Noninvasive assessment of subclinical atherosclerosis in normotensive gravidae with gestational diabetes

The effect of gestational diabetes mellitus on carotid artery intima-media thickness in and after pregnancy: a systematic review and meta-analysis

AIMS

The association between gestational diabetes mellitus (GDM) and common carotid artery (CCA) intima-media thickness (IMT) is still controversial. This systematic review and meta-analysis was performed to assess the correlation between GDM and CCA-IMT in and after pregnancy.

METHODS

PubMed and EMBASE databases were systematically reviewed on April 2023. Studies measuring CCA-IMT in both pregnant women with GDM and women with previous history of GDM (pGDM) vs. healthy controls were included. The subtotal and overall standardized mean differences (SMDs) of CCA-IMT were calculated using the random-effect model.

RESULTS

Nineteen studies with a total of 302 GDM and 861 pGDM women were analyzed. The average value of CCA-IMT measured in GDM/pGDM (0.59 ± 0.12 mm) was slightly increased in comparison to the accepted reference limits of IMT according to age classes. Substantial heterogeneity was detected for the studies involving both GDM and pGDM women, with an overall statistic I2 of 86.0% (p < 0.001). Large SMDs were obtained for the studies conducted on both GDM and pGDM women, with an overall SMD of 0.89 (95%CI 0.63-1.15, p < 0.001). Egger's test for a regression intercept gave a p-value of 0.37, indicating no publication bias. On meta-regression analysis, all potential confounders (number of patients, age at pregnancy, body mass index, measuring time, follow-up duration and GDM criteria) were not significantly associated with effect modification.

CONCLUSIONS

GDM in and after pregnancy is independently associated with subclinical atherosclerosis. The association between GDM and carotid remodeling is potentially mediated by the longstanding underlying risk.

High Folate, Perturbed One-Carbon Metabolism and Gestational Diabetes Mellitus

Folate is a dietary micronutrient essential to one-carbon metabolism. The World Health Organisation recommends folic acid (FA) supplementation pre-conception and in early pregnancy to reduce the risk of fetal neural tube defects (NTDs). Subsequently, many countries (~92) have mandatory FA fortification policies, as well as recommendations for periconceptional FA supplementation. Mandatory fortification initiatives have been largely successful in reducing the incidence of NTDs. However, humans have limited capacity to incorporate FA into the one-carbon metabolic pathway, resulting in the increasingly ubiquitous presence of circulating unmetabolised folic acid (uFA). Excess FA intake has emerged as a risk factor in gestational diabetes mellitus (GDM). Several other one-carbon metabolism components (vitamin B12, homocysteine and choline-derived betaine) are also closely entwined with GDM risk, suggesting a role for one-carbon metabolism in GDM pathogenesis. There is growing evidence from in vitro and animal studies suggesting a role for excess FA in dysregulation of one-carbon metabolism. Specifically, high levels of FA reduce methylenetetrahydrofolate reductase (MTHFR) activity, dysregulate the balance of thymidylate synthase (TS) and methionine synthase (MTR) activity, and elevate homocysteine. High homocysteine is associated with increased oxidative stress and trophoblast apoptosis and reduced human chorionic gonadotrophin (hCG) secretion and pancreatic β-cell function. While the relationship between high FA, perturbed one-carbon metabolism and GDM pathogenesis is not yet fully understood, here we summarise the current state of knowledge. Given rising rates of GDM, now estimated to be 14% globally, and widespread FA food fortification, further research is urgently needed to elucidate the mechanisms which underpin GDM pathogenesis.

Prognostic indicators of persistent carotid intima-media thickness increase in postpartum period in a population of normotensive women with gestational diabetes mellitus

OBJECTIVE

The association between gestational diabetes mellitus (GDM) and common carotid artery (CCA)-intima media thickness (IMT) is still controversial. In the present study, we aimed to compare the CCA-IMT measured in GDM women to that obtained in healthy pregnant women in the third trimester of pregnancy. Secondly, we investigated the main independent predictors of persistent CCA-IMT increase (defined as CCA-IMT ≥ 0.6 mm) in postpartum period in GDM women.

STUDY DESIGN

30 consecutive GDM women and 30 healthy pregnant women matched for anagraphic age (34.1 ± 4.5 vs 32.8 ± 4.2 yrs, p = 0.25), ethnicity (caucasian 56.7 vs 63.3%, p = 0.59), gestational age (36.2 ± 1.7 vs 36.5 ± 1.6 weeks, p = 0.48) and cardiovascular risk factors were examined in this prospective case-control study. All women underwent obstetric visit, blood tests, conventional transthoracic echocardiography implemented with two-dimensional speckle tracking echocardiography analysis of left ventricular and left atrial myocardial strain parameters and carotid ultrasound examination at two time points: 36-38 weeks' gestation and 6-10 weeks after delivery.

RESULTS

At 36.2 ± 1.7 weeks of gestation, CCA-IMT was significantly increased in GDM women than controls (0.81 ± 0.11 vs 0.55 ± 0.12, p < 0.001). Twelve GDM women (40% of the total) were found with persistent CCA-IMT increase (0.76 ± 0.14 mm) in postpartum period (8.2 ± 2.2 weeks), whereas the remaining 18 (60% of the total) showed a normalization in CCA-IMT (0.56 ± 0.1 mm). At multivariate logistic regression analysis, third trimester body mass index (BMI) (OR 1.78, 95%CI 1.24-2.54, p = 0.01), glycosylated hemoglobin (HbA1C) (OR 1.51, 95%CI 1.13-1.89, p = 0.03) and neutrophil-to-lymphocyte ratio (NLR) (OR 1.68, 95%CI 1.25-4.65, p = 0.02) resulted to be independently associated with persistent CCA-IMT increase in postpartum period in GDM women. A BMI ≥ 29.2 Kg/m², an HbA1C ≥ 37.5 mmol/mol and a NLR ≥ 5.5 were the best cut-off values for identifying GDM women with persistent CCA-IMT increase in postpartum period.

CONCLUSIONS

GDM is associated with increased CCA-IMT during pregnancy. This increase may be persistent in postpartum period in GDM women with obesity, uncontrolled diabetes and increased inflammatory markers.

Endothelial Dysfunction in Pregnancy Complications

The endothelium, which constitutes the inner layer of blood vessels and lymphatic structures, plays an important role in various physiological functions. Alterations in structure, integrity and function of the endothelial layer during pregnancy have been associated with numerous gestational complications, including clinically significant disorders, such as preeclampsia, fetal growth restriction, and diabetes. While numerous experimental studies have focused on establishing the role of endothelial dysfunction in pathophysiology of these gestational complications, their mechanisms remain unknown. Numerous biomarkers of endothelial dysfunction have been proposed, together with the mechanisms by which they relate to individual gestational complications. However, more studies are required to determine clinically relevant markers specific to a gestational complication of interest, as currently most of them present a significant overlap. Although the independent diagnostic value of such markers remains to be insufficient for implementation in standard clinical practice at the moment, inclusion of certain markers in predictive multifactorial models can improve their prognostic value. The future of the research in this field lies in the fine tuning of the clinical markers to be used, as well as identifying possible therapeutic techniques to prevent or reverse endothelial damage.

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

AIMS

It is reported that elevated homocysteine (Hcy) level represents an independent risk factor for gestational diabetes mellitus (GDM). However, the relationship between Hcy level and GDM remains controversial. Our study aimed to systematically review available literature linking Hcy to GDM for a comprehensive understanding of the relationship between circulating Hcy level and GDM in humans.

METHODS

PubMed, The Cochrane Library, and Web of Science were searched for studies published up to January 2021. Manual searches of references of the relevant studies were also conducted. Standard mean difference (SMD) with 95% confidence interval (95%CI) were calculated to evaluate the relationship between Hcy level and GDM using the Review Manager 5.3 and Stata 12.0.

RESULTS

Of 106 references reviewed, 12 studies with a total of 712 GDM patients contributed to the present meta-analysis. Hcy level was significantly elevated in women with GDM compared with those without GDM (SMD = 0.55; 95% CI: 0.25-0.85, p = .0003). In the subgroup meta-analyses, this evidence was more consistent among women with Hcy sampling during the second trimester (SMD = 0.76, 95% CI: 0.34-1.18, p = .0004) and with average age ≥30 years (SMD = 0.69, 95% CI: 0.25-1.12, p = .002).

CONCLUSION

The evidence indicated that the level of circulating Hcy was significantly elevated among women with GDM compared with those with normal glucose tolerance, especially with mean age ≥30 years and in the second trimester.

Increased risk for microvascular complications among women with gestational diabetes in the third trimester

AIMS

The risk of microvascular disease has been thought to commence with the onset of overt diabetes. Women with gestational diabetes have only had a short-term exposure to frank hyperglycemia, but, due to underlying β-cell dysfunction, they may also have had long-term exposure to mild degrees of hyperglycemia. The aim of the study was to determine whether women with gestational diabetes are at increased risk for microalbuminuria and retinopathy compared to women with normal glucose tolerance in pregnancy.

METHODS

We recruited women aged ≥ 25 years with singleton pregnancies at 32 to 40 weeks' gestational age, with and without gestational diabetes. Women with hypertension, preeclampsia, or pre-gestational diabetes were excluded.

RESULTS

Of 372 women included in the study, 195 had gestational diabetes. The prevalence of microalbuminuria was 15% among those with gestational diabetes versus 6% in those with normal glucose tolerance (adjusted odds ratio 2.4, 95% confidence interval 1.1 to 5.2, p = 0.006). Diastolic blood pressure and HbA1c were associated with microalbuminuria. The prevalence of retinopathy did not differ between groups (10% versus 11%).

CONCLUSIONS

Women with gestational diabetes have an increased risk of microalbuminuria in the third trimester, despite having been exposed to only a brief period of overt hyperglycemia.

Pregnancy and post-partum muscle and cerebral oxygenation during intermittent exercise in gestational diabetes: A pilot study

OBJECTIVE

This pilot, prospective, observational, cohort study aimed to examine, for the first time, the in vivo alterations in the oxygenation of the forearm skeletal muscles and the prefrontal lobes during intermittent exercise in women diagnosed with gestational diabetes mellitus (GDM), during and after pregnancy.

STUDY DESIGN

Nine pregnant women, diagnosed with GDM, performed a 3-min intermittent handgrip exercise protocol (at 35% of Maximal Voluntary Contraction) during pregnancy (mean 27th gestational week) and following labor (mean 71 weeks). During the protocol, muscle and cerebral oxygenation were assessed with near-infrared spectroscopy. Resting vascular parameters [carotid intima-media thickness (cIMT) and hemodynamic parameters (using rheocardiography)], and hematological/biochemical parameters during pregnancy and after delivery have been compared.

RESULTS

Although changes were observed in certain hematological parameters (p< 0.05), cIMT and hemodynamic parameters were not altered post-partum. In addition, both muscle and cerebral oxygenation parameters during handgrip were not significantly altered post-partum.

CONCLUSIONS

Despite significant changes in specific hematological parameters in women with GDM, impairments in muscle and cerebral oxygenation during exercise remained at one year after labor. These results indicate that alterations in vascular parameters and muscle/cerebral oxygenation associated with GDM do not entirely reverse post-partum. Future studies are needed to examine which interventions will lead to improvements in microvascular parameters and prevent type 2 diabetes.

Serum homocysteine level and gestational diabetes mellitus: A meta-analysis

Aims/Introduction

Homocysteine levels during pregnancy in women with gestational diabetes mellitus (GDM) have been studied; however, it remains unclear whether hyperhomocysteinemia is a useful predictor of insulin resistance. The present study aimed to evaluate the relationship between homocysteine level and GDM.

Materials and Methods

PubMed, Elsevier, Web of Science and CNKI were searched for relevant studies published up to January 2015. Manual searches of references of the relevant original studies were carried out. Meta‐analysis was used to assessed the relationship between homocysteine level and GDM using the stata 12.0 software.

Results

Homocysteine levels were significantly elevated in women with GDM compared with those without GDM (weighted mean difference 0.77, 95% confidence interval 0.44–1.10). This evidence was more consistent during the second trimester measurement of homocysteine (weighted mean difference 0.95, 95% confidence interval 0.67–1.23) and for women aged older than 30 years (weighted mean difference 0.90, 95% confidence interval 0.63–1.17).

Conclusions

The present meta‐analysis shows that homocysteine level is significantly elevated among women with GDM compared with women with normal glucose tolerance, and this finding persists more during the second trimester.

Maternal lipid levels during pregnancy and gestational diabetes: a systematic review and meta-analysis

BACKGROUND

Lipid levels during pregnancy in women with gestational diabetes mellitus (GDM) have been extensively studied; however, it remains unclear whether dyslipidaemia is a potential marker of preexisting insulin resistance.

OBJECTIVE

To evaluate the relationship between lipid measures throughout pregnancy and GDM.

SEARCH STRATEGY

We searched PubMed-MedLine and SCOPUS (inception until January 2014) and reference lists of relevant studies.

SELECTION CRITERIA

Publications describing original data with at least one raw lipid (total cholesterol, high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], or triglyceride) measurement during pregnancy in women with GDM and healthy pregnant controls were retained.

DATA COLLECTION AND ANALYSIS

Data extracted from 60 studies were pooled and weighted mean difference (WMD) in lipid levels was calculated using random effects models. Meta-regression was also performed to identify sources of heterogeneity.

MAIN RESULTS

Triglyceride levels were significantly elevated in women with GDM compared with those without GDM (WMD 30.9, 95% confidence interval [95% CI] 25.4-36.4). This finding was consistent in the first, second and third trimesters of pregnancy. HDL-C levels were significantly lower in women with GDM compared with those without GDM in the second (WMD -4.6, 95% CI -6.2 to -3.1) and third (WMD -4.1, 95% CI -6.5 to -1.7) trimesters of pregnancy. There were no differences in aggregate total cholesterol or LDL-C levels between women with GDM and those without insulin resistance.

AUTHOR'S CONCLUSIONS

Our meta-analysis shows that triglycerides are significantly elevated among women with GDM compared with women without insulin resistance and this finding persists across all three trimesters of pregnancy.

Homocysteine levels in women with a history of gestational diabetes mellitus

BACKGROUND

Previous gestational diabetes (pGDM) is a risk factor of type 2 diabetes, hypertension and cardiovascular diseases. Homocysteine is one of markers of cardiovascular risk. The aim of this study was to assess the homocysteine levels in women with pGDM and to evaluate its relationship with current carbohydrate metabolism and nourishment status.

METHODS

The study group comprised 199 women at 7.8 ± 1.0 years after pGDM and 50 control women in whom pGDM was excluded. The analyzed parameters: BMI, WHR, body composition (Tanita SC-330S analyzer), glucose and insulin levels in oral glucose tolerance test (OGTT), insulin resistance index (HOMA-IR), HbA1c, lipid profile, homocysteine, creatinine and creatinine clearance. The Mann-Whitney test and Chi-squared test were used for comparison of continuous and nominal variables, respectively. Correlations between continuous variables in each group were analyzed using Spearman's rank correlation coefficient (Rs). A logarithmic transformation was applied for variables with non-normal distribution.

RESULTS

There were no differences between the pGDM women and controls in terms of age, number of childbirths, time from indexed pregnancy, pre-pregnancy BMI, or current anthropometric parameters. In pGDM women HbA1c and all glucose levels in OGTT were significantly higher, but still within the normal range. No significant differences were found in homocysteine levels, HOMA-IR, blood lipids, creatinine and creatinine clearance. Homocysteine levels did not differ significantly in subgroups categorized according to the current OGTT results or BMI. Carbohydrate metabolism disorders, overweight and obesity were associated with higher creatinine clearance. Positive correlation between homocysteine and creatinine (r = 0.21, p < 0.004), and a negative correlation with creatinine clearance (r = -0.16, p < 0.03) were found.

CONCLUSIONS

In women with pGDM, homocysteine is not a marker of glucose tolerance disturbances and cardiovascular risk. Increased glomerular filtration rate, observed in more severe disorders of carbohydrate metabolism and greater BMI, may temporarily protect against an increase of proatherogenic homocysteine.

Association of gestational diabetes mellitus (GDM) with subclinical atherosclerosis: a systemic review and meta-analysis

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with an elevated risk of adverse health outcomes such as type 2 diabetes and cardiovascular diseases. Carotid intima-media thickness (cIMT) is increasingly used as a noninvasive marker for subclinical atherosclerosis. Whether there is a direct correlation between GDM and elevated cIMT is still controversial.

METHODS

PubMed, Embase and reference lists of relevant papers were reviewed. Studies assessing the relationship between GDM and cIMT were included. Weighted Mean Difference (WMD) of cIMT was calculated using random-effect models.

RESULTS

Fifteen studies with a total of 2247 subjects were included in our analysis, giving a pooled WMD of 0.05 (95% confidence interval [CI] 0.03 -0.07). Furthermore, meta regression and subgroup analysis found that the association between GDM and larger cIMT already existed during pregnancy, and this relation was stronger in obese GDM patients.

CONCLUSIONS

GDM in and after pregnancy is associated with subclinical atherosclerosis. Weight control may be helpful to prevent cardiovascular diseases for GDM patients.