The association between serum selenium level and gestational diabetes mellitus: A systematic review and meta-analysis

Serum selenium, selenoprotein P, and glutathione peroxidase 3 during early and late pregnancy in association with gestational diabetes mellitus: Prospective Odense Child Cohort

BACKGROUND

Diet is an important modifiable risk factor for gestational diabetes mellitus (GDM) and its related complications; however, the role of essential micronutrients such as selenium (Se), particularly in populations with low Se intake, is inconclusive.

OBJECTIVES

The aim was to investigate the association of 3 established biomarkers of Se status with GDM, gestational glucose metabolism, and large for gestational-age offspring.

METHODS

This study included 1346 pregnant females with 2294 serum samples from the prospective, population-based Odense Child Cohort study, Denmark. Serum Se, selenoprotein P (SELENOP) concentrations, and glutathione peroxidase 3 (GPX3) activity were measured in early and late pregnancy, and fasting glucose and insulin assessments in late pregnancy. Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) was calculated, and the GDM definition was according to the WHO 2013 threshold of fasting venous plasma glucose of ≥5.1 mmol/L. A subcohort underwent an oral glucose tolerance test. Regression models adjusted for various confounders quantified dose-dependent associations.

RESULTS

Se and SELENOP declined during pregnancy. There were dose-dependent inverse associations of early GPX3 with late pregnancy GDM (WHO 2013), fasting glucose, insulin, HOMA-IR, and 2 h glucose. The odds ratio (OR) of GDM was 0.33 (95% CI: 0.16, 0.65) for 1 log-scale-increment in early GPX3 activity. Late pregnancy GPX3 and SELENOP were inversely associated with GDM and HOMA-IR; the OR of GDM was 0.21 (95% CI: 0.12, 0.38) and 0.52 (95% CI: 0.35, 0.77), for 1 log-scale-increment of GPX3 and SELENOP, respectively. A decline in Se biomarkers during pregnancy was associated with a higher risk of GDM and higher HOMA-IR. Low GPX3 activity in late pregnancy was associated with a higher risk of large for gestational-age offspring, partly (∼20%) mediated by fasting glucose concentrations (P = 0.006).

CONCLUSIONS

Low serum Se in pregnancy, particularly GPX3 activity, is independently associated with risk of GDM and large for gestational age. Offering Se status assessment in pregnancy identifies females at high risk for GDM who may benefit from Se substitution.

Blood manganese level and gestational diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

Previous studies evaluating the relationship between blood manganese (Mn) level and gestational diabetes mellitus (GDM) in pregnant women showed inconsistent results. A systematic review and meta-analysis was therefore performed to investigate the above association.

METHODS

Relevant observational studies were obtained by search of electronic databases including Medline, Embase, Cochrane Library and Web of Science from database inception to 10 March 2023. Two authors independently performed database search, literature identification and data extraction. A randomised-effects model was selected to pool the data by incorporating the influence of potential heterogeneity. Subgroup analysis was performed to evaluate the influence of study characteristics on the results of the meta-analysis.

RESULTS

Six datasets from five observational studies, involving 91,249 pregnant women were included in the meta-analysis. Among the participants, 3597 (3.9%) were diagnosed as GDM. Overall, pooled results showed that a high blood level of Mn was associated with a higher risk of GDM (compared between women with highest versus lowest category blood Mn, odds ratio: 1.31, 95% confidence interval: 1.19-1.44, p < .001) with no significant heterogeneity (p for Cochrane Q-test = 0.93, I2 = 0%). Subgroup analyses according to study design, mean maternal age, matrix or methods for measuring blood Mn, and the incidence of GDM also showed consistent results (p for subgroup difference all >.05).

CONCLUSIONS

Results of the meta-analysis suggest that a high blood Mn level may be a risk factor of GDM in pregnant women. Studies are needed to determine the underlying mechanisms, and to investigate if the relationship between blood Mn level and GDM is dose-dependent.

The effect of selenium supplementation in pregnant women on maternal, fetal, and newborn outcomes: a systematic review and meta-analysis

OBJECTIVE

Low maternal selenium status has been associated with poor pregnancy outcomes, including preterm birth. This study aimed to evaluate available evidence of the effects of selenium supplementation during pregnancy on preterm birth and related maternal, fetal, and newborn outcomes.

DATA SOURCES

MEDLINE, Embase, CINAHL, Global Index Medicus, and the Cochrane Library were systematically searched on June 23, 2022, without language or time restrictions.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials and nonrandomized interventional studies were included if they compared the effects of selenium supplementation with placebo or no treatment among pregnant women. The review protocol was registered in the International Prospective Register of Systematic Reviews (identification number: CRD42022383669).

METHODS

For outcomes reported by ≥1 study, a meta-analysis was conducted. Because of the small number of studies and high clinical heterogeneity between populations, random-effects models were used. The Risk of Bias 2 and Risk Of Bias In Non-randomized Studies - of Interventions tools were used to assess study quality, and Grading of Recommendations Assessment, Development, and Evaluation analysis was used to determine the certainty of evidence for each outcome.

RESULTS

Literature searches identified 5105 unique records, and 32 studies met the eligibility criteria. Of note, 11 reports were not included for analysis following research integrity assessments. Moreover, 10 trials and 3 observational studies met the inclusion criteria; however, only 8 trials (1851 women) and 1 prospective cohort study (71,728 women) reported on at least 1 review outcome. Our results could not determine the effect of selenium supplementation on preterm birth at <37 weeks of gestation (relative risk, 0.65; 95% confidence interval, 0.26-1.63; very low certainty evidence) and <34 weeks of gestation (relative risk, 1.05; 95% confidence interval, 0.59-1.44; very low certainty evidence).

CONCLUSION

There is limited evidence on the effects of selenium supplementation during pregnancy. Further trials, with larger sample sizes, more representative populations, and reliable assessment of maternal selenium status at trial entry, are required.

The Association Between the Imbalance of Single-Carbon Nutrients in Early Pregnancy and Gestational Diabetes Mellitus Risk is Influenced by Serum Selenium Status: A Cohort Study

Purpose

The role of imbalanced one-carbon nutrients in gestational diabetes mellitus (GDM) risk has garnered significant interest, yet existing studies yield inconsistent results. Our objective was to assess whether the association between an unbalanced ratio of folate to vitamin B12 and GDM risk is influenced by the status of other micronutrients.

Methods

This cohort study included 366 singleton-pregnancy Han women enrolled at the Shunyi District Maternal and Child Health Hospital in Beijing, China. During the first trimester of pregnancy, we measured red blood cell (RBC) folate, serum levels of vitamin B12, vitamin D, and selenium. We examined the association between the imbalanced status of RBC folate and vitamin B12 and GDM risk using logistic regression, stratified by serum selenium or vitamin D status.

Results

Among the 366 women, 67 (18.3%) were diagnosed with GDM, 201 (54.9%) had vitamin D deficiency, and 245 (66.9%) had selenium deficiency. Overall, women with higher RBC folate/vitamin B12 ratios did not exhibit a significantly higher risk of GDM compared to those in reference tertile (all P > 0.05). Subsequently, we divided women into deficient and non-deficient groups based on serum selenium or vitamin D levels. In women with selenium deficiency, those in the highest tertile of the RBC folate/vitamin B12 ratio had the highest odds of GDM [OR: 3.40 (1.16-9.97), P=0.026] after adjusting for covariates. However, similar findings were not observed in pregnancies with normal selenium status. Irrespective of vitamin D status, women with higher RBC folate/vitamin B12 ratios did not exhibit a significantly increased risk of GDM.

Conclusion

Micronutrient deficiencies are common in early pregnancy. Women with a higher folate/vitamin B12 ratio coupled with selenium deficiency in early pregnancy have a higher GDM risk. These findings underscore the importance of micronutrient assessment in early pregnancy and subsequent interventions for micronutrient deficiencies.

Risk Estimation of Gestational Diabetes Mellitus in the First Trimester

CONTEXT

There is no early, first-trimester risk estimation available to predict later (gestational week 24-28) gestational diabetes mellitus (GDM); however, it would be beneficial to start an early treatment to prevent the development of complications.

OBJECTIVE

We aimed to identify early, first-trimester prediction markers for GDM.

METHODS

The present case-control study is based on the study cohort of a Hungarian biobank containing biological samples and follow-up data from 2545 pregnant women. Oxidative-nitrative stress-related parameters, steroid hormone, and metabolite levels were measured in the serum/plasma samples collected at the end of the first trimester from 55 randomly selected control and 55 women who developed GDM later.

RESULTS

Pregnant women who developed GDM later during the pregnancy were older and had higher body mass index. The following parameters showed higher concentration in their serum/plasma samples: fructosamine, total antioxidant capacity, testosterone, cortisone, 21-deoxycortisol; soluble urokinase plasminogen activator receptor, dehydroepiandrosterone sulfate, dihydrotestosterone, cortisol, and 11-deoxycorticosterone levels were lower. Analyzing these variables using a forward stepwise multivariate logistic regression model, we established a GDM prediction model with a specificity of 96.6% and sensitivity of 97.5% (included variables: fructosamine, cortisol, cortisone, 11-deoxycorticosterone, SuPAR).

CONCLUSION

Based on these measurements, we accurately predict the development of later-onset GDM (24th-28th weeks of pregnancy). Early risk estimation provides the opportunity for targeted prevention and the timely treatment of GDM. Prevention and slowing the progression of GDM result in a lower lifelong metabolic risk for both mother and offspring.

A machine learning approach for early prediction of gestational diabetes mellitus using elemental contents in fingernails

The aim of this pilot study was to predict the risk of gestational diabetes mellitus (GDM) by the elemental content in fingernails and urine with machine learning analysis. Sixty seven pregnant women (34 control and 33 GDM patient) were included. Fingernails and urine were collected in the first and second trimesters, respectively. The concentrations of elements were determined by inductively coupled plasma-mass spectrometry. Logistic regression model was applied to estimate the adjusted odd ratios and 95% confidence intervals. The predictive performances of multiple machine learning algorithms were evaluated, and an ensemble model was built to predict the risk for GDM based on the elemental contents in the fingernails. Beryllium, selenium, tin and copper were positively associated with the risk of GDM while nickel and mercury showed opposite result. The trained ensemble model showed larger area under curve (AUC) of receiver operating characteristic curve (0.81) using fingernail Ni, Cu and Se concentrations. The model was validated by external data set with AUC = 0.71. In summary, the results of the present study highlight the potential of fingernails, as an alternative sample, together with machine learning in human biomonitoring studies.

Association between Plasma Trace Element Concentrations in Early Pregnancy and Gestational Diabetes Mellitus in Shanghai, China

(1) Background: Trace elements play important roles in gestational diabetes mellitus (GDM), but the results from reported studies are inconsistent. This study aimed to examine the association between maternal exposure to V, Cr, Mn, Co, Ni, and Se in early pregnancy and GDM. (2) Methods: A nested case-control study with 403 GDM patients and 763 controls was conducted. Trace elements were measured using inductively coupled plasma-mass spectrometry in plasma collected from pregnant women in the first trimester of gestation. We used several statistical methods to explore the association between element exposure and GDM risk. (3) Results: Plasma V and Ni were associated with increased and decreased risk of GDM, respectively, in the single-element model. V and Mn were found to be positively, and Ni was found to be negatively associated with GDM risk in the multi-element model. Mn may be the main contributor to GDM risk and Ni the main protective factor against GDM risk in the quantile g computation (QGC). 6.89 μg/L~30.88 μg/L plasma Ni was identified as a safe window for decreased risk of GDM. (4) Conclusions: V was positively associated with GDM risk, while Ni was negatively associated. Ni has dual effects on GDM risk.

Association between blood selenium levels and gestational diabetes mellitus: A systematic review and meta-analysis

Introduction

The association between blood (serum or plasma) selenium concentrations and gestational diabetes mellitus (GDM) has been evaluated in some studies. However, the reported findings are debatable, and only case-control and cross-sectional studies were included.

Objective

This research aimed to assess the association between blood selenium levels and GDM by analyzing existing literature. To provide a reference for the prevention and treatment of GDM, we included prospective studies which are not included in previous studies to collate more high-quality evidence and better test the etiological hypothesis between blood Se concentrations and GDM.

Methods

The PubMed, EMBASE, and Web of Science databases were retrieved for literature up to September 2022, and relevant references were manually searched. Raw data from relevant studies were extracted, and a random effect model was adopted for meta-analysis. The total effects were reported as weighted mean differences. All data were analyzed using Stata 16.0 software.

Results

Fourteen studies involving 890 pregnant women with GDM and 1618 healthy pregnant women were incorporated in the meta-analysis. Pregnancies with GDM had significantly lower blood selenium levels than those with normal glucose tolerance (weighted mean difference = -8.11; 95% confidence interval: -12.68 to -3.54, P = 0.001). Subgroup analyses showed that the association between blood selenium levels and GDM was consistent in the residents of Asia and Africa, but not in European. This trend was significant in the second and third trimester subgroups, but not in the first trimester subgroup. Articles published in 2006-2015 also showed this trend, but those published before 2005 and 2016-2019 did not show significant results. This difference was evident in non-prospective studies, but not significant in prospective studies. Studies using the Carpenter and Coustan diagnostic criteria were consistent with this trend, whereas studies using other diagnostic criteria found no differences. In addition, in terms of blood selenium measurement methods, atomic absorption spectrometry showed more significant differences than other methods. In the subgroup analysis based on the sample size of included studies and the quality of the studies, each subgroup showed statistical differences.

Conclusion

Lower blood selenium concentrations are associated with GDM as shown in our study. Therefore, supplementing an appropriate amount of selenium may be helpful for GDM prevention and treatment.

Potential Benefits of Selenium Supplementation in Reducing Insulin Resistance in Patients with Cardiometabolic Diseases: A Systematic Review and Meta-Analysis

BACKGROUND

Selenium is a trace element that has been reported to be effective in regulating glucose and lipid metabolism. However, there is conflicting evidence from different clinical trials of selenium supplementation in treating cardiometabolic diseases (CMDs).

OBJECTIVE

This meta-analysis aimed to identify the effects of selenium supplementation on insulin resistance, glucose homeostasis, and lipid profiles in patients with CMDs.

METHODS

Randomized controlled trials (RCTs) of selenium supplementation for treating CMDs were screened in five electronic databases. Insulin levels, homeostatic model assessment of insulin resistance (HOMA-IR), fasting plasma glucose (FPG), and glycosylated hemoglobin A1C (HbA1c) were defined as the primary outcome markers, and lipid profiles were considered the secondary outcome markers.

RESULTS

Ten studies involving 526 participants were included in the meta-analysis. The results suggested that selenium supplementation significantly reduced serum insulin levels (standardized men difference [SMD]: -0.53; 95% confidence interval [CI] [-0.84, -0.21], p = 0.001, I² = 68%) and HOMA-IR (SMD: -0.50, 95% CI [-0.86, -0.14], p = 0.006, I² = 75%) and increased high-density lipoprotein cholesterol (HDL-C) levels (SMD: 0.97; 95% CI [0.26, 1.68], p = 0.007, I² = 92%), but had no significant effect on FPG, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and very low-density lipoprotein cholesterol (VLDL-C).

CONCLUSION

Current evidence supports the beneficial effects of selenium supplementation on reducing insulin levels, HOMA-IR, and increasing HDL-C levels. Selenium supplementation may be an effective strategy for reducing insulin resistance in patients with CMDs. However, more high-quality clinical studies are needed to improve the certainty of our estimates.

Selenium supplementation and pregnancy outcomes

In vertebrates and invertebrates, selenium (Se) is an essential micronutrient, and Se deficiency or excess is associated with gonadal insufficiency and gamete dysfunction in both males and females, leading to implantation failure, altered embryonic development and, ultimately, infertility. During pregnancy, Se excess or deficiency is associated with miscarriage, pre-eclampsia (hypertension of pregnancy), gestational diabetes, fetal growth restriction and preterm birth. None of this is surprising, as Se is present in high concentrations in the ovary and testes, and work in animal models has shown that addition of Se to culture media improves embryo development and survival in vitro in association with reduced reactive oxygen species and less DNA damage. Selenium also affects uterine function and conceptus growth and gene expression, again in association with its antioxidant properties. Similarly, Se improves testicular function including sperm count, morphology and motility, and fertility. In animal models, supplementation of Se in the maternal diet during early pregnancy improves fetal substrate supply and alters fetal somatic and organ growth. Supplementation of Se throughout pregnancy in cows and sheep that are receiving an inadequate or excess dietary intake affected maternal whole-body and organ growth and vascular development, and also affected expression of angiogenic factors in maternal and fetal organs. Supplemental Se throughout pregnancy also affected placental growth, which may partly explain its effects on fetal growth and development, and also affected mammary gland development, colostrum yield and composition as well as postnatal development of the offspring. In conclusion, Se supplementation in nutritionally compromised pregnancies can potentially improve fertility and pregnancy outcomes, and thereby improve postnatal growth and development. Future research efforts should examine in more detail and more species the potential benefits of Se supplementation to reproductive processes in mammals.