Impact of vitamin D deficiency on maternal and birth outcomes in the Saudi population: a cross-sectional study

Associations of maternal serum folate, vitamin B12 and their imbalance with gestational diabetes mellitus: The mediation effects of the methionine cycle related metabolites

BACKGROUND & AIMS

Maternal high level of folate and low level of vitamin B12, namely "folate and vitamin B12 imbalance", has been found to be associated with metabolic disorders, such as gestational diabetes mellitus (GDM). The aims of this study were to explore the associations of maternal serum folate, vitamin B12 and their imbalance in early pregnancy with GDM, and to explore the potential mediation effects of the methionine cycle related metabolites on the above associations.

METHODS

This nested case-control study (172 GDM case-control pairs) was conducted based on a prospective birth cohort. Serum concentrations of 5-methyltetrahydrofolate (5-MTHF), vitamin B12 and methionine cycle related metabolites [S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) and Homocysteine (Hcy)] were detected. 5-MTHF (nmol/L)/vitamin B12 (pmol/L) times 1000 was calculated to indicate the imbalance status of folate and vitamin B12. Conditional logistic regression was performed to analyze the associations of 5-MTHF, vitamin B12 and their imbalance with GDM. The mediation effect models were applied to explore the mechanism.

RESULTS

High serum level of 5-MTHF in early pregnancy was related to a higher risk of GDM (OR = 2.00, 95%CI: 1.19-3.37). Compared with the group of the lowest tertile concentration of vitamin B12, the group of the highest concentration had a lower risk of GDM (OR = 0.33, 95%CI: 0.11-0.97). Higher 5-MTHF/vitamin B12 was associated with a higher risk of GDM (OR = 1.67, 95%CI: 1.08-2.56). Besides, no significant mediation effect of methionine cycle related metabolites was found on the associations of folate, vitamin B12 and the imbalance status with the risk of GDM.

CONCLUSIONS

High maternal serum folate, low vitamin B12 levels and the resulting imbalance may increase the risk of GDM. The theory of "folate trap" could not explain the effect of folate, vitamin B12 and their imbalance on 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.

Vitamin D Deficiency and Its Association With Vitamin D Receptor Gene Variants Among Malaysian Women With Hypertensive Disorders in Pregnancy: Protocol for a Nutrigenomics Study

BACKGROUND

Vitamin D deficiency has been associated with hypertensive disorders in pregnancy (HDP). The risk of developing HDP was reported to be further augmented among individuals with a vitamin D receptor (VDR) genetic variant. However, the reported roles of VDR variants in hypertensive disorders are inconsistent among different populations. Given the relatively higher incidence of vitamin D deficiency among Malaysian pregnant women and the high incidence of HDP in this population, we hypothesize that there may be associations between the risk of vitamin D deficiency and HDP with VDR genetic variants.

OBJECTIVE

This paper outlines the protocol for a study to determine the association of vitamin D status and VDR sequence variants among Malaysian pregnant women with HDP.

METHODS

This prospective study consists of two phases. The first phase is a cross-sectional study that will entail gathering medical records, a questionnaire survey, and laboratory testing for vitamin D status, with a planned recruitment of 414 pregnant women. The questionnaire will be utilized to assess the risk factors for vitamin D deficiency. The vitamin D status will be obtained from measurement of the vitamin D (25-hydroxyvitamin D3) level in the blood. The second phase is a case-control study involving a Malay ethnic cohort with vitamin D deficiency. Participants will be divided into two groups with and without HDP (n=150 per group). Genomic DNA will be extracted from the peripheral blood monocytes of participants using the Qiagen DNA blood kit, and VDR sequence variants will be determined using polymerase chain reaction-high-resolution melting (PCR-HRM) analysis. Sanger sequencing will then be used to sequence randomly selected samples corresponding to each identified variant to validate our PCR-HRM results. The VDR genotype and mutation frequencies of BsmI, ApaI, TaqI, and FokI will be statistically analyzed to evaluate their relationships with developing HDP.

RESULTS

As of December 2023, 340 subjects have been recruited for the phase 1 study, 63% of whom were determined to have vitamin D deficiency. In the phase 2 study, 50 and 22 subjects have been recruited from the control and case groups, respectively. Recruitment is expected to be completed by March 2024 and all analyses should be completed by August 2024.

CONCLUSIONS

The outcome of the study will identify the nonmodifiable genetic components contributing to developing vitamin D deficiency leading to HDP. This will in turn enable gaining a better understanding of the contribution of genetic variability to the development of HDP, thus providing more evidence for a need of customized vitamin D supplementation during pregnancy according to the individual variability in the response to vitamin D intake.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05659173; https://clinicaltrials.gov/study/NCT05659173.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/53722.

Seasonal Variations in 25-Hydroxyvitamin D Levels among Pediatric Patients Attending the Healthcare Centre

Vitamin D plays an essential role in maintaining bone density, building the immune system, and regulating cell growth alongside other key biological functions. Limited data are available about the seasonal variation in vitamin D levels in the pediatric population in Saudi Arabia. This study aimed to investigate the seasonal influence on the pediatric circulating levels of 25(OH)D. A total of 1790 pediatric outpatients who visited the University healthcare centre were included in this study. Overall, there was a noticeably high prevalence (69%) of both combined 25(OH)D deficiency and insufficiency. The highest mean serum concentration of 25(OH)D was recorded in summer (29 ng/mL) and autumn (27 ng/mL). The deficient and insufficient categories were predominant, accounting for 33% and 36%, respectively. Comparable patterns were recorded during autumn, winter, and spring. Interestingly, the 25(OH)D level was significantly associated with the four seasons (p = 0.001), with females having a higher prevalence of 25(OH)D deficiency in the spring and summer than males. Furthermore, only in autumn and winter, we found a significant association between gender and 25(OH)D status (p < 0.001 for both). Another association between nationality and the circulating levels 25(OH)D was found during autumn and winter (p < 0.001 and p = 0.01), respectively. In all seasons, age had a negative impact on serum (OH)D levels. However, this relationship was statistically significant (p < 0.05) only in summer, autumn, and winter. Gender was a significant predictor, with 25(OH)D levels in autumn and winter and an odds ratio of 1.67 in autumn and 2 in winter, indicating that being men had a positive influence on circulating 25(OH)D levels. There were highly significant differences in 25(OH)D concentrations among different age categories. The Saudi population experiences low levels of vitamin D, particularly in autumn and winter periods. This study showed that seasonality, age category, nationality, and gender influence vitamin D status, suggesting the need for tailored intervention and monitoring of 25(OH)D status to reach adequate levels of vitamin D. Healthcare practitioners and policymakers may consider the interplay between age, nationality, gender, and seasonal variations when addressing vitamin D status and a targeted supplementation approach for high-risk groups that may develop health issues.

Relationship Between Vitamin D Level and Gestational Diabetes Mellitus: A Cross-Sectional Study

Aim

To determine the correlation between vitamin D levels and gestational diabetes mellitus.

Materials and Methods

Cross-sectional observational study, conducted in Gauhati Medical College and Hospital, over a period of 1 year, on 350 antenatal patients, with gestational age beyond 24 weeks, keeping in mind the inclusion and exclusion criteria. Age, obstetric score, religion, BMI were noted for all patients. They underwent screening for gestational diabetes mellitus using DIPSI (Diabetes in Pregnancy Study Group of India) guidelines and were divided into two groups. Vitamin D estimation by CLIA method (chemiluminescence method) was done in both groups and results were compared. Association between vitamin D levels and gestational diabetes mellitus was studied using Chi Square Test.

Results

The prevalence of vitamin D deficiency in antenatal patients was found to be 63.7%. 73% of gestational diabetes mellitus patients were deficient in vitamin D. There was a statistically significant association seen between vitamin D level and Gestational diabetes mellitus (p value-0.046). There was 1.34 times increased risk of developing gestational diabetes mellitus when the vitamin D levels were deficient as compared to when the vitamin levels were within the normal range.

Conclusion

There was a high level of vitamin D deficiency in the pregnant women of North East. Due to lack of screening of vitamin D levels, many pregnant women suffer from adverse feto-maternal outcomes. There is a need to identify them early in pregnancy, provide vitamin D supplementation and to decrease the likelihood of them developing complications.

Effects of vitamin D on insulin resistance and fasting blood glucose in pregnant women with insufficient or deficient vitamin D: a randomized, placebo-controlled trial

BACKGROUND

Gestational diabetes is one of the most common metabolic disorders during pregnancy. Some studies have reported the effect of vitamin D deficiency on the incidence of this disorder. Therefore, the purpose of the present study was to determine the effect of vitamin D supplementation on fasting blood glucose (FBG) levels, fasting blood insulin (FBI) levels and insulin resistance index (HOMA-IR) (primary outcomes) and symptoms of depression, musculoskeletal pain, frequency of gestational diabetes and the frequency of abortion (secondary outcomes).

METHODS

In this triple-blind randomized controlled trial, 88 pregnant women at 8-10 weeks of pregnancy who had the vitamin D of less than 30 ng/ml were randomly assigned to the vitamin D group (n = 44) and control group (n = 44) using block randomization. The vitamin D group received 4,000 units of vitamin D tablets daily and the control group received placebo tablets for 18 weeks. Independent t-test, Mann-Whitney U and ANCOVA tests were used to analyze the data.

RESULTS

After the intervention, there was no statistically significant difference between the two groups in terms of FBG (P = 0.850), FBI (P = 0.353), HOMA-IR (P = 0.632), mean score of depressive symptoms (P = 0.505), frequency of gestational diabetes (P = 0.187) and frequency of abortion (P = 1.000) and there was only a difference in terms of serum vitamin D level (P = 0.016) and musculoskeletal pain including knee pain (P = 0.025), ankle pain (P < 0.001) and leg pain (P < 0.001).

CONCLUSION

Vitamin D could improve the musculoskeletal pain in pregnant women but couldn't decrease FBG, FBI, HOMA-IR, depression symptoms score, incidence of GDM and abortion.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials (IRCT): IRCT20120718010324N59. Date of registration: 4/11/2020. URL: https://en.irct.ir/user/trial/50973/view ; Date of first registration: 21/11/2020.

Relationship between Maternal Vitamin D Levels and Adverse Outcomes

Vitamin D (VD), a fat-soluble vitamin, has a variety of functions that are important for growth and development, including regulation of cell differentiation and apoptosis, immune system development, and brain development. As such, VD status during pregnancy is critical for maternal health, fetal skeletal growth, and optimal pregnancy outcomes. Studies have confirmed that adverse pregnancy outcomes, such as preeclampsia, low birth weight, neonatal hypocalcemia, poor postnatal growth, skeletal fragility, and increased incidence of autoimmune diseases, can be associated with low VD levels during pregnancy and infancy. Thus, there is growing interest in the role of VD during pregnancy. This review summarizes the potential adverse health outcomes of maternal VD status during pregnancy for both mother and offspring (gestational diabetes mellitus, hypertensive gestational hypertension, intrauterine growth restriction, miscarriage, stillbirth, and preterm birth) and discusses the underlying mechanisms (regulation of cytokine pathways, immune system processing, internal secretion, placental function, etc.) of VD in regulating each of the outcomes. This review aims to provide a basis for public health intervention strategies to reduce the incidence of adverse pregnancies.

Vitamin D Levels in Early and Middle Pregnancy and Preeclampsia, a Systematic Review and Meta-Analysis

Vitamin D (VitD) shows a beneficial role in placentation, the immune system, and angiogenesis, and thus, VitD status may link to the risk of preeclampsia. A meta-analysis was conducted to investigate the association between VitD status in early and middle pregnancy and the risk of preeclampsia. A total of 22 studies with 25,530 participants were included for analysis. Women with VitD insufficiency or deficiency had a higher preeclampsia rate compared to women with replete VitD levels (OR 1.58, 95% CI 1.39–1.79). Women with VitD deficiency had a higher preeclampsia rate compared to women with replete or insufficient VitD levels (OR 1.35, 95% CI 1.10–1.66). Women with insufficient VitD levels had a higher preeclampsia rate compared to women with replete VitD levels (OR 1.44, 95% CI 1.24–1.66). Women with deficient VitD levels had a higher preeclampsia rate compared to women with replete VitD levels (OR 1.50, 95% CI 1.05–2.14). Sensitivity analysis showed the results were stable after excluding any one of the included studies. In conclusion, our systematic review suggested that VitD insufficiency or deficiency was associated with an increased risk of preeclampsia.

The Association of Maternal Vitamin D Status during Pregnancy and Neonatal Anthropometric Measurements: A Longitudinal Study in Minangkabau Pregnant Women, Indonesia

The prevalence of vitamin D deficiency (VDD) appears to be increasing. VDD during pregnancy has been associated with several adverse pregnancy outcomes. This study aimed to investigate the association between VDD and fetal anthropometric measurement. This prospective cohort study consisted of 232 pregnant women in their first trimester who were recruited at the antenatal clinics and they maintained to be subjects of the study until their delivery time. Serum 25-hydroxyvitamin D (25(OH)D) concentration was measured at first and third trimester using enzyme-linked immunosorbent assay. The prevalence of VDD in the first-trimester was 82.8%. Mean of 25(OH)D concentration in the third-trimester was significantly higher than in the first trimester (14.00 (6.98) vs. 21.22 (10.17) ng/mL). After adjusting age, pre-pregnancy BMI, and gestational age at delivery, it was found that VDD during pregnancy was not significantly associated with neonatal anthropometry (p>0.05). It was concluded that VDD was common in a tropical country. Large, well designed, multicentre observational studies are required to determine whether VDD enhances the risk of adverse pregnancy outcomes.

Ineffectiveness of antenatal guidance intervention for vitamin D insufficiency and deficiency in pregnant women in Kyoto, Japan

AIM

The aim of this study was to investigate the vitamin D status among healthy pregnant women in Japan, and to evaluate the effectiveness of the antenatal health guidance intervention for the pregnant women who were informed about their low vitamin D levels.

METHODS

We measured the level of 25-hydroxyvitamin D (25[OH]D) using chemiluminescent immunoassay among the singleton pregnant women who received at antenatal routine check-up (8-24 weeks of gestation) with written consent during September 2017-September 2018. The measurement values were informed by the concerned physician and health guidance intervention was given to the pregnant women with inadequate Vitamin D status (25[OH]D < 30 ng/mL). At around 36 weeks of gestation, the measurement of 25(OH)D and a questionnaire regarding behavioral changes after the guidance was conducted.

RESULTS

The average value of 25(OH)D of 1192 pregnant women before the guidance was 14.89 ± 4.85 ng/mL, and the prevalence of sufficient vitamin D status (25(OH)D ≥ 30 ng/mL) was 0.67% (8/1192). Nine hundred eighty-two pregnant women who had inadequate vitamin D status were followed, thereafter-guidance prevalence of sufficiency was 1.02% (10/982); insufficiency, 14.66% (144/982); and deficiency, 84.32% (828/982), respectively. Although the prevalence of deficiency was decreased after guidance intervention significantly, the prevalence was still high and the effect on behavioral changes was a little.

CONCLUSION

The prevalence of vitamin D sufficient status among pregnant women in Japan was extremely low, which is a serious condition. It was also revealed the effectiveness of the antenatal health guidance intervention for pregnant women was not enough.

Vitamin D status and healthy Egyptian adolescents: Where do we stand?

Vitamin D deficiency is a worldwide public health problem. Low vitamin D and its consequences among children and adolescents could be considered as one of the most important health-related problems. This study aimed to estimate the prevalence of vitamin D deficiency in healthy Egyptian adolescents and investigate factors associated with vitamin D status.A cross-sectional study was conducted on 572 school children (270 males and 302 females) aged 14 to 18 years, who were randomly selected from high schools in one governorate in Egypt. Data were collected through a self-administered questionnaire. Vitamin D level, serum calcium, phosphorus, alkaline phosphates were measured.Vitamin D deficiency was almost present in all the studied Egyptian healthy adolescents (99%), 94.8% had vitamin D deficiency and 4.2% had vitamin D insufficiency. Girls had a higher prevalence of vitamin D deficiency than boys. There was a significant association between lack of physical activity, sun exposure, and vitamin D deficiency.Vitamin D deficiency and insufficiency are highly prevalent. In sunny countries, the special pattern of conservative clothing and the lack of outdoor physical activity might be the underlying factors for the high prevalence in females. Vitamin D supplementation seems to be mandatory to halt the problem.

Vitamin D Levels in Mother-Baby Pairs: A Cross-Sectional Prospective Study in a Rwandan Tertiary Hospital

BACKGROUND

Exposure to the sunlight contributes largely to the production of vitamin D. However, vitamin D deficiency is a reality in tropical countries, despite enjoying enough sunlight, especially bearing women in their last trimester whose foetuses exclusively depend on their reserves. This work aimed at demonstrating the state of vitamin D in mother-baby pairs and associated factors in one of the University Hospitals in Rwanda.

METHODS

This cross-sectional prospective study was performed on mother-baby pairs at Kigali University Hospital. Mother's serum 25-hydroxyvitamin D levels were considered as outcomes compared with demographic, clinical and biological markers. Correlation analysis was conducted in order to assess the association between serum 25-hydroxyvitamin D levels for the couple mothers-babies.

RESULTS

Approximately 38% of women and 65% of neonates had deficiency in 25-hydroxyvitamin D (<20 ng/ml). The use of a vitamin D rich diet within 24 h recall (p < 0.01) or 1 week recall (p < 0.001) before delivery was associated with appropriate vitamin D levels in mothers. Interestingly, a strong positive correlation was found between maternal and neonatal serum 25-hydroxyvitamin D levels (r = 0.760).

CONCLUSIONS

There was a high rate of vitamin D deficiency in mothers and their babies. Babies born from women with deficiency were likely to develop low levels of vitamin D. This stresses on the need to strengthen the interventions for preventing vitamin D deficiency in the couple mothers-babies such as supplement in vitamin D before and after delivery, improving the quality of meals and regular contact with sunlight.

Prevalence of Gestational Diabetes Mellitus in the Middle East and North Africa, 2000-2019: A Systematic Review, Meta-Analysis, and Meta-Regression

Women in the Middle East and North Africa (MENA) region are burdened with several risk factors related to gestational diabetes mellitus (GDM) including overweight and high parity. We systematically reviewed the literature and quantified the weighted prevalence of GDM in MENA at the regional, subregional, and national levels. Studies published from 2000 to 2019 reporting the prevalence of GDM in the MENA region were retrieved and were assessed for their eligibility. Overall and subgroup pooled prevalence of GDM was quantified by random-effects meta-analysis. Sources of heterogeneity were investigated by meta-regression. The risk of bias (RoB) was assessed by the National Heart, Lung, and Blood Institute's tool. One hundred and two research articles with 279,202 tested pregnant women for GDM from 16 MENA countries were included. Most of the research reports sourced from Iran (36.3%) and Saudi Arabia (21.6%), with an overall low RoB. In the 16 countries, the pooled prevalence of GDM was 13.0% (95% confidence interval [CI], 11.5-14.6%, I² , 99.3%). Nationally, GDM was highest in Qatar (20.7%, 95% CI, 15.2-26.7% I² , 99.0%), whereas subregionally, GDM was highest in Gulf Cooperation Council (GCC) countries (14.7%, 95% CI, 13.0-16.5%, I² , 99.0%). The prevalence of GDM was high in pregnant women aged ≥30 years (21.9%, 95% CI, 18.5-25.5%, I² , 97.1%), in their third trimester (20.0%, 95% CI, 13.1-27.9%, I² , 98.8%), and who were obese (17.2%, 95% CI, 12.8-22.0%, I² , 93.8%). The prevalence of GDM was 10.6% (95% CI, 8.1-13.4%, I² , 98.9%) in studies conducted before 2009, whereas it was 14.0% (95% CI, 12.1-16.0%, I² , 99.3%) in studies conducted in or after 2010. Pregnant women in the MENA region are burdened with a substantial prevalence of GDM, particularly in GCC and North African countries. Findings have implications for maternal health in the MENA region and call for advocacy to unify GDM diagnostic criteria.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018100629.

Vitamin D during pregnancy and its association with birth outcomes: a Brazilian cohort study

BACKGROUND/OBJECTIVES

Evidence is lacking on how variation in vitamin D concentrations during gestation affects perinatal outcomes. Therefore, we evaluated the association between vitamin D serum concentrations during pregnancy and neonatal outcomes.

METHODS

A prospective cohort of 180 healthy Brazilian pregnant women was followed and plasma 25-hydroxyvitamin [25(OH)D, nmol/L] was measured at 5-13 (baseline), 20-26 and 30-36 gestational weeks. Birth weight (BW), birth length (BL), BW z-scores, BL z-scores, first minute Apgar, small for gestational age (SGA), large for gestational age (LGA) and preterm birth were the outcomes. Multiple linear and Poisson regression models were estimated. Best linear unbiased prediction of random coefficients model was used to determine the association between the mean rate of change in vitamin D during pregnancy concentrations and neonatal outcomes.

RESULTS

Mean (SD) BW was 3300 (600) g, BW z-score 0.34 (1.11), BL 49.3 (3.3) cm, BL z-score 0.44 (1.5), and first minute Apgar score 8.2 (1.4). Prevalence of SGA, LGA and preterm birth were 6%, 18% and 13%, respectively. 25(OH)D was directly associated with the risk of preterm birth at all trimesters. Incidence-rate ratios were 1.02, 1.05 and 1.04 for the 1st, 2nd and 3rd trimester, respectively. Mean rate of change during pregnancy in 25(OH)D was directly associated with BW z-score (β: 0.36, 95% CI 0.07; 0.65), LGA risk (IRR: 1.97, 95% CI 1.07; 3.63) and preterm birth (IRR: 7.35, 95% CI 2.99; 18.07).

CONCLUSIONS

Mean 25(OH)D rate of change during pregnancy was directly associated with BW z-scores, and increased LGA and preterm birth risk.

Study on the levels of 25(OH)D, inflammation markers and glucose and fat metabolism indexes in pregnant women of Han nationality in Jiangsu province with gestational diabetes mellitus

The aim of this study is to investigate the levels of 25(OH)D, inflammation markers and glucose and fat metabolism indexes in pregnant women with Gestational diabetes mellitus (GDM).One hundred and ten cases GDM and 100 cases healthy pregnant women in the First People's Hospital of Lianyungang City from October 2016 to December 2018 were recruited for this observational cross-sectional study. Each participant's anthropometric and demographic data was recorded. Blood samples were collected and analyzed to determine the levels of 25(OH)D, high sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-alpha (TNF-α), fasting blood glucose, fasting blood insulin, hemoglobin A1c (HbA1c), homeostasis model assessment of insulin resistance (HOMA-IR), cholesterol and triglycerides.Inflammatory markers and glucose and fat metabolism indexes were all significantly higher in the GDM group than that in the control group, while Serum 25(OH)D level in the GDM group was significantly lower. Serum 25(OH)D levels were negatively correlated with hs-CRP, while not with TNF-α. Furthermore, Serum 25(OH)D, hs-CRP and TNF-α levels were all associated with increased risk of developing GDM.Nowadays, the reports on the association between 25(OH)D level and GDM were controversial. Our results are consistent with the view that there was association between 25(OH)D level and GDM, and expand the literature by showing the roles of 25(OH)D, inflammation markers as well as glucose and fat metabolism indexes in the risk of developing GDM in the pregnant women with the low overall levels of 25(OH)D before delivery. This broadens our knowledge on the pathophysiology of GDM, which may be helpful in prevention and treatment of GDM.

Vitamin D, preeclampsia and prematurity: A systematic review and meta-analysis of observational and interventional studies

BACKGROUND

Vitamin D has important functions outside of bone metabolism. Deficiency has been associated with several adverse outcomes during pregnancy such as preeclampsia and prematurity. There is an increasing body of literature on this topic with studies performed to date having produced contradictory results.

OBJECTIVE

To synthesize the literature about vitamin D deficiency and its association with preeclampsia and prematurity in order to determine if maternal vitamin D insufficiency and/or deficiency during pregnancy is associated with the prevalence of preeclampsia and prematurity.

DESIGN

A systematic review and meta-analysis of observational and interventional studies.

METHODS

Two independent researchers reviewed the included studies according to PRISMA reporting guidelines. A protocol for this review was registered in PROSPERO with the registration number: "CRD42019136318". Three electronic databases (PubMed, ScienceDirect and Web of Science); were searched in order to identify eligible studies. Observational and interventional studies were selected which had been published in the last 6 years, and analysed the association between maternal vitamin D concentrations during pregnancy and the development of preeclampsia and/or preterm birth. Data were extracted and presented in tables and figures. Fixed and random-effects meta-analyses were performed on the studies which provided enough sample data to calculate odds ratios. Results from both statistical methods were compared. Meta-analysis cut-off points for vitamin D insufficiency and deficiency were defined as <75nmol/L and <50nmol/L, respectively.

RESULTS

Fifty-five studies met the inclusion criteria. Fixed-effects meta-analysis of the interventional studies indicated that vitamin D supplementation acts as a prevention factor for preeclampsia and prematurity. Fixed-effects meta-analysis of observational studies concluded that vitamin D insufficiency and deficiency are associated with a higher risk of developing preeclampsia. However, prematurity and vitamin D were only associated when maternal vitamin D concentrations was <75 nmol/L. Random-effects meta-analysis found no significant association between vitamin D, preeclampsia and prematurity in either observational or interventional studies.

CONCLUSION

Higher vitamin D concentrations during pregnancy could be associated with a decreased risk of preeclampsia and prematurity but statistical significance of associations depends on the study design used. Well-designed clinical trials with vitamin D supplementation are needed in order to better define associations.

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.

The prevalence of hypovitaminosis D and its risk factors in pregnant women and their newborns in the Middle East: A systematic review

BACKGROUND

Pregnant women and newborns are at risk for vitamin D deficiency (VDD). Also, poor health outcomes for pregnant women with VDD are reported in the published literature.

OBJECTIVE

The aim of this systematic review was to estimate the prevalence of hypovitaminosis D and the associated risk factors for hypovitaminosis D in Middle Eastern pregnant women and their newborns.

RESULTS

The prevalence of circulating 25-hydroxyvitamin D (25(OH)D) < 50 nmol/L as a marker of vitamin D status in pregnant women and their newborns was between 24.5-98% and 22-100%, respectively. The prevalence of 25(OH) D < 25 nmol/L in pregnant women and their newborns was over a wide range between 16.7-80% and 22-82%, respectively. Predictors for low maternal and neonatal 25(OH)D concentrations included decreased vitamin D synthesis due to reduced exposure to sunlight and decreased nutritional intake of vitamin D. A predictor of low neonatal 25(OH)D concentrations included maternal vitamin D status and the correlation between vitamin D concentrations in maternal and cord blood.

CONCLUSION

The high prevalence of VDD in the pregnant women of the Middle East underscores the necessity of implementing national prevention and intervention strategies. A clear policy for clinicians and healthcare workers is needed for screening and maintaining sufficient vitamin D status during pregnancy.

Maternal vitamin D deficiency during pregnancy and low birth weight: a systematic review and meta-analysis

OBJECTIVE

The object of the present study was to estimate the relationship between maternal vitamin D deficiency during pregnancy and low birth weight by systematically review prevalence studies.

METHODS

We collected data from relevant studies published up to April 2019 using predefined inclusion/exclusion criteria. And all the studies were searched in PubMed, Embase, Cochrane Library, and Web of Science.

RESULTS

A total of 16 studies met the criteria and were included in the meta-analysis. When compared with normal serum levels of vitamin D, the maternal vitamin D deficiency had an increased risk of low birth weight (OR = 2.39; 95%CI 1.25-4.57; p = .008), and same results were found in the comparison of the mean (the total mean birth weight decreased by 0.08 kg; 95%CI -0.10 to -0.06; p < .001).

CONCLUSION

The evidence from this meta-analysis indicates a consistent association between vitamin D deficiency during pregnancy and an increased risk of low birth weight, and preventing maternal vitamin D deficiency may be an important public health strategy to help decrease the risk of low birth weight.

High Prevalence of Vitamin D Deficiency in Pregnant Women in South China

Objective: To investigate the vitamin D status of pregnant women in the Liuzhou area and assess the effects of maternal vitamin D status on the cord blood of their newborns. Subjects and methods: This study included 8852 pregnant women and 2000 newborns. The serum 25-hydroxyvitamin D [25(OH)D] levels of the 8852 pregnant women and the cord blood of 2000 newborns were measured. Results: The results showed that the average level of 25(OH)D in pregnant women in this area was 76.55 nmol/L, and women in different trimesters had different vitamin D levels (p < 0.001). The overall prevalence of vitamin D deficiency (<75 nmol/L) in pregnant women was 62.34%, and the proportion of severe deficiency (<25 nmol/L) was 0.25%. Vitamin D deficiency was more prevalent in the winter and spring than in the summer and autumn (p < 0.001). Pregnant women who had regular vitamin D supplementation had higher levels of 25(OH)D than the women with discontinuous supplementation or no supplementation (p < 0.001). Conclusions: Vitamin D deficiency was prevalent in pregnant women in the Liuzhou area. There were differences in vitamin D levels between the three trimesters and different seasons. For pregnant women with vitamin D deficiency, it is important to scientifically determine the appropriate level of vitamin D supplementation to ensure the health of mothers and babies.

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.

Knowledge, attitude and practice of health care practitioners in Saudi Arabia, with regard to prevention of vitamin D deficiency in infancy

Objectives:

To understand the knowledge, attitude, and practice of healthcare practitioners in Saudi Arabia, with regard to vitamin D supplementation.

Methods:

A cross-sectional survey was conducted among healthcare practitioners in the Tabuk region of Saudi Arabia between January 2015 and December 2016. A questionnaire assessing knowledge, attitude and practice with regard to prevention of vitamin D deficiency was distributed to 100 healthcare practitioners.

Results:

There was a good understanding of the importance of vitamin D deficiency; and overall practices were good. The average knowledge score was 4.75/8 (range 2-7), largely due to 85% of recipients identifying sun exposure between 6-7 am as the optimal time. There was a lack of understanding also, that as little as 10 minutes exposure is of benefit.

Conclusion:

This study highlights the need for distribution of the recommendations for vitamin D supplementation in KSA, as widely as possible. This study suggests that healthcare practitioners understand the importance of correction of vitamin D deficiency. Deficiencies in knowledge with regard to sun exposure were identified. Dissemination of this information is, therefore, likely to impact significantly on the practice of a receptive clinical population.

Role of vitamin D in pregnancy and Toll-like receptor pathway

There is a growing concern about the impacts of hypovitaminosis D on the health of pregnant woman, fetal development, childhood, and adult life. Variations in maternal nutrition during gestation and/or lactation play a critical role in the physiological and metabolic development of the fetus and neonate, which can induce phenotypic changes and trigger important consequences throughout life, such as type 2 diabetes, cardiovascular disease, obesity, and hypertension. Vitamin D plays a role in regulating cell proliferation and differentiation and in modulating the innate and adaptive immune response. Also, vitamin D correlates with changes in cytokines, anti and proinflammatory, as well as prevents inflammation induced by changes in myometrial cells mediated by the nuclear factor kappa B pathway. Further investigation is required regarding these relationship.

Maternal vitamin D deficiency increases the risk of adverse neonatal outcomes in the Chinese population: A prospective cohort study

BACKGROUND

Although vitamin D (vitD) deficiency is a common problem in pregnant women, in China, few studies have focused on the relationship between maternal vitD deficiency throughout the three trimesters and subsequent neonatal outcomes in China.

METHODS

Between 2015 and 2016, maternal serum and neonate cord blood samples were collected from 1978 mother-neonate pairs from Liuzhou city.

RESULTS

The mean concentrations of 25-hydroxy vitD (25(OH)D) were 16.17±6.27 and 15.23±5.43 ng/ml in the mother and neonate groups, respectively, and the prevalence values of vitD deficiency in the two groups were 78.18% and 83.27%, respectively. Logistic regression showed that maternal vitD deficiency independently increased the risk of gestational diabetes mellitus (GDM) (adjust OR, aOR 1.08; P = 0.026). A relatively lower risk of vitD deficiency was observed in the third trimester than in the first and second trimester (aOR 0.80; P = 0.004). VitD-calcium cosupplementation during pregnancy improves the vitD deficiency in both the maternal and neonatal groups (aOR 0.56, 0.66; P<0.001 and 0.021, respectively). Maternal vitD deficiency significantly increased the risk of neonatal low birth weight (LBW) (aOR 2.83; P = 0.005) and small-for-gestational-age (SGA) (aOR 1.17; P = 0.015). There was a positive correlation between maternal and neonatal vitD deficiency (r = 0.879, P<0.001). VitD supplementation during pregnancy significantly reduced the risk of giving birth to LBW infants (OR = 0.47, 95%CI = 0.33-0.68, P<0.001).

CONCLUSIONS

Further research focusing on the consumption of vitD with calcium during pregnancy and the consequential clinical outcomes in Chinese pregnant women is warranted.

Systematic Review of Vitamin D and Hypertensive Disorders of Pregnancy

This narrative systematic review evaluates growing evidence of an association between low maternal vitamin D status and increased risk of hypertensive disorders. The inclusion of interventional, observational, and dietary studies on vitamin D and all hypertensive disorders of pregnancy is a novel aspect of this review, providing a unique contribution to an intensively-researched area that still lacks a definitive conclusion. To date, trial evidence supports a protective effect of combined vitamin D and calcium supplementation against preeclampsia. Conflicting data for an association of vitamin D with gestational hypertensive disorders in observational studies arises from a number of sources, including large heterogeneity between study designs, lack of adherence to standardized perinatal outcome definitions, variable quality of analytical data for 25-hydroxyvitamin D (25(OH)D), and inconsistent data reporting of vitamin D status. While evidence does appear to lean towards an increased risk of gestational hypertensive disorders at 25(OH)D concentrations <50 nmol/L, caution should be exercised with dosing in trials, given the lack of data on long-term safety. The possibility that a fairly narrow target range for circulating 25(OH)D for achievement of clinically-relevant improvements requires further exploration. As hypertension alone, and not preeclampsia specifically, limits intrauterine growth, evaluation of the relationship between vitamin D status and all terms of hypertension in pregnancy is a clinically relevant area for research and should be prioritised in future randomised trials.

Vitamin D Does Not Play a Functional Role in Adipose Tissue Development in Rodent Models

SCOPE

Several studies have proposed a role of vitamin D in adipogenesis. Here, we sought to study the impact of the vitamin D receptor (Vdr) on adipocyte size in young and old mice and the effect of maternal vitamin D deficiency on fetal adipogenesis.

METHODS AND RESULTS

Histological analysis of adipose tissues shows that Vdr knockout (KO) mice have smaller adipocytes than wild-type (WT) mice. Next, we compare young and old Vdr-KO and WT mice and find no differences in adipocyte sizes between weaned Vdr-KO and WT mice. However, 1-year-old Vdr-KO mice, suffering from alopecia, have smaller-sized adipocytes than WT mice, although they consume more food. To elucidate whether vitamin D can directly impact adipocyte development at a critical stage of adipogenesis, we feed rat dams a vitamin D deficient (0 IU kg-1 ) or vitamin D adequate (1000 IU kg-1 ) diet. Neither DNA microarray analysis of the adipose tissues of the newborn rats nor the adipocyte sizes of 21-day-old offspring show significant differences between the two groups.

CONCLUSION

Data indicate that vitamin D does not play a fundamental role in adipogenesis because vitamin D does not affect fetal adipogenesis. Moreover, the smaller adipocytes observed in adult Vdr-KO mice are presumably caused by an increased energy expenditure due to alopecia.

Vitamin D and risk of preterm birth: Up-to-date meta-analysis of randomized controlled trials and observational studies

AIM

We performed a meta-analysis of randomized controlled trials (RCT) and observational studies to answer the two following questions: (i) whether low maternal circulating 25 hydroxyvitamin D (25-OHD) is associated with an increased risk of preterm birth (PTB) or spontaneous PTB (sPTB); and (ii) whether vitamin D supplementation alone during pregnancy can reduce the risk of PTB.

METHODS

Literature search was carried out using Pubmed, Web of Science and Embase databases up to June 2016. Pooled OR or relative risk (RR) with 95%CI were computed using fixed or random effects models depending on the size of heterogeneity. Subgroup analysis was used to explore potential sources of between-study heterogeneity. Publication bias was evaluated using Egger's test and Begg's test.

RESULTS

Twenty-four articles (six RCT and 18 observational studies) were identified. Maternal circulating 25-OHD deficiency (pooled OR, 1.25; 95%CI: 1.13-1.38) rather than insufficiency (pooled OR, 1.09; 95%CI: 0.89-1.35) was associated with an increased risk of PTB, and vitamin D supplementation alone during pregnancy could reduce the risk of PTB (pooled RR, 0.57; 95%CI: 0.36-0.91). This was also the case for the sPTB subgroup (circulating 25-OHD <50 vs >50 nmol/L; pooled OR, 1.45; 95%CI: 1.20-1.75).

CONCLUSIONS

Maternal circulating 25-OHD deficiency could increase PTB risk and vitamin D supplementation alone during pregnancy could reduce PTB risk. Extrapolation of the results, however, must be done with caution, and there is urgent need for larger, better-designed RCT to confirm this effect.

The Prevalence of Micronutrient Deficiencies and Inadequacies in the Middle East and Approaches to Interventions

Micronutrient deficiencies and inadequacies constitute a global health issue, particularly among countries in the Middle East. The objective of this review is to identify micronutrient deficits in the Middle East and to consider current and new approaches to address this problem. Based on the availability of more recent data, this review is primarily focused on countries that are in advanced nutrition transition. Prominent deficits in folate, iron, and vitamin D are noted among children/adolescents, women of childbearing age, pregnant women, and the elderly. Reports indicate that food fortification in the region is sporadic and ineffective, and the use of dietary supplements is low. Nutrition monitoring in the region is limited, and gaps in relevant information present challenges for implementing new policies and approaches to address the problem. Government-sponsored initiatives are necessary to assess current dietary intakes/patterns, support nutrition education, and to reduce food insecurity, especially among vulnerable population groups. Public-private partnerships should be considered in targeting micronutrient fortification programs and supplementation recommendations as approaches to help alleviate the burden of micronutrient deficiencies and inadequacies in the Middle East.

Vitamin D status correction in Saudi Arabia: an experts' consensus under the auspices of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis, and Musculoskeletal Diseases (ESCEO)

BACKGROUND

Vitamin D deficiency is common in the Middle East and in Saudi Arabia, in particular. While several international recommendations on the management of vitamin D deficiency have been documented and practiced globally, these recommendations should be adapted to the conditions of the Middle Eastern region. To address this challenge, the Prince Mutaib Chair for Biomarkers of Osteoporosis (PMCO) in King Saud University (KSU), Riyadh, KSA, together with local experts and in cooperation with the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO), organized a panel that formulated unified recommendations in the diagnosis and treatment of vitamin D deficiency in the region.

METHODS

The selection of local and international experts commenced during the 2nd International Vitamin D Symposium conducted in Riyadh, Saudi Arabia, last January 20--21, 2016. Reviews of the most recent literature were done, and face-to-face meetings were conducted for revisions and final recommendations.

RESULTS

Vitamin D sufficiency is defined as circulating serum 25(OH)D ≥50 nmol (≥20 ng/ml) for the general population and vitamin D adequacy as serum 25(OH)D >75 nmol/L l (>30 ng/ml) for the frail and osteoporotic elderly. Despite overwhelming prevalence of vitamin D deficiency, universal screening is not recommended. Recommendations for the general population, children, pregnant/lactating women, post-menopausal women, the elderly, and those with subsequent metabolic diseases were provided.

RESULTS

Vitamin D sufficiency is defined as circulating serum 25(OH)D ≥50 nmol (≥20 ng/ml) for the general population and vitamin D adequacy as serum 25(OH)D >75 nmol/L l (>30 ng/ml) for the frail and osteoporotic elderly. Despite overwhelming prevalence of vitamin D deficiency, universal screening is not recommended. Recommendations for the general population, children, pregnant/lactating women, post-menopausal women, the elderly, and those with subsequent metabolic diseases were provided.

CONCLUSION

Vitamin D supplementation/correction is advised in all persons whose serum 25(OH)D falls below 50 nmol/l (20 ng/ml), and achieving a target of 75 nmol/l (30 ng/ml) is particularly suited for frail, osteoporotic, and older patients. Conducting well-designed clinical trials in the region that will address economic implications and investigations on the treatment persistence and compliance to vitamin D treatment in the region are encouraged.

Extremely High Prevalence of Maternal and Neonatal Vitamin D Deficiency in the Arab Population

BACKGROUND

Vitamin D deficiency is a global public health problem. The published literature on vitamin D deficiency is limited among Arab pregnant women and its association with different metabolic markers.

OBJECTIVE

To determine the prevalence of vitamin D deficiency in Arab pregnant women and neonates and its association with various biomarker profiles.

METHODS

This is a multicenter study taken from a large prospective project in Riyadh, the capital city of Saudi Arabia. Maternal biochemical levels were measured routinely. Maternal and neonatal 25(OH)D levels were assessed using a chemiluminescence immunoassay. A total of 1,097 pregnant women >16 years old with gestational ages <24 weeks were recruited from different tertiary hospitals in Riyadh between February 2011 and June 2012.

RESULTS

Almost 85% of pregnant subjects had 25(OH)D level <50 nmol/L. Vitamin D deficiency among neonates was 88%. Maternal 25(OH)D was significantly associated with neonatal 25(OH)D (r = 0.54, p < 0.01), as well as serum calcium (r = 0.16, p = 0.02) and phosphate levels (r = 0.17, p = 0.02), and had an inverse correlation with parathyroid hormone (r = -0.22, p = 0.001).

CONCLUSION

Maternal and neonatal vitamin D deficiency is alarmingly high in Arabs and significantly associated with each another. Universal screening for serum 25(OH)D may be appropriate for Arab mothers and vitamin D supplementation mandatory until term. The study puts a spotlight on vitamin D deficiency with the hope that health professionals will address it adequately to prevent the known long-term consequences for metabolism and bone health of both mothers and their children.