First-trimester circulating 25-hydroxyvitamin D levels and development of gestational diabetes mellitus

First-Trimester Prediction of Gestational Diabetes Mellitus Based on Maternal Risk Factors

OBJECTIVE

To develop and validate a new first-trimester model for the prediction of gestational diabetes mellitus (GDM) based on maternal demographic characteristics and elements of medical history.

DESIGN

Prospective cohort study.

SETTING

Inner-city hospital.

POPULATION

41 587 women with singleton pregnancies at 11+0-13+6 weeks' gestation, including 4231 (10.2%) who subsequently developed GDM.

METHODS

Logistic regression model for GDM was developed and fivefold cross-validation was performed to assess the calibration and predictive performance of the model, assessed by the area under the receiver operating characteristic curve (AUROC) and detection rates (DRs) at different screen positive rates (SPRs).

MAIN OUTCOME MEASURE

GDM.

RESULTS

In both parous women with a previous history of GDM and nulliparous women or parous women with no history of GDM, significant contributors to the prediction of GDM were maternal age, weight, height, ethnicity and family history of diabetes mellitus. In parous women with no previous history of GDM, there was a contribution from the birthweight z-score of the previous pregnancy. There was good agreement between the predicted risk and observed incidence of GDM (intercept 0.000, 95% CI: -0.034, 0.034; slope 1.000, 95% CI: 0.967, 1.033). The AUROC curve was 0.757 (95% CI: 0.749, 0.765). The performance was higher for GDM treated with insulin versus metformin or diet alone. At SPR of 40%, the DR of the insulin, metformin and diet alone group was 87.2% (95% CI: 84.9, 89.3), 80.0% (77.8, 82.0) and 61.5% (59.2, 63.7), respectively.

CONCLUSION

Assessment of risk for GDM can be achieved in the first trimester based on maternal risk factors.

First-trimester nuclear magnetic resonance-based metabolomic profiling increases the prediction of gestational diabetes mellitus

BACKGROUND

Current strategies for predicting gestational diabetes mellitus demonstrate suboptimal performance.

OBJECTIVE

To investigate whether nuclear magnetic resonance-based metabolomic profiling of maternal blood can be used for first-trimester prediction of gestational diabetes mellitus.

STUDY DESIGN

This was a prospective study of 20,000 women attending routine pregnancy care visits at 11 to 13 weeks' gestation. Metabolic profiles were assessed using a high-throughput nuclear magnetic resonance metabolomics platform. To inform translational applications, we focused on a panel of 34 clinically validated biomarkers for detailed analysis and risk modeling. All biomarkers were used to generate a multivariable logistic regression model to predict gestational diabetes mellitus. Data were split using a random seed into a 70% training set and a 30% validation set. Performance of the multivariable models was measured by receiver operating characteristic curve analysis and detection rates at fixed 10% and 20% false positive rates. Calibration for the combined risk model for all gestational diabetes mellitus was assessed visually through a figure showing the observed incidence against the predicted risk for gestational diabetes mellitus. A sensitivity analysis was conducted excluding the 64 women in our cohort who were diagnosed with gestational diabetes mellitus before 20 weeks' gestation.

RESULTS

The concentrations of several metabolomic biomarkers, including cholesterol, triglycerides, fatty acids, and amino acids, differed between women who developed gestational diabetes mellitus and those who did not. Addition of biomarker profile improved the prediction of gestational diabetes mellitus provided by maternal demographic characteristics and elements of medical history alone (before addition: area under the receiver operating characteristic curve, 0.790; detection rate, 50% [95% confidence interval, 44.3%-55.7%] at 10% false positive rate; and detection rate, 63% [95% confidence interval, 57.4%-68.3%] at 20% false positive rate; after addition: 0.840; 56% [50.3%-61.6%]; and 73% [67.7%-77.8%]; respectively). The performance of combined testing was better for gestational diabetes mellitus treated by insulin (area under the receiver operating characteristic curve, 0.905; detection rate, 76% [95% confidence interval, 67.5%-83.2%] at 10% false positive rate; and detection rate, 85% [95% confidence interval, 77.4%-90.9%] at 20% false positive rate) than gestational diabetes mellitus treated by diet alone (area under the receiver operating characteristic curve, 0.762; detection rate, 47% [95% confidence interval, 37.7%-56.5%] at 10% false positive rate; and detection rate, 64% [95% confidence interval, 54.5%-72.7%] at 20% false positive rate). The calibration plot showed good agreement between the observed incidence of gestational diabetes mellitus and the incidence predicted by the combined risk model. In the sensitivity analysis excluding the women diagnosed with gestational diabetes mellitus before 20 weeks' gestation, there was a negligible difference in the area under the receiver operating characteristic curve compared with the results from the entire cohort combined.

CONCLUSION

Addition of nuclear magnetic resonance-based metabolomic profiling to risk factors can provide first-trimester prediction of gestational diabetes mellitus.

Vitamin D and Gestational Diabetes Mellitus in the IEU OpenGWAS Project: A Two-Sample Bidirectional Mendelian Randomization Study

BACKGROUND

Gestational diabetes mellitus (GDM) is one of the most prevalent pregnancy problems, and there is still debate over the relationship between vitamin D and GDM.

OBJECTIVES

Our objective is to investigate the correlation between vitamin D and GDM by employing Mendelian randomization (MR) with summary data obtained from genome-wide association studies (GWAS).

METHODS

Data on exposures and outcomes, namely vitamin D, vitamin D insufficiency, and GDM, were acquired from the IEU OpenGWAS Project. Bidirectional MR analysis was performed utilizing the inverse variance weighted (IVW) method as the principal analytical approach. The complementary approaches employed in this study encompassed weighted median, simple mode, weighted mode, and MR-Egger regression. A series of sensitivity analysis were conducted in order to assess the reliability of the obtained results.

RESULTS

The data were acquired from the IEU OpenGWAS Project. Following the application of the three assumptions of MR, 13 single nucleotide polymorphisms (SNPs) were included in the MR analysis for vitamin D levels and vitamin D deficiency on GDM, and 10 and 26 SNPs were included for GDM on vitamin D levels and deficiency, respectively. The findings from the IVW analysis revealed a significant positive correlation between vitamin D levels and GDM (OR = 1.057, 95% CI: 1.011-1.104, p = 0.015). Conversely, a negative correlation was seen between vitamin D deficiency and GDM (OR = 0.979, 95% CI: 0.959-0.999, p = 0.039). The results of the reverse MR study revealed no evidence of reverse causation between GDM and vitamin D. The findings from multiple MR approaches were in line with the direction of IVW analysis. Sensitivity analysis revealed no evidence of heterogeneity, pleiotropy, or outliers, suggesting the robustness of the results.

CONCLUSIONS

There exists a causal association between vitamin D and GDM, whereby vitamin D levels serve as a risk factor for GDM.

Association of VDR gene variant rs2228570-FokI with gestational diabetes mellitus susceptibility in Arab women

Gestational diabetes mellitus (GDM) has been linked with adverse pregnancy outcomes. Vitamin D receptor (VDR) gene variants have been associated with diabetes mellitus susceptibility and related complications. This study assessed the association between VDR gene polymorphism (rs2228570) and GDM risk among pregnant Arab women. A total of 368 pregnant Saudi women who were screened for GDM at 24-28 weeks of gestation and genotyped for the VDR gene variant (rs2228570) were included in this cross-sectional study. Circulatory insulin levels, fasting blood glucose (FBG), glycated hemoglobin (HbA1c), and vitamin D (25(OH)D) were measured. There were 108 women with GDM and 260 women without GDM. The genotype frequency of women with GDM was CC 60.2 %, CT 33.3 %, TT 6.9 %, and CT + TT 39.8 %; for non-GDM women, were CC 61.1 %, CT 31.5 %, TT 6.9 %, and CT + TT 38.4 %. No association was found between the VDR gene variant (rs2228570-FokI) and GDM susceptibility after adjustment for covariates. Serum 25(OH)D had a significant inverse association with FBG (r = -0.49, p = 0.01) and HbA1c (r = -0.45, p = 0.03) among carriers of the TT-genotype. Furthermore, a significant inverse correlation was observed between serum 25(OH)D and HOMA-β (r = -0.20, p = 0.035) in individuals with the T-allele. Among pregnant Saudi women, glycemic indices appear to be influenced by vitamin D, suggesting a possible role it may play in mitigating the metabolic changes associated with GDM, particularly among individuals with specific genetic backgrounds. In our study population, rs2228570-FokI did not appear to be a significant contributor to GDM risk.

Association between eating habits during adolescence and gestational diabetes: data from the Japan environment and children's study

Purpose

It is difficult to change pre-pregnancy eating habits, yet establishing healthy eating habits before pregnancy is important for preventing gestational diabetes mellitus (GDM). This study aimed to examine whether the weight-loss behavior of avoiding between-meal and midnight snacking in teenagers is associated with a reduction in the risk of subsequent GDM.

Methods

We used a dataset (jecs-an-20,180,131) from a nationwide, prospective birth cohort study, the Japan Environment and Children's Study (JECS). We included 89,227 (85.7% of the total) mother-infant pairs with live births. Participants in their second or third trimester were asked to report their weight-loss behavior during their teenage years. The prevalence of GDM was investigated. Differences in maternal characteristics were examined using chi-square tests. Crude and adjusted logistic regression models were constructed to assess the associations of various maternal characteristics with the weight-loss behavior of avoiding between-meal and midnight snacking during teenage years.

Results

A total of 2,066 (2.3%) participants had GDM. Weight-loss behavior in teenagers was associated with a decreased risk of GDM. Among participants with normal weight or overweight prior to pregnancy, the adjusted odds ratios were 0.79 (95% confidence interval, 0.70-0.89) and 0.82 (95% confidence interval, 0.69-0.98), respectively.

Conclusions

The results suggest that teenage weight-loss behaviors, such as avoiding between-meal and midnight snacking, are associated with a decreased risk of developing GDM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01294-2.

Associations of cord blood meta-inflammation and vitamin D with neurodevelopmental delay: A prospective birth cohort study in China

Aim

To estimate the associations of cord meta-inflammatory markers with neurodevelopment, including the potential impact of cord blood vitamin D levels.

Method

The prospective cohort study comprised 7198 participants based on the Maternal & Infants Health in Hefei study. Cord blood C-peptide, high-sensitive C-reactive protein (hsCRP), high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, total cholesterol, triglycerides and 25(OH)D levels were measured. The Gesell Developmental Schedules were used to assess neurodevelopmental outcomes in offspring.

Results

After adjusting potential confounders, per quartile increase in cord blood 25(OH)D concentrations was associated with a decreased risk of neurodevelopmental delay [hazard ratios (HR) 0.65 (95% CI 0.57, 0.74)]. Conversely, significant positive associations with cord blood serum C-peptide levels above the 90th percentile [HR 2.38 (95% CI 1.81, 3.13)] and higher levels of cord hsCRP (per quartile increase) [HR 1.18 (95% CI 1.01, 1.37)] with neurodevelopmental delay were observed. These associations could vary by quartiles of cord blood 25(OH)D levels: the adjusted HRs in neurodevelopmental delay comparing children with vs without hyperinsulinemia were 1.28 (95% CI: 1.03, 1.59) for quartiles 1 (lowest), and 1.06 (95% CI: 0.78, 1.44) for quartile 4 (highest).

Conclusions

Immune activation and metabolic abnormalities in fetal circulation were associated with neurodevelopmental delay in offspring, which could be attenuated by higher cord blood 25(OH)D levels in a dose-response manner.

Vitamin D Deficiency During the First Trimester of Pregnancy and the Risk of Developing Gestational Diabetes Mellitus

OBJECTIVE

To investigate the relationships among various factors that affect serum vitamin D levels and vitamin D in the first trimester and the risk of developing gestational diabetes mellitus (GDM).

DESIGN

A prospective cohort design.

SETTING

The family health center of Ankara, Turkey.

PARTICIPANTS

Out of 889 pregnant women who participated in the study in the first trimester (6-13 weeks gestation), 814 participated in GDM screening in the second trimester (24-28 weeks gestation).

METHODS

We determined serum vitamin D levels, demographic data, various biochemical and anthropometric parameters, and factors that affect vitamin D synthesis of participants in the first trimester and used logistic regression analysis to analyze the effects of the associations among vitamin D deficiency and the other variables on the occurrence of GDM.

RESULTS

Vitamin D deficiency in the first trimester was present in 425 (82.5%) participants. In the second trimester, 198 participants (24.3%) were diagnosed with GDM through oral glucose tolerance test screening. We detected GDM in the second trimester in 5.7% of participants who had vitamin D deficiency in the first trimester. Even after adjustment for vitamin D intake, clothing style, and duration of exposure to the sun, the risk of GDM was significantly greater in participants who were vitamin D deficient than those who were not deficient. The risk of GDM among women with vitamin D deficiency was sustained or increased significantly after we adjusted for age, parity, prepregnancy body mass index, history of diabetes, triglyceride levels, vitamin D intake, clothing style, and length of sun exposure, OR = 10.60, p < .001, 95% confidence interval [2.82, 39.76].

CONCLUSIONS

Our results suggest that vitamin D deficiency in the first trimester may significantly increase the risk of developing GDM.

Early pregnancy vitamin D insufficiency and gestational diabetes mellitus

OBJECTIVES

To test the hypothesis that a link existed between vitamin D levels in the first trimester and gestational diabetes mellitus (GDM).

METHODS

The 25-hydroxyvitamin D₃ levels were tested in the first trimester and pregnant outcomes were followed up in 1726 women.

RESULTS

Only 5.9% of pregnant women have sufficient 25(OH)D₃ . More women with GDM are in the status of 25(OH)D₃ insufficiency than women with normal glucose tolerance (NGT) (p < 0.05). Age (odds ratio [OR]: 1.047, 95% confidence interval [CI]: 1.014-1.081), pre-pregnancy body mass index (BMI) (OR: 1.132, 95%CI: 1.092-1.173) were risk factors of GDM while 25-(OH) D₃ (OR: 0.979, 95%CI: 0.960-0.999) was a protective factor. After adjusted for maternal age and pre-pregnancy BMI, 25(OH)D₃ insufficiency (<30 ng/mL) is an independent predictor of GDM (OR: 2.122, 95%CI: 1.084-4.155); 25(OH)D₃ level correlated with fasting blood glucose in the first trimester negatively.

CONCLUSION

Vitamin D insufficiency in early pregnancy was significantly associated with an increased risk for GDM in Chinese women.

Vitamin D Status and Gestational Diabetes in Russian Pregnant Women in the Period between 2012 and 2021: A Nested Case-Control Study

Several meta-analyses found an association between low maternal serum 25-hydroxyvitamin D (25(OH)D) level and gestational diabetes mellitus (GDM). However, some of them reported significant heterogeneity. We examined the association of serum 25(OH)D concentration measured in the first and in the second halves of pregnancy with the development of GDM in Russian women surveyed in the periods of 2012−2014 and 2018−2021. We conducted a case−control study (including 318 pregnant women) nested on two previous studies. In 2012−2014, a total of 214 women (83 GDM and 131 controls) were enrolled before 15 weeks of gestation and maternal serum 25(OH)D concentrations were measured twice: at 8th−14th week of gestation and simultaneously with two-hour 75 g oral glucose tolerance test (OGTT) at 24th−32nd week of gestation. In the period of 2018−2021, 104 women (56 GDM and 48 controls) were included after OGTT and 25(OH)D concentrations were measured at 24th−32nd week of gestation. Median 25(OH)D levels were 20.0 [15.1−25.7] vs. 20.5 [14.5−27.5] ng/mL (p = 0.565) in GDM and control group in the first half of pregnancy and 25.3 [19.8−33.0] vs. 26.7 [20.8−36.8] ng/mL (p = 0.471) in the second half of pregnancy, respectively. The prevalence rates for vitamin D deficiency (25(OH)D levels < 20 ng/mL) were 49.4% and 45.8% (p = 0.608) in the first half of pregnancy and 26.2% vs. 22.1% (p = 0.516) in the second half of pregnancy in women who developed GDM and in women without GDM, respectively. The frequency of vitamin D supplements intake during pregnancy increased in 2018−2021 compared to 2012−2014 (p = 0.001). However, the third trimester 25(OH)D levels and prevalence of vitamin D deficiency (25.5 vs. 23.1, p = 0.744) did not differ in women examined in the periods of 2012−2014 and 2018−2021. To conclude, there was no association between gestational diabetes risk and maternal 25(OH)D measured both in the first and in the second halves of pregnancy. The increased prevalence of vitamin D supplements intake during pregnancy by 2018−2021 did not lead to higher levels of 25(OH)D.

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.

PM2.5 exposure and maternal glucose metabolism in early pregnancy: Associations and potential mediation of 25-hydroxyvitamin D

Gestational diabetes mellitus (GDM) has become a new global epidemic with a rapidly increasing prevalence. Previous studies have suggested that air pollution is associated with GDM risk, but the results are inconsistent, and mechanistic studies are limited. Based on a hospital-based cohort, a total of 6374 participants were included in this study. Individual daily PM2.5 exposure at a 1-km resolution was predicted using a full-spatiotemporal-coverage model. The results of multiple linear regression showed that glycated hemoglobin (HbA1c) was significantly associated with PM2.5 both in the 1-month preconception and in the first trimester of pregnancy. Additionally, HbA1c decreased 0.437% (95% CI: -0.629, -0.244) as the serum 25-hydroxyvitamin D (25(OH)D) increased by one interquartile range (IQR) (9.2 ng/ml). An IQR increase in PM2.5 exposure was also negatively associated with serum 25(OH)D (estimated change% and 95% CI: -7.249 (-9.054, -5.408) in the 1-month preconception and - 13.069 (-15.111, -10.979) in the first trimester of pregnancy). Mediation analysis showed that serum 25(OH)D status mediated the association between HbA1c and PM2.5 exposure both in the preconception and in the first trimester (mediated percent: 2.00% and 4.05% (Sobel p＜0.001), respectively). The result suggested a vicious cycle among PM2.5 exposure, lower serum VD status and a higher HbA1c. More studies are warranted since the protective effect of 25(OH)D against glucose disorders associated with air pollution in this study was limited.

The Association between Maternal Serum Vitamin D Levels and Gestational Diabetes Mellitus among Filipino Patients: A Cross-Sectional Study

Objectives

To determine the association between low maternal serum vitamin D and gestational diabetes mellitus (GDM) among Filipino women in St. Luke’s Medical Center, Quezon City.

Methodology

A cross-sectional study involving pregnant women at outpatient clinics in a tertiary hospital in the Philippines. Simultaneous testing for fasting blood sugar, 75g oral glucose tolerance test and serum vitamin D was done. Participants were classified as GDM versus non-GDM, and normal versus low serum vitamin D. Univariate and multivariate statistics were done to determine relationship between vitamin D and GDM.

Results

Of 211 included women, 198 (93.8%) had low vitamin D levels, and 56 (26.5%) had GDM. Vitamin D was significantly higher in the GDM group (21.0±8.1 vs 18.8±5.3 ng/mL, p=0.0189). The proportion of women with low vitamin D levels was significantly higher among those without GDM (96.1% vs 87.5%, OR=0.28, p=0.029]. After adjusting for age, parity, history of GDM and pre-pregnancy BMI, no significant association was observed (adjusted OR=0.66, p=0.522). No correlation was seen between vitamin D and FBS (r=0.28, p=0.095), 1-hour post-75 g OGTT (r=0.26, p=0.643), and 2-hour post-75 g OGTT (r=0.28, p=0.113).

Conclusion

There was an association found between maternal serum vitamin D level and GDM in the univariate analysis, but none was evident after adjusting for possible confounders. The unanticipated high prevalence of low vitamin D levels among pregnant Filipinos needs to be verified in future studies.

Association between Gene Polymorphisms of Vitamin D Receptor and Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

(1) Background: Studies on the association between Vitamin D receptor gene polymorphism and gestational diabetes mellitus have been inconsistent. The aim of this study was to summarize available evidence on the association between polymorphisms of Vitamin D receptor genes and susceptibility to gestational diabetes mellitus. (2) Methods: We searched databases of PubMed, Web of Science, Embase, China national knowledge infrastructure (CNKI), China science and technology journal database (VIP), and Wanfang Data for relevant articles. A systematic review and a meta-analysis were done to compare the distribution of Vitamin D receptor gene polymorphisms in gestational diabetes mellitus patients with those in controls using allelic, codominant, dominant, and recessive models. (3) Results: A total of eight eligible articles were included in the systematic review and of them, six articles were included in the meta-analysis. The vitamin D receptor gene rs7975232 polymorphism was associated with gestational diabetes mellitus under the allelic model (odds ratio = 1.28, 95% confidence interval 1.06–1.56), codominant model (CC vs. AA odds ratio = 1.97, 95% confidence interval 1.28–3.05), and recessive model (odds ratio = 1.83, 95% confidence interval 1.27–2.64) in the case of low heterogeneity. High heterogeneity existed in studies on the association of vitamin D receptor genes rs1544410, rs2228570, and rs731236 with gestational diabetes mellitus, and the most common sources of heterogeneity were the year of publication and matching. (4) Conclusion: Polymorphism of the vitamin D receptor gene rs7975232 may be associated with risk of developing gestational diabetes mellitus. Future studies should be designed to include standardized data collection and matching for important confounding factors such as body mass index, age, and race.

Prevalence of Gestational Diabetes Mellitus and Its Associated Risk Factors in Boo-Ali Hospital, Tehran

BACKGROUND

Gestational diabetes mellitus (GDM) represents the most common metabolic complication during pregnancy. GDM is associated with maternal and fetal complications. Approximately 7% of all pregnancies are affected by GDM, resulting in more than 200,000 cases worldwide annually, and the prevalence may vary from 1% to 14% among all pregnancies. Accordingly, this study attempted to determine the prevalence and some risk factors of GDM.

MATERIALS AND METHODS

This hospital-based cross-sectional study was carried out at Boo-Ali hospital in Tehran, the capital of Iran. Four hundred non-diabetics pregnant women with a gestational age of 24-28 weeks who attended the Boo-Ali hospital outpatient department were included in our study. Demographic and anthropometric data including age, gravida, para, gestational age, family history of diabetes, history of GDM, weight, height, and body mass index (BMI) were collected. Blood samples were collected from the women at 24-28 weeks to diagnose GDM by oral glucose tolerance test (OGTT). We measured the 25-OH-D level in participants at 24-28 weeks.

RESULTS

Among the 400 pregnant women, 46 (11.5%) had GDM based on OGTT, and the mean age of GDM women were 30.78± 5.96 years. Among selected variables, BMI ≥25kg/m2, family history, and GDM history were associated with increased risks of GDM (odds ratio=2.49, 95% confidence interval [CI] 1.22-5.07;3.52, 95% CI 1.84-6.70; 19.57, and 95% CI 6.16-62.17, respectively). The association was more robust in the positive GDM history of women.

CONCLUSION

High prevalence of GDM highlights more attention of health-care givers in screening pregnant women with risk factors. BMI as a modifiable risk factor for GDM needs more attention, and positive family history and previous GDM history should be considered in the core activities of pregnant women.

Vitamin D in gestational diabetes mellitus and its association with hyperglycaemia, insulin sensitivity and other factors

We investigated if vitamin D is independently associated with hyperglycaemia in gestational diabetes mellitus (GDM). Serum 25 hydroxy vitamin D (25OHD), fasting blood glucose (FBG), HbA1c, fructosamine, insulin sensitivity (QUICKI equation), body mass index, clothing style and outdoor activity were measured in 58 pregnant women with GDM during the third trimester. 25OHD was also measured in 20 women with normal pregnancies. There was no significant difference in mean 25OHD concentrations between GDM (14.43 ± 5.27 ng/ml) and normal (15.45 ± 5.29 ng/ml) pregnancies, p = .354. However, a higher percentage of GDM subjects had 25OHD concentration <19.8 ng/ml (86 versus 65%, p = .003). 25OHD did not correlate with FBG, HbA1c, fructosamine, insulin sensitivity or insulin dosage (p > .05). On multivariate analysis, only ethnicity (p = .006) and outdoor activity (p = .004) were associated with 25OHD. We conclude that the lower 25OHD levels in our GDM patients were related to ethnicity and outdoor activity (Study FF-2017-111, National University of Malaysia, 16 March 2017).IMPACT STATEMENTWhat is already known on this subject? Vitamin D deficiency in pregnancy is widespread and particularly in certain ethnic groups. Low vitamin D levels may be an aetiological factor for gestational diabetes mellitus (GDM) but previous studies provide conflicting results perhaps due to confounding factors.What do the results of this study add? In this study of pregnant women with GDM from different ethnic backgrounds, we analysed serum 25-hydroxy vitamin D (25OHD) levels together with other confounding factors, that is, body mass index, ethnicity and sunlight exposure. Furthermore, instead of using consensus values, we determined cut-offs for different vitamin D status from normal pregnancies matched for gestational age and ethnicity. We found that a higher percentage of GDM subjects had lower vitamin D status but there was no correlation with hyperglycaemia or insulin sensitivity. The study showed that lower vitamin D levels in GDM was associated with ethnicity and less outdoor activity.What the implications are of these findings for clinical practice and/or further research? In GDM patients, low vitamin D levels may be modifiable by supplementation or lifestyle change. Longitudinal studies are needed to determine whether this would impact on the occurrence of GDM.

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

Background and Aims:

The association of gestational diabetes mellitus and serum Vitamin D levels in different trimesters of pregnancy has been studied recently. We conducted this study in an prospective observational cohort of well-characterized healthy pregnant women to examine the relationship between 1^st trimester Vitamin D levels and Gestational Diabetes Mellitus (GDM) status during pregnancy.

Methods:

All pregnant women attending the out-patient department of Gynecology & Obstetrics, aged less than 35 years, and who were in their first trimester were included in the study. Socio-demographic, anthropometric details, clinical details, food frequency questionnaire and physical activity data was collected using validated pretested questionnaire.

Results:

The comparison between those with GDM and those with normal glucose levels has been illustrated. Women in the GDM are older than those in the non-GDM group. The women in GDM group were taller, heavier and their BMI was greater than those in the non-GDM group. There were no significant differences in dietary intake at baseline between mothers with GDM and those with normal glucose levels. Further, it was found that Vitamin D concentration of <30 nmol/L was found among higher among those with GDM and the relationship was statistically significant.

Conclusion:

There is an association between maternal Vitamin D deficiency and increased risk for GDM in early pregnancy among Kashmiri women.

Early Pregnancy Vitamin D Binding Protein Is Independently Associated with the Development of Gestational Diabetes: A Retrospective Cohort Study

BACKGROUND

Vitamin D-binding protein (VDBP) has been implicated in several adverse pregnancy outcomes either directly or indirectly via influencing the concentrations of biologically active vitamin D metabolites. However, human studies exploring these metabolites in pregnancy remain sparse. Here, we examine whether VDBP and total, free, and bioavailable 25-hydroxyvitamin D (25(OH)D) metabolites in early pregnancy are associated with subsequent adverse pregnancy outcomes.

METHODS

We conducted a retrospective analysis of 304 pregnant women in early pregnancy (<20 weeks gestation). The demographic characteristics, anthropometric data, and total 25(OH)D were measured and plasma or serum samples were collected and bio-banked. Using these samples, we measured VDBP (polyclonal ELISA) and albumin (automated colorimetry), and calculated free and bioavailable 25(OH)D using validated formulae. Pregnancy outcomes were derived from scanned medical records. Regression models were used to analyse the relationships between vitamin D metabolites in early pregnancy and subsequent pregnancy outcomes (gestational diabetes mellitus (GDM), pre-eclampsia, preterm birth), with adjustment for predetermined clinically relevant maternal factors including age, body mass index (BMI), and ethnicity.

RESULTS

Lower VDBP concentrations were associated with higher glucose levels and a greater likelihood of developing GDM at 26-28 weeks gestation (odds ratio [OR] (95% CI) = 0.98 (0.97,0.99), p = 0.015). This finding remained significant after adjustment for maternal covariates including age, BMI, and ethnicity (β = -0.003, p = 0.03). Lower total, free and bioavailable 25(OH)D, but not VDBP, were associated with a shorter length of gestation, but only the relationship with total 25(OH)D remained significant after adjustment for the above maternal covariates (β = 0.02, p = 0.006).

CONCLUSIONS

This is the first study to examine VDBP, and total, free and bioavailable 25(OH)D in relation to pregnancy outcomes in a well characterised multi-ethnic cohort of pregnant women. Our findings show that VDBP and total 25(OH)D are associated with GDM and length of gestation, respectively; however, further investigations using large-scale prospective studies are needed to confirm our findings.

Relationship between vitamin D status in the first trimester of pregnancy and gestational diabetes mellitus - A nested case-control study

BACKGROUND & AIMS

Gestational diabetes mellitus (GDM) is one of the most frequent medical complications during pregnancy. It has been associated with many adverse pregnancy, fetal and neonatal outcomes, as well as with an increased risk for mothers and children in the long term. There is a growing interest in vitamin D and its potential role in the development of metabolic disorders. However, the medical literature is not consensual. The aim of this study was to assess the risk of GDM according to vitamin D status during the first trimester.

METHODS

This study is a nested case-control study performed from a multicenter prospective observational cohort of pregnant women assessed for 25-hydroxyvitamin D levels (25OHD). Three hundred ninety-three patients were included in the initial cohort. After applying exclusion criteria, a total of 1191 pregnant women were included. Two hundred fifty women with GDM (cases) were matched to 941 women without GDM (controls) for parity, age, body mass index before pregnancy, the season of conception, and phototype. This study was funded by a grant from the "Programme Hospitalier de Recherche Publique 2010".

RESULTS

The GDM risk was significantly greater for patients with 25OHD levels <20 ng/mL (OR = 1∙42, 95% CI 1∙06-1∙91; p = 0∙021). However, there was no significant relationship with other thresholds. The study of 25OHD levels with the more precise cutting of 5 units intervals showed a variable relationship with GDM risk, as the risk was low for very low 25OHD levels, increased for moderated levels, decreased for normal levels, and finally increased for higher levels.

CONCLUSION

According to our study, there seems to be no linear relationship between GDM and 25OHD levels in the first trimester of pregnancy since GDM risk does not continuously decrease as 25OHD concentrations increase. Our results most probably highlight the absence of an association between 25OHD levels and GDM risk.

Vitamin D Status and Pregnancy Complications: Serum 1,25-di-hydroxyl-Vitamin D and its Ratio to 25-hydroxy-Vitamin D are Superior Biomarkers than 25-hydroxy-Vitamin D

Vitamin D (VitD) deficiency during pregnancy has been associated with adverse neonatal outcomes and increased risk of late pregnancy complications. We planned to correlate serum VitD biomarkers; 25-hydroxyvitamin D (25-OH-VitD) and 1,25-dihydroxyvitamin D (1,25-diOH-VitD) levels; and their ratio with the frequency of feto-maternal pregnancy complications. A prospective cross-sectional case-control study was conducted at Aljouf Maternity and Children Hospital, Sakaka, Saudi Arabia, during the period of September 1, 2017 to September 30, 2019. 322 pregnant women were stratified into 2 groups: controls (110 cases) and complicated group (212 cases). The later comprised severe preeclamptic toxemia associated with intrauterine growth restriction (58 cases), gestational diabetes mellitus (GDM; 82 cases), abortion (26 cases), undisturbed ectopic pregnancy (16 cases), premature rupture of membranes (PROM; 14 cases), and, inevitable preterm labour (16 cases). After clinical assessment, peripheral blood samples were collected. Serum biomarkers were measured using specific immunoassays. The direct 1,25-diOH-VitD/25-OH-VitD ratio was calculated. Serum 25-OH-VitD indicated widely spreading VitD deficiency among participants with significantly higher levels in controls vs. GDM subgroup only. 1,25-diOH-VitD levels and the ratio were markedly reduced in the six complicated subgroups vs. controls, with non-significant differences amongst the complicated subgroups. ROC analysis showed very high sensitivity and specificity, to differentiate patients from controls, only for 1,25-diOH-VitD (AUC = 0.965; 0.947 - 0.983, p <0.001) followed by the ratio but not 25-OH-VitD. In conclusions, 25-OH-VitD did not show significant changes except for GDM. 1,25-diOH-VitD levels and the ratio showed strong associations with pregnancy complications. Serum 1,25-di-OH-VitD and its ratio to 25-OH-VitD are more reliable and physiologically relevant biomarkers for VitD status in pregnancy.

Serum vitamin D deficiency and risk of gestational diabetes mellitus: a meta-analysis

INTRODUCTION

This meta-analysis was performed to confirm the relationship of gestational diabetes mellitus (GDM) and vitamin D.

MATERIAL AND METHODS

PubMed and CNKI databases were searched for relevant articles. Standard mean difference (SMD) along with 95% CI was used to compare vitamin D level between women with GDM and healthy subjects. The correlation coefficient between the vitamin D and homeostasis model assessment-insulin resistance index (HOMA-IR) was analyzed.

RESULTS

The vitamin D level of GDM subjects was much lower than healthy subjects (SMD = -0.71, 95% CI: -0.91, -0.50). Vitamin D deficiency was associated with high risk of GDM (OR = 1.15, 95% CI: 1.07-1.23). Vitamin D was negatively correlated with HOMA-IR (r = -0.62, 95% CI: -0.85, -0.39). The analysis showed no publication bias (Egger's: p = 0.197; Begg's: p = 0.786).

CONCLUSIONS

Vitamin D is closely associated with the onset of GDM.

The association of vitamin D status and supplementation during pregnancy with gestational diabetes mellitus: a Chinese prospective birth cohort study

BACKGROUND

Previous studies have shown conflicting findings regarding the relation of vitamin D status and supplementation during pregnancy with gestational diabetes mellitus (GDM). Most of these studies hypothesized that 25-hydroxyvitamin D [25(OH)D] concentrations were associated with GDM risk and glucose metabolism based on linear association models.

OBJECTIVES

We aimed to estimate the associations of 25(OH)D concentrations and vitamin D supplementation with GDM risk and glucose metabolism and determine the threshold concentrations of 25(OH)D that could significantly affect glucose metabolism and GDM risk.

METHODS

In a prospective birth cohort study, we collected information about sociodemographic characteristics, health status, and lifestyle from 4984 pregnant women. Vitamin D supplementation and 25(OH)D concentrations were assessed in the second trimester. Data from the 75-g oral-glucose-tolerance test were obtained at 24-28 weeks of gestation.

RESULTS

A total of 922 (18.5%) women were diagnosed with GDM. Compared with women with 25(OH)D concentrations <25 nmol/L, the GDM risk was significantly lower in women with 25(OH)D concentrations ranging from 50 to 75 nmol/L (RR: 0.74; 95% CI: 0.58, 0.95) and >75 nmol/L (RR: 0.40; 95% CI: 0.22, 0.70). The curve-fitting models suggested a significant large reduction in GDM risk, fasting plasma glucose, and area under the curve of glucose with increasing 25(OH)D concentrations only for concentrations >50 nmol/L. Consistently, GDM risk was significantly reduced only in women who took 400-600 IU vitamin D/d (RR: 0.83; 95% CI: 0.70, 0.97) with a mean 25(OH)D concentration of 50 nmol/L but not in women taking vitamin D sometimes with a mean 25(OH)D concentration of 40 nmol/L.

CONCLUSIONS

GDM risk was significantly reduced only in pregnant women with 25(OH)D concentrations >50 nmol/L. Pregnant women taking 400-600 IU vitamin D/d with mean 25(OH)D concentrations of 50 nmol/L had a lower risk of GDM.

The relationship between vitamin D and insulin resistance before delivery in advanced maternal age

BACKGROUND

With the widely implementation of universal two-child policy, the number of pregnant women in advanced maternal age (AMA) will increase gradually. We aimed to assess the association of vitamin D levels and insulin resistance (IR) during the late pregnancy in AMA.

METHODS

A total of 80 pregnant women were consecutively enrolled in the cross-sectional study before delivery from the August 2016 to June 2017 at the department of gynecology and obstetrics in the hospital of ZhongDa, affiliated to Southeast University. At delivery, serum 25(OH) D and metabolism parameters including glucose and lipid levels were measured. IR was calculated by the method of homeostasis model assessment 2(HOMA2).

RESULTS

Pregnant women in AMA with vitamin D deficiency have higher fasting insulin (14.70(8.76-34.65) and 10.89(7.15-16.12), respectively, P = 0.031) and HOMA-IR indices (1.78(1.07-4.14) and 1.30(0.83-1.89), respectively, P = 0.024) than those with vitamin D non-deficiency. Serum 25(OH) D levels were inversely associated with HOMA-IR indices (r = - 0.25, P = 0.025). In multivariable analysis for adjusting confounder factors, vitamin D non-deficiency was also negatively correlated with HOMA-IR compared to vitamin D deficiency (β = - 1.289, P = 0.026).

CONCLUSIONS

Taken together, our findings suggest that serum 25(OH) D levels were inversely associated with HOMA-IR in AMA. Furthermore, pregnant women in AMA with vitamin D deficiency might have higher HOMA-IR levels than those with vitamin D non-deficiency.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (No. ChiCTR-RRC-16008714). retrospectively registered.

Significance of Vitamin D on the Susceptibility of Gestational Diabetes Mellitus - A Meta-Analysis

Vitamin D plays an important role in glucose tolerance by stimulating insulin secretion and evidences suggest a contradictory result on the association between vitamin D status and risk of developing gestational diabetes mellitus (GDM). The present updated meta-analysis has been undertaken to find out the joined effect of vitamin D status on the risk of effect GDM considering previously published articles. Data were collected through literature search using electronic databases to retrieve relevant published research articles using various combinations of the following keywords, "vitamin D," "vitamin D deficiency," "cholecalciferol," "25-hydroxyvitamin D," "25(OH) D," "gestational diabetes mellitus," and "GDM." A total of 36 studies including 7,596 GDM cases and 23,377 non-GDM controls were involved in this study. Overall, pooled meta-analysis showed that pregnant women diagnosed with GDM have 18% higher risk of GDM risk when compared with controls [odds ratio (OR) = 1.18, 95% confidence interval (CI) 1.10-1.25; P = 0.00] with high heterogeneity (I² = 73.29). The mean difference was also significantly different between cases and controls (OR = -0.18, 95% CI - 0.22 to - 0.14; P = 0.00). Subgroup analysis showed significant results with age more than 30 years, Asian and European regions, and case-control, cross-sectional, and nested case-control study design. Low concentration of vitamin D is associated with the development of GDM. Although in future more studies especially systematically designed clinical trials based on vitamin D supplementation with large sample size on different population are needed to elucidate the exact concentration of vitamin D during pregnancy as well as before and after pregnancy.

Relationship of Early Vitamin D Concentrations and Gestational Diabetes Mellitus in Indian Pregnant Women

Background: A high prevalence of vitamin D deficiency exists in pregnant Indian women (~90%). Increasing evidence suggests that vitamin D could play a pivotal role in maintaining normal glucose homeostasis. We aimed to determine the association between maternal vitamin D concentrations in early pregnancy and the risk of gestational diabetes mellitus (GDM). Methods: A prospective observational study was conducted on healthy pregnant women (n = 392) attending routine antenatal care at St. John's Medical College Hospital, Bangalore recruited at ~12 weeks of gestation. At baseline, details on socio-economic status, obstetric history, dietary intakes, and anthropometry were collected. Venous plasma total vitamin D concentration was assessed using tandem liquid chromatography mass spectrophotometry (LC-MS/MS). Oral glucose tolerance test (OGTT) at recruitment, followed by glucose tolerance test (GTT) at mid-pregnancy was conducted. GDM was diagnosed and confirmed using the International Association of Diabetes and Pregnancy Study Groups (IADPSG) classification. Univariate and adjusted logistic regression models were used to evaluate the associations between total vitamin D concentrations at enrollment with GDM. Results: Of the cohort, 10.2% were diagnosed as GDM. Women with GDM were older (26 vs. 24 years) and heavier (51.6 vs. 51.2 kg) compared to the rest. A higher prevalence of GDM was observed among women with 1st trimester plasma total vitamin D in the lowest quartile (≤23.6 nmol/L) compared to the subjects in the other three quartiles (16.1 vs. 8.6%, p = 0.033). Adjusted multivariable regression analysis showed that women in the lowest quartile of plasma total vitamin D had twice the odds of GDM compared to women belonging to the remaining quartiles [OR = 2.32 (95%CI: 1.10, 4.91), p = 0.028]. Conclusions: Low plasma total vitamin D concentrations in early pregnancy may be associated with a higher risk of GDM.

Effect of vitamin D deficiency on the 75 g oral glucose tolerance test screening and insulin resistance

Gestational diabetes mellitus (GDM), is the most common medical complications of pregnancy. This study aimed to clarify the effect of second-trimester vitamin D deficiency on the 75 g oral glucose tolerance test (OGTT) screening and insulin resistance. A total of 120 pregnant women with a singleton pregnancy at a gestational age of 26-28 weeks were analyzed. Participants were divided into two groups according to 25-hydroxyvitamin D levels; vitamin D deficiency, and control groups. For GDM scan, 75 g OGTT was preferred. GDM prevalence was 17.5% in vitamin D deficiency group and 13.75% in control group, there is no significant difference in GDM prevalence (p = 0.149). Fasting plasma glucose and 1-h plasma glucose levels were significantly higher in the vitamin D deficiency group than in the control group (p < .001 and p < .001, respectively). No significant differences were observed between 2-hour plasma glucose levels (p = .266). The HOMA-IR level was significantly higher in the vitamin D deficiency group than in the control group (p < .001). The findings of the present study suggested that vitamin D deficiency in the second trimester was inversely correlated with fasting and 1-h plasma glucose after 75 g glucose challenge test; also, low 25 OHD₃ levels were associated with insulin resistance.

Comparison of free and total 25-hydroxyvitamin D in normal human pregnancy

Vitamin D status correct monitoring during pregnancy is critically important for both maternal and fetal health. 25-Hydroxyvitamin D (25(OH)D) - a prohormone of a biologically active 1,25-dihydroxyvitamin D (1,25(OH)₂D), despite the lack of biological activity, during the past decades has been routinely used as a main biomarker characterizing vitamin D status. About 85% of 25(OH)D in the bloodstream is bound to its specific carrier - vitamin D-binding protein (DBP), the remaining 15% are loosely bound to albumin, and only less than 0.1% are free in the circulation ("free 25(OH)D"). Total 25(OH)D is the sum of DBP-bound, albumin-bound and free 25(OH)D. According to a "free hormone hypothesis", only free 25(OH)D is able to induce a biological effect. Normal pregnancy is characterized by elevated serum DBP levels, and due to this fact the diagnostic strength of serum total 25(OH)D has been questioned. Free 25(OH)D might be a better characteristic of vitamin D status in this settings. We aimed to compare the diagnostic strength of a routine total 25(OH)D with directly measured free 25(OH)D in normal pregnancy by comparing the association strength between free and total 25(OH)D with biomarkers of bone health (PTH, calcium, bone-specific alkaline phosphatase (BSAP)), lipid metabolism (adiponectin, LDL, HDL), kidney function (urea), endocrine parameters (T4, T3, TSH), and group B water-soluble vitamins. The study was conducted in 368 healthy white pregnant women - residents of north-east Germany. Free 25(OH)D showed an overall better associations with gestational age, markers of bone metabolism (calcium (rho = 0.141, p = 0.007 with free 25(OH)D; rho = 0.060, p = 0.251 with total 25(OH)D) and BSAP (rho = -0.203, p < 0.001 with free 25(OH)D; rho = -0.108, p = 0.038 with total 25(OH)D), lipid metabolism parameters (adiponectin (rho = 0.142, p = 0.008 with free 25(OH)D; rho = 0.054, p = 0.307 with total 25(OH)D), LDL cholesterol (rho = -0.191, p < 0.001 with free 25(OH)D; rho = 0.033, p = 0.539 with total 25(OH)D)) and a kidney function marker (urea (rho = 0.114, p = 0.032 with free 25(OH)D; rho = 0.008, p = 0.887 with total 25(OH)D)) than total 25(OH)D. In conclusion, the current study revealed that free 25(OH)D is a more precise determinant of the vitamin D status during normal human pregnancy than total 25(OH)D. In the settings of normal pregnancy, free 25(OH)D revealed better associations with markers of bone metabolism (calcium, BSAP), lipid metabolism (adiponectin, LDL cholesterol, LDL/HDL ratio) and kidney function (urea) than total 25(OH)D.

Vitamin D deficiency status and its related risk factors during early pregnancy: a cross-sectional study of pregnant Minangkabau women, Indonesia

Background

Vitamin D deficiency (VDD) is a common problem in reproductive-aged women and has become a major public health problem worldwide. The effect of VDD in pregnancy has been associated with several adverse pregnancy outcomes. This study aims to assess the serum levels of 25-hydroxyvitamin D (25(OH)D) in the first trimester and its associated factors (socio-demographics, pregnancy profiles, dietary intake, and maternal anthropometry measurements) for the determination of vitamin D deficiency status in early pregnancy.

Methods

A cross-sectional study of 239 pregnant mothers in West Sumatra, Indonesia was conducted. We measured lifestyle, socio-demographics and pregnancy profile through a structured questionnaire and interview process. A semi quantitative-food frequency questionnaire (SQ-FFQ) was used to analyse the dietary intake of the pregnant women. Serum 25(OH)D concentrations were measured at < 13 weeks gestation using ELISA and logistic regression models were employed to identify the predictors of low vitamin D status.

Results

The prevalence of first-trimester maternal VDD and sufficiency were 82.8 and 17.2% respectively. The median 25(OH)D was 13.15 ng/mL (3.00–49.29 ng/mL). The significant independent predictors were no working status (OR: 0.029;0.001–0.708) (p = 0.030); nulliparous parity status (OR: 7.634;1.550–37.608) (p = 0.012); length of outdoor activity status of less than an hour (OR: 9.659;1.883–49.550) (p = 0.007); and no consumption of supplements before pregnancy (OR: 4.49;1.081–18.563) (p = 0.039).

Conclusions

The prevalence of VDD is common in early pregnancy among Minangkabau women. Recommendations and policies to detect and prevent such insufficiency during pregnancy should be developed by considering the associated factors.

Severe 25(OH)vitamin-D deficiency: A risk factor for development of gestational diabetes mellitus

OBJECTIVE

To estimate the level of 25 (OH)vitamin D in gestational diabetes mellitus (GDM) and to find the correlation between level of 25(OH)vitamin D and GDM.

MATERIALS AND METHODS

The study was conducted on 50 diagnosed patients of GDM attending antenatal clinic in the obstetrics and gynecology department of Pt. B.D. Sharma PGIMS, Rohtak. 50 age and gestational age matched normoglycemic women were taken as control group. Procedure of study was explained to the participants and informed consent was taken.

RESULTS

GDM women had higher age, BMI, and positive family history of type 2 DM as compared to pregnant women without GDM. The mean vitamin D in GDM women was 32.64 ± 24.33 nmol/L while in controls it was 39.90 ± 21.86 nmol/L(P = 0.033). The prevalence of severe vitamin D deficiency(<25 nmol/L) was found to be 44% among GDM women (22 out of 50 GDM women) and 20% among women with normoglycemia (10 out of 50 normoglycemic controls) with significant p value of 0.010 and odds ratio of 1.833. GDM women with BMI>25 kg/m² had 1.799 times chances to be severely deficit in vitamin D than women with BMI<25 kg/m² 6 GDM women had mild vitamin D deficiency (>50 but <75 nmol/L) and 16 had moderate deficiency (>25 but <50 nmol/L). Only 6 GDM patients were found to be sufficient for vitamin D(>75 nmol/L).

CONCLUSION

Severe vitamin D deficiency in second trimester of pregnancy is significantly associated with elevated risk for GDM.

Maternal risk factors and newborn infant vitamin D status: a scoping literature review

Low vitamin D (VitD) status is common among newborn infants, more so in temperate latitudes with evidence that maternal VitD deficiency is a major risk factor given that the neonate relies solely on maternal-fetal transfer of VitD. This scoping review was conducted to provide an overview of the latest evidence from studies regarding the impact of maternal risk factors on infant 25-hydryoxyvitamin D [25(OH)D] concentrations with a focus on studies in Canada and the United States. Several maternal risk factors that contribute to low maternal-fetal 25(OH)D concentrations have been reported over many decades, but no clear pattern has been established for multiethnic populations. For example, darker skin pigmentation and ethnicity are common risk factors for low VitD status. Studies in predominantly white women showed that supplementation of VitD during pregnancy causes significant increases in maternal serum 25(OH)D which often improves cord serum 25(OH)D values. In addition, VitD recommendations by health care professionals and adherence to supplementation by pregnant women appear to positively influence maternal and infant 25(OH)D concentrations. Conversely, winter season, obesity, lower socioeconomic status including lifestyle factors (smoking), and use of medication pose risk for lower maternal-fetal transfer of VitD. However, there is still a dearth of pertinent data on the relationship between some of the maternal risk factors and newborn 25(OH)D concentrations, for instance, relationships between gestational diabetes and neonatal VitD status. Additional research is required to determine if the same target for 25(OH)D concentrations applies for pregnant women, neonates, and infants.

Disparities in the timing and measurement methods to assess vitamin D status during pregnancy: A Narrative Review

Studies that examined associations between low circulating 25-hydroxyvitamin D (25(OH)D) and adverse pregnancy outcomes used various designs, assay methods and time points for measurement of 25(OH)D concentrations, which creates some confusion in the current literature. We aimed to investigate the variability in the timing and measurement methods used to evaluate vitamin D status during pregnancy. Analysis of 198 studies published between 1976 and 2017 showed an important variability in the choice of 1) threshold values for 25(OH)D insufficiency or deficiency, 2) 25(OH)D measurement methods, and 3) trimester in which 25(OH)D concentrations were measured. Blood samples were taken once during pregnancy in a large majority of studies, which may not be representative of vitamin D status throughout pregnancy. Most studies reported adjustment for confounding factors including season of blood sampling, but very few studies used the 25(OH)D gold standard assay, the LC-MS/MS. Prospective studies assessing maternal 25(OH)D concentrations 1) by standardized and validated methods, 2) at various time points during pregnancy, and 3) after considering potential confounding factors, are needed.

The role of vitamin D in perinatology. An up-to-date review

The role of vitamin D in perinatology is a subject of major interest in current medicine. There is growing evidence about the role of maternal vitamin D levels in pregnancy outcomes. The aim of this review is to summarize the current literature about the role of vitamin D in perinatology. Evidence from this review suggests associations between low levels of maternal vitamin D and higher risk of certain obstetrical complications. Vitamin D has been found to be related to preeclampsia, gestational diabetes mellitus, low birth weight, and preterm birth. The current literature supports vitamin D supplementation in pregnant women, but more high-quality data are necessary. The problem that remains is how to achieve an optimal 25-hydroxyvitamin D level. To determine the real benefits of vitamin D supplementation in pregnancy, we need high-quality trials in larger groups.

VDR Variants rather than Early Pregnancy Vitamin D Concentrations Are Associated with the Risk of Gestational Diabetes: The Ma'anshan Birth Cohort (MABC) Study

AIM

This study investigated the associations among early pregnancy vitamin D concentrations, seasonality, and vitamin D metabolic gene variants and how these variables related alone and in interaction with the risk of gestational diabetes mellitus (GDM).

METHODS

Research participants were women from the Ma'anshan birth cohort study in China. The overall study included 3110 women to explore the association between early pregnancy vitamin D concentrations and the risk of GDM. In the current analysis, a nested case-control study of 274 GDM cases and 380 controls was conducted to investigate seven vitamin D metabolic gene variants and the risk of GDM. Vitamin D concentrations were measured by radioimmunoassay. Genotypes were determined by improved multiple ligase detection reaction. Interactions between genetic variants and vitamin D as predictors of the risk of GDM were evaluated by a pair-wise analysis under a multiplicative interaction model.

RESULTS

Vitamin D concentrations were not significantly associated with the risk of GDM (OR = 0.79, 95% CI = 0.55-1.13) after adjusting for seasonality. Fall-winter conceptions had a 37% decreased risk of GDM compared with spring-summer conceptions (OR = 0.63, 95% CI = 0.49-0.81), independent of vitamin D concentrations. Two VDR gene variants rs1544410 (OR = 2.03, 95% CI = 1.17-3.51 for CT versus CC) and rs731236 (OR = 2.42, 95% CI = 1.29-4.55 for GA versus AA) were significantly associated with the risk of GDM. No interactions among genetic variants and vitamin D concentrations were detected.

CONCLUSION

Early pregnancy vitamin D insufficiency or deficiency was not significantly associated with the risk of GDM. The results of this study emphasize the importance of genetic variants in VDR and conception season as factors that affect the risk of GDM.

Histone H3 lysine 9 acetylation is downregulated in GDM Placentas and Calcitriol supplementation enhanced this effect

Despite the ever-rising incidence of Gestational Diabetes Mellitus (GDM) and its implications for long-term health of mothers and offspring, the underlying molecular mechanisms remain to be elucidated. To contribute to this, the present study's objectives are to conduct a sex-specific analysis of active histone modifications in placentas affected by GDM and to investigate the effect of calcitriol on trophoblast cell's transcriptional status. The expression of Histone H3 lysine 9 acetylation (H3K9ac) and Histone H3 lysine 4 trimethylation (H3K4me3) was evaluated in 40 control and 40 GDM (20 male and 20 female each) placentas using immunohistochemistry and immunofluorescence. The choriocarcinoma cell line BeWo and primary human villous trophoblast cells were treated with calcitriol (48 h). Thereafter, western blots were used to quantify concentrations of H3K9ac and the transcription factor FOXO1. H3K9ac expression was downregulated in GDM placentas, while H3K4me3 expression was not significantly different. Cell culture experiments showed a slight downregulation of H3K9ac after calcitriol stimulation at the highest concentration. FOXO1 expression showed a dose-dependent increase. Our data supports previous research suggesting that epigenetic dysregulations play a key role in gestational diabetes mellitus. Insufficient transcriptional activity may be part of its pathophysiology and this cannot be rescued by calcitriol.

Maternal Vitamin D Deficiency and the Risk of Small for Gestational Age: A Meta-analysis

BACKGROUND

Inconsistencies among studies still exist in regard to the associations between maternal vitamin D deficiency and the risk of small for gestational age.

METHODS

We conducted a meta-analysis of observational studies to evaluate these associations. We searched electronic databases for literature published in PubMed, Medline, Web of Science, Embase and the Cochrane Library up to Dec 2016 using the following keywords: "vitamin D" or "cholecalciferol" or "25-OHD" or "25-hydroxyvitamin D" in combination with "small for gestational age" or "SGA" or "fetal outcome" or "pregnancy outcome".

RESULTS

Twelve studies involving 19,027 participants were included in this meta-analysis. Pregnant women with vitamin D deficiency (25-OHD levels<50 nmol/L) experienced an increased risk of SGA (odds ratio (OR) =1.41, 95% confidence interval (CI): 1.14, 1.75). The vitamin D concentration of the SGA group was lower than that of the non-SGA group (mean difference: -1.75 nmol/L, 95%CI: -3.23, -0.27).

CONCLUSION

Maternal vitamin D deficiency during pregnancy may be associated with an increased risk of SGA.

Weekly High Dose Versus Daily Low Dose Vitamin D3 in Treatment of Vitamin D3 Deficiency in Pregnancy: A Randomized Controlled Clinical Trial

Objective: To compare administration of weekly high dose versus daily low dose vitamin D₃ in treatment of vitamin D₃ deficiency in pregnancy. Materials and methods: A randomized controlled clinical trial was performed between July 2016 until 2 July 2017 on 215 pregnant women with vitamin D₃ deficiency (serum levels < 30 ng/ml) and gestational age less than 14 weeks. The participants were randomly assigned to 2 treatment groups of A: receiving 1000 unit vitamin D₃ daily, and B: 50,000 units weekly for 10 weeks. At 24-28 weeks of gestation, serum levels of vitamin D₃ were measured again. Data entry and statistical analysis were performed by SPSS software v. 20 and P value less than 0.05 was considered as statistically significant level. Results: Primary mean serum vitamin D3 level in group A was: 17.3 ± 6.8 and in group B: 15.2 ± 7.3 ng/ml while mean serum vitamin D3 level after treatment in group A was significantly lower than group B (31.9 ± 118 B vs. 42.9 ± 15.5, p-value: < 0.001); both groups were successfully treated, no remarkable side effects were observed in either groups. Conclusion: As both regimens treat vitamin D deficiency successfully and consuming weekly high dose vitamin D₃ makes more acceptable serum levels for mothers with no apparent side effects weekly high dose vitamin D₃ can be safely administered for vitamin D₃ deficiency in pregnancy, if further studies show similar results.

Plasma concentrations of lipids during pregnancy and the risk of gestational diabetes mellitus: A longitudinal study

BACKGROUND

Abnormal lipid profiles have been associated with gestational diabetes mellitus (GDM), but studies with longitudinal measures of lipids throughout pregnancy are sparse. The aim of the present study was to characterize longitudinal changes in lipid profiles throughout pregnancy and prospectively examine the associations of plasma lipid concentrations with risk of GDM.

METHODS

This study was a nested case-control study including 107 GDM cases and 214 matched non-GDM controls from participants in the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies - Singleton cohort. Blood samples were collected longitudinally at Gestational Weeks (GW) 10-14, 15-26 (fasting sample), 23-31, and 33-39. Plasma concentrations of triglycerides, total cholesterol, and high-density lipoprotein cholesterol (HDL-C) were measured by enzymatic assays. Low-density lipoprotein cholesterol (LDL-C) was calculated using Friedewald's formula.

RESULTS

Plasma triglycerides, total cholesterol, and LDL-C increased as pregnancy progressed. At GW 10-14, the adjusted odds ratios (aORs) of GDM comparing the highest versus lowest quartile were 3.15 (95% confidence interval [CI] 1.38-7.15; P _trend  = 0.002) for triglycerides and 0.44 (95% CI 0.18-1.09; P _trend  = 0.045) for HDL-C. At GW 15-26, the aORs were 6.57 (95% CI 2.25-19.17; P _trend  = 0.001) for triglycerides and 0.23 (95% CI 0.08-0.63; P _trend  = 0.005) for HDL-C. No significant associations were observed for total cholesterol and LDL-C concentrations with risk of GDM.

CONCLUSIONS

Higher plasma triglyceride and lower HDL-C concentrations in early and mid-pregnancy were significantly associated with a greater risk of GDM. Total cholesterol and LDL-C concentrations during pregnancy were not significantly associated with GDM risk.

Maternal vitamin D supplementation during pregnancy

Introduction

Maternal vitamin D status in pregnancy has been linked to many health outcomes in mother and offspring. A wealth of observational studies have reported on both obstetric outcomes and complications, including pre-eclampsia, gestational diabetes, mode and timing of delivery. Many foetal and childhood outcomes are also linked to vitamin D status, including measures of foetal size, body composition and skeletal mineralization, in addition to later childhood outcomes, such as asthma.

Sources of data

Synthesis of systematic and narrative reviews.

Areas of agreement and controversy

The findings are generally inconsistent in most areas, and, at present, there is a lack of data from high-quality intervention studies to confirm a causal role for vitamin D in these outcomes. In most areas, the evidence tends towards maternal vitamin D being of overall benefit, but often does not reach statistical significance in meta-analyses.

Growing points and areas timely for developing research

The most conclusive evidence is in the role of maternal vitamin D supplementation in the prevention of neonatal hypocalcaemia; as a consequence the UK department of health recommends that pregnant women take 400 IU vitamin D daily. High-quality randomized placebo-controlled trials, such as the UK-based MAVIDOS trial, will inform the potential efficacy and safety of vitamin D supplementation in pregnancy across a variety of outcomes.

Vitamin D Deficiency Prevalence and Predictors in Early Pregnancy among Arab Women

Data regarding the prevalence and predictors of vitamin D deficiency during early pregnancy are limited. This study aims to fill this gap. A total of 578 Saudi women in their 1^st trimester of pregnancy were recruited between January 2014 and December 2015 from three tertiary care antenatal clinics in Riyadh, Saudi Arabia. Information collected includes socio-economic, anthropometric, and biochemical data, including serum vitamin D (25(OH)D) levels, intake of calcium and vitamin D, physical activity, and sun exposure indices. Pregnant women with 25(OH)D levels <50 nmol/L were considered vitamin D deficient. The majority of participants (n = 468 (81%)) were vitamin D deficient. High levels of indoor activity, whole body clothing, multiparity, total cholesterol/HDL ratio(>3.5), low HDL-cholesterol, and living in West Riyadh were significant independent predictors for vitamin D deficiency, with odds ratios (ORs) (95% confidence interval) of 25.4 (5.5–117.3), 17.8 (2.3–138.5), 4.0 (1.7–9.5), 3.3 (1.4–7.9), 2.8 (1.2–6.4), and 2.0 (1.1–3.5), respectively. Factors like increased physical activity, sun exposure at noon, sunrise or sunset, high educational status, and residence in North Riyadh were protective against vitamin D deficiency with ORs 0.2 (0.1–0.5); 0.2 (0.1–0.6); 0.3 (0.1–0.9); and 0.4 (0.2–0.8), respectively. All ORs were adjusted for age, BMI, sun exposure, parity, summer season, vitamin D intake, multivitamin intake, physical activity, education, employment, living in the north, and coverage with clothing. In conclusion, the prevalence of vitamin D deficiency among Saudi women during early pregnancy was high (81%). Timely detection and appropriate supplementation with adequate amounts of vitamin D should reduce the risks of vitamin D deficiency and its complications during pregnancy.

Maternal Early Pregnancy Plasma Concentration of 25-Hydroxyvitamin D and Risk of Gestational Diabetes Mellitus

We examined whether 25-Hydroxyvitamin D [25(OH) D] concentrations, measured at the first prenatal visit, would be associated with risk of gestational diabetes mellitus (GDM). From July 2015 to June 2016, consecutive women who admitted to the two-obstetrics center in china were included. Relevant data were collected between 24 and 28 weeks of gestation, including fasting plasma glucose (FPG) and 25(OH) D concentrations at the first prenatal visit and the one-step GDM screened with 75-g oral glucose tolerance test (OGTT). Blood from women at first prenatal visit was available for 827 women and 101 of them developed GDM (12.2%). The GDM distribution across the 25(OH) D quartiles ranged between 3.9% (fourth quartile, Q4) and 26.1% (first quartile, Q1). The median plasma concentration of 25(OH) D at first prenatal visit was significantly lower in women who developed GDM compared with those not developed (p < 0.001). In multivariate models comparing the 25(OH) D of Q1, second (Q2) and third quartiles (Q3) against the Q4, it observed that concentrations of 25(OH) D in Q1 and Q2 were associated with later developed GDM, and risk of GDM was increased by 240 and 48%, respectively. The women group with combined vitamin D deficiency and obesity had an OR of 4.66 [95% CI (2.91-8.15); p < 0.001] for GDM compared to those without vitamin D deficiency and obesity. Low 25(OH) D concentrations at the first prenatal visit were associated with increased risk of GDM and might be useful in identifying women at risk of GDM for performing early prevention strategies.

Effects of Vitamin D Deficiency on Incidence Risk of Gestational Diabetes Mellitus: A Systematic Review and Meta-analysis

INTRODUCTION

Proper nutrition is important for overall health, and it reduces healthcare costs associated with malnutrition. Many studies have investigated vitamin D deficiency and its role in gestational diabetes and controversial data have reported. A comprehensive consideration of articles in this field provides the possibility of a general study of this relationship. This meta-analysis is an evaluation of the relationship between vitamin D deficiency and gestational diabetes.

MATERIAL AND METHODS

Different databases (such as PubMed, Science Information Institute, EmBase, Scopus, and the Cochrane Library) were searched for studies and eligible English articles published before February 2017 that have reported the risk of gestational diabetes in relation to vitamin D deficiency. This relationship was measured using odds ratios (ORs) with a confidence interval (CI) of 95%. The influence of each study was measured through sensitivity analysis. Funnel plots, Egger regression tests, and the Begg-Mazumdar correlation test were used to determine bias or publication bias. STATA (version 11.2) was used for all analyses.

RESULTS

Twenty-six studies were selected as eligible for this research and included in the final analysis. In general, vitamin D deficiency among mothers may be related to an increased risk of gestational diabetes (OR = 1.18; 95% CI, 1.01-1.35; p < 0.001). The serum level of 25(OH)D is less meaningful in people with gestational diabetes than in those who have normal glucose tolerance. Subgroup analysis showed that the results concerning this association may vary with study design but do not change with country of origin.

CONCLUSION

Some evidence has shown that vitamin D deficiency may increase the risk of gestational diabetes.

Body size modifies the relationship between maternal serum 25-hydroxyvitamin D concentrations and gestational diabetes in high-risk women

Obesity increases the risk of low 25-hydroxyvitamin D (25(OH)D) concentrations and gestational diabetes (GDM). We explored whether the association between GDM and change in 25(OH)D concentrations measured in the first (7-18 wk) and second (20-27 wk) trimesters of pregnancy is dependent on maternal BMI. The study was a prospective study of 219 women with BMI of ≥30 kg/m², a history of GDM, or both. The participants were stratified by first-trimester BMI: BMI of <25.0, 25.0-29.9, 30.0-34.9, and ≥35 kg/m². In the BMI group ≥35 kg/m², those who did not develop GDM during the follow-up showed higher increase in serum 25(OH)D concentrations compared with women who developed GDM (43.2 vs. 11.5%; P < 0.001). No associations between 25(OH)D concentrations and GDM were observed in other BMI groups. These findings give an important aspect of the role of maternal body size in the association between vitamin D and GDM in high-risk women.

Role of Placental VDR Expression and Function in Common Late Pregnancy Disorders

Vitamin D, besides its classical role in bone metabolism, plays a distinct role in multiple pathways of the feto-maternal unit. Calcitriol is the major active ligand of the nuclear vitamin D receptor (VDR). The vitamin D receptor (VDR) is expressed in different uteroplacental parts and exerts a variety of functions in physiologic pregnancy. It regulates decidualisation and implantation, influences hormone secretion and placental immune modulations. This review highlights the role of the vitamin D receptor in physiologic and disturbed pregnancy, as preeclampsia, fetal growth restriction, gestational diabetes and preterm birth. We discuss the existing literature regarding common VDR polymorphisms in these pregnancy disorders.

Advanced maternal age and adverse pregnancy outcomes: A systematic review and meta-analysis

BACKGROUND

Advanced maternal age (AMA; ≥35 years) is an increasing trend and is reported to be associated with various pregnancy complications.

OBJECTIVE

To determine the risk of stillbirth and other adverse pregnancy outcomes in women of AMA.

SEARCH STRATEGY

Embase, Medline (Ovid), Cochrane Database of Systematic Reviews, ClinicalTrials.gov, LILACS and conference proceedings were searched from ≥2000.

SELECTION CRITERIA

Cohort and case-control studies reporting data on one or more co-primary outcomes (stillbirth or fetal growth restriction (FGR)) and/or secondary outcomes in mothers ≥35 years and <35 years.

DATA COLLECTION AND ANALYSIS

The effect of age on pregnancy outcome was investigated by random effects meta-analysis and meta-regression. Stillbirth rates were correlated to rates of maternal diabetes, obesity, hypertension and use of assisted reproductive therapies (ART).

MAIN RESULTS

Out of 1940 identified titles; 63 cohort studies and 12 case-control studies were included in the meta-analysis. AMA increased the risk of stillbirth (OR 1.75, 95%CI 1.62 to 1.89) with a population attributable risk of 4.7%. Similar trends were seen for risks of FGR, neonatal death, NICU unit admission restriction and GDM. The relationship between AMA and stillbirth was not related to maternal morbidity or ART.

CONCLUSIONS

Stillbirth risk increases with increasing maternal age. This is not wholly explained by maternal co-morbidities and use of ART. We propose that placental dysfunction may mediate adverse pregnancy outcome in AMA. Further prospective studies are needed to directly test this hypothesis.

Gestational Diabetes Mellitus, Fetal Growth and Vitamin D

Vitamin D is an important secosteroid hormone in skeletal and non-skeletal systems. Vitamin D has relevance to muscle and immune function, hypertension, diabetes mellitus, cancer, and pregnancy because vitamin D receptors (VDR) are present in many non-skeletal tissues. Vitamin D acts on target tissues via the binding of its active form to VDR. As vitamin D affects not only bone metabolism but also glucose metabolism, vitamin D deficiency may affect the development of gestational diabetes mellitus and fetal growth. Although vitamin D deficiency is prevalent during pregnancy, there are conflicting reports on the effect of vitamin D deficiency on pregnancy complications, such as fetal growth restriction and gestational diabetes. This article reviews published papers on the effects of vitamin D on gestational diabetes and fetal growth.

Relationship between vitamin D and gestational diabetes in overweight or obese pregnant women may be mediated by adiponectin

SCOPE

Maternal vitamin D deficiency has been implicated in adverse pregnancy outcomes. However, the association between vitamin D and inflammation, particularly adipokines, remains unexplored in pregnancy.

METHODS AND RESULTS

In 102 overweight or obese pregnant women at high-risk of gestational diabetes mellitus (GDM), we investigated relationships between maternal 25-hydroxyvitamin D (25(OH)D) concentrations at 12-15 wk gestation (baseline) and serum lipids, inflammatory markers, novel adipokines (omentin-1, visfatin, high molecular weight (HMW) adiponectin), and subsequent pregnancy outcomes (GDM, preeclampsia, preterm birth [PTB]). After adjustment for maternal factors (age, BMI, parity, ethnicity, and smoking status), baseline 25(OH)D concentrations were inversely associated with total cholesterol and triglycerides, and positively associated with HMW-adiponectin. Higher baseline 25(OH)D concentrations were associated with decreased fasting and 1-h post-OGTT glucose and reduced risk of GDM at 26-28 wk, as well as with longer gestation and reduced risk of PTB upon additional adjustment for caesarean section. Adding HMW-adiponectin to the multivariable models attenuated most associations, and HMW-adiponectin was a significant predictor in the models.

CONCLUSION

Our findings suggest that lower maternal 25(OH)D concentrations in overweight/obese pregnant women at high-risk of GDM are associated with increased cardiometabolic risks during pregnancy and adverse pregnancy outcomes, and that these associations may be mediated by HMW-adiponectin.