Oral Glucose Tolerance Test Glucose Research Articles

Associations between blood markers of glucose metabolism and characteristics of circulating lymphocytes

AimsThe pathophysiology of diabetes is not fully understood; recent research indicates close relations with immunological alterations. Therefore, the aim of this study was to investigate the associations between markers of glucose metabolism and characteristics of blood lymphocytes in a population-based cohort. MethodsThe analysis was based on data from 219 non-diabetic participants of the MEGA study in Augsburg, Germany, who were recruited between 2018 and 2021. The majority of participants were examined two different times with a time lag of 9 months. Fasting venous blood samples were taken and oral glucose tolerance tests (OGTT) were performed at both visits. Immune cells were analyzed from fresh blood using flow cytometry. The associations between fasting blood glucose levels, glucose levels at 2 hours after oral glucose bolus and glycated hemoglobin (HbA1c) concentrations and the quantity of different lymphocyte subsets were analyzed using linear mixed regression models with random intercept. P values were FDR-adjusted. ResultsHbA1c was negatively associated with the marginal zone B cells (IgD+ CD27+ B cells). Fasting glucose was positively associated with natural killer (NK) cells and 2-hour OGTT glucose was positively associated with NKT cells. Finally, HbA1c showed significantly negative associations with the CD57-PD1-NKT cell subset. ConclusionMarkers of glucose metabolism showed significant associations with B cell, NK cell and NKT cell subsets, which clearly indicates a relation between glucose metabolism and the adaptive immune system.

The relationship between glucose patterns in OGTT and adverse pregnancy outcomes in twin pregnancies.

Traditional fixed thresholds for oral glucose tolerance test (OGTT) results may inadequately prevent adverse pregnancy outcomes in twin pregnancies. This study explores latent OGTT patterns and their association with adverse outcomes. This study retrospectively analyzed 2644 twin pregnancies using latent mixture models to identify glucose level patterns (high, HG; medium, MG; and low, LG) and their relationship with maternal/neonatal characteristics, gestational age at delivery, and adverse outcomes. Three distinct glucose patterns, HG, MG, and LG patterns were identified. Among the participants, 16.3% were categorized in the HG pattern. After adjustment, compared with the LG pattern, the HG pattern was associated with a 1.79-fold, 1.66-fold, and 1.32-fold increased risk of stillbirth, neonatal respiratory distress, and neonatal hyperbilirubinemia, respectively. The risk of neonatal ICU admission for MG and HG patterns increased by 1.22 times and 1.32 times, respectively, compared with the LG pattern. As gestational weeks increase, although there is an overlap in the confidence intervals between the HG pattern and other patterns in the restricted cubic splines analysis, the trend suggests that pregnant women with the HG pattern are more likely to face risks of their newborns requiring neonatal intensive care unit admission, and adverse comprehensive outcomes, compared with other patterns. In addition, with age and body mass index increasing in HG mode, gestation weeks at delivery tend to be later than in other modes. Distinct OGTT glucose patterns in twin pregnancies correlate with different risks of adverse perinatal outcomes. The HG pattern warrants closer glucose monitoring and targeted intervention.

Maternal glucose homeostasis during pregnancy in women with overweight or obesity and offspring metabolic health

Gestational diabetes mellitus (GDM) adversely affects offspring glucose homeostasis and risk of developing obesity. Here, we examined the association between glycemia in pregnant women with overweight or obesity without GDM and offspring metabolic health. Maternal fasting glucose concentrations and glucose 2-h after an oral glucose tolerance test (OGTT) were measured in 208 women with a pre-pregnancy body mass index (BMI) of 28–45 kg/m2 without GDM. Offspring outcomes were collected at birth, 3, and 5 years of age. Linear mixed models with time as fixed factor and subject ID as random effects were used for analysis. No associations were found between maternal fasting or 2-h glucose concentrations with offspring glucose and insulin concentrations from birth to 5 years of age. However, maternal fasting glucose in GW 28 and 36, and 2-h OGTT glucose in GW 28 were positively associated with C-peptide concentration at birth. Maternal fasting glucose concentrations in GW 28 and 36 were positively associated with weight-for-length, and maternal fasting glucose in GW 36 was associated with BMI z-score at birth. In summary, blood glucose in pregnant women with overweight or obesity is positively associated with offspring C-peptide concentration, weight-for-length, and BMI z-score at birth, even in the absence of GDM.

Glucose tolerance two years after gestational diabetes classified by old Swedish or new WHO diagnostic criteria

AimTo explore how introduction of the lower WHO gestational diabetes (GDM) glucose criteria in Sweden affected prediabetes/type-2-diabetes (T2D) incidence two years postpartum. MethodsWomen included in the PREvention of PostPartum (PREPP) diabetes study were diagnosed with GDM according to EASD 1991 criteria (GDMOLD; n = 93) or only WHO 2013 criteria (GDMWHO; n = 174). Both groups were further stratified by BMI, and BMI-matched normoglycemic pregnancy controls were included (n = 88). Postpartum assessments included oral glucose tolerance tests (OGTT) and anthropometric measurements. ResultsThere was a higher postpartum incidence of T2D in GDMOLD versus GDMWHO (P < 0.001). Despite similar BMI, GDMOLD exhibited higher fasting and OGTT glucose levels, lower fat-free-mass, and hip circumference compared to GDMWHO. In normal-weight women, both GDM groups displayed higher HOMA-IR and lower fat-free-mass compared to controls, with GDMOLD additionally showing lower HOMA-β, slower insulin release during OGTT, and worse glucose tolerance than GDMWHO. Among obese women, the main differences were lower fat-free-mass and hip circumference in GDMOLD. ConclusionThe lower glucose cut-offs during pregnancy resulted in lower postpartum incidence of T2D, irrespective of BMI. Fat-free-mass emerged as a key determinant in glucose levels across BMI categories, while lower beta-cell function played a significant role in normal-weight women.

Effect of dietary myo-inositol supplementation on the insulin resistance and the prevention of gestational diabetes mellitus: an open-label, randomized controlled trial.

Myo-inositol (MI) is an insulin-sensitizing dietary supplement, enhancing the transfer of glucose into the cell. Gestational diabetes mellitus (GDM) is characterized by abnormal glucose tolerance, which is associated with elevated insulin resistance. The present study aimed to assess the effect of MI supplementation during pregnancy on the incidence of GDM. We performed a single-center, open-label, randomized controlled trial. A cohort of 200 pregnant women at 11-13+6 weeks of gestation were randomly assigned in two groups: MI group (n = 100) and control group (n = 100). The MI group received MI and folic acid (4000 mg MI and 400 mcg folic acid daily), while the control group received folic acid alone (400 mcg folic acid daily) until 26-28 weeks of gestation, when the 75 g Oral Glucose Tolerance Test (OGTT) was performed for the diagnosis of GDM. Clinical and metabolic outcomes were assessed. The incidence of GDM was significantly higher in the MI group (14.9%) compared to the control group (28.5%) (P = 0.024). Women treated with MI had significantly lower OGTT glucose values, than those not treated with MI (P < 0.001). The insulin resistance as assessed by HOMA-IR was significantly lower in the MI group versus control (P = 0.045). Furthermore, MI group had significantly higher insulin sensitivity as measured by the Matsuda Index, compared to the control group (P = 0.037). MI supplementation seems to be an effective option to improve the glycemic control of pregnant women and prevent the onset of GDM. ISRCTN registry: ISRCTN16142533. Registered 09 March 2017.

Relationship Between Early-Pregnancy Glycemia and Adverse Outcomes: Findings From the TOBOGM Study.

We evaluated associations between early-pregnancy oral glucose tolerance test (OGTT) glucose and complications in the Treatment of Booking Gestational Diabetes Mellitus (TOBOGM) cohort to inform prognostic OGTT thresholds. Individuals with risk factors for hyperglycemia were recruited for an international, multicenter, randomized controlled gestational diabetes mellitus (GDM) (World Health Organization 2013 criteria) treatment trial. A 2-h 75-g OGTT was performed at <20 weeks' gestation. Individuals with early treated hyperglycemia in pregnancy were excluded from the primary analysis. Early OGTT glucose concentrations were analyzed continuously and in glycemic categories (normal, low band, and high band). Overall, 3,645 individuals had an OGTT at (mean ± SD) 15.6 ± 2.5 weeks. For each 1-SD increase in fasting, 1-h, and 2-h glucose values, there were continuous positive associations with late GDM: adjusted odds ratio (aOR) 2.04 (95% CI 1.82-2.27), 3.05 (2.72-3.43), and 2.21 (1.99-2.45), respectively. There were continuous positive associations between 1-h and 2-h glucose and the perinatal composite (birth <37 + 0 weeks, birth trauma, birth weight ≥4,500 g, respiratory distress, phototherapy requirement, stillbirth/neonatal death, and shoulder dystocia), with aOR 1.15 (95% CI 1.04-1.26) and 1.14 (1.04-1.25), respectively, and with large-for-gestational-age offspring, with aOR 1.18 (1.06-1.31) and 1.26 (1.01-1.25), respectively. Significant associations were also observed between 1-h glucose and cesarean section and between fasting and 2-h glucose and neonatal hypoglycemia. In categorical analysis, only the high-band 1-h glucose (≥10.6 mmol/L [191 mg/dL]) predicted the perinatal composite. There is a continuous positive association between early-pregnancy OGTT glucose and complications. In individuals with hyperglycemia risk factors, only the high-glycemic-band 1-h glucose corresponded to increased risk of major perinatal complications.

The association between visceral adipose thickness and gestational diabetes mellitus in the first trimester

Objective: To investigate the association between visceral adipose tissue (VAT) thickness in early pregnancy and the risk of gestational diabetes mellitus (GDM). Methods: Based on the Qingdao Women and Children Health Cohort, pregnant women in the first trimester (11-13+6 weeks of gestation) were enrolled in this cohort study between May 2019 and October 2022. The VAT was measured in first trimester and determined as the distance from the inner margin of the rectus abdominis muscle to the anterior wall of the great artery using multi-functional color ultrasound. The 75 g oral glucose tolerance test (OGTT) results were followed up at 24-28 weeks and the participants were divided into GDM group and non-GDM group. The pregnant women were divided into 4 groups according to the VAT quartile. Log-binomial model and linear regression model were used to analyze the association between VAT and GDM/blood glucose. Results: A total of 3 686 pregnant women were included in this study, the mean age of participants was (30.56±4.05) years and 722 were diagnosed with GDM, with an incidence of 19.6%. The log-binomial regression model results showed that compared with VAT thickness Q1 (VAT<14.70 mm), the GDM risk in Q3 (21.65≤VAT≤29.69 mm) and Q4 (VAT ≥29.70 mm) increased by 34% [RR(95%CI): 1.34 (1.08-1.67)], and 61% [RR(95%CI): 1.61 (1.30-2.00)], respectively. Among women with gestational age<35 years old, compared with VAT thickness Q1, the risk of GDM increased by 42% in Q3 [RR(95%CI): 1.42 (1.22-1.65)] and 70% [RR(95%CI): 1.70 (1.46-1.98)] in Q4, whereas no associations were found in women with gestational age ≥35 years old (P>0.05). The association between VAT and GDM risk was only found in pregnant women with pre-pregnancy BMI <24.0 kg/m2, and the GDM risk increased by 57% [RR(95%CI): 1.57 (1.22-2.04)] in Q3 and 65% [RR(95%CI): 1.65 (1.24-2.19)] in Q4 compare with Q1. The results of multiple linear regression analysis showed that VAT was positively correlated with fasting blood glucose, 1-hour blood glucose after 75 g OGTT and 2-hours blood glucose after 75 g OGTT (all Pfor trend<0.001). Conclusion: High VAT thickness in early pregnancy is an independent risk factor for GDM, and the GDM risk increases with the raising of VAT depth.

Comparison of metformin, myoinositol and metformin-myoinositol combined treatments for polycystic ovary syndrome.

The objective of this study was to assess the effectiveness of myoinositol (4 g myoinositol + 400 mcg folic acid/day) compared with metformin (average 1700 mg/day), as well as the combined efficacy of both treatments in managing insulin-resistant polycystic ovary syndrome (PCOS) among women. We retrospectively analyzed the records of 68 reproductive-age PCOS patients with insulin resistance over a 3-month period. Oral glucose tolerance tests (OGTT) (75 gr) were conducted to measure glucose levels at 0 and 120 min. Moreover, changes in prolactin, thyroid stimulating hormone, high-density lipoprotein, low-density lipoprotein, triglyceride levels, total cholesterol, follicle-stimulating hormone, luteinizing hormone, total testosterone, free testosterone, and dehydroepiandrosterone sulfate (DHEA-S) levels were evaluated pre- and post-treatment over a 3-month period. Statistically significant improvements were observed in menstrual regularity, body mass index (BMI), modified Ferriman Gallwey scores, OGTT glucose levels at 0 and 120 min, total testosterone, free testosterone, and DHEA-S levels across all groups (p<0.005). No significant variances were observed in terms of BMI, modified Ferriman Gallwey scores, or androgen levels across the three treatment cohorts. The combination of myoinositol and metformin did not confer additional benefits compared with either treatment alone.

Oral Glucose Tolerance Test as a Risk Marker for Developing Post-Transplant Diabetes Mellitus

IntroductionThe incidence of post-transplant diabetes mellitus (PTDM) can reach 30% during the first 6 months after kidney transplantation (KT), increasing the risk of graft failure and mortality. There is no well-established biomarker for predicting PTDM occurrence. This study evaluated the association between the abnormal 2-hour oral glucose tolerance test (OGTT) and the PTDM incidence. MethodsA retrospective single-center study, including adult kidney transplant recipients from deceased donors, was performed between March 2021 and June 2022. Exclusion criteria: age <18 years; pretransplant diabetes mellitus (DM); death with a functioning graft; loss of follow-up and/or graft failure before 6 months post-transplant. The results of pretransplant OGTT, fasting (FPG), and afternoon plasma glucose levels at hospitalization and FPG in the first, second, and third months post-transplant were evaluated. For analysis, patients were grouped according to the PTDM diagnosis: PTDM and non-PTDM. ResultsFrom 164 KT performed in the period, 50 (30%) were included, most male (n = 34, 68%), with a mean age of 48.3 ± 12.5 years. Nine patients (18%) developed PTDM, 44% between 3 and 6 months. General characteristics and immunosuppressive therapy were similar between the groups. The mean FPG in the pretransplant OGTT was significantly higher in the PTDM group compared with the non-PTDM group (85.7 ± 7.9 vs 79.1 ± 8.2, P = .03). The number of patients classified as impaired glucose tolerance (IGT) on the pre-transplant OGTT was significantly higher in the PTDM group. ConclusionIGT in the pretransplant OGTT was associated with PTDM cases in kidney transplant recipients without a previous diagnosis of DM.

Hypoglycemic effects of mountain caviar extract and inhibitory mechanism of saponins, including momordin Ic, on glucose absorption.

Mountain caviar is a fruit of Kochia scoparia that contains momordin Ic as a major saponin constituent. Its extract (MCE) has been shown to suppress blood glucose elevations in the human oral glucose tolerance test (OGTT) as well as increases in blood glucose in OGTT, gastric emptying (GE), and glucose incorporation in the small intestine in rats. However, the effects of MCE and momordin Ic on glucose absorption in mice and these action mechanisms have not been examined for more than 2 decades. Therefore, we herein investigated the effects of MCE, its saponin fraction, and momordin Ic on blood glucose elevations in mice. Mouse blood glucose elevation tests were performed on carbohydrate-loaded mice. The mountain caviar saponin fraction significantly delayed blood glucose elevations in glucose-, sucrose-, and soluble starch-loaded mice. In glucose-loaded mice, the saponin fraction, MCE, and momordin Ic significantly suppressed rapid glucose elevations after glucose loading, but not sucrose loading. A mouse GE study was performed by loading with glucose and phenolphthalein solution. Momordin Ic and MCE strongly suppressed mouse GE. Intestinal glucose absorption was evaluated by the incorporation of 2-deoxyglucose (2-DG) into Caco-2 cell layers and mouse duodenum wall vesicles. The results obtained showed that momordin Ic inhibited the incorporation of 2-DG into Caco-2 cells and mouse duodenum vesicles. Collectively, these results suggest that MCE, particularly the principal saponin, momordin Ic, preferably suppressed glucose-induced blood glucose elevations and delayed carbohydrate-induced glucose elevations in mice. The underlying mechanism was found to involve the suppression of GE and intestinal glucose absorption.

Gestational diabetes mellitus, hypertension, and dyslipidemia as the risk factors of preeclampsia

Gestational diabetes mellitus (GDM) is a known risk factor for gestational hypertension which further progress toward conditions like proteinuria, dyslipidemia, thrombocytopenia, pulmonary edema leading to Preeclampsia (PE). Pregnancy can be a challenging time for many women, especially those diagnosed with GDM and PE. Thus, the current prospective study investigates the association of OGTT glucose levels with systolic and diastolic blood pressure and lipid profile parameters in pregnant women diagnosed with GDM and PE. A total of 140 pregnant women were stratified into GDM (n = 50), PE (n = 40) and controls (n = 50). Two hour 75 g oral glucose tolerance test (OGTT) was performed for screening GDM. Biochemical parameters analysis of OGTT, total cholesterol (TC), triglyceride (Tg), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), urinary albumin and creatinine were tested to find urinary albumin creatinine ratio (uACR). Statistical analysis was performed using ANOVA followed by post hoc test and regression analysis. Among the studied groups, GDM and PE groups showed no significant difference in age and increased BMI. Increased 2 h OGTT & TC in GDM group; elevated uACR, systolic/diastolic blood pressure, Tg, HDL-C, LDL-C in PE group was observed and differ significantly (p < 0.0001) with other groups. A significant positive effect of 2 h OGTT was observed on blood pressure (R2: GDM = 0.85, PE = 0.71) and lipid profile determinants (R2: GDM = 0.85, PE = 0.33) at p < 0.0001. The current study concludes that glucose intolerance during the later weeks of pregnancy is associated with gestational hypertension and hyperlipidemia as a risk factor for PE. Further research is needed for a detailed assessment of maternal glucose metabolism at various pregnancy stages, including the use of more sensitive markers such as C-peptide and their relation to pregnancy-related hypertensive disorders.

Utilizing the Glucose and Insulin Response Shape of an Oral Glucose Tolerance Test to Predict Dysglycemia in Children with Overweight and Obesity, Ages 8-18 Years.

Common dysglycemia measurements including fasting plasma glucose (FPG), oral glucose tolerance test (OGTT)-derived 2 h plasma glucose, and hemoglobin A1c (HbA1c) have limitations for children. Dynamic OGTT glucose and insulin responses may better reflect underlying physiology. This analysis assessed glucose and insulin curve shapes utilizing classifications-biphasic, monophasic, or monotonically increasing-and functional principal components (FPCs) to predict future dysglycemia. The prospective cohort included 671 participants with no previous diabetes diagnosis (BMI percentile ≥ 85th, 8-18 years old); 193 returned for follow-up (median 14.5 months). Blood was collected every 30 min during the 2 h OGTT. Functional data analysis was performed on curves summarizing glucose and insulin responses. FPCs described variation in curve height (FPC1), time of peak (FPC2), and oscillation (FPC3). At baseline, both glucose and insulin FPC1 were significantly correlated with BMI percentile (Spearman correlation r = 0.22 and 0.48), triglycerides (r = 0.30 and 0.39), and HbA1c (r = 0.25 and 0.17). In longitudinal logistic regression analyses, glucose and insulin FPCs predicted future dysglycemia (AUC = 0.80) better than shape classifications (AUC = 0.69), HbA1c (AUC = 0.72), or FPG (AUC = 0.50). Further research should evaluate the utility of FPCs to predict metabolic diseases.

Maternal overweight and obesity and its association with metabolic changes and fetal overgrowth in the absence of gestational diabetes mellitus: A prospective cohort study.

Previous studies indicated an association between fetal overgrowth and maternal obesity independent of gestational diabetes mellitus (GDM). However, the underlying mechanisms beyond this possible association are not completely understood. This study investigates metabolic changes and their association with fetal and neonatal biometry in overweight and obese mothers who remained normal glucose-tolerant during gestation. In this prospective cohort study 893 women who did not develop GDM were categorized according to their pregestational body mass index (BMI): 570 were normal weight, 220 overweight and 103 obese. Study participants received a broad metabolic evaluation before 16 weeks and were followed up until delivery to assess glucose levels during the oral glucose tolerance test (OGTT) at mid-gestation as well as fetal biometry in ultrasound and pregnancy outcome data. Increased maternal BMI was associated with an adverse metabolic profile at the beginning of pregnancy, including a lower degree of insulin sensitivity (as assessed by the quantitative insulin sensitivity check index) in overweight (mean difference: -2.4, 95% CI -2.9 to -1.9, p < 0.001) and obese (mean difference: -4.3, 95% CI -5.0 to -3.7, p < 0.001) vs normal weight women. Despite not fulfilling diagnosis criteria for GDM, overweight and obese mothers showed higher glucose levels at fasting and during the OGTT. Finally, we observed increased measures of fetal subcutaneous tissue thickness in ultrasound as well as higher proportions of large-for-gestational-age infants in overweight (18.9%, odds ratio [OR] 1.74, 95% CI 1.08-2.78, p = 0.021) and obese mothers (21.0%, OR 1.99, 95% CI 1.06-3.59, p = 0.027) vs normal weight controls (11.8%). The risk for large for gestational age was further determined by OGTT glucose (60 min: OR 1.11, 95% CI 1.02-1.21, p = 0.013; 120 min: OR 1.13, 95% CI 1.02-1.27, P = 0.025, for the increase of 10 mg/dL) and maternal triglyceride concentrations (OR 1.11, 95% CI 1.01-1.22, p = 0.036, for the increase of 20 mg/dL). Mothers affected by overweight or obesity but not GDM had a higher risk for fetal overgrowth. An impaired metabolic milieu related to increased maternal BMI as well as higher glucose levels at mid-gestation may impact fetal overgrowth in women still in the range of normal glucose tolerance.

Previous High-Intensity Breastfeeding Lowers the Risk of an Abnormal Fasting Glucose in a Subsequent Pregnancy Oral Glucose Tolerance Test.

Breastfeeding is associated with reduced lifetime cardiometabolic risk, but little is known regarding the metabolic benefit in a subsequent pregnancy. The primary aim of this study was to investigate the association between breastfeeding duration and intensity and next pregnancy oral glucose tolerance test (OGTT) results. A retrospective cohort study was conducted from March 2020 to October 2022. All multiparous women who met inclusion criteria and gave birth during the study period were eligible for inclusion. Analysis was stratified by risk for gestational diabetes (GDM). High GDM risk criteria included previous GDM and BMI > 35 kg/m2. The association between breastfeeding duration and high-intensity breastfeeding (HIBF) and subsequent pregnancy OGTT were assessed with multivariate logistic models adjusted for statistically and clinically relevant covariables. There were 5374 multiparous participants who met the inclusion criteria for analysis. Of these, 61.7% had previously breastfed for >6 months, and 43.4% were at high risk for GDM. HIBF was associated with 47% reduced odds of an abnormal fasting glucose in a subsequent pregnancy OGTT (aOR 0.53; 95%CI 0.38-0.75; p < 0.01). There was no association between HIBF and other glucose results on the OGTT. Women who smoked were least likely to breastfeed at high intensity (aOR 0.31; 95%CI 0.21-0.47; p < 0.01). South Asian women had 65% higher odds of HIBF than women who identified as White/European (aOR 1.65; 1.36-2.00; p < 0.01). This study highlights the importance of exclusive breastfeeding to potentially reduce the prevalence of GDM and may also translate into long-term reduction of cardiometabolic risk.

An extended minimal model of OGTT: estimation of α- and β-cell dysfunction, insulin resistance, and the incretin effect.

Loss of insulin sensitivity, α- and β-cell dysfunction, and impairment in incretin effect have all been implicated in the pathophysiology of type 2 diabetes (T2D). Parsimonious mathematical models are useful in quantifying parameters related to the pathophysiology of T2D. Here, we extend the minimum model developed to describe the glucose-insulin-glucagon dynamics in the isoglycemic intravenous glucose infusion (IIGI) experiment to the oral glucose tolerance test (OGTT). The extended model describes glucose and hormone dynamics in OGTT including the contribution of the incretin hormones, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1), to insulin secretion. A new function describing glucose arrival from the gut is introduced. The model is fitted to OGTT data from eight individuals with T2D and eight weight-matched controls (CS) without diabetes to obtain parameters related to insulin sensitivity, β- and α-cell function. The parameters, i.e., measures of insulin sensitivity, a1, suppression of glucagon secretion, k1, magnitude of glucagon secretion, γ2, and incretin-dependent insulin secretion, γ3, were found to be different between CS and T2D with P values < 0.002, <0.017, <0.009, <0.004, respectively. A new rubric for estimating the incretin effect directly from modeling the OGTT is presented. The average incretin effect correlated well with the experimentally determined incretin effect with a Spearman rank test correlation coefficient of 0.67 (P < 0.012). The average incretin effect was found to be different between CS and T2D (P < 0.032). The developed model is shown to be effective in quantifying the factors relevant to T2D pathophysiology.NEW & NOTEWORTHY A new extended model of oral glucose tolerance test (OGTT) has been developed that includes glucagon dynamics and incretin contribution to insulin secretion. The model allows the estimation of parameters related to α- and β-cell dysfunction, insulin sensitivity, and incretin action. A new function describing the influx of glucose from the gut has been introduced. A new rubric for estimating the incretin effect directly from the OGTT experiment has been developed. The effect of glucose dose was also investigated.

Myoinositols Prevent Gestational Diabetes Mellitus and Related Complications: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Although gestational diabetes mellitus (GDM) has several short- and long-term adverse effects on the mother and the offspring, no medicine is generally prescribed to prevent GDM. The present systematic review and meta-analysis aimed to investigate the effect of inositol supplementation in preventing GDM and related outcomes. Systematic search was performed in CENTRAL, MEDLINE, and Embase until 13 September 2023. Eligible randomized controlled trials (RCTs) compared the efficacy of inositols to placebo in pregnant women at high risk for GDM. Our primary outcome was the incidence of GDM, whereas secondary outcomes were oral glucose tolerance test (OGTT) and maternal and fetal complications. (PROSPERO registration number: CRD42021284939). Eight eligible RCTs were identified, including the data of 1795 patients. The incidence of GDM was halved by inositols compared to placebo (RR = 0.42, CI: 0.26-0.67). Fasting, 1-h, and 2-h OGTT glucose levels were significantly decreased by inositols. The stereoisomer myoinositol also reduced the risk of insulin need (RR = 0.29, CI: 0.13-0.68), preeclampsia or gestational hypertension (RR = 0.38, CI: 0.2-0.71), preterm birth (RR = 0.44, CI: 0.22-0.88), and neonatal hypoglycemia (RR = 0.12, CI: 0.03-0.55). Myoinositol decrease the incidence of GDM in pregnancies high-risk for GDM. Moreover, myoinositol supplementation reduces the risk of insulin need, preeclampsia or gestational hypertension, preterm birth, and neonatal hypoglycemia. Based on the present study 2-4 g myoinositol canbe suggested from the first trimester to prevent GDM and related outcomes.

Gestational glucose intolerance and pregnancy outcomes: a retrospective study in the primary care setting of Macau.

Although glucose intolerance is prevalent in Macau, it is rarely assessed during pregnancy. This study examined short-term maternal and neonatal outcomes at different maternal glucose levels in Macau. A total of 2388 pregnant women who received antenatal care at Health Centers and delivered at the Centro Hospitalar Conde de São Januário between June 2018 and December 2019 were included in this study. Gestational diabetes mellitus (GDM) was diagnosed using Carpenter and Coustan criteria, involving a 50 g glucose challenge test (GCT) followed by a 100g oral glucose tolerance test (OGTT). Participants were categorized into 4 groups: normal glucose tolerance if GCT was negative; mild gestational hyperglycemia in this study if positive GCT without GDM; GDM patients with normal fasting blood glucose (FBG) or high FBG in OGTT. Logistic regression analysis was employed to compare pregnancy outcomes among these 4 groups. Due to the limited number of cases, we combined several adverse maternal outcomes, including pregnancy-induced hypertension, assisted delivery, primary Caesarean section, moderate to severe perineal trauma, and postpartum hemorrhage, into a composite measure. The results showed higher rates of the aforementioned outcomes for mild gestational hyperglycemia and GDM with high FBG in OGTT groups [adjusted odds ratio (aOR) 1.32, 95% confidence interval (CI) 1.06-1.64; aOR 2.04, 95% CI 1.24-3.37], as well as macrosomia risk (aOR 2.02, 95% CI 1.11-3.66; aOR 5.04, 95% CI 2.03-12.52) and large-for-gestational age infants (aOR 1.48, 95% CI 1.02-2.16; aOR 4.34, 95% CI 2.31-8.15). Pregnancy outcomes were similar for normal glucose tolerance and GDM with normal FBG in OGTT. Mild gestational hyperglycemia raised the likelihood of adverse maternal outcomes and excessive infant birth weights. Even after achieving target glucose levels, GDM patients with elevated fasting glucose readings in OGTT remained at significant risk for these events. Instead, fasting normoglycemic GDM was treated effectively at Macau Health Centers.

Hypoglycemia in children and young adults with cystic fibrosis during oral glucose tolerance testing vs. continuous glucose monitoring.

Hypoglycemia is common in people with cystic fibrosis (pwCF) during oral glucose tolerance tests (OGTTs) and in the free-living setting, yet its pathophysiology remains unclear. To evaluate hypoglycemia in children and young adults with CF by OGTT and continuous glucose monitoring (CGM). A 3-h OGTT was performed in children and young adults with CF and healthy controls (HC). Individuals were classified as experiencing hypoglycemia on OGTT (glucose <70 mg/dL) or not. Insulin, C-peptide, glucose, glucagon, and incretins were measured. CGM was performed for 7 days in the free-living setting. Measures of insulin sensitivity, beta cell function accounting for insulin sensitivity, and insulin clearance were calculated. A total of 57 participants (40 CF and 17 HC) underwent assessment. Rates of hypoglycemia by OGTT were similar in pwCF (53%, 21/40) compared to HC (35%, 6/17), p = 0.23. PwCF compared to HC had higher A1c; on OGTT higher and later glucose peaks, later insulin peaks; and on CGM more glucose variability. CF Hypo+ versus CF Hypo- had higher lung function, higher insulin sensitivity, higher beta cell function accounting for insulin sensitivity, and decreased CGM variability. When comparing CF Hypo+ to HC Hypo+, although rates of hypoglycemia are similar, pwCF had blunted glucagon responses to hypoglycemia. OGTT hypoglycemia was not associated with CGM hypoglycemia in any group. Youth with CF have increased insulin sensitivity and impaired glucagon response to hypoglycemia on OGTT. Hypoglycemia on OGTT did not associate with free-living hypoglycemia.

Insulin Sensitivity and β-Cell Function During Early and Late Pregnancy in Women With and Without Gestational Diabetes Mellitus.

To evaluate the metabolic alterations associated with gestational diabetes mellitus (GDM) in women with overweight or obesity. We compared fasting and postprandial plasma glucose and free fatty acid (FFA) concentrations, insulin sensitivity (IS; Matsuda index), and β-cell function (i.e., β-cell responsiveness to glucose) by using a frequently sampled oral glucose tolerance test (OGTT) at 15 and 35 weeks' gestation in women with overweight or obesity who had GDM (n = 29) or did not have GDM (No-GDM; n = 164) at 35 weeks. At 15 weeks, IS and β-cell function were lower, and fasting, 1-h, and total area-under-the-curve plasma glucose concentrations during the OGTT were higher (all P < 0.05) in the GDM than in the No-GDM group. At 35 weeks compared with 15 weeks, IS decreased, β-cell function increased, and postprandial suppression of plasma FFA was blunted in both the GDM and No-GDM groups, but the decrease in IS and the increase in postprandial FFA concentration were greater and the increase in β-cell function was less (all P ≤ 0.05) in the GDM than in the No-GDM group. A receiver operating characteristic curve analysis showed that both fasting plasma glucose and 1-h OGTT glucose concentration at 15 weeks are predictors of GDM, but the predictive power was <30%. Women with overweight or obesity and GDM, compared with those without GDM, have worse IS and β-cell function early during pregnancy and a greater subsequent decline in IS and blunted increase in β-cell function. Increased fasting and 1-h OGTT plasma glucose concentration early during pregnancy are markers of increased GDM risk, albeit with weak predictive power.

Carbohydrate Intake and Oral Glucose Tolerance Test Results in the Postpartum Period.

The American Diabetes Association (ADA) recommends a 3-day preparatory diet prior to a diagnostic oral glucose tolerance test (OGTT), a test often recommended in postpartum individuals with a history of gestational diabetes (GDM). Evaluate the relationship between carbohydrate intake and OGTT glucose in 2 cohorts of postpartum individuals. We performed analyses of postpartum individuals from 2 prospective studies with recent GDM (Balance after Baby Intervention, BABI, n = 177) or risk factors for GDM (Study of Pregnancy Regulation of INsulin and Glucose, SPRING, n = 104) .We measured carbohydrate intake using 24-hour dietary recalls (SPRING) or Food Frequency Questionnaire (BABI) and performed 2-hour 75-g OGTTs. The main outcome measure was 120-minute post-OGTT glucose. There was no relationship between carbohydrate intake and 120-minute post-OGTT glucose level in either study population (SPRING: β = 0.03, [-5.5, 5.5] mg/dL, P = .99; BABI: β = -3.1, [-9.5, 3.4] mg/dL, P = .35). Adding breastfeeding status to the model did not change results (SPRING β = -0.14, [-5.7, 5.5] mg/dL, P = .95; BABI β = -3.9, [-10.4, 2.7] mg/dL, P = .25). There was, however, an inverse relationship between glycemic index and 120-minute post OGTT glucose (BABI: β = -1.1, [-2.2, -0.03] mg/dL, P = .04). Carbohydrate intake is not associated with post-OGTT glucose levels among postpartum individuals. Dietary preparation prior to the OGTT may not be necessary in this population.