (70.1 vs 75.9 nmol/l, p = 0.031) than in their control counterparts. Analyses were adjusted for month of sample collection, human leucocyte antigen genotype, maternal type 1 diabetes and sex.

CONCLUSIONS/INTERPRETATION

The results suggest that early postnatal vitamin D may confer protection against the development of type 1 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00179777.

Pathophysiological Role and Therapeutic Implications of Vitamin D in Autoimmunity: Focus on Chronic Autoimmune Diseases

Vitamin D is a pleiotropic secosteroid yielding multiple actions in human physiology. Besides the canonical regulatory activity on bone metabolism, several non-classical actions have been described and the ability of vitamin D to partake in the regulation of the immune system is particularly interesting, though far stronger and convincing evidence has been collected in in vitro as compared to in vivo studies. Whether vitamin D is able to regulate at physiological concentrations the human immune system remains unproven to date. Consequently, it is not established if vitamin D status is a factor involved in the pathogenesis of immune-mediated diseases and if cholecalciferol supplementation acts as an adjuvant for autoimmune diseases. The development of autoimmunity is a heterogeneous process, which may involve different organs and systems with a wide range of clinical implications. In the present paper, we reviewed the current evidences regarding vitamin D role in the pathogenesis and management of different autoimmune diseases.

Type 1 diabetes-early life origins and changing epidemiology

Type 1 diabetes is a chronic, immune-mediated disease characterised by the destruction of insulin-producing cells. Standardised registry data show that type 1 diabetes incidence has increased 3-4% over the past three decades, supporting the role of environmental factors. Although several factors have been associated with type 1 diabetes, none of the associations are of a magnitude that could explain the rapid increase in incidence alone. Moreover, evidence of changing prevalence of these exposures over time is insufficient. Multiple factors could simultaneously explain the changing type 1 diabetes incidence, or the magnitude of observed associations could have been underestimated because of exposure measurement error, or the mismodelling of complex exposure-time-response relationships. The identification of environmental factors influencing the risk of type 1 diabetes and increased understanding of the cause at the individual level, regardless of the ability to explain the changing incidence at the population level, is important because of the implications for prevention.

Geographical variation in the incidence of type 1 diabetes in the Nordic countries: A study within NordicDiabKids

BACKGROUND

The incidence of type 1 diabetes (T1D) is high in the Nordic countries with geographic differences between as well as within countries.

OBJECTIVE

To describe the geographical distribution of the incidence of T1D among children in four Nordic countries, an area where the population is considered genetically similar.

METHODS

Data on children 0 to 14 years of age and diagnosed with T1D 2006 to 2011 was collected from four Nordic national pediatric quality diabetes registries. Data included year of diagnosis (2006-2011), sex, and age at diagnosis. Figures for number of children at risk during 2006 to 2011-as well as total population, proportion with foreign background and size of populated areas of geographic regions-were collected from official statistics.

RESULTS

The total incidence during the study period for all four countries was 35.7/100 000 person years but differed between the countries (range 18.2-44.1; P < .001). The incidence difference between the countries was most obvious in the highest age group, 10 to 14 years of age, whereas there was no difference in the youngest age group 0 to 5 years of age. Iceland had similar incidence in the entire country, whereas the other countries had areas with different incidence. Densely populated areas, such as major cities, had the lowest incidence.

CONCLUSION

The incidence of T1D differed between the Nordic countries and also between the neighboring countries and generally decreased with population density. This indicates that environmental factors may contribute to the level of incidence of T1D.

The serum concentration of βCGRP is novel marker for type 1 diabetes

Objective

Dysregulation of neuropeptides, such as calcitonin gene-related peptide (CGRP) is thought to play significant roles in diabetes. In the present study, we investigated the importance of beta-calcitonin gene related peptide (βCGRP, CALCB) in the development of type 1 diabetes (T1D).

Methods

There were fifty-eight patients with T1D and 320 age and gender-matched healthy controls in Chinese Han population were included, the genotypes of CALCB were analyzed by direct sequencing and the clinicopathologic parameters of patients were also evaluated.

Results

Among the SNPs genotyped, the C allele of CALCB_rs3829220 T (c.224G + 846) and rs382922 C (c.224G + 848) were positively associated with T1D (OR = 2.67 and 3.42, respectively). Serum βCGRP of patients is 1.58 times higher compare to normal control. Immunohistochemistry analysis revealed βCGRP expression in the infiltrating lymphocytes of pancreas from T1D mice as compared to normal control.

Conclusion

Our findings indicate that the presence of βCGRP is a probable molecular basis for the initial events triggered in T1D.

Chances of live birth after exposure to vitamin D-fortified margarine in women with fertility problems: results from a Danish population-based cohort study

OBJECTIVE

To study the association between extra vitamin D from a mandatory margarine fortification program and chance of live birth among infertile women.

DESIGN

Nationwide cohort study.

SETTING

Not applicable.

PATIENT(S)

The study population consisted of 16,212 women diagnosed with infertility from June 1, 1980, to August 31, 1991.

INTERVENTIONS(S)

We took advantage of the mandatory vitamin D fortification program of margarine in Denmark that was abruptly stopped on May 31, 1985. The termination of the vitamin D fortification served as a cutoff point to separate the study population into various exposure groups.

MAIN OUTCOME MEASURE(S)

Odds ratios and 95% confidence intervals for the association between vitamin D exposure status and chance of a live birth within 12, 15, and 18 months after first infertility diagnosis.

RESULT(S)

Women who were diagnosed with infertility during the vitamin D-exposed period had an increased chance of a live birth compared with women diagnosed with infertility during the nonexposed period. For women diagnosed with infertility during the wash-out period, the chance of a live birth was also increased, but somewhat lower. Similar estimates were obtained with longer follow-up, in women with anovulatory infertility, and little seasonal variation was observed when calendar period of conception was applied.

CONCLUSION(S)

Our findings suggest that infertile women exposed to extra vitamin D from a margarine fortification program had an increased chance of live birth compared with women not exposed to extra vitamin D from fortification.

Perinatal Whole Blood Zinc Status and Cytokines, Adipokines, and Other Immune Response Proteins

(1) Background: Zinc is an essential micronutrient and zinc deficiency is associated with immune dysfunction. The neonatal immune system is immature, and therefore an optimal neonatal zinc status may be important. The aim of this study was to investigate the possible association between neonatal whole blood (WB)-Zinc content and several immune markers. (2) Methods: In total, 398 healthy newborns (199 who later developed type 1 diabetes and 199 controls) from the Danish Newborn Screening Biobank had neonatal dried blood spots (NDBS) analyzed for WB-Zinc content and (i) cytokines: Interleukin (IL)-1β, IL-4, IL-6, IL-8, IL-10, IL-12 (p70), interferon gamma, tumor necrosis factor alpha, and transforming growth factor beta; (ii) adipokines: leptin and adiponectin; (iii) other immune response proteins: C-reactive protein (CRP), and mannose-binding lectin (MBL), and soluble triggering receptors expressed on myeloid cells1 (sTREM-1). WB-Zinc content was determined using laser ablation inductively coupled plasma mass spectrometry. For each analyte, the relative change in mean level was modelled by a robust log-normal model regression. (3) Results: No association was found between WB-Zinc content and all the immune response markers in either the unadjusted or adjusted models overall or when stratifying by case status. (4) Conclusions: In healthy Danish neonates, WB-Zinc content was not associated with cytokines, adipokines, CRP, MBL or sTREM, which does not indicate a strong immunological function of neonatal zinc status.

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.

Serum 25-Hydroxyvitamin D Concentrations at Birth in Children Screened for HLA-DQB1 Conferred Risk for Type 1 Diabetes

CONTEXT

Vitamin D has several effects on the immune system that might be of relevance for the pathogenesis of type 1 diabetes (T1D).

OBJECTIVE

To evaluate whether umbilical cord serum concentrations of 25-hydroxy-vitamin D (25[OH]D) differ in children developing either islet autoimmunity (IA) or overt T1D during childhood and adolescence.

DESIGN

Umbilical cord serum samples from 764 children born from 1994 to 2004 with HLA-DQB1 conferred risk for T1D participating in the Type 1 Diabetes Prediction and Prevention Study were analyzed for 25(OH)D using an enzyme immunoassay.

SETTING

DIPP clinics in Turku, Oulu, and Tampere University Hospitals, Finland.

PARTICIPANTS

Two hundred fifty children who developed T1D diabetes at a median age of 6.7 years (interquartile range [IQR] 4.0 to 10.1 years) and 132 additional case children who developed IA, i.e., positivity for multiple islet autoantibodies. Cases were matched for date of birth, gender, and area of birth with 382 control children who remained autoantibody negative. The median duration of follow up was 9.8 years (IQR 5.7 to 13.1 years).

MAIN OUTCOME MEASURE

The median 25(OH)D concentrations.

RESULTS

The median 25(OH)D concentration in cord serum was low [31.1 nmol/L (IQR 24.0 to 41.8); 88% <50 nmol/L], but not statistically different between children who developed T1D or IA and their control groups (P = 0.70). The levels were associated mainly with geographical location, year and month of birth, age of the mother, and maternal intake of vitamin D during pregnancy.

CONCLUSIONS

The 25(OH)D concentrations at birth are not associated with the development of T1D during childhood.

Maternal and Newborn Vitamin D-Binding Protein, Vitamin D Levels, Vitamin D Receptor Genotype, and Childhood Type 1 Diabetes

OBJECTIVE

Circumstantial evidence links 25-hydroxy vitamin D [25(OH)D], vitamin D-binding protein (DBP), vitamin D-associated genes, and type 1 diabetes (T1D), but no studies have jointly analyzed these. We aimed to investigate whether DBP levels during pregnancy or at birth were associated with offspring T1D and whether vitamin D pathway genetic variants modified associations between DBP, 25(OH)D, and T1D.

RESEARCH DESIGN AND METHODS

From a cohort of >100,000 mother/child pairs, we analyzed 189 pairs where the child later developed T1D and 576 random control pairs. We measured 25(OH)D using liquid chromatography-tandem mass spectrometry, and DBP using polyclonal radioimmunoassay, in cord blood and maternal plasma samples collected at delivery and midpregnancy. We genotyped mother and child for variants in or near genes involved in vitamin D metabolism (GC, DHCR7, CYP2R1, CYP24A1, CYP27B1, and VDR). Logistic regression was used to estimate odds ratios (ORs) adjusted for potential confounders.

RESULTS

Higher maternal DBP levels at delivery, but not in other samples, were associated with lower offspring T1D risk (OR 0.86 [95% CI 0.74-0.98] per μmol/L increase). Higher cord blood 25(OH)D levels were associated with lower T1D risk (OR = 0.87 [95% CI 0.77-0.98] per 10 nmol/L increase) in children carrying the VDR rs11568820 G/G genotype (P _interaction = 0.01 between 25(OH)D level and rs11568820). We did not detect other gene-environment interactions.

CONCLUSIONS

Higher maternal DBP level at delivery may decrease offspring T1D risk. Increased 25(OH)D levels at birth may decrease T1D risk, depending on VDR genotype. These findings should be replicated in other studies. Future studies of vitamin D and T1D should include VDR genotype and DBP levels.

Maternal dietary supplement use and development of islet autoimmunity in the offspring: TEDDY study

OBJECTIVE

We investigated the association between maternal use of vitamin D and omega-3 fatty acids (n-3 FAs) supplements during pregnancy and risk of islet autoimmunity (IA) in the offspring.

METHODS

The Environmental Determinants of Diabetes in the Young (TEDDY) Study is prospectively following 8676 children with increased genetic risk for type 1 diabetes in Finland, Germany, Sweden, and the United States. Blood samples were collected every 3 months between 3 and 48 months of age then every 6 months thereafter to determine persistent IA. Duration, frequency, and supplement dose during pregnancy were recalled by mothers at 3 to 4 months postpartum. Cumulative intakes of supplemental vitamin D and n-3 FAs were analyzed as continuous or binary variables. We applied time-to-event analysis to study the association between maternal supplement use and IA, adjusting for country, human leukocyte antigen-DR-DQ genotype, family history of type 1 diabetes and sex. Secondary outcomes included insulin autoantibodies (IAA) or glutamic acid decarboxylase (GADA) as the first appearing autoantibody.

RESULTS

As of February 2018, there were 747 (9.0%) children with IA. Vitamin D supplement intake during pregnancy (any vs none) was not associated with risk for IA (hazard ratio [HR] 1.11; 95% confidence interval [CI] 0.94, 1.31); neither was cumulative vitamin D supplement intake. Supplemental n-3 FA intake was similarly not associated with IA risk (HR: 1.19, 95% CI 0.98, 1.45). Similar lack of association was observed for either IAA or GADA as the first appearing autoantibody.

CONCLUSIONS

The TEDDY cohort showed no evidence of benefit regarding IA risk for vitamin D or n-3 FA supplementation during pregnancy.

The Role of Vitamin D Binding Protein, Total and Free 25-Hydroxyvitamin D in Diabetes

Vitamin D is important for bone health, but may also have extra-skeletal effects. Vitamin D and its binding protein DBP have immunological effects and may therefore be important in the development of type 1 diabetes (T1DM), and low serum levels of 25-hydroxyvitamin D (25(OH)D) are associated with later development of type 2 diabetes (T2DM). However, it has so far been difficult to convincingly show an effect of vitamin D supplementation on prevention or treatment of diabetes. The serum level of 25(OH)D has traditionally been used as a marker of a subject's vitamin D status. This measurement includes both 25(OH)D bound to DBP and albumin as well as the free from of 25(OH)D. However, according to the free hormone hypothesis, the free form is the biologically active. Previously the free form of 25(OH)D had to be calculated based on measurements of 25(OH)D, DBP, and albumin, but recently a method for direct measurement of free 25(OH)D has become commercially available. This is important in clinical conditions where the amount of DBP is affected, and has caused a renewed interest in which vitamin D metabolite to measure in clinical situations. In the present review the relations between DBP, total and free 25(OH)D in T1DM and T2DM are described.

Lack of Association Between Maternal or Neonatal Vitamin D Status and Risk of Childhood Type 1 Diabetes: A Scandinavian Case-Cohort Study

Studies on vitamin D status during pregnancy and risk of type 1 diabetes mellitus (T1D) lack consistency and are limited by small sample sizes or single measures of 25-hydroxyvitamin D (25(OH)D). We investigated whether average maternal 25(OH)D plasma concentrations during pregnancy are associated with risk of childhood T1D. In a case-cohort design, we identified 459 children with T1D and a random sample (n = 1,561) from the Danish National Birth Cohort (n = 97,127) and Norwegian Mother and Child Cohort Study (n = 113,053). Participants were born between 1996 and 2009. The primary exposure was the estimated average 25(OH)D concentration, based on serial samples from the first trimester until delivery and on umbilical cord plasma. We estimated hazard ratios using weighted Cox regression adjusting for multiple confounders. The adjusted hazard ratio for T1D per 10-nmol/L increase in the estimated average 25(OH)D concentration was 1.00 (95% confidence interval: 0.90, 1.10). Results were consistent in both cohorts, in multiple sensitivity analyses, and when we analyzed mid-pregnancy or cord blood separately. In conclusion, our large study demonstrated that normal variation in maternal or neonatal 25(OH)D is unlikely to have a clinically important effect on risk of childhood T1D.

Intake of polyunsaturated fatty acids and risk of preclinical and clinical type 1 diabetes in children-a systematic review and meta-analysis

BACKGROUND/OBJECTIVES

The association between the intake of polyunsaturated fatty acids (PUFAs) and the risk of preclinical and clinical type 1 diabetes (T1D) in children has generated conflicting results. Thus, we aimed to evaluate the definite effects of PUFAs on the risk of preclinical and clinical T1D.

SUBJECTS/METHODS

Three databases were systematically searched up to July 18, 2017 to identify relevant observational studies, without language restriction. Any study included should report the risk of preclinical or clinical T1D in children with PUFAs supplementation compared with the controls, and report relative risks (RRs) or odds ratios (ORs) or provide data for estimation. Pooled RRs (or ORs) with 95% confidence intervals (CI) were calculated using random-effects models irrespective of statistical heterogeneity assessed by I² statistic.

RESULTS

We identified seven studies (three prospective cohort studies and four case-control studies) on PUFAs intake during pregnancy or during early life in children. The pooled RR between the risk of preclinical T1D and n-3 PUFAs supplementation against controls was 0.98 (95%CI, 0.85-1.13), with no heterogeneity. The results were similar after the intake during pregnancy, but not during early life in children (pooled RR, 0.45; 95%CI, 0.21-0.96; P = 0.039). N-3 PUFAs supplementation was not associated with a significant reduction in the risk of clinical T1D in children (pooled RR, 0.87; 95%CI, 0.71-1.08), with substantial heterogeneity(I² = 64.7%). No association was also found between n-6 PUFAs intake and the risk of preclinical (1.07; 0.97-1.017) or clinical T1D (1.05; 0.92-1.20) in children.

CONCLUSIONS

The result of the meta-analysis does not support that n-3 or n-6 PUFAs supplementation in children affects the overall risk of preclinical or clinical T1D. However, n-3 PUFAs intake in early life might reduce the risk of preclinical T1D. Therefore, this finding should be verified by more and well-designed prospective research in the future.

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

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

Plasma 25-Hydroxyvitamin D Concentration and Risk of Islet Autoimmunity

We examined the association between plasma 25-hydroxyvitamin D [25(OH)D] concentration and islet autoimmunity (IA) and whether vitamin D gene polymorphisms modify the effect of 25(OH)D on IA risk. We followed 8,676 children at increased genetic risk of type 1 diabetes at six sites in the U.S. and Europe. We defined IA as positivity for at least one autoantibody (GADA, IAA, or IA-2A) on two or more visits. We conducted a risk set sampled nested case-control study of 376 IA case subjects and up to 3 control subjects per case subject. 25(OH)D concentration was measured on all samples prior to, and including, the first IA positive visit. Nine polymorphisms in VDR, CYP24A, CYP27B1, GC, and RXRA were analyzed as effect modifiers of 25(OH)D. Adjusting for HLA-DR-DQ and ancestry, higher childhood 25(OH)D was associated with lower IA risk (odds ratio = 0.93 for a 5 nmol/L difference; 95% CI 0.89, 0.97). Moreover, this association was modified by VDR rs7975232 (interaction P = 0.0072), where increased childhood 25(OH)D was associated with a decreasing IA risk based upon number of minor alleles: 0 (1.00; 0.93, 1.07), 1 (0.92; 0.89, 0.96), and 2 (0.86; 0.80, 0.92). Vitamin D and VDR may have a combined role in IA development in children at increased genetic risk for type 1 diabetes.

Genetic determinants of serum 25-hydroxyvitamin D concentration during pregnancy and type 1 diabetes in the child

Objective

The in utero environment plays an important role in shaping development and later life health of the fetus. It has been shown that maternal genetic factors in the metabolic pathway of vitamin D associate with type 1 diabetes in the child. In this study we analyzed the genetic determinants of serum 25-hydroxyvitamin D (25OHD) concentration during pregnancy in mothers whose children later developed type 1 diabetes and in control mothers.

Study design

474 mothers of type 1 diabetic children and 348 mothers of non-diabetic children were included in the study. We previously selected 7 single nucleotide polymorphisms (SNPs) in four genes in the metabolic pathway of vitamin D vitamin based on our previously published data demonstrating an association between genotype and serum 25OHD concentration. In this re-analysis, possible differences in strength in the association between the SNPs and serum 25OHD concentration in mothers of type 1 diabetic and non-diabetic children were investigated. Serum 25OHD concentrations were previously shown to be similar between the mothers of type 1 diabetic and non-diabetic children and vitamin D deficiency prevalent in both groups.

Results

Associations between serum 25OHD concentration and 2 SNPs, one in the vitamin D receptor (VDR) gene (rs4516035) and one in the group-specific component (GC) gene (rs12512631), were stronger during pregnancy in mothers whose children later developed type 1 diabetes than in mothers whose children did not (p_interaction = 0.03, 0.02, respectively).

Conclusions

We show for the first time that there are differences in the strength of genetic determinants of serum 25OHD concentration during pregnancy between the mothers of type 1 diabetic and non-diabetic children. Our results emphasize that the in utero environment including maternal vitamin D metabolism should be important lines of investigation when searching for factors that lead to early programming of type 1 diabetes.

Neonatal vitamin D status from archived dried blood spots and future risk of fractures in childhood: results from the D-tect study, a population-based case-cohort study

Background: Whether antenatal and neonatal vitamin D status have clinical relevance in fracture prevention has not been examined extensively, although observational studies indicate that fetal life may be a sensitive period in relation to bone growth and mineralization during childhood.Objective: We examined whether 25-hydroxyvitamin D₃ [25(OH)D₃] concentrations in stored neonatal dried blood spot (DBS) samples are associated with pediatric fracture risk. We hypothesized that in particular, low neonatal vitamin D status may be a risk factor for fracture incidence among children.Design: In a register-based case-cohort study design, the case group was composed of 1039 individuals who were randomly selected from a total of 82,154 individuals who were born during 1989-1999 and admitted to a Danish hospital with a fracture of the forearm, wrist, scaphoid bone, clavicle, or ankle at age 6-13 y. The subcohort was composed of 1600 individuals randomly selected from all Danish children born during 1989-1999. The neonatal 25(OH)D₃ concentrations in DBS samples were assessed by using highly sensitive chromatography-tandem mass spectrometry.Results: The mean ± SD 25(OH)D₃ concentration for all subjects was 27.7 ± 18.9 nmol/L [median (IQR): 23.5 nmol/L (13.3, 37.3 nmol/L)] and showed significant monthly variation (P < 0.0001) with the highest values in July and August. Individuals in the middle quintile of neonatal 25(OH)D₃ had lower odds of sustaining a fracture than did those in the lowest quintile (adjusted OR: 0.75; 95% CI: 0.58, 0.96), but a global test did not show any significant overall association (adjusted P = 0.13).Conclusions: This study suggested that neonatal vitamin D status does not influence subsequent fracture risk in childhood. This is in accordance with studies that report no association between antenatal maternal vitamin D status and childhood fractures. Further studies are needed to examine fracture risk in relation to prenatal vitamin D status in a randomized controlled setting.

25-Hydroxyvitamin D and Peripheral Immune Mediators: Results from Two Nationwide Danish Pediatric Cohorts

(1) Background: We aimed to examine if 25-hydroxyvitamin D (25(OH)D) was related to the peripheral immunological and inflammatory signature both at birth, and in newly diagnosed patients with childhood type 1 diabetes (T1D) and their healthy controls; (2) Methods: The birth cohort consisted of 470 patients and 500 healthy controls. Dried blood samples were collected from the neonates in the period 1981–1999. The newly diagnosed cohort consisted of 460 patients and 453 siblings. Serum samples were collected in the period 1997–2005. A variety of peripheral immune mediators were measured and compared to total 25(OH)D levels (25(OH)D₂ + 25(OH)D₃). For each immune mediator, the relative change (RC) in the mean level was modeled by robust log-normal regression and correction for multiple testing was performed; (3) Results: Two associations were identified; there was a negative association between 25(OH)D (10 nmol/L increase) and leptin (RC (95% confidence interval (CI)), 0.98 (0.96; 1.00)), and a positive association between 25(OH)D (10 nmol/L increase) and the chemokine, chemokine (c-x-c motif) ligand (CXCL) 8 (RC (95% CI), 1.07 (1.01; 1.13)); (4) Conclusion: CXCL8 and leptin have significant associations with levels of 25(OH)D in the newly diagnosed cohort. These results do not indicate a strong influence of 25(OH)D on the peripheral immunological or inflammatory signature.