A prospective study of prepregnancy dietary iron intake and risk for gestational diabetes mellitus

Diagnostic and prognostic value of triglyceride glucose index: a comprehensive evaluation of meta-analysis

OBJECTIVE

The present umbrella review aims to collate and summarize the findings from previous meta-analyses on the Triglyceride and Glucose (TyG) Index, providing insights to clinicians, researchers, and policymakers regarding the usefulness of this biomarker in various clinical settings.

METHODS

A comprehensive search was conducted in PubMed, Scopus, and Web of Science up to April 14, 2024, without language restrictions. The AMSTAR2 checklist assessed the methodological quality of the included meta-analyses. Statistical analyses were performed using Comprehensive Meta-Analysis (CMA) software.

RESULTS

A total of 32 studies were finally included. The results revealed significant associations between the TyG index and various health outcomes. For kidney outcomes, a high TyG index was significantly associated with an increased risk of contrast-induced nephropathy (CIN) (OR = 2.24, 95% CI: 1.82-2.77) and chronic kidney disease (CKD) (RR = 1.46, 95% CI: 1.32-1.63). High TyG index was significantly associated with an increased risk of type 2 diabetes mellitus (T2DM) (RR = 3.53, 95% CI: 2.74-4.54), gestational diabetes mellitus (GDM) (OR = 2.41, 95% CI: 1.48-3.91), and diabetic retinopathy (DR) (OR = 2.34, 95% CI: 1.31-4.19). Regarding metabolic diseases, the TyG index was significantly higher in patients with obstructive sleep apnea (OSA) (SMD = 0.86, 95% CI: 0.57-1.15), metabolic syndrome (MD = 0.83, 95% CI: 0.74-0.93), and non-alcoholic fatty liver disease (NAFLD) (OR = 2.36, 95% CI: 1.88-2.97) compared to those without these conditions. In cerebrovascular diseases, a higher TyG index was significantly associated with an increased risk of dementia (OR = 1.14, 95% CI: 1.12-1.16), cognitive impairment (OR = 2.31, 95% CI: 1.38-3.86), and ischemic stroke (OR = 1.37, 95% CI: 1.22-1.54). For cardiovascular outcomes, the TyG index showed significant associations with an increased risk of heart failure (HF) (HR = 1.21, 95% CI: 1.12-1.30), atrial fibrillation (AF) (SMD = 1.22, 95% CI: 0.57-1.87), and hypertension (HTN) (RR = 1.52, 95% CI: 1.25-1.85).

CONCLUSION

The TyG index is a promising biomarker for screening and predicting various medical conditions, particularly those related to insulin resistance and metabolic disorders. However, the heterogeneity and methodological quality of the included studies suggest the need for further high-quality research to confirm these findings and refine the clinical utility of the TyG index.

MitoNEET preserves muscle insulin sensitivity during iron overload by regulating mitochondrial iron, reactive oxygen species and fission

Iron overload (IO) is known to contribute to metabolic dysfunctions such as type 2 diabetes and insulin resistance. Using L6 skeletal muscle cells overexpressing the CDGSH iron-sulfur domain-containing protein 1 (CISD1, also known as mitoNEET) (mitoN) protein, we examined the potential role of MitoN in preventing IO-induced insulin resistance. In L6 control cells, IO resulted in insulin resistance which could be prevented by MitoN as demonstrated by western blot of p-Akt and Akt biosensor cells. Mechanistically, IO increased; mitochondrial iron accumulation, mitochondrial reactive oxygen species (ROS), Fis1-dependent mitochondrial fission, mitophagy, FUN14 domain-containing protein 1 (FUNDC1) expression, and decreased Parkin. MitoN overexpression was able to reduce increases in mitochondrial iron accumulation, mitochondrial ROS, mitochondrial fission, mitophagy and FUNDC1 upregulation due to IO. MitoN did not have any effect on the IO-induced downregulation of Parkin. MitoN alone also upregulated peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) protein levels, a master regulator of mitochondrial biogenesis. The use of mitochondrial antioxidant, Skq1, or fission inhibitor, Mdivi-1, prevented IO-induced insulin resistance implying both mitochondrial ROS and fission play a causal role in the development of insulin resistance. Taken together, MitoN is able to confer protection against IO-induced insulin resistance in L6 skeletal muscle cells through regulation of mitochondrial iron content, mitochondrial ROS, and mitochondrial fission.

Scientific opinion on the tolerable upper intake level for iron

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the tolerable upper intake level (UL) for iron. Systematic reviews were conducted to identify evidence regarding high iron intakes and risk of chronic diseases, adverse gastrointestinal effects and adverse effects of iron supplementation in infancy, young childhood and pregnancy. It is established that systemic iron overload leads to organ toxicity, but no UL could be established. The only indicator for which a dose-response could be established was black stools, which reflect the presence of large amounts of unabsorbed iron in the gut. This is a conservative endpoint among the chain of events that may lead to systemic iron overload but is not adverse per se. Based on interventions in which black stools did not occur at supplemental iron intakes of 20-25 mg/day (added to a background intake of 15 mg/day), a safe level of intake for iron of 40 mg/day for adults (including pregnant and lactating women) was established. Using allometric scaling (body weight0.75), this value was scaled down to children and adolescents and safe levels of intakes between 10 mg/day (1-3 years) and 35 mg/day (15-17 years) were derived. For infants 7-11 months of age who have a higher iron requirement than young children, allometric scaling was applied to the supplemental iron intakes (i.e. 25 mg/day) and resulted in a safe level of supplemental iron intake of 5 mg/day. This value was extended to 4-6 month-old infants and refers to iron intakes from fortified foods and food supplements, not from infant and follow-on formulae. The application of the safe level of intake is more limited than a UL because the intake level at which the risk of adverse effects starts to increase is not defined.

Impact of Maternal Micronutrient Intake on Gestational Diabetes Risk: Results from Greece's BORN2020 Prospective Cohort Study

Understanding how maternal micronutrient intake and dietary habits impact gestational diabetes mellitus (GDM) is crucial. Data from 797 pregnant women were prospectively analyzed to assess GDM status with the oral glucose tolerance test (OGTT). Nutritional intake was evaluated using a validated food frequency questionnaire (FFQ) across two periods: Period A, covering 6 months before pregnancy, and Period B, from pregnancy onset to mid-gestation (24 weeks). Micronutrient intakes were compared against the European Food Safety Authority (EFSA) dietary reference values (DRVs) and were used to estimate the mean adequacy ratio (MAR) to assess dietary adequacy. GDM was diagnosed in 14.7% (n = 117) of women with the characteristics of a higher mean maternal age (MA) and pre-pregnancy body mass index (BMI). Out of the 13 vitamins assessed, biotin, folate, niacin, and pantothenic acid were found significantly higher in the GDM group, as did iron, magnesium, manganese, phosphorus, and zinc from the 10 minerals. The results were influenced by the timing of the assessment. Importantly, MAR was higher during pregnancy and was found to increase the risk of GDM by 1% (95%CI: 1, 1.02). A sensitivity analysis revealed that reducing MAR significantly raised the GDM risk by 68% (95%CI: 1.02, 2.79). No association was revealed between adherence to the Mediterranean diet (MD) and GDM risk. These findings highlight areas for further investigation into whether dietary modifications involving these specific micronutrients could effectively influence GDM outcomes.

Ferritin and iron supplements in gestational diabetes mellitus: less or more?

Iron metabolism has been found to be closely related to gestational diabetes mellitus (GDM). Excessive ferritin levels were shown to be related to an increased risk of GDM because of iron overload which may lead to insulin resistance and β-cell injury by enhancing oxidative stress and inflammatory responses. On the contrary, insufficient ferritin levels can cause a number of obstetric complications, such as high incidence rates of anaemia and gestational hypertension. Therefore, high or low ferritin levels may have adverse effects on the mother and the foetus, putting clinicians in a dilemma when giving pregnant women iron supplements. This also explains why there have been more conflicting findings in the studies on dietary or oral iron supplementation during pregnancy. Hence, there is an urgent need for more evidence and strategies for appropriate recommendations for ferritin levels and iron supplementation during pregnancy to prevent iron insufficiency without causing iron overload and increasing the risk of GDM. Therefore, we gave an updated review on the association of GDM with ferritin metabolism, ferritin levels and iron supplementation based on the summary of the latest research.

Bioinformatics Prediction and Experimental Validation of the Role of Macrophage Polarization and Ferroptosis in Gestational Diabetes Mellitus

Purpose

Gestational diabetes mellitus (GDM) is a common metabolic disorder during pregnancy that is associated with placental inflammation and adverse pregnancy outcomes. However, the mechanisms of inflammation in GDM are still unclear.

Methods

Bulk transcriptome, single-cell transcriptome, clinical information, and samples were collected from GSE154414, GSE70493, GSE173193 and a retrospective cohort. Bioinformatics prediction was used to explore the mechanisms of placental inflammation, and multiplex immunofluorescence was used to validate the results.

Results

First, we found that GDM is characterized by low-grade inflammation and is linked to several adverse pregnancy outcomes, as supported by our collected clinical data. Additionally, we identified ten hub genes (FCGR3B, CXCR1, MMP9, ITGAX, CCL5, GZMB, S100A8, LCN2, TGFB1, and LTF) as potential therapy targets and confirmed the binding of corresponding predictive therapeutic agents by molecular docking. Transcriptome sequencing analysis has shown that macrophages are primarily responsible for the emergence of placental inflammation, and that M1 macrophage polarization increased while M2 macrophage polarization decreased in GDM when compared to the control sample. Multiplex immunofluorescence staining of CD68, CD80, and ACSL4 was performed and suggested that ferroptosis of macrophages may contribute to placental inflammation in GDM.

Conclusion

In conclusion, our findings provide a better understanding of the mechanisms of inflammation in GDM and suggest potential therapeutic targets for this condition.

Disrupted Balance of the Oxidant-Antioxidant System in the Pathophysiology of Female Reproduction: Oxidative Stress and Adverse Pregnancy Outcomes

The significance of oxidative stress in the pathophysiology of male reproductive processes has been closely studied in the last two decades. Recently, it has become clear that oxidative stress can lead to numerous pathological conditions during female reproductive processes as well, contributing to the development of endometriosis, polycystic ovary syndrome and various forms of infertility. During pregnancy, physiological generation of reactive oxygen species (ROS) occurs in association with several developmental processes including oocyte maturation and implantation. An overproduction of ROS can lead to disturbances in fetal development and increases the risk for missed abortion, intrauterine growth restriction, pre-eclampsia, premature delivery and gestational diabetes. Our review focuses on the etiological role of the disrupted oxidant-antioxidant system during human gestation as it relates to adverse pregnancy outcomes.

Molecular pathways and nutrigenomic review of insulin resistance development in gestational diabetes mellitus

Gestational diabetes mellitus is a condition marked by raised blood sugar levels and insulin resistance that usually occurs during the second or third trimester of pregnancy. According to the World Health Organization, hyperglycemia affects 16.9% of pregnancies worldwide. Dietary changes are the primarily alternative treatment for gestational diabetes mellitus. This paper aims to perform an exhaustive overview of the interaction between diet, gene expression, and the metabolic pathways related to insulin resistance. The intake of foods rich in carbohydrates can influence the gene expression of glycolysis, as well as foods rich in fat, can disrupt the beta-oxidation and ketogenesis pathways. Furthermore, vitamins and minerals are related to inflammatory processes regulated by the TLR4/NF-κB and one carbon metabolic pathways. We indicate that diet regulated gene expression of PPARα, NOS, CREB3L3, IRS, and CPT I, altering cellular physiological mechanisms and thus increasing or decreasing the risk of gestational diabetes. The alteration of gene expression can cause inflammation, inhibition of fatty acid transport, or on the contrary help in the modulation of ketogenesis, improve insulin sensitivity, attenuate the effects of glucotoxicity, and others. Therefore, it is critical to comprehend the metabolic changes of pregnant women with gestational diabetes mellitus, to determine nutrients that help in the prevention and treatment of insulin resistance and its long-term consequences.

High Dietary Iron in Western Diet-Fed Male Rats Causes Pancreatic Islet Injury and Acute Pancreatitis

BACKGROUND

High dietary iron has been linked to an increased type 2 diabetes risk. We have previously shown that intrauterine growth restriction (IUGR) and feeding a Western diet (WD) to male Sprague-Dawley rats independently, as well as together, cause pancreatic islet inflammation, fibrosis, and hemosiderosis.

OBJECTIVES

To investigate whether iron has a role in the pathogenesis of this inflammatory islet injury caused by IUGR and WD intake.

METHODS

Male Sprague-Dawley offspring of bilateral uterine artery ligated (IUGR) and sham-operated (Sham) dams, fostered to nonoperated dams, were fed a WD [45% sucrose, 19.4% protein and 23% fat (w/w)] containing low iron (LI, 20 mg/kg) or high iron (HI, 500 mg/kg) from weaning. Four groups were studied: Sham-LI, Sham-HI, IUGR-LI, and IUGR-HI. Serial measurements of rat body weight, blood glucose, lipids and insulin, an intraperitoneal glucose tolerance test (age 13 wk), and histological analysis of pancreas and liver (age 14 wk) were recorded. The effects of iron, IUGR, and their interaction, on these measurements have been analyzed.

RESULTS

WD with HI compared with LI caused an 11% greater weight gain by age 14 wk (P < 0.001), impaired glucose tolerance [AUC for glucose (G-AUC) 17% higher; P < 0.001), acute pancreatitis (17/18, HI; 6/17, LI; P < 0.001), pancreas-associated fat necrosis and saponification (7/18, HI; 0/17 LI; P < 0.01), and a trend to islet fibrotic injury (7/18, HI; 1/17 LI; P = 0.051). Although pancreatic and hepatic steatosis was evident in almost all WD-fed rats, pancreatic and hepatic iron accumulation was prevalent only in HI-fed rats (P < 0.0001 for both), being only mild in the livers. IUGR, independent of dietary iron, also caused impairment in glucose tolerance (G-AUC: 17% higher; P < 0.05).

CONCLUSIONS

A postweaning WD containing HI, independent of IUGR, causes acute pancreatitis and islet injury in Sprague-Dawley rats suggesting a role of dietary iron in the development of steatopancreatitis.

Impact of iron supplementation on gestational diabetes mellitus: A literature review

Gestational diabetes mellitus (GDM) is a common complication of pregnancy, affecting 14% of pregnancies worldwide, and the prevention of pathological hyperglycaemia during pregnancy is meaningful for global public health. The role of iron supplementation in the progression of GDM has been of significant interest in recent years. Iron is a micronutrient that is vital during pregnancy; however, given the toxic properties of excess iron, it is probable that prophylactic iron supplementation will increase the risk of adverse pregnancy outcomes, including GDM. It is critical to clarify the effect of iron supplementation on the risk of GDM. Therefore, in this review, we comprehensively assess the role of iron in pregnancy. This review aimed to analyse the necessity of iron supplementation and maintenance of iron homeostasis during pregnancy, particularly reviewing the role and function of iron in beta cells and examining the mechanisms of excess iron contributing to the pathogenesis of GDM. Moreover, we aimed to discuss the association of haemoglobin and ferritin with GDM and identify priority areas for research.

The association of iron status, supplement iron in the first-trimester pregnancy with gestational diabetes mellitus: A nested case-control study

AIMS

The objective of this study was to examine whether the level of iron and iron supplements in the first-trimester pregnancy is associated with gestational diabetes mellitus (GDM).

METHODS

This was a nested case-control study using data from an established cohort in the Hunan Provincial Maternal and Child Health Hospital (HPMCHH) in South China. A total of 119 patients with GDM and 238 controls were enrolled in the study. Iron status indicators were tested in early pregnancy. Information on iron supplements use was collected by questionnaires. Binary logistic regression was used to obtain odds ratio (OR). The relative excess risk of interaction (RERI) was applied to evaluate the interaction.

RESULTS

We observed that pregnant women with normal ferritin levels (≥30 ng/ml) and iron supplements were associated with a 3.701-fold increased risk of GDM (OR: 3.701, 95% CI: 1.689-8.112) compared with the ferritin <30 ng/ml and without iron supplements group. Similarly, pregnant women with normal serum iron (SI) levels (≥9 μmol/L) and iron supplements were associated with a 5.447-fold increased risk of GDM (OR: 5.447, 95% CI: 2.246-13.209) compared with the SI < 9 μmol/L and without iron supplement group. We found an additive interaction between ferritin and iron supplements on the presence of GDM (RERI: 1.164, 95%CI: 0.333-1.994) and SI and iron supplements on the risk of GDM (RERI: 6.375, 95%CI: 4.494-8.256).

CONCLUSION

Pregnant women with normal ferritin or SI levels and iron supplements could significantly increase the risks for GDM.

Iron as a therapeutic target in chronic liver disease

It was clearly realized more than 50 years ago that iron deposition in the liver may be a critical factor in the development and progression of liver disease. The recent clarification of ferroptosis as a specific form of regulated hepatocyte death different from apoptosis and the description of ferritinophagy as a specific variation of autophagy prompted detailed investigations on the association of iron and the liver. In this review, we will present a brief discussion of iron absorption and handling by the liver with emphasis on the role of liver macrophages and the significance of the iron regulators hepcidin, transferrin, and ferritin in iron homeostasis. The regulation of ferroptosis by endogenous and exogenous mod-ulators will be examined. Furthermore, the involvement of iron and ferroptosis in various liver diseases including alcoholic and non-alcoholic liver disease, chronic hepatitis B and C, liver fibrosis, and hepatocellular carcinoma (HCC) will be analyzed. Finally, experimental and clinical results following interventions to reduce iron deposition and the promising manipulation of ferroptosis will be presented. Most liver diseases will be benefited by ferroptosis inhibition using exogenous inhibitors with the notable exception of HCC, where induction of ferroptosis is the desired effect. Current evidence mostly stems from in vitro and in vivo experimental studies and the need for well-designed future clinical trials is warranted.

The Effect of Dietary Protein Intake on the Risk of Gestational Diabetes

Background. The results of epidemiological studies on the association between dietary protein intake and gestational diabetes mellitus (GDM) are controversial. Thus, this systematic review and meta-analysis of cohort studies were established to attain comprehensive findings regarding the association between dietary protein and the risk of GDM. Methods. Bibliographic databases including PubMed, Scopus, Web of Science, and Google Scholar were searched to discover papers related to dietary protein and the risk of GDM. The summary relative risks with 95% confidence intervals (CIs) were estimated through a random effect model for the analysis of the highest versus the lowest categories of dietary proteins. Results. A significantly increased risk of GDM among women who consumed the highest amount of animal protein was observed (summarized risk estimate: 1.52; 95% CI: 1.07, 2.17; I2 = 50.8%). No significant associations were identified regarding vegetable protein (summarized risk estimate:0.99, 95% CI: 0.80 to 1.23, I2 = 63.8%) and total protein (summarized risk estimate: 1.12; 95% CI: 0.88, 1.41; I2 = 35.4%). Conclusion. This review revealed that total protein intake had no relationship with the risk of GDM, while animal protein increases this risk. Further larger prospective cohort studies are required to confirm our results.

Early pregnancy hemoglobin is associated with the risk of gestational diabetes mellitus: a retrospective cohort study

This study aimed to determine the association between hemoglobin (Hb) concentration and Hb change, during early to mid-pregnancy with the risk of gestational diabetes mellitus (GDM). This was a clinic-based retrospective cohort study of 1951 healthy pregnant women (18-45 years old) with a singleton gestation attending antenatal care at government health clinics. Hb concentration at first prenatal visit and each trimester was extracted from the antenatal cards. Hb changes from first prenatal visit to first and second trimester as well as from second to third trimester were calculated. Multivariate logistic regression was used with adjustment for covariates. Women with GDM had significantly higher Hb concentrations (Hb 1) at first prenatal visit (< 12 weeks) compared with non-GDM women (11·91 g/dl v.11·74 g/dl). Hb 1 and Hb changes (Hb change 2) from first prenatal visit to the second trimester (23-27th weeks) were significantly associated with GDM risk, with an adjusted OR of 1·14 (95 % CI 1·01, 1·29) and 1·25 (95 % CI 1·05, 1·49), respectively. The significant associations between Hb 1 and Hb change 2 with the risk of GDM were found among non-Malays, overweight/obese and women aged 35 years and above. Women with higher Hb concentrations in early pregnancy were at higher risk of GDM, and such association was significant among women aged 35 years and above, non-Malays and overweight/obese. This raises a potential concern for elevated Fe status in early pregnancy as a risk factor of GDM among Fe-replete women.

Iron Supplementation in Pregnancy and Risk of Gestational Diabetes: A Narrative Review

Pregnant women frequently supplement their diets with iron to treat any cryptic anemia, on the assumption that if anemia is not present, there will be no negative consequences. However, in women who are already iron-replete, it has been suggested that this can lead to iron overload and an increased risk of certain pregnancy complications. One such complication is gestational diabetes. Fourteen clinical trials, case-control or cohort studies (found using Pubmed/Scopus/Web of Science) have investigated links between iron supplementation in pregnancy and risk of gestational diabetes, several of them finding significant associations with increased risk. Potential mechanisms include increased oxidative stress leading to insulin resistance and inadequate compensatory insulin secretion. Current evidence suggests that dietary supplementation with iron in pregnancy may increase a pregnant woman's chance of developing gestational diabetes, although available evidence is somewhat contradictory, and the magnitude of any increased risk appears relatively small. Meta-analyses have suggested the presence of significant heterogeneity in results between studies, urging a degree of caution in interpreting these results. It is currently suggested that advice to pregnant women about whether to supplement their diets with iron or not should consider both their current iron status and their other established risk factors for gestational diabetes.

Prepregnancy Protein Source and BCAA Intake Are Associated with Gestational Diabetes Mellitus in the CARDIA Study

Diet quality and protein source are associated with type 2 diabetes, however relationships with GDM are less clear. This study aimed to determine whether prepregnancy diet quality and protein source are associated with gestational diabetes mellitus (GDM). Participants were 1314 Black and White women without diabetes, who had at least one birth during 25 years of follow-up in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort study. The CARDIA A Priori Diet Quality Score (APDQS) was assessed in the overall cohort at enrollment and again at Year 7. Protein source and branched-chain amino acid (BCAA) intake were assessed only at the Year 7 exam (n = 565). Logistic regression analysis was used to determine associations between prepregnancy dietary factors and GDM. Women who developed GDM (n = 161) were more likely to have prepregnancy obesity and a family history of diabetes (p < 0.05). GDM was not associated with prepregnancy diet quality at enrollment (Year 0) (odds ratio [OR]: 1.01; 95% confidence interval [CI] 0.99, 1.02) or Year 7 (odds ratio [OR]: 0.97; 95% confidence interval [CI] 0.94, 1.00) in an adjusted model. Conversely, BCAA intake (OR:1.59, 95% CI 1.03, 2.43) and animal protein intake (OR: 1.06, 95% CI 1.02, 1.10) as a proportion of total protein intake, were associated with increased odds of GDM, while proportion of plant protein was associated with decreased odds of GDM (OR: 0.95, 95% CI 0.91, 0.99). In conclusion, GDM is strongly associated with source of prepregnancy dietary protein intake but not APDQS in the CARDIA study.

Iron Metabolism and Ferroptosis in Physiological and Pathological Pregnancy

Iron is a vital element in nearly every living organism. During pregnancy, optimal iron concentration is essential for both maternal health and fetal development. As the barrier between the mother and fetus, placenta plays a pivotal role in mediating and regulating iron transport. Imbalances in iron metabolism correlate with severe adverse pregnancy outcomes. Like most other nutrients, iron exhibits a U-shaped risk curve. Apart from iron deficiency, iron overload is also dangerous since labile iron can generate reactive oxygen species, which leads to oxidative stress and activates ferroptosis. In this review, we summarized the molecular mechanism and regulation signals of placental iron trafficking under physiological conditions. In addition, we revealed the role of iron metabolism and ferroptosis in the view of preeclampsia and gestational diabetes mellitus, which may bring new insight to the pathogenesis and treatment of pregnancy-related diseases.

Dietary iron modulates hepatic glucose homeostasis via regulating gluconeogenesis

Iron exerts significant influences on glucose metabolism. However, the regulatory mechanisms underlying disordered glucose response remains largely unclear. The aim of this study was to examine the impact of dietary iron on hepatic gluconeogenesis in mice and in rat liver-derived cells. High iron models of C57BL/6J mice were fed with 1.25 g Fe/kg diets for 9 weeks, and high-iron BRL-3A cell models were treated with 250 μmol/L FeSO₄ for 12 h and 24 h. Our data showed that higher iron intake resulted in higher hepatic iron without iron toxicity, and reduced body weight gain with no difference of food intakes. High dietary iron significantly increased 61% of hepatic glycogen deposition, but exhibited impairment in glucose responses in mice. Moreover, high dietary iron suppressed hepatic gluconeogenesis by repressing the expression of key gluconeogenic enzymes, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase. Meanwhile, mice fed with higher iron diets exhibited both decreased AMP-activated protein kinase (AMPK) activity and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) protein levels. Furthermore, in BRL-3A cells, iron treatment increased cellular glucose uptake, and altered gluconeogenesis rhythmically by regulating the activation of AMPK and expression of PGC-1α successively. This study demonstrated that dietary high iron was able to increase hepatic glycogen deposition by enhancement of glucose uptake, and suppress hepatic gluconeogenesis by regulation of AMPK and PGC-1α.

Materno-fetal iron transfer and the emerging role of ferroptosis pathways

A successful pregnancy and the birth of a healthy baby depend to a great extent on the controlled supply of essential nutrients via the placenta. Iron is essential for mitochondrial energy supply and oxygen distribution via the blood. However, its high reactivity requires tightly regulated transport processes. Disturbances of maternal-fetal iron transfer during pregnancy can aggravate or lead to severe pathological consequences for the mother and the fetus with lifelong effects. Furthermore, high intracellular iron levels due to disturbed gestational iron homeostasis have recently been associated with the non-apoptotic cell death pathway called ferroptosis. Therefore, the investigation of transplacental iron transport mechanisms, their physiological regulation and potential risks are of high clinical importance. The present review summarizes the current knowledge on principles and regulatory mechanisms underlying materno-fetal iron transport and gives insight into common pregnancy conditions in which iron homeostasis is disturbed. Moreover, the significance of the newly emerging ferroptosis pathway and its impact on the regulation of placental iron homeostasis, oxidative stress and gestational diseases will be discussed.

Association between pre-conceptional carbohydrate quality index and the incidence of gestational diabetes: the SUN cohort study

The aim of the study was to investigate the association between pre-gestational carbohydrate quality index (CQI) and the incidence of gestational diabetes mellitus (GDM). Data from the 'Seguimiento Universidad de Navarra' (SUN) cohort were used, which includes 3827 women who notified at least one pregnancy between December 1999 and December 2019. We used a validated semi-quantitative 136-item FFQ to evaluate dietary exposures at baseline and at 10-year follow-up. The CQI was defined by four criteria: glycaemic index, whole-grain/total-grain carbohydrate, dietary fibre intake and solid/total carbohydrate ratio. We fitted generalised estimating equations with repeated measurements of the CQI to assess its relationship with incident GDM. A total of 6869 pregnancies and 202 new cases of incident GDM were identified. The inverse association between the global quality of carbohydrate and the development of GDM was not statistically significant: OR the highest v. the lowest CQI category: 0·67, 95 % CI (0·40, 1·10), Pfor trend = 0·10. Participants at the highest CQI category and with daily carbohydrate amounts ≥50 % of total energy intake had the lowest incidence of GDM (OR = 0·29 (95 % CI (0·09, 0·89)) compared with those with the lowest quality (lowest CQI) and quantity (≤40 %). Further studies are needed to overcome the limitations of our study. Those studies should jointly consider the quality and the quantity of dietary carbohydrates, as the quality might be of importance, especially in women with a higher intake of carbohydrates.

Development and evaluation of an online questionnaire to identify women at high and low risk of developing gestational diabetes mellitus

BACKGROUND

Established risk factors for Gestational Diabetes Mellitus (GDM) include age, ethnicity, family history of diabetes and previous GDM. Additional significant influences have recently been demonstrated in the literature. The oral glucose tolerance test (OGTT) used for GDM diagnosis has sub-optimal sensitivity and specificity, thus often results in GDM misdiagnoses. Comprehensive screening of risk factors may allow more targeted monitoring and more accurate diagnoses, preventing the devastating consequences of untreated or misdiagnosed GDM. We aimed to develop a comprehensive online questionnaire of GDM risk factors and triangulate it with the OGTT and continuous glucose monitoring (CGM) parameters to better evaluate GDM risk and diagnosis.

METHODS

Pregnant women participating in two studies on the use of CGM for GDM were invited to complete the online questionnaire. A risk score, based on published literature, was calculated for each participant response and compared with the OGTT result. A total risk score (TRS) was then calculated as a normalised sum of all risk factors. Triangulation of OGTT, TRS and CGM score of variability (CGMSV) was analysed to expand evaluation of OGTT results.

RESULTS

Fifty one women completed the questionnaire; 29 were identified as 'high-risk' for GDM. High-risk ethnic background (p < 0.01), advanced age, a family diabetic history (p < 0.05) were associated with a positive OGTT result. The triangulation analysis (n = 45) revealed six (13%) probable misdiagnoses (both TRS and CGMSV discordant with OGTT), consisting of one probable false positive and five probable false negative by OGTT results.

CONCLUSIONS

This study identified pregnant women at high risk of developing GDM based on an extended evaluation of risk factors. Triangulation of TRS, OGTT and CGMSV suggested potential misdiagnoses of the OGTT. Future studies to explore the correlation between TRS, CGMSV and pregnancy outcomes as well as additional GDM pregnancy biomarkers and outcomes to efficiently evaluate OGTT results are needed.

Dietary Protein Patterns during Pregnancy Are Associated with Risk of Gestational Diabetes Mellitus in Chinese Pregnant Women

Controversies around the association between dietary protein intake and gestational diabetes mellitus (GDM) persist. To the best of our knowledge, this association has not previously been reported from the perspective of dietary protein patterns. We aimed to investigate the relationship between dietary protein patterns and GDM risk in pregnant women, and 1014 pregnant women (20–28 weeks of gestation) were recruited in Guangzhou, China, during 2017–2018. Maternal dietary information was collected by a validated food frequency questionnaire, which covered the most common foods consumed in Guangzhou, China. GDM was identified by a 75g oral glucose tolerance test. A K-means cluster analysis was conducted to aggregate individuals into three groups, which were determined by the major sources of protein. Logistic regression was employed to explore the relationship between dietary protein patterns and the risk of GDM. Among the 1014 participants, 191 (18.84%) were diagnosed with GDM. In the total population, when comparing the highest quartile with the lowest, we found that total protein and animal protein intake increased the risk of GDM with the adjusted odds ratios (95%CI) being 6.27, 5.43 (1.71–23.03, 1.71–17.22), respectively. Pregnant women were further divided into three dietary protein patterns, namely, white meat, plant–dairy–eggs, and red meat protein patterns. Compared to women with the plant–dairy–eggs protein pattern, those with the red meat protein pattern (OR: 1.80; 95%CI: 1.06–3.07) or white meat protein pattern (OR: 1.83; 95%CI: 1.04–3.24) had an increased risk of GDM. Higher dietary intakes of total or animal protein during mid-pregnancy were related to an increased risk of GDM. Furthermore, we first found that, compared to women with the plant–dairy–eggs protein pattern, women with the red meat or white meat protein patterns had a higher risk of GDM.

Associations of Habitual Mineral Intake with New-Onset Prediabetes/Diabetes after Acute Pancreatitis

Associations between habitual dietary intake of minerals and glucose metabolism have been extensively studied in relation to metabolic disorders. However, similar research has yet to be conducted in individuals after acute pancreatitis (AP). The main aim was to investigate the associations between habitual intake of 13 minerals and glycaemic status: new-onset prediabetes/diabetes after AP (NODAP), pre-existing prediabetes/type 2 diabetes (T2DM), and normoglycaemia after AP (NAP). Associations between the dietary intake of minerals and markers of glucose metabolism (glycated haemoglobin and fasting plasma glucose) were also studied. The EPIC-Norfolk food frequency questionnaire was used in a cross-sectional fashion to determine the habitual intake of 13 dietary minerals. ANCOVA as well as multiple linear regression analyses were conducted and five statistical models were built to adjust for covariates. The study included 106 individuals after AP. In the NODAP group, intake of 4 minerals was significantly less when compared with the NAP group: iron (B = -0.076, p = 0.013), nitrogen (B = -0.066, p = 0.003), phosphorous (B = -0.046, p = 0.006), and zinc (B = -0.078, p = 0.001). Glycated haemoglobin was significantly associated with iodine intake (B = 17.763, p = 0.032) and manganese intake (B = -17.147, p = 0.003) in the NODAP group. Fasting plasma glucose was significantly associated with manganese intake (B = -2.436, p = 0.027) in the NODAP group. Habitual intake of minerals differs between individuals with NODAP, T2DM, and NAP. Prospective longitudinal studies and randomised controlled trials are now warranted to further investigate the associations between mineral intake and NODAP.

Triglyceride glycemic index as a biomarker for gestational diabetes mellitus: a systemic review and meta-analysis

BACKGROUND

Triglyceride glycemic (TyG) index is a novel tool for assessing insulin resistance (IR). Recently, TyG index as a potential biomarker for gestational diabetes mellitus (GDM) has been studied, but its performance is yet inconclusive. Thus, we performed this systemic review and meta-analysis to evaluate the performance of TyG index in predicting GDM.

METHODS

Studies published before March 1, 2021, with comparison of TyG index between GDM patients and healthy controls were retrieved from multiple databases (PubMed, Web of Science, The Cochrane Library, and Embase). The mean difference (MD) of TyG index in GDM patients and healthy controls was pooled using random-effect models.

RESULTS

Differentiation of TyG index between patients with GDM and controls showed significant results. Overall, there is a four-fold increase in TyG index in GDM patients compared with controls (MD: 0.22, 95% CI: 0.07-0.36, P = 0.003; I2 = 71%, P = 0.009). In subgroup analyses according to gestational time, TyG index in the second trimester predicted GDM with low heterogeneity (MD: 0.26, 95% CI: 0.15-0.37, P < 0.001; I2 = 0%, P = 0.54), while no such correlation was found in the first trimester.

CONCLUSION

TyG index, especially in the second trimester, could be a promising biomarker for predicting GDM.

Improving nutrition for the prevention of gestational diabetes: Current status and perspectives

Gestational diabetes mellitus (GDM) is a common complication of pregnancy and a serious public health problem. It carries significant risks of short-term and long-term adverse health effects for both mothers and their children. Risk factors, especially modifiable risk factors, must be considered to prevent GDM and its consequences. Observational studies have identified several nutritional and lifestyle factors associated with the risk of GDM. The results of intervention studies examining the effects of diet and lifestyle on the prevention of GDM are contradictory. Differences in the study populations, types and intensity of intervention, time frame of the intervention, and diagnostic criteria for GDM may explain the heterogeneity in the results of intervention studies. This review provides an overview of new diets and other factors that may help prevent GDM. The main results of epidemiological studies assessing the risk factors for GDM, as well as the results and methodological problems of intervention studies on the prevention of GDM and their meta-analyses, are discussed. In addition, the evidence that gene and lifestyle interactions influence the development of GDM, as well as prospects for increasing the effectiveness of interventions designed to prevent GDM, including new data on the possible uses of personalized diet therapy, are highlighted.

Association between maternal plasma ferritin concentration, iron supplement use, and the risk of gestational diabetes: a prospective cohort study

BACKGROUND

The association between iron supplementation and gestational diabetes mellitus (GDM) is still inconclusive, and this association has not been extensively studied in relation to plasma ferritin in the early second trimester.

OBJECTIVES

We aimed to prospectively examine the independent and combined associations of plasma ferritin concentrations and iron supplement use with GDM.

METHODS

We studied 2117 women from the Tongji Maternal and Child Health Cohort in Wuhan, China. Plasma ferritin around 16 weeks' gestation was measured by ELISA kits and information on iron supplement use was collected by questionnaires. GDM was diagnosed by a 75-g oral-glucose-tolerance test (OGTT) at 24-28 weeks' gestation. A log-Poisson regression model was used to estimate the RR of GDM associated with plasma ferritin and iron supplementation.

RESULTS

The median and IQR of plasma ferritin was 52.1 (29.6-89.9) ng/mL, and 863 (40.8%) participants reported use of iron supplements during the second trimester. A total of 219 (10.3%) participants developed GDM. Adjusted RRs (95% CIs) for GDM across increasing quartiles of plasma ferritin were 1.00 (reference), 2.14 (1.37, 3.34), 2.03 (1.30, 3.19), and 2.72 (1.76, 4.21), respectively. After adjustment, supplemental iron ≥60 mg/d during the second trimester was associated with an increased risk of GDM compared with nonusers (RR: 1.37; 95% CI: 1.02, 1.84).

CONCLUSIONS

Both elevated plasma ferritin concentrations in the early second trimester and use of ≥60 mg/d of supplemental iron during pregnancy are independently associated with increased risk of GDM. Further clinical trials with precision nutrition approaches considering both baseline iron status and supplement use are needed to evaluate the benefits and risks of iron supplementation during pregnancy.

Novel metabolic marker Afamin: A predictive factor for Large-for-Gestational-Age (LGA) fetus estimation in pregnancies with gestational diabetes mellitus?

OBJECTIVE

Gestational diabetes mellitus (GDM) affects both maternal and fetal/infant outcomes during and after pregnancy. The reason for the high incidence of large-for-gestational-age (LGA) infants in GDM patients despite close monitorization of glucose levels with early detection of the disease remains unclear to date. Our study aims to investigate the levels of the third-trimester novel marker afamin in GDM versus non-GDM pregnancies in terms of glycemic control status and their utility in the prediction of LGA fetuses.

MATERIAL AND METHODS

This prospective case-control study analysis involved 49 pregnant women with GDM diagnosed using the 75-g oral glucose tolerance test (75-g OGTT) and 40 randomly selected women with a similar body mass index (BMI) and gestational age (GA). Blood samples were collected in the third trimester of pregnancy. The afamin level was determined using a human afamin ELISA kit according to the manufacturer's procedure.

RESULTS

There was no significant difference found in BMI or GA of patients. Third-trimester afamin levels were 93.91 mg/L and 83.87 mg/L in the GDM and non-GDM groups, respectively (p=0.625). Afamin values of patients were not correlated with age, BMI, GA, HgA1c, 75-g OGTT fasting and 75-g OGTT 1-hour, or 75-g OGTT 2-hour values (p>0.05). GDM patients with LGA fetuses had significantly higher afamin values than patients with appropriate-for-gestational-age (AGA) fetuses (120.8 mg/L versus 91.26 mg/L, respectively). Between GDM patients with either LGA or AGA fetuses, there was no statistically significant difference found for age, BMI, GAs, insulin dose, 75-g OGTT results, or HgA1c values.

CONCLUSION

Our findings conclude that novel marker afamin levels could predict the risk of LGA infants independently of glycemic control status and provide insight into the pathogenesis of LGA fetuses, thus helping to reduce the risk of associated complications.

Periconceptional iron supplementation and risk of gestational diabetes mellitus: A prospective cohort study

AIMS

Iron supplementation has been recommended for healthy pregnancy, but concerns have been raised regarding the potential adverse effects. We sought to examine the impact of periconceptional iron supplement use on subsequent gestational diabetes mellitus (GDM) risk.

METHODS

Participants (N = 5101) with information on periconceptional micronutrient supplementation and diagnosis of GDM were involved. Information on iron supplementation and general characteristics were collected at enrollment and follow-up visits. GDM was diagnosed by oral glucose tolerance tests (OGTT) conducted at 24-28 weeks of gestation. Robust Poisson regression model was used to estimate the relative risks (RRs) and 95% confidence intervals (CI) for the effect of iron supplement use on GDM.

RESULTS

10.5% of the participants were diagnosed with GDM and the incidence was significantly higher in users with iron >30 mg/d for more than 3 months (Iron >30-L) than in nonusers. Adjusted RRs (95% CI) were 1.53 (1.21, 1.93) in Iron >30-L group, 1.14 (0.80, 1.61) in users with iron >30 mg/d for<3 months (Iron > 30-S) and 1.15 (0.86, 1.54) in users with iron ≤30 mg/d for any duration (Iron ≤30) respectively, compared to nonusers. This link in Iron >30-L group was even stronger (adjusted RR: 1.70, 95% CI: 1.25, 2.31) when restricting the analysis among primiparous and iron-replete participants without family history of diabetes. There were no significant differences in birth outcomes among groups.

CONCLUSIONS

Periconceptional iron supplementation >30 mg/d for long-term was associated with increased GDM risk. The need and safety of prophylactic iron supplement in iron-replete pregnant women should be reconsidered.

Hemoglobin concentration and iron supplement during pregnancy were associated with an increased risk of gestational diabetes mellitus

BACKGROUND

Hemoglobin (Hb) measurement is a conventional test during perinatal visits. Hb concentration is related to iron supplement. However, studies focusing on Hb levels, iron supplement, and pregnancy outcomes are scarce. This study aimed to determine whether Hb levels and iron supplement were associated with the risk of gestational diabetes mellitus (GDM).

METHODS

A running hospital-based cohort was conducted from August, 2011. The demographic data and medical information were collected individually through questionnaires and patient medical records. Multiple linear regression was applied for the association between Hb levels, iron supplement, and blood glucose. Multiple logistic regression was used for evaluating odds ratios between Hb levels, iron supplement, and GDM.

RESULTS

Hb levels during first (T1) and second trimester (T2) of pregnancy were significantly and positively associated with blood glucose and GDM risk. After adjusting for age, prepregnancy body mass index, and other risk factors, pregnant women with Hb ≥ 11 g/dL and iron supplement had higher postprandial blood glucose at 1 hour (Hb ≥ 11 g/dL in T2 and iron supplement in T1: β = 0.860，P = <0.001; Hb ≥ 11 g/dL in T2 and iron supplement in T2: β = 0.960，P < 0.001; Hb ≥ 11 g/dL in T1 and iron supplement in T2: β = 1.133, P = 0.033) and GDM risks (odds ratio [OR] = 1.53, 95% confidence interval [CI]: 1.05-2.24; OR = 1.92, 95% CI: 1.13-3.35; OR = 2.15, 95% CI: 1.07-4.34, respectively), compared with those with Hb < 11 g/dL and without iron supplement.

CONCLUSION

High Hb concentration and iron supplements without anemia increased postprandial blood glucose and risks for GDM. It indicates that pregnant women with good Hb levels should not be advised to take iron supplements during pregnancy.

Western Dietary Patterns, Foods, and Risk of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

An increasing number of epidemiological studies suggest that adherence to Western dietary patterns (WDPs) is associated with risk of gestational diabetes mellitus (GDM), but results remain inconsistent. Therefore, we conducted a systematic review and meta-analysis of the effect of WDPs and typical Western dietary foods on GDM. A literature search was performed in PubMed, Embase, Web of Knowledge, and the Cochrane Library up to December 2019. Cohort studies investigating the combined associations of WDPs with incidence of GDM were included. Reviewers were paired, and they independently reviewed and assessed studies, extracted data, and evaluated study quality. Pooled HRs were calculated using random-effects models. Heterogeneity and publication bias tests were also conducted. Twenty-one prospective cohort studies with 191,589 participants, including 12,331 women with GDM, were included in our analysis. The pooled risk ratio (RR) of WDPs was 1.52 (95% CI: 1.21, 1.91), indicating a significant association with GDM risk in Western countries. Potatoes (pooled RR: 1.12; 95% CI: 0.93, 1.35) showed a nonsignificant (P > 0.05) relation to GDM risk. However, consumption of animal meat (pooled RR: 1.35; 95% CI: 1.16, 1.57) and fast food (pooled RR: 1.75; 95% CI: 1.41, 2.19) showed a positive association with the risk of developing GDM. Subgroup analysis demonstrated that the consumption of red meat and processed red meat increased the risk of GDM more than either poultry or fish intake. Our study provides further evidence for understanding the relation between dietary factors and increased GDM risk and contributes to reducing the incidence of GDM through healthy diets.

Prevention of Gestational Diabetes: The Role of Dietary Intake, Physical Activity, and Weight before, during, and between Pregnancies

Gestational diabetes mellitus (GDM) is the most common complication of pregnancy and a significant clinical and public health problem with lifelong and intergenerational adverse health consequences for mothers and their offspring. The preconception, early pregnancy, and interconception periods represent opportune windows to engage women in preventive and health promotion interventions. This review provides an overview of findings from observational and intervention studies on the role of diet, physical activity, and weight (change) during these periods in the primary prevention of GDM. Current evidence suggests that supporting women to increase physical activity and achieve appropriate weight gain during early pregnancy and enabling women to optimize their weight and health behaviors prior to and between pregnancies have the potential to reduce rates of GDM. Translation of current evidence into practice requires further development and evaluation of co-designed interventions across community, health service, and policy levels to determine how women can be reached and supported to optimize their health behaviors before, during, and between pregnancies to reduce GDM risk.

Associations of Dietary Bioactive Compounds with Maternal Adiposity and Inflammation in Gestational Diabetes: An Update on Observational and Clinical Studies

Gestational diabetes mellitus (GDM) is a common complication of pregnancy that adversely affects maternal and offspring health. Maternal obesity, oxidative stress, and inflammation have been implicated in GDM. In non-pregnant adults, intakes of dietary bioactive compounds inversely associate with insulin resistance and inflammation. However, associations of dietary bioactive compounds with biomarkers of adiposity, antioxidant vitamin and mineral status, oxidative stress, and inflammation in GDM have not been fully elucidated. We addressed this gap by conducting a semi-quantitative review of observational studies and randomized controlled trials published between 2010 and 2020 and retrieved from Google Scholar, Medline, and PubMed. Our analysis revealed that women with GDM are more likely to consume a pro-inflammatory diet before pregnancy and tend to consume fewer antioxidant vitamins and minerals during pregnancy than healthy pregnant women. Women with GDM also have lower blood levels of vitamins A, C, and D and certain adipokines. Several dietary bioactive compounds were noted to improve antioxidant status and biomarkers of inflammation. The Dietary Approaches to Stop Hypertension (DASH) diet and soybean oligosaccharides increased antioxidant enzyme levels. Supplementing n-3 fatty acids, probiotics, synbiotics, and trace elements increased antioxidant enzymes and reduced hs-CRP and MDA. Improvements in inflammation by vitamin D may be contingent upon co-supplementation with other dietary bioactive compounds.

Association of the Dietary-Based Diabetes-Risk Score (DDS) with the risk of gestational diabetes mellitus in the Seguimiento Universidad de Navarra (SUN) project

It is crucial to identify people at risk for type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM) to implement preventive interventions in order to address these pandemics. A simple score exclusively based on dietary components, the Dietary-Based Diabetes-Risk Score (DDS) showed a strong inverse association with incident T2DM. The objective was to assess the association between DDS and the risk of GDM in a cohort of Spanish university graduates. The 'Seguimiento Universidad de Navarra' project is a prospective and dynamic cohort which included data of 3455 women who notified pregnancies between 1999 and 2012. The diagnosis of GDM is self-reported and further confirmed by physicians. A validated 136-item semi-quantitative FFQ was used to assess pre-gestational dietary habits. The development of the DDS was aimed to quantify the association between the adherence to this a priori dietary score and T2DM incidence. The score exclusively included dietary components (nine food groups with reported inverse associations with T2DM incidence and three food groups which reported direct associations with T2DM). Three categories of adherence to the DDS were assessed: low (11-24), intermediate (25-39) and high (40-60). The upper category showed an independent inverse association with the risk of incident GDM compared with the lowest category (multivariate-adjusted OR 0·48; 95 % CI 0·24, 0·99; P for linear trend: 0·01). Several sensitivity analyses supported the robustness of these results. These results reinforce the importance of pre-gestational dietary habits for reducing GDM and provide a brief tool to practically assess the relevant dietary habits in clinical practice.

Association between the ferritin level and risk of gestational diabetes mellitus: A meta-analysis of observational studies

AIMS/INTRODUCTION

The relationship between ferritin and the risk of gestational diabetes mellitus (GDM) has not been established. Thus, we carried out a meta-analysis based on the current literature.

MATERIALS AND METHODS

We searched relevant databases on Embase, PubMed, Cochrane Library and Web of Science before 10 May 2019 to determine the relationship between ferritin and the risk of GDM. The relative risks and 95% confidence intervals of GDM risk were summarized using a random effects model. Studies using categories of ferritin as exposure were combined by dose-response analysis. We carried out both linear and non-linear trends. We also carried out subgroup analysis, whether or not the studies adjusted for potential confounders, and meta-regression analysis to explore the source of heterogeneity. Sensitivity analysis was carried out to explore the robustness of the meta-analysis results.

RESULTS

A total of 10 studies involving 4,690 participants were identified. The summary relative risk comparing persons with the highest concentration categories of ferritin with the lowest concentration categories of ferritin was 1.87 (95% confidence interval 1.50-2.34; I2  = 20.1%). Linear dose-response showed that an increase in ferritin of 10 μg/L increased the risk of GDM by 8% (1.08, 95% confidence interval 1.05-1.13, I2  = 55.1%; n = 4). A non-linear dose-response relationship also showed a consistently increasing risk of GDM with increased ferritin. No evidence of publication bias was detected.

CONCLUSIONS

The findings from this meta-analysis suggest that increased ferritin levels are associated with an increased risk of GDM; however, we require further prospective cohort studies to confirm the results, especially the dose-response relationship between ferritin and GDM.

Dietary Patterns and Dietary Adaptations in Women with and without Gestational Diabetes: Evidence from the Growing Up in New Zealand Study

Diet is a cornerstone of the management of gestational diabetes (GDM). We investigated differences in dietary patterns and dietary adaptations among pregnant women with and without GDM participating in the Growing Up in New Zealand study. Presence of GDM was determined using coded clinical data and plasma glucose results meeting the New Zealand Society for the Study of Diabetes diagnostic criteria. Women answered a food frequency questionnaire and questions regarding dietary changes and information received during pregnancy. Women with GDM had lower adherence scores than those without GDM for 'Junk' (mean (SD) score -0.28 (0.95) versus 0.02 (1.01) p < 0.0005) and 'Traditional/White bread' dietary patterns (-0.18 (0.93) versus 0.01 (1.01) p = 0.002). More women with GDM reported avoiding foods high in fat or sugar (25.3% versus 5.7%, p < 0.05) compared to women without GDM. A greater proportion of women with GDM compared with those without GDM received information from dietitians or nutritionists (27.0% versus 1.7%, p < 0.05) or obstetricians (12.6% versus 7.5%, p < 0.05). More women diagnosed before the antenatal interview received advice from dietitians or nutritionists compared with those diagnosed after (46.9% versus 6.0%, p < 0.05). Women with GDM appear to make positive changes to their diet in response to advice received from health care professionals.

The association of elevated serum ferritin concentration in early pregnancy with gestational diabetes mellitus: a prospective observational study

BACKGROUND/OBJECTIVES

The results linking body iron stores to the risk of gestational diabetes mellitus (GDM) are conflicting. We aimed to measure the serum ferritin level of women in early pregnancy and evaluate the risk of GDM in a Chinese urban population.

SUBJECTS/METHODS

In total, 851 pregnant women between 10 and 20 weeks of gestation took part in the prospective, observational study conducted. The women were divided into four groups by quartiles of serum ferritin levels (Q1-4). Their blood samples were collected and assayed for several biochemical variables at the beginning of the study, and the women were followed up with a 75-g oral glucose tolerance test at 24-28 weeks of gestation.

RESULTS

The participants had an average serum ferritin concentration of 65.67 μg/L. GDM prevalence within each serum ferritin quartile was 9.4%, 14.6%, 18.8% and 19.3%, respectively, (P = 0.016). The odds ratio for GDM in the ferritin Q2-4 was 1.64 (CI: 0.90-2.99), 2.23 (CI: 1.26-3.96) and 2.31 (CI: 1.30-4.10), compared with Q1, respectively. This association persisted after adjusting for potential confounders factors. In addition, in Q4, pregnant women with a pre-pregnancy body mass index ≥24 kg/m², maternal age ≤35 years old or haemoglobin≥ 110 g/L did have an increased risk of developing GDM.

CONCLUSIONS

Elevated serum ferritin concentrations in early gestation are associated with an increased risk of GDM, especially in pregnant women who have a high baseline iron storage status with no anaemia or who are overweight/obese. Individual iron supplementation should be considered to minimize the risk of GDM.

Iron-Related Factors in Early Pregnancy and Subsequent Risk of Gestational Diabetes Mellitus: the Ma'anshan Birth Cohort (MABC) Study

Iron is an essential micronutrient while its excessive load has been related to the etiology of diabetes. We used data of 3289 pregnant women from the Ma'anshan birth cohort (MABC) study in China to examine the associations of three iron-related factors (i.e., serum iron (SI) concentration, hemoglobin level, and use of iron supplements) with risk of gestational diabetes mellitus (GDM). Emphatically explore the potential non-linear relationship between SI concentration and risk of GDM. SI concentration was measured in fasting blood using inductively coupled plasma mass spectrometry (ICP-MS). GDM diagnosis was determined by 75 g oral glucose tolerance test at 24~28 weeks. Restricted cubic splines with three knots were used to examine potential non-linear relationship between SI concentration and GDM risk. We observed a U-shape relation between SI concentration in the first trimester and risk of GDM. In the multivariate-adjusted model, compared with the middle level (ln(SI), 7.1-7.7 μg/L), both the lowest level (ln(SI) ≤ 7.1 μg/L) (odds ratio (OR) = 1.35, 95% confidence interval (CI) = 1.04-1.76) and the highest level (ln(SI) > 7.7 μg/L) (OR = 1.63, 95%CI = 1.16-2.28) increased risk of GDM. Associations of hemoglobin level in the first trimester and risk of GDM attenuated to non-significance after adjustment for pre-pregnancy body mass index (BMI) and blood pressure. Pre-pregnancy iron supplement use was associated with an increased risk of GDM (OR = 1.57, 95%CI = 1.06-2.32). In conclusion, the three iron-related factors are all related to GDM risk on some level.

Gestational diabetes mellitus

Hyperglycaemia that develops during pregnancy and resolves after birth has been recognized for over 50 years, but uniform worldwide consensus is lacking about threshold hyperglycaemic levels that merit a diagnosis of 'gestational diabetes mellitus' (GDM) and thus treatment during pregnancy. GDM is currently the most common medical complication of pregnancy, and prevalence of undiagnosed hyperglycaemia and even overt diabetes in young women is increasing. Maternal overweight and obesity, later age at childbearing, previous history of GDM, family history of type 2 diabetes mellitus and ethnicity are major GDM risk factors. Diagnosis is usually performed using an oral glucose tolerance test (OGTT), although a non-fasting, glucose challenge test (GCT) is used in some parts of the world to screen women for those requiring a full OGTT. Dietary modification and increased physical activity are the primary treatments for GDM, but pharmacotherapy, usually insulin, is used when normoglycaemia is not achieved. Oral hypoglycaemic agents, principally metformin and glibenclamide (glyburide), are also used in some countries. Treatment improves immediate pregnancy outcomes, reducing excess fetal growth and adiposity and pregnancy-related hypertensive disorders. GDM increases the risk of long-term complications, including obesity, impaired glucose metabolism and cardiovascular disease, in both the mother and infant. Optimal management of mother and infant during long-term follow-up remains challenging, with very limited implementation of preventive strategies in most parts of the world.

Pregnancy dietary cholesterol intake, major dietary cholesterol sources, and the risk of gestational diabetes mellitus: A prospective cohort study

BACKGROUND & AIMS

The Scientific Report of 2015 Dietary Guidelines Advisory Committee recommended the elimination of dietary cholesterol limits. However, cholesterol intake increases during pregnancy and studies regarding the association between dietary cholesterol and gestational diabetes mellitus (GDM) are limited. We evaluate the association of total dietary cholesterol and different sources of cholesterol intake during pregnancy, with GDM risk and blood glucose levels in a Chinese prospective cohort study.

METHODS

A total of 2124 pregnant women from the Tongji Maternal and Child Health Cohort was included. A validated semi-quantitative food frequency questionnaire was used to assess dietary cholesterol intake prior to GDM diagnosis. GDM was diagnosed by the 75-g 2-h oral glucose tolerance test. Cubic-restricted spline function and logistic regression analyses were used to evaluate the association between dietary cholesterol intake during pregnancy and GDM. Generalized linear models were conducted to examine the associations of cholesterol intake with fasting blood glucose (FBG), 1-h post-load blood glucose (PBG) and 2-h PBG.

RESULTS

The average dietary cholesterol intake was 379.1 mg/d, and cholesterol from eggs explained 64.2% of the variability. Total dietary cholesterol intake and cholesterol from eggs rather than other foods, were linearly associated with GDM risk, with adjusted OR for GDM of 2.10 (95%CI: 1.24, 3.58) for total cholesterol intake and 1.83 (95%CI: 1.08, 3.07) for cholesterol from eggs comparing the highest versus lowest quintile. A 100-mg/d increase in total cholesterol and cholesterol from eggs intake were associated with an increased GDM risk by 18% and 16%, respectively. Moreover, higher maternal dietary total cholesterol could increase FBG and 1-h PBG, while cholesterol from eggs increased FBG only.

CONCLUSION

Higher dietary cholesterol from eggs intake during pregnancy was associated with greater risk of GDM.

Evaluation of Plasma Trace Elements in Different Stages of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is considered as the hepatic manifestation of metabolic syndrome. Its global prevalence is estimated between 25 and 45%, occurring mainly in overweight individuals with unhealthy dietary habits and low levels of physical activity. Many studies have investigated the association of trace elements with liver diseases, though not with NAFLD. In this work, we investigated trace element levels in plasma of patients and not-patients and their possible association with various stages of the disease. Inductively coupled plasma mass spectrometry (ICP-MS) was employed for the determination of As, Ba, Cd, Co, Cs, Cu, Fe, Rb, Sr, Tl, and Zn in the plasma of 189 free-living residents of Athens, Greece, either healthy or patients with mild, moderate, or severe NAFLD. The disease was diagnosed by abdominal ultrasound; blood samples were analyzed for total, HDL and LDL cholesterol, triglycerides, fasting glucose, fasting insulin, and liver enzymes, namely aspartate aminotransferase (AST), alanine transaminase (ALT), and γ-glutamyltransferase (Gamma-GT); insulin resistance was determined by the homeostatic model assessment (HOMA-IR). Zinc exhibited a statistically significant negative association with the severity of the disease, while cesium showed a statistically significant positive association. Moreover, thallium and iron were inversely associated with insulin levels. Trace element determination in plasma could be useful for establishing relationships with NAFLD status of patients. Further research is required for the verification and interpretation of these findings.

Association of a plant-based dietary pattern in relation to gestational diabetes mellitus

AIM

The prevalence of gestational diabetes mellitus (GDM), which has adverse effects on mothers and their offspring, is increasing worldwide. The role of a plant-based dietary pattern as a determinant of GDM is not well understood. Therefore, we examined the association between plant-based dietary patterns and the risk of GDM.

METHODS

We enrolled 460 pregnant women in this case-control study, of them 200 were cases and 260 were controls. Dietary intake of participants was evaluated using three 24-hour dietary records. Adherence to the plant-based dietary patterns was scored using three indices of the overall plant-based dietary index (PDI), healthy plant-based diet (hPDI) and unhealthy plant-based diet index (uPDI). The risk of GDM was compared across tertiles of PDI, hPDI and uPDI.

RESULTS

After multivariable adjustment, we demonstrated that the high PDI score was inversely associated with risk of GDM (OR = 0.47; 95% CI: 0.28-0.78, P = 0.004), but there was no significant association between hPDI (OR = 1.03; 95% CI: 0.64-1.65, P = 0.884) or uPDI (OR = 1.65; 95% CI: 0.98-2.78, P = 0.06) and GDM risk.

CONCLUSIONS

We found that following an overall plant-based diet was associated with lower risk of GDM. Future studies are warranted with longitudinal designs to confirm these findings.

Dietary patterns during pregnancy and risk of gestational diabetes: a prospective cohort study in Western China

BACKGROUND

Previous research has demonstrated the association between maternal dietary patterns and gestational diabetes (GDM), but evidence in Asian populations remains limited and inconsistent. This study investigated the association between dietary patterns during early pregnancy and the risk of GDM among pregnant women in Western China.

METHODS

A prospective cohort study was conducted among 1337 pregnant women in Western China. Dietary intakes were assessed at 15-20 weeks of gestation using a validated food frequency questionnaire. GDM was diagnosed by oral glucose tolerance tests at 24-28 weeks of gestation. Exploratory factor analysis was performed to derive dietary patterns, and logistic regression models were used to examine the association between dietary patterns and GDM.

RESULTS

A total of 199 women (14.9%) developed GDM. Three dietary patterns were identified, namely, a plant-based pattern, a meat-based pattern and a high protein-low starch pattern. Notwithstanding a lack of association between dietary patterns and GDM risk in the whole cohort, there was a significant reduction in GDM risk among overweight women (BMI ≥24 kg/m²); the odds ratio being 0.29 (95% confidence interval 0.09 to 0.94) when comparing the highest versus the lowest score of the high protein-low starch pattern.

CONCLUSIONS

There was no significant association between early pregnancy dietary patterns and GDM risk later in pregnancy for women in Western China, but high protein-low starch diet was associated with lower risk for GDM among women who were overweight at pre-pregnancy.

Hemoglobin levels during the first trimester of pregnancy are associated with the risk of gestational diabetes mellitus, pre-eclampsia and preterm birth in Chinese women: a retrospective study

BACKGROUND

Hemoglobin (Hb) measurement is a standard test among pregnant women during the first perinatal visit that is used to evaluate physical status and anemia. However, studies focusing on Hb levels and pregnancy outcomes are scarce. This study aimed to determine whether Hb levels in early pregnancy were associated with the risk of gestational diabetes mellitus (GDM), pre-eclampsia (PE) and preterm birth.

METHODS

A hospital-based retrospective study was conducted among 21,577 singleton, non-smoking pregnancies between June 2013 and January 2015. The demographic data and medical information of each participant were collected individually through questionnaires and patient medical records. Odds ratios were generated using a multivariate logistic regression analysis to evaluate the relative risk of GDM, PE and preterm birth continuously and across different hemoglobin ranges in the overall population and in women from different pre-pregnancy body mass index (BMI) categories, respectively. The level of statistical significance was set at 0.05.

RESULTS

(1) For women who were underweight, normal-weight, overweight and obese, early pregnancy Hb levels were 127.8 ± 10.1 g/L, 129.6 ± 9.7 g/L, 132.2 ± 9.5 g/L and 133.4 ± 9.4 g/L, respectively. (2) Women with GDM and PE had significantly increased Hb levels during early pregnancy compared with controls, whereas women with preterm birth processed significantly decreased Hb levels. (3) After adjusting for confounders, the risks for GDM and PE increased with high maternal Hb (OR: 1.27 for Hb 130-149; OR: 2.06 for Hb ≥ 150 g/L), and the risk for preterm birth decreased with high maternal Hb (OR: 1.30 for Hb 130-149; OR: 2.38 for Hb ≥ 150 g/L) and increased with low maternal Hb (OR: 1.41 for Hb <  110 g/L). Among women whose BMI was < 24 kg/m2, high GDM (OR: 1.27 for Hb 130-149; OR: 1.84 for Hb ≥ 150 g/L) and low preterm rates (OR: 0.77 for Hb 130-149; OR: 0.23 for Hb ≥ 150 g/L) were observed with high Hb, whereas in women whose BMI was ≥24 kg/m2, only high GDM rates were observed with Hb > 150 g/L (OR: 2.33).

CONCLUSION

These findings suggest that Hb levels during early pregnancy play a role in predicting the risk of GDM, PE and preterm birth.

Associations of Diet and Physical Activity with Risk for Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

Rising rates of gestational diabetes mellitus (GDM) and related complications have prompted calls to identify potentially modifiable risk factors that are associated with gestational diabetes mellitus (GDM). We systematically reviewed the scientific literature for observational studies examining specific dietary and/or physical activity (PA) factors and risk of GDM. Our search included PubMed, Medline, CINAHL/EBSCO, Science Direct and EMBASE, and identified 1167 articles, of which 40 met our inclusion criteria (e.g., singleton pregnancy, reported diet or PA data during pre-pregnancy/early pregnancy and GDM as an outcome measure). Studies were assessed for quality using a modified Quality Criteria Checklist from American Dietetic Association. Of the final 40 studies, 72% obtained a positive quality rating and 28% were rated neutral. The final analysis incorporated data on 30,871 pregnant women. Dietary studies were categorised into either caffeine, carbohydrate, fat, protein, calcium, fast food and recognized dietary patterns. Diets such as Mediterranean Diet (MedDiet), Dietary Approaches to Stop Hypertension (DASH) diet and Alternate Healthy Eating Index diet (AHEI) were associated with 15–38% reduced relative risk of GDM. In contrast, frequent consumption of potato, meat/processed meats, and protein (% energy) derived from animal sources was associated with an increased risk of GDM. Compared to no PA, any pre-pregnancy or early pregnancy PA was associated with 30% and 21% reduced odds of GDM, respectively. Engaging in >90 min/week of leisure time PA before pregnancy was associated with 46% decreased odds of GDM. We conclude that diets resembling MedDiet/DASH diet as well as higher PA levels before or in early pregnancy were associated with lower risks or odds of GDM respectively. The systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42016027795.

Iron Status and Gestational Diabetes-A Meta-Analysis

A meta-analysis of the association of iron overload with gestational diabetes mellitus (GDM) may inform the health debate. We performed a meta-analysis investigating the association of iron biomarkers and dietary iron exposure with GDM. We identified 33 eligible studies (N = 44,110) published in 2001–2017. The standardized mean differences (SMD) in women who had GDM compared to pregnant women without were 0.25 µg/dL (95% CI: 0.001–0.50) for iron, 1.54 ng/mL (0.56–2.53) for ferritin, 1.05% (0.02 to 2.08) for transferrin saturation, and 0.81 g/dL (0.40–1.22) for hemoglobin. Adjusted odds ratio for GDM were 1.58 (95% CI: 1.20–2.08) for ferritin, 1.30 (1.01–1.67) for hemoglobin, and 1.48 (1.29–1.69) for dietary heme intake. We did not find any differences in TIBC or transferrin concentration in women with and without GDM. We also did not find any association of increased transferrin receptor or increased intake of total dietary iron, non-heme iron or supplemental iron, with increased odds ratios for GDM. Considerable heterogeneity was present among the studies (0–99%), but no evidence of publication bias. Accumulating evidence suggests that circulating and dietary iron biomarkers among pregnant women are associated with GDM, but the results should be interpreted with caution due to the high heterogeneity of analyses. Randomized trials investigating the benefits of iron reduction in women at high risk for GDM are warranted.

Trace Elements and Vitamin D in Gestational Diabetes

Gestational diabetes mellitus (GDM), one of the most common pregnancy complications, is defined as glucose intolerance with onset or first recognition during pregnancy. Its prevalence varies worldwide in dependence on characteristics of the underlying population and applied diagnostic criteria. The etiology is multifactorial and not sufficiently elucidated. Available evidence suggests that the base of pathogenesis is relatively diminished insulin secretion coupled with pregnancy-induced insulin resistance. Modifiable and non-modifiable risk factors for development have been identified. Trace elements and vitamin D could be contributed to modifiable factors for prediction the risk in a large population. Essential trace elements in pregnancy are necessary to overcome systemic oxidative, metabolic and inflammatory stress. Evidence, still inconclusive, has been accumulated about the relation between higher incidence of vitamin D failure/deficiency during pregnancy and GDM. The lower level of 25-OH vitamin D could be associated with increased risk for anemia development, also including pregnant women. This review intends to provide an overview of the possible link between both vitamin D and trace elements as risk factors for GDM development.