Serum Vitamin D levels and gestational diabetes mellitus: analysis of early pregnancy cohort from a teaching hospital of Kashmir Valley

MicroRNA-125b regulates vitamin D resistance by targeting CYP24A1 in the progression of gestational diabetes mellitus

Vitamin D deficiency is prevalent in pregnancy and has been associated with increased occurrences of preeclampsia, cesarean delivery, neonatal bacterial vaginosis, and gestational diabetes. CYP24A1, recognized as a key factor in vitamin D metabolism homeostasis, encodes 24-hydroxylase responsible for converting 25(OH)D3 and 1,25(OH)2D3 into inactive metabolites. Recently, we have reported CYP24A1 overexpression in patients with gestational diabetes mellitus (GDM) and trophoblast cells exposed to hyperglycemia. In this study, we explored miRNA-mediated regulation of CYP24A1 in GDM progression, validating our findings through silencing experiments in a trophoblast cell line. In silico tools identified miR-125b-5p as a putative target of CYP24A1. Expression analysis revealed downregulation of miR-125b-5p in blood samples from early GDM and GDM compared to healthy pregnant women, positively correlating with vitamin D levels. Hyperglycemic exposure in human trophoblastic cell lines (BeWo) decreased miR-125b-5p expression, concomitant with an increase in CYP24A1. To confirm the regulatory role of miR-125b on CYP24A1, we transfected BeWo cells with antimiR-125b or miR-125b mimic. AntimiR-125b transfection heightened CYP24A1 levels, while miR-125b mimic overexpression resulted in decreased CYP24A1 expression. These findings establish miR-125b as a regulator of CYP24A1. To explore the influence of miR-125b on vitamin D metabolism, trophoblast cells overexpressing miR-125b were treated with 0.1 and 1 µM calcitriol. Hyperglycemic conditions exhibited a reduction in CYP24A1 levels. Collectively, our results indicate that miR-125b may regulate vitamin D metabolism by targeting CYP24A1, contributing to GDM progression. These findings may pave the way for understanding vitamin D resistance in concurrent GDM development and identifying novel miRNAs targeting CYP24A1.

Influence of hypovitaminosis D during pregnancy on glycemic and lipid profile, inflammatory indicators and anthropometry of pregnant and newborn

BACKGROUND & AIMS

Hypovitaminosis D currently represents a public health problem and is related to the emergence of chronic diseases. Furthermore, this vitamin deficiency has been associated with pregnancy complications, and it can also influence newborn's growth and development. The purpose of this review is to understand the effects of vitamin D nutritional status on women during pregnancy, as well as its impact on newborn's health.

METHODS

Review of observational studies, published between 2020 and 2021. The research was carried out in the following databases: Pubmed and SciELO. The search terms used to select the articles were: vitamin D, 25(OH)D, serum levels, pregnancy, lactation, gene expression, maternal results, complications, pre-eclampsia, obesity, gestational diabetes, and children. As inclusion criteria, were considered observational studies that addressed the topic and answered the review aims.

RESULTS

52 articles were identified and at the end of the selection process, 19 articles were considered, in which they met all the established eligibility criteria. According to the findings in this review, hypovitaminosis D is related to gestational diabetes, pre-eclampsia and gestational weight gain, changes in laboratory parameters as well as outcomes in newborns.

CONCLUSIONS

Hypovitaminosis D can adversely influence pregnancy and newborn's health, evidencing the need to assess the nutritional status of vitamin D, as well as the existence, or not, of a clinic during pregnancy. It is important that new scientific evidence is published to support this hypothesis.

Impact of maternal hypovitaminosis D on birth and neonatal outcome - a prospective cohort study

OBJECTIVE

Vitamin D deficiency in pregnant women is of special concern as mother is the only source of vitamin D for the developing fetus, and maternal hypovitaminosis D has been implicated in a number of maternal and neonatal adverse outcomes. The objective of this study was to assess the association of maternal circulating 25-hydroxy vitamin D3 [25(OH)D] concentration with cord blood 25(OH)D and adverse birth and neonatal outcomes.

METHODS

This prospective cohort study was conducted in Mahatma Gandhi Medical College and Research Institute (MGMCRI) from January 2020 to December 2020. 121 babies born to mothers with singleton pregnancy tested for serum 25(OH)D level on admission for safe confinement were included in the study and cord blood of the babies were sampled for 25(OH)D. Based on the maternal 25(OH)D level, babies were categorized as those born to mothers with sufficient vitamin D level and those born to mothers with hypovitaminosis D (deficient/insufficient) and primary and secondary outcome was compared between two groups.

RESULTS

Maternal and cord blood hypovitaminosis D was observed in 65% of mothers and 68.6% of babies, respectively. Maternal vitamin D level was the single most significant predictor of cord blood vitamin D level with five-fold increased risk of cord blood hypovitaminosis D in babies born to mothers with hypovitaminosis D. Birthweight (t = -2.219, p = .028) and preterm birth (aOR = 4.417, 95% CI: 1.03-18.9) was significantly associated with maternal hypovitaminosis D and a trend toward increased risk of LBW (aOR - 2.1, 95%CI: 0.6-7.3), SGA babies (aOR - 1.5, 95% CI: 0.5-4.7), perinatal depression (aOR - 1.5, 95% CI: 0.4-5.8) and neonatal hyperbilirubinemia (aOR = 2.68, 95%CI: 0.942-7.6) was observed.

CONCLUSIONS

Hypovitaminosis D in pregnant women is a significant health issue affecting both the mother and her baby. Safest dose for supplementation during pregnancy to prevent adverse perinatal outcome needs to be evaluated.

Association between maternal vitamin D levels and risk of adverse pregnancy outcomes: a systematic review and dose-response meta-analysis

Epidemiological studies have investigated the associations between vitamin D and the risk of adverse pregnancy outcomes; however, the results are conflicting and dose-response relationships remain to be confirmed. This study aimed to summarize previous studies on the associations of vitamin D levels with the risk of gestational diabetes mellitus (GDM), pre-eclampsia (PE), gestational hypertension (GH), and caesarean section (C-section), and to clarify the dose-response trends. PubMed, Embase, Scopus, and Web of Science were searched to identify eligible articles. A total of 69 prospective observational studies including cohort studies, case-cohort studies, or nested case-control studies were included in the current systematic review, of which 68 studies were available for meta-analysis. Compared with the lowest level, the highest level of 25(OH)D was significantly associated with a lower risk of GDM (RR: 0.76; 95% CI: 0.66-0.87), PE (RR: 0.74; 95% CI: 0.60-0.90;), and GH (RR: 0.87; 95% CI: 0.79-0.97); however, no significant relationship was found for C-section (RR: 1.00; 95% CI: 0.90-1.12). There was significant between-study heterogeneity for GDM (I² = 69.2%; P_{heterogeneity} < 0.001), PE (I² = 52.0%; P_{heterogeneity} = 0.001), and C-section (I² = 59.1%; P_{heterogeneity} < 0.001), while no heterogeneity was found for GH (I² = 0.0%; P_{heterogeneity} = 0.676). For each 25 nmol L^-1 increase in 25(OH)D, the pooled RR was 0.92 (95% CI: 0.86-0.97) for GDM and 0.89 (95% CI: 0.84-0.94) for PE, respectively. Notably, the dose-response analysis showed a non-linear relationship between maternal 25(OH)D levels and the risk of PE (P_{non-linearity} = 0.009). Our meta-analysis provides further scientific evidence of the inverse association between 25(OH)D levels and the risk of GDM, PE, and GH, which may be useful for the prevention of pregnancy complications. However, more evidence from prospective studies is needed regarding the dietary intake of vitamin D during pregnancy.

Plasma 25(OH)D Concentrations and Gestational Diabetes Mellitus among Pregnant Women in Taiwan

Vitamin D’s function in the development of gestational diabetes mellitus (GDM) is not consistent in the literature. We examined the association between maternal plasma 25(OH)D concentration and GDM risk. A national cross-sectional study (1497 pregnant women) was conducted between 2017 and 2019 across Taiwan. Blood samples were drawn at recruitment to assess 25(OH)D concentrations, including vitamin D deficiency (VDD) (<20 ng/mL), insufficiency (<32 ng/mL), and sufficiency (≥32 ng/mL). GDM was detected from 24 to 28 weeks of gestation with the results extracted from the antenatal visit records. The prevalence of GDM was 2.9%. Logistic model analysis showed that 25(OH)D concentrations were not significantly associated with the risk of GDM (adjusted odds ratio (AOR) = 0.97, p = 0.144). However, subjects with VDD had a significantly greater risk of GDM (AOR = 2.26, p = 0.041), but not in those with vitamin D insufficiency (AOR = 1.20, p = 0.655). Furthermore, cubic piecewise spline regression was used to explore the relationship between five-unit intervals of 25(OH)D and the predicted probability of GDM. As the proportion of GDM increased for low 25(OH)D concentrations, it decreased at moderate concentrations and increased again at higher concentrations. These findings revealed a nonlinear relationship between 25(OH)D and GDM risk. VDD would be risky for GDM occurrence.

Vitamin D status and vitamin D deficiency risk factors among pregnancy of Shanghai in China

Background

There is increasing awareness that vitamin D deficiency in pregnant women may be associated with several adverse effects for the mother and newborn. The risks for vitamin D deficiency are unclear. This study was to assess vitamin D nutritional status and vitamin D deficiency risk factors among pregnant women in Shanghai in China.

Methods

This study is a cross-sectional study conducted in the Sixth Affiliated People’s Hospital of Shanghai Jiao Tong University. A total of 953 healthy pregnant women participated, serological examinations and other variables included serum 25-hydroxyvitamin D [25(OH)D], total blood cholesterol (TCh), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) cholesterol, triglycerides at the first antenatal visit (12–14 weeks) pregnancy parity and age, body mass index (BMI) before pregnancy, and completed OGTTs test. Associations between vitamin D deficiency and possible predictors (age group, pre-pregnancy BMI, parity, and gestational hyperlipemia) were assessed with a multinomial logistic regression analysis. And also used to investigate the effects of 25(OH)D and the other variables on the occurrence of gestational diabetes mellitus.

Results

The mean vitamin D level of pregnancy was 16 (a range from 11 to 21) ng/ml, and severe vitamin D deficiency was 31.8% (303); vitamin D deficiency was 40.7% (388); vitamin D insufficiency was 25.1% (239); normal vitamin D was 2.4%(23). Vitamin D deficiency risk factors were age over 30, parity over 2, overweight, obese, and hyperlipemia. The increasing level of vitamin D nutritional status in pregnancy is significantly related to reducing gestational diabetes mellitus. Vitamin D deficiency is a risk factor for gestational diabetes mellitus.

Conclusions

It is a high prevalence of vitamin D deficiency in Chinese pregnancy in Shanghai. Aging more than 30 years, the parity of more than 2, overweight and obesity, and hyperlipemia are risk factors for vitamin D deficiency. Vitamin D deficiency is a risk factor for gestational diabetes mellitus. Public health strategies to prevent vitamin D deficiency should focus on those risks to promote health pregnancy of Shanghai in China.