Concentration of 25-hydroxyvitamin D from neonatal dried blood spots and the relation to gestational age, birth weight and Ponderal Index: the D-tect study

Leptin and IGF-1 in Infancy Are Associated With Variants in DHCR7 and CYP2R1 That Relate With Type 1 Diabetes and 25OHD

CONTEXT

Vitamin D has been variably implicated in risk of developing type 1 diabetes based on cohorts of at-risk individuals. Emergent type 1 diabetes in childhood is putatively preceded by altered growth.

OBJECTIVE

We explored whether polymorphisms in vitamin D metabolism genes modify risk of type 1 diabetes via effects on growth in a prospective, population-based cohort of infants.

METHODS

The Cambridge Baby Growth Study enrolled newborns from Cambridgeshire, UK, for follow-up in infancy. In 612 infants, we genotyped single nucleotide polymorphisms in vitamin D metabolism genes that relate with type 1 diabetes: rs10741657 and rs12794714 in CYP2R1, rs12785878 in DHCR7, and rs10877012 in CYP27B1. Multivariate linear regression analyses tested associations between genotypes and anthropometric indices (weight, length, and skinfold thickness) or growth-related hormones (C-peptide, IGF-1, and leptin) in infancy.

RESULTS

Birth weight showed borderline associations with the diabetes risk-increasing alleles in CYP2R1, rs10741657 (β = -.11, P = .02) and rs12794714 (β = -.09, P = .04). The risk-increasing allele rs12794714 was also associated with higher IGF-1 levels at age 24 months (β = .30, P = .01). At age 3 months, the risk-increasing allele rs12785878 in DHCR7, known to negatively associate with 25-hydroxyvitamin D levels, showed a positive association with leptin levels (β = .23, P = .009), which was pronounced in girls (P = .004) vs boys (P = .7).

CONCLUSION

The vitamin D metabolism genes DHCR7 and CYP2R1 might influence infancy leptin and IGF-1 levels respectively. These findings open the possibility for a developmental role of vitamin D that is mediated by growth-related hormones with implications for the onset of type 1 diabetes autoimmunity.

Genetic correlates of vitamin D-binding protein and 25-hydroxyvitamin D in neonatal dried blood spots

The vitamin D binding protein (DBP), encoded by the group-specific component (GC) gene, is a component of the vitamin D system. In a genome-wide association study of DBP concentration in 65,589 neonates we identify 26 independent loci, 17 of which are in or close to the GC gene, with fine-mapping identifying 2 missense variants on chromosomes 12 and 17 (within SH2B3 and GSDMA, respectively). When adjusted for GC haplotypes, we find 15 independent loci distributed over 10 chromosomes. Mendelian randomization analyses identify a unidirectional effect of higher DBP concentration and (a) higher 25-hydroxyvitamin D concentration, and (b) a reduced risk of multiple sclerosis and rheumatoid arthritis. A phenome-wide association study confirms that higher DBP concentration is associated with a reduced risk of vitamin D deficiency. Our findings provide valuable insights into the influence of DBP on vitamin D status and a range of health outcomes.

Impact of vitamin D on maternal and fetal health: A review

The role of vitamin D in improving maternal health and reducing the risk of developmental disorders in fetus has been an important domain of research since the past few years. Vitamin D, owing to its immunomodulatory, anti-inflammatory, developmental roles, and regulating calcium homeostasis, is predicted to have a significant influence on maternal and fetal health status. Several observational studies and clinical trials, determining the impact of vitamin D on gestational diabetes, C-section, postpartum depression, pre-eclampsia, miscarriages, and preterm delivery, have been elaborated in this review. In addition, fetal birth defects including neurological development, reduced birth weight, respiratory infections, bone development, and altered anthropometrics have also been summarized with available evidences. Other important mechanisms related to the roles of vitamin D in the body are also explained. Furthermore, recent studies determining the effect of vitamin D at genetic level will also help in understanding and future design of research in the area of maternal and fetal health.

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.

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 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.

Prevalence and Correlates of Vitamin D Deficiency among Young South African Infants: A Birth Cohort Study

Early-life vitamin D deficiency is associated with adverse child health outcomes, but the prevalence of vitamin D deficiency and its correlates in infants remains underexplored, particularly in sub-Saharan Africa. We aimed to investigate the prevalence of vitamin D deficiency and its correlates among young infants in South Africa. This study included 744 infants, aged 6–10 weeks from the Drakenstein Child Health Study, a population-based birth cohort. Infants were categorized into distinct categories based on serum 25(OH)D concentration level including deficient (<50 nmol/L), insufficient (50–74 nmol/L), and sufficient (≥75 nmol/L). Using multivariable Tobit and logistic regression models, we examined the correlates of serum 25(OH)D₃ levels. The overall prevalence of vitamin D deficiency was 81% (95% confidence intervals (CI]) 78–83). Multivariable regression analysis showed that serum 25(OH)D₃ concentration was independently associated with study site, socioeconomic status, and sex. Birth in winter and breastfeeding were the strongest predictors of lower serum 25(OH)D₃ concentration levels. Compared to non-breastfed children, children breastfed were at higher risk of vitamin D deficiency (AOR, 1.96; 95% CI, 1.04–3.67) and breastfeeding for more than one month was associated with greater likelihood of vitamin D deficiency (AOR, 5.40; 95% CI, 2.37–12.32) and lower vitamin D concentrations (−16.22 nmol/L; 95% CI, −21.06, −11.39). Vitamin D deficiency in infants is ubiquitous, under-recognised, and strongly associated with season of birth and breastfeeding in this setting. Nutritional interventions with vitamin D supplementation in national health programs in low- and middle-income countries are urgently needed to improve early-life vitamin D status in infants.

Failure of national antenatal vitamin D supplementation programme puts dark skinned infants at highest risk: A newborn bloodspot screening study

OBJECTIVES

To determine the prevalence of vitamin D deficiency on dried blood spots (DBS) obtained at newborn blood spot screening (NBS) and thereby test the efficacy of the UK national antenatal supplementation programme in an increasingly ethnically diverse English population. To evaluate the seasonal and ethnic variation in neonatal plasma 25 hydoxyvitamin D (25OHD) and its determinants.

DESIGN

Three thousand random DBS samples received at a single regional newborn screening laboratory (52° N) over two one-week periods, one in winter (February 2019) and one in summer (August 2019), were collected. Data was collected from NBS cards on birth weight, gestational age, maternal age, ethnicity, and post code which was replaced with index of multiple deprivation (IMD). 25OHD concentrations were measured on 6 mm sub-punch from DBS using quantitative liquid chromatography tandem mass spectrometry adjusted to equivalent plasma values. 25OHD variation with season was assessed using Mann-Whitney U test and ethnic groups compared using Kruskal-Wallis test. Linear regression was used to assess the determinants of 25OHD concentrations.

RESULTS

25OHD measurements were available in 2999 (1580 males) subjects [1499 winter-born and 1500 summer-born]. The majority were white British (59.1%) and born at term (mean ± SD gestational age of 38.8 ± 1.8 weeks) with a mean (±SD) birth weight of 3306 (±565) grams. The overall prevalence of vitamin D deficiency [25OHD<30 nmol/L (12 μg/L)] was 35.7% (n = 1070) and insufficiency [30-50 nmol/L (12-20 μg/L)] 33.7% (n = 1010). The median (IQR) 25OHD concentration was significantly lower in the winter-born compared to summer-born [29.1 (19.8, 40.6) vs 49.2 (34.3, 64.8) nmol/L respectively; p < 0.001]. Across both seasons, when compared to white British babies (41.6 nmol/L), the median 25OHD concentrations were significantly lower in babies of black (30.3 nmol/L; p < 0.001), Asian (31.3 nmol/L; p < 0.001), any other mixed (32.9 nmol/L; p < 0.001), mixed white and black (33.7 nmol/L; p < 0.05) and any other white (37.7 nmol/L; p < 0.05) ethnicity. The proportion of deficiency was also higher in babies of Asian (48%), black (47%) and mixed ethnicity (38-44%) compared to any other white (34%) or white British (30%) ethnicity. Season of birth, ethnicity, gestation and maternal age accounted for almost 24% of the variation in 25OHD concentrations.

CONCLUSION

The current UK antenatal supplementation programme fails to protect newborns from vitamin D deficiency, especially those from minority ethnic groups who are at high risk of vitamin D deficiency. Nearly 70% of all newborns and 85% of winter-borns had 25OHD concentrations below 50 nmol/L (20 μg/L). Almost 50% of babies of Black or Asian origin were deficient at birth, which explains their high risk of hypocalcaemic complications and rickets if left unsupplemented. Our findings call for an immediate review of the delivery of antenatal and infant vitamin D supplementation programmes and implementation of food fortification in the long term.