Fasting Oral Glucose Tolerance Test Research Articles

A comparison study of maternal and perinatal outcomes with gestational diabetes mellitus, impaired glucose tolerance, and normal glucose tolerance

Gestational diabetes mellitus (GDM) and impaired glucose tolerance (IGT), which are growing health concerns globally, are the most common metabolic and endocrine perinatal issues. It is a contentious entity with competing policies and procedures. Most physicians in the United States employ a two-step procedure, starting with a 50-g non-fasting oral glucose challenge test at 24 to 28 weeks and moving on to a 100-g fasting test for women who receive a positive screening result. Instead, doctors use the Diabetes in Pregnancy Study Group India (DIPSI) technique and conduct just a 75-g, two-hour fasting oral glucose tolerance test. The prospective observational study was approved by the hospital's institutional ethics committee and was conducted from April 2020 to September 2021 at the department of obstetrics and gynecology at Stanley Medical College Hospital in Chennai, Tamil Nadu, India. The patients were chosen in accordance with the inclusion criteria, which called for first-trimester pregnant women without diabetes mellitus. Both oral and written consent were also obtained. DIPSI performed the screening. The WHO standards have been updated to be a one-step process with a single glycemic value. According to the results of this study, GDM is linked to harmful consequences that might affect both the mother and the foetus. The short- and long-term consequences in both the mother and the newborn can be greatly reduced with early detection and timely therapy of this illness. In this study, birth weights ranging from 2.5 to 3.5 kg were the same for GDM and IGT moms. IGT mothers should also be followed up on, and we should be more watchful at birth, even though we monitor GDM mothers.

Does prediabetes diagnosed by hemoglobinA1c or oral glucose tolerance test predict coronary artery disease in patients suspected of chronic coronary syndrome?

Abstract Introduction The presence of prediabetes worsens the prognosis of coronary artery disease, as patients with prediabetes are known to have an almost doubled cardiovascular mortality risk compared to normoglycemic patients. In clinical practice, HemoglobinA1c (HbA1c) has replaced the oral glucose tolerance test (OGTT) in the diagnosis of prediabetes. However, the background for the HbA1c threshold is based on the development of microvascular complications and progression to established diabetes. It remains unclear whether the substitution of OGTT with HbA1c results in an underestimation of prediabetics with a high risk of coronary artery disease, or if HbA1c is associated with macrovascular complications in prediabetic patients. Purpose We aimed to investigate whether HbA1c- or OGTT-diagnosed prediabetes could predict presence and severity of coronary artery disease in patients suspected of chronic coronary syndrome. Methods This was a descriptive cross-sectional study of 702 patients referred to a coronary CT angiography due to suspicion of chronic coronary syndrome. Coronary artery calcification (CAC)-score, presence of plaque and significant stenosis (>50%), and plaque characteristics were evaluated. All patients had a fasting OGTT and blood samples performed. Patients were categorized according to glycemic status by HbA1c and OGTT, and compared to their test-specific range. Results Prediabetes was detected by HbA1c 167 (24%) or OGTT 272 (39%), and an overlap in classification by both tests was seen in 98 (22%) of participants. Both classifications of prediabetes showed increased presence of plaques, significant stenosis, calcified plaques, and correspondingly, a low frequency of a CAC-score=0 compared to their test-specific normal. Additionally, the HbA1c-prediabetics had an increased frequency of a high CAC score >400 compared to normal HbA1c (23% vs. 10%, p<0.0001). In the multiple logistic regression analysis the HbA1c-prediabetics had an odds ratio (OR) of 1.5 for plaque presence (confidence interval (CI) 1.0;2.4) and OR 2.1 for a CAC-score >400 (CI 1.3;3.5). None of the associations for the OGTT-prediabetics were significant in the logistic regression analysis. Receiver operating characteristic curves were applied to the significant logistic associations. The HbA1c-prediabetics had an area under the curve (AUC)=0.77 for plaque presence and AUC=0.81 for CAC-score >400. Conclusion Prediabetes defined by HbA1c can predict presence and severity of coronary artery disease. Although OGTT identified more patients as having prediabetes, their risk of coronary artery disease was not attributable to prediabetes. Thus, our results support the replacement of OGTT with HbA1c in clinical practice.

A community health worker-led program to improve access to gestational diabetes screening in urban slums of Pune, India: Results from a mixed methods study.

The World Health Organization recommends all pregnant women receive screening for gestational diabetes (GDM) with a fasting oral glucose tolerance test (OGTT). However, very few women receive recommended screening in resource-limited countries like India. We implemented a community health worker (CHW)-delivered program to evaluate if home-based, CHW-delivered OGTT would increase GDM screening in a low-resource setting. We conducted a mixed methods study in two urban slum communities in Pune, India. CHWs were trained to deliver home-based, point-of-care fasting OGTT to women in their third trimester of pregnancy. The primary outcome was uptake of CHW-delivered OGTT. Secondary outcomes included GDM prevalence and linkage to GDM care. Individual interviews were conducted with purposively sampled pregnant women, CHWs, and local clinicians to assess barriers and facilitators of this approach. From October 2021-June 2022, 248 eligible pregnant women were identified. Of these, 223 (90%) accepted CHW-delivered OGTT and 31 (14%) were diagnosed with GDM. Thirty (97%) women diagnosed with GDM subsequently sought GDM care; only 10 (33%) received lifestyle counseling or pharmacologic therapy. Qualitative interviews indicated that CHW-delivered testing was considered highly acceptable as home-based testing saved time and was more convenient than clinic-based testing. Inconsistent clinical management of GDM was attributed to providers' lack of time to deliver counseling, and perceptions that low-income populations are not at risk for GDM. Convenience and trust in a CHW-delivered GDM screening program resulted in high access to gold-standard OGTT screening and identification of a high GDM prevalence among pregnant women in two urban slum communities. Appropriate linkage to care was limited by clinician time constraints and misperceptions of GDM risk. CHW-delivered GDM screening and counseling may improve health education and access to preventive healthcare, offloading busy public clinics in high-need, low-resource settings.

Relationship Between Gestational Diabetes Mellitus and Postpartum Diastasis Recti Abdominis in Women in the First Year Postdelivery.

Postpartum diastasis recti abdominis (DRA) influences women's appearance and health. Gestational diabetes mellitus (GDM) can affect the structure of the rectus abdominis muscles. However, the relationship between GDM and postpartum DRA is unknown. The objective of this study was to investigate the relationship between GDM and postpartum DRA. This retrospective cohort study included 241 women in the first year postdelivery. Women with GDM were matched with those without GDM using propensity score matching. They underwent an oral glucose tolerance test during pregnancy and a random blood glucose test before delivery. At follow-up, DRA was diagnosed by palpation, and interrectus distance was measured using ultrasound to evaluate the severity of DRA. The strength of the rectus abdominis was evaluated using the manual muscle testing method. Among the 241 participants, 174 (72.2%) had postpartum DRA, and 46 women with GDM were matched with 46 women without GDM on the basis of propensity scores. Women with GDM had higher odds of experiencing postpartum DRA (adjusted odds ratio = 4.792; 95% CI = 1.672 to 13.736) and larger interrectus distance values at the upper part of the rectus abdominis than those without GDM. There was a weak and positive correlation between the fasting oral glucose tolerance test level and the interrectus distance values (0.267 ≤ r ≤ 0.367). GDM was associated with postpartum DRA in women in the first year of delivery. Women with GDM had larger interrectus distance values at the upper part of the rectus abdominis than those without GDM. The fasting oral glucose tolerance test level showed a positive and weak correlation with the severity of postpartum DRA. Women with GDM have higher odds of experiencing postpartum DRA than those without GDM. The upper part of the rectus abdominis deserves increased focus during and after rehabilitation. Controlling the fasting oral glucose tolerance test level may help reduce the severity of postpartum DRA.

Impaired Glucose Tolerance and Visceral Adipose Tissue Thickness among Lean and Non-Lean People with and without Spinal Cord Injury.

After spinal cord injury (SCI), multiple adaptations occur that influence metabolic health and life quality. Prolonged sitting and inactivity predispose people with SCI to body composition changes, such as increased visceral adipose tissue (VAT) thickness, which is often associated with impaired glucose tolerance. Our goal is to understand whether VAT is an index of leanness, and, secondarily, whether mobility methods influence glucose tolerance for people living with SCI. A total of 15 people with SCI and 20 people without SCI had fasting oral glucose tolerance tests (OGTT) and VAT thickness (leanness) measured during a single session. Glucose was 51% and 67% greater for individuals with SCI relative to those without SCI after 60 and 120 min of an OGTT (p < 0.001). Glucose area under the curve (AUC) was 28%, 34%, and 60% higher for non-lean people with SCI than lean people with SCI and non-lean and lean people without SCI, respectively (p = 0.05, p = 0.009, p < 0.001). VAT was associated with glucose AUC (R2 = 0.23, p = 0.004). Taken together, these findings suggest that leanness, as estimated from VAT, may be an important consideration when developing rehabilitation programs to influence metabolism among people with SCI.

Prediction of pre-diabetes and type 2 diabetes nine years postpartum using serum metabolome in pregnant women with gestational diabetes requiring pharmacological treatment

AimsWe examined the association between serum metabolome in women with pharmacologically treated gestational diabetes (GDM) and measures of glucose metabolism 9 years postpartum. MethodsSerum targeted metabolome, adiponectin, inflammatory markers, and insulin-like growth factor-binding protein-1 phosphoisoforms were analyzed at the time of diagnosing GDM. Glucose metabolism and insulin resistance were assessed at 9 years postpartum. Data from 119 subjects were available for analyses. Associations between baseline measures and future measures of glycemia were examined with univariate regressions and multivariate prediction models. This is a secondary analysis of a previous prospective trial (NCT02417090). ResultsBaseline serum markers were most strongly related to measures of insulin resistance at 9-years follow-up. In multivariate analyses combination of IDL cholesterol, early gestational weight gain and in oral glucose tolerance test fasting and 2-h glucose predicted development of disorders of glucose metabolism (pre-diabetes and/or type 2 diabetes) better than clinical predictors alone (ROC-AUC 0.75 vs. 0.65, p = 0.020). ConclusionsSerum metabolome in pregnancy in women with GDM is related to future glucose metabolism and insulin resistance. Compared to clinical variables alone metabolome might result in better prediction of future disorders of glucose metabolism and could facilitate personalized risk stratification for postpartum interventions and follow-up.

Associations between pregnancy glucose measurements and risk of preterm birth: a retrospective cohort study of commercially insured women in the United States from 2003 to 2021

To investigate associations between glucose measurements during pregnancy and risk of preterm birth (PTB). Retrospective cohort study of commercially insured women with singleton live births in the United States from 2003 to 2021 using longitudinal medical claims, socioeconomic data, and eight glucose results from different fasting and post-load tests performed between 24 and 28 weeks of gestation for gestational diabetes screening. Risk ratios of PTB (<37 weeks) were estimated via Poisson regression for z-standardized glucose measures. Non-linear relationships for continuous glucose measures were examined via generalized additive models. Elevations in all eight glucose measures were associated with increased risk (adjusted risk ratio point estimates: 1.05-1.19) of PTB for 196,377 women with non-fasting 50-gglucose challenge test (one glucose result), 31,522 women with complete 100-g, 3-hour fasting oral glucose tolerance test (OGTT) results (four glucose results), and 10,978 women with complete 75-g, 2-hour fasting OGTT results (three glucose results). Associations were consistent after adjusting for and stratifying by sociodemographic and clinical factors. Substantial non-linear relationships (U-, J-, and S-shaped) were observed between several glucose measurements and PTB. Elevations in various glucose measures were linearly and non-linearly associated with increased PTB risk, even before diagnostic thresholds for gestational diabetes.

Clinical Updates on Screening and Diagnosis Criteria for Gestational Diabetes Mellitus Patients, as well as Therapeutic Management

The most prevalent metabolic and endocrine perinatal issue is gestational diabetes mellitus (GDM), which is an increasing health problem worldwide. It is a controversial entity, with conflicting guidelines and treatment protocols. In the United States, most doctors utilise a two-step strategy, first with a 50-g non fasting oral glucose challenge test at 24 to 28 weeks and then a 100-g fasting test for women who have a positive screening result. Alternatively, Clinicians take a one step Diabetes in Pregnancy Study Group India (DIPSI) method and perform simply a 75-g two hour fasting oral glucose tolerance test. The DIPSI approach of antenatal GDM screening has been demonstrated to be straightforward, cost effective, easy to use, patient friendly, and convenient. When comparing the findings to the gold standard of the International Association of Diabetes and Pregnancy Study Group (IADPSG), DIPSI shows high specificity and acceptable sensitivity. To maintain euglycemia, glucose monitoring, dietary changes, exercise, and, if necessary, medicines are used. Although insulin therapy is the most common treatment, glyburide and metformin may become more popular. Prenatal testing with nonstress tests and amniotic fluid indices, commencing in the third trimester, is commonly used to assess foetal well-being in women undergoing medication. The delivery technique and time are contentious. Women who have gestational diabetes are at a significant risk of developing type 2 diabetes later in life. As a result, along with routine diabetes screening, lifestyle adjustment should be recommended.

63-OR: A Model-Based Clinical Trial Simulation Tool to Optimize Clinical Trial Designs for Type 1 Diabetes Prevention Studies

Trials seeking to delay or prevent type 1 diabetes (T1D) continue to face multiple challenges, including both clinical endpoint (s) and cohort selection. While it is clear that individuals who possess islet cell autoantibodies (AAbs) are at elevated risk for developing T1D, it remains unclear as to what additional factors, including metabolic activities and anthropometric data, may contribute to this increased risk. The aim of this project was to inform T1D prevention trial designs by developing a quantitative joint model based-clinical trial simulation (CTS) tool. Individual-level data obtained from the NIH TEDDY and TrialNet TNnatural history studies were used in this tool’s development. To describe T1D disease progression quantitatively, both longitudinal and time-to-event variables were simultaneously quantified as a joint model, with results from a 2-hour oral glucose tolerance test (OGTT) assessed at each visit included as a time-varying longitudinal covariate affecting the T1D diagnosis event. Our study focused on individuals at risk of developing T1D with two or more AAbs. Among the investigated individuals, those with a high BMI and the presence of GADA AAb at baseline had less risk, while those with an elevated HbA1c value, high fasting OGTT value, increased fasting OGTT to 2-hour OGTT ratio, and the presence of the IA2A AAb at baseline had higher risk. The developed model based-CTS tool, where users can specify the trial design, participants’ characteristics and hypothetical drug effect, provides a framework to perform T1D prevention clinical trial simulations with the intention to assist in future trial design decision-making processes. Disclosure J.F. Morales: None. R. Muse: None. J. Podichetty: None. S. David: None. M.A. Atkinson: None. M.J. Haller: Advisory Panel; SAB Biotherapeutics. Consultant; MannKind Corporation, Sanofi. M. Campbell-Thompson: Consultant; TRex Bio. K. Romero: None. I. O'Doherty: None. S. Schmidt: None. S. Kim: None. Funding JDRF (grant #: 2-SRA-2020-903-A-N) ; NIDDK Central Repositories

Characteristics of pregnancy with gestational diabetes mellitus and the consecutive pregnancy as predictors for future diabetes mellitus type 2

AimTo explore possible obstetrical history-related, modifiable risk factors of future type 2 diabetes mellitus (T2DM), with focus on characteristics of the index gestational diabetes mellitus (GDM) pregnancy and the consecutive pregnancy. MethodsThis retrospective, population-based, cohort study included 788 women with GDM, who had consecutive deliveries at Emek Medical Center during 1991–2012. Women with pre-existing diabetes were excluded. Factors associated with T2DM development were examined using stepwise multiple Cox regression model. ResultsOverall 178 women developed T2DM (23%). Multivariable analysis demonstrated that the most significant independent risk factors for T2DM development were birth weight ≥ 4000 g (HRadj1.7 95% CI [1.001–2.8]), fasting oral glucose tolerance test value (OGTT, HRadj1.03 95% CI [1.01–1.04], 1-hour post-OGTT glucose value (HRadj1.01 95% CI [1.006–1.02]), earlier gestational week in which GDM was diagnosed (HRadj 0.96 95% CI [0.93–0.99]), higher parity (HRadj 1.15 95% CI [1.06–1.25] and GDM recurrence in the consecutive delivery (HRadj2.4 95% CI [1.6–3.7]). Kaplan Meier survival curve of the time from the consecutive pregnancy until T2DM development showed a statistically significant effect of GDM recurrence and the risk for T2DM. Body mass index (BMI) gain between pregnancies and inter-pregnancy interval were not independent risk factors for T2DM. ConclusionsObstetric characteristics of women with GDM and particularly GDM recurrence are associated with increased risk for T2DM. Strategies to prevent those factors and especially GDM recurrence might reduce the risk of future T2DM.

Urinary phthalate and DINCH metabolite concentrations and gradations of maternal glucose intolerance.

Studies suggest a link between pregnancy phthalate exposures and gestational diabetes mellitus (GDM). Few studies have evaluated associations between phthalate biomarkers (individual or mixtures) with gradations of maternal glucose intolerance. In a subset of 606 women participating in LIFECODES pregnancy cohort, a combination of 50-gram 1-h non-fasting glucose load test (GLT) and 100-gram 3-h fasting oral glucose tolerance test was used to determine pregnancy glycemic status (median: 27weeks gestation): normoglycemia (n=136), impaired glucose tolerance (IGT) (n=296), and GDM (n=174). Nineteen metabolites of phthalates and their replacements were measured during each trimester. We used multivariable logistic regression models to evaluate associations between biomarkers (in quartiles) and maternal glycemic status (GDM v. normoglycemia and IGT v. normoglycemia), adjusting for potential confounders. We also used principal component analysis to evaluate associations jointly accounting for metabolites as chemical mixtures. Higher 1st trimester mono-3-carboxypropyl phthalate (MCPP) was associated with decreased odds of GDM (Q4 v. Q1: 0.30; 95% CI: 0.13, 0.67) and IGT (Q4 v. Q1 OR: 0.37; 95% CI: 0.17, 0.79). Higher 2nd trimester mono-isobutyl phthalate (MiBP) was associated with increased IGT (Q4 v. Q1 OR: 2.07; 95% CI: 1.06, 4.07), and 2nd trimester mono-3-hydroxybutyl phthalate (MHBP) was non-monotonically associated with increased GDM (Q2 v. Q1 OR: 3.21; 95% CI: 1.54, 6.87). Mixture analyses showed similar associations (Q4 v. Q1 for 2nd trimester dibutyl phthalates metabotlites mixtures OR: 2.08; 95% CI: 1.04, 4.22). Some phthalate biomarkershad trimester-specific associations with glycemic outcomes, with long and short term health implications.

Analysis of risk factors for gestational diabetes mellitus in elderly multipara women in the next pregnancy

Objective: To investigate the risk factors for gestational diabetes mellitus (GDM) in elderly multipara women in the next pregnancy. Methods: A total of 219 elderly multipara women with 2 consecutive delivery records in Tianjin Binhai New Area Tanggu Obstetrics and Gynecology Hospital from January 2018 to May 2019 were included. Among them, 141 had normal glucose tolerance (NGT) and 78 of them had GDM. The clinical data of the previous and current pregnancy were collected to analyze the risk factors of GDM in elderly multipara women. Results: The average ages of 219 elderly women in previous pregnancy and this pregnancy were (31.9±2.2) and (36.7±1.5) years old, and the prevalence of GDM was 35.62% (78 cases). Compared to NGT group, GDM patients had higher fasting blood glucose(previous (5.51±1.43) vs (4.63±0.62) mmol/L; current (5.26±0.63) vs (4.59±0.30) mmol/L, 1 h blood glucose(previous (11.74±2.36) vs (9.50±1.82) mmol/L; current (11.03±2.03) vs (9.51±1.14) mmol/L) in 75 g oral glucose tolerance test (OGTT) in both previous and current pregnancy. The rates of cesarean section, in both previous and current pregnancy were higher in GDM group (previous 34.6% vs 4.3%; current 52.6% vs 22.0%). Furthermore, prenatal weight and body mass index (BMI) of the previous pregnancy, pre-pregnancy weight and BMI, and prenatal BMI of this pregnancy were also higher in GDM group, and the differences were all statistically significant (all P<0.05). Logistic multivariate regression analysis indicated cesarean section history (OR=10.80, 95%CI: (4.09-28.54)), GDM history of previous pregnancy (OR=10.64, 95%CI: (4.02-28.20)), 75 g OGTT fasting blood glucose≥ 4.86 mmol/L (OR=2.70, 95%CI: (1.27-5.70)), 1 h blood glucose after glucose administration ≥ 8.45 mmol/L (OR=1.78, 95%CI: (1.37-2.31)) were risk factors for GDM in elderly multipara women of this pregnancy. Conclusion: The risk of GDM in elderly multipara women with a history of cesarean section and GDM increases significantly. Results of OGTT in previous pregnancy also has predictive value.

IDF-MENA Region Guidelines for Management of Hyperglycemia in Pregnancy

Introduction: Hyperglycaemia in pregnancy (HIP) is the most common medical disorder complicating pregnancy. This includes women who have pre-existing Type 1 and Type 2 diabetes mellitus (DM) and those diagnosed to have gestational diabetes mellitus (GDM), with glucose intolerance identified for the first time in pregnancy. In the Middle East and North Africa region, the prevalence of DM in women of reproductive age group is high and it varies widely between different regions due to variation in screening and diagnostic criteria for the identification of GDM. Universal blood glucose screening at first antenatal booking visit helps in identifying women with HIP. Women who are screen negative at first antenatal should subsequently be screened with a fasting oral glucose tolerance test (OGTT) around 24-28 weeks to identify GDM. There is a clear evidence that the identification and management of hyperglycaemia improves pregnancy outcomes. Antenatal care involves more visits as these women are at higher risk of fetal malformations, preterm labour and stillbirth. Timing of delivery is based on glycaemic control, fetal wellbeing, and the presence of co-morbidities. Objective: The objective of this article is to provide guidelines regarding the management of hyperglycemia in pregnancy. Materials and Methods: These recommendations are made after reviewing various existing guidelines including American College of Obstetricians and Gynecologists, Royal College of Obstetricians and Gynecologists, and American College of Sports Medicine. A literature search was done using PubMed, Cochrane Database, Google Scholar, EMBASE, various systematic reviews, and original articles. Search was done using key words “Hyperglycemia in pregnancy,” “gestational diabetes mellitus,” and “diabetes in pregnancy.” Conclusion: Hyperglycemia in pregnancy can be managed effectively if appropriate measures are taken and potential consequences can be avoided.

Environmental exposure to perfluoroalkyl substances in early pregnancy, maternal glucose homeostasis and the risk of gestational diabetes: A prospective cohort study.

Humans are widely exposed to environmental perfluoroalkyl substances (PFAS), which may affect glucose homeostasis. However, research linking PFAS exposure to glucose homeostasis during pregnancy is limited and the results were inconsistent. We aimed to investigate the association between PFAS exposure and glucose homeostasis in pregnancy in a large prospective cohort. A total of 2747 pregnant women who participated in the Shanghai Birth Cohort, had blood samples in early pregnancy and completed a 75g oral glucose tolerance test (OGTT) at 24-28 gestational weeks were included. 10 PFAS were determined by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS-MS) in the plasma samples in early pregnancy. Logistic regression was used to explore the associations between PFAS concentrations and gestational diabetes mellitus (GDM), while multiple linear regression was used to model the associations between PFAS and OGTT fasting, 1-h and 2-h glucose levels. Potential confounders were adjusted. Bayesian kernel machine regression (BKMR) and a quantile-based g-computation approach (qgcomp) were employed to explore the joint and independent effects of PFAS on glucose homeostasis. The incidence of GDM was 11.8%. One log-unit increment in plasma concentrations in early pregnancy was associated with an increased risk of GDM for perfluorobutane sulfonate (PFBS) (adjusted odd ratio (aOR)=1.23, 95% confidence interval (95% CI): 1.05, 1.44) and perfluoroheptanoic acid (PFHpA) (aOR=1.25, 95% CI: 1.07, 1.46). Perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorohexanesulfonate (PFHxS) and PFHpA were positively correlated with 1-h and 2-h glucose levels. Results of the mixed exposure model showed that the joint effects of PFAS were significantly associated with abnormal glucose homeostasis; In the BKMR model, PFAS mixture exposure was positively associated with the GDM incidence, 1-h and 2-h glucose levels and negatively correlated with FBG level. A similar trend could be observed in qgcomp and the positive correlation between PFAS and 2-h glucose level was significant (β=0.12, 95% CI: 0.04, 0.20). PFOS, PFNA and PFHpA may be the main contributors after controlling for other PFAS congeners. PFOS was significantly correlated with GDM incidence and 2-h glucose level, and PFHpA was significantly associated with FBG and 2-h glucose levels. The above associations were more prominent among women with a normal prepregnant BMI. Environmental exposure to PFAS may affect glucose homeostasis in pregnancy and increase the risk of GDM, especially in normal weight women.

Non-fasting OGTT versus Fasting OGTT for screening of Hyperglycaemia in Pregnancy (HIP).

Objectives:To compare the reliability of non-fasting oral glucose tolerance test (OGTT) versus fasting OGTT for screening of hyperglycaemia in pregnancy (HIP).Methods:This cross sectional analytic study was conducted by the Department of Obstetrics & Gynaecology, Isra University Karachi Campus from October 2016 to April 2017. A total of 225 pregnant women irrespective of gestational age were included in the study. They underwent non fasting 75 grams OGTT. Venous plasma glucose was done 02 hours after the glucose load. Same women were advised to come again within three to seven days for fasting OGTT. Venous plasma glucose (VPG) was estimated in fasting and 2 hours post glucose load.Results:Using the non-fasting OGTT, out of 204 women, 32 were diagnosed with hyperglycemia. All these 204 women were again called for fasting OGTT three to seven days after the initial non-fasting OGTT. Only nine were diagnosed with hyperglycemia, out of these nine women, seven women who were screen positive on non-fasting OGTT were found to be screen positive on fasting OGTT as well. However, only two women were additionally diagnosed with hyperglycemia who were initially screen negative on non-fasting OGTT. The non-fasting OGTT has diagnosed HIP with sensitivity of 77.7%, specificity of 87.1%, positive predictive value of 21.8% and negative predictive value of 98.8%.Conclusion:The use of the non-fasting OGTT at first antenatal visit may be a practical approach to detect the HIP as screening and diagnostic tool in the resource constrained settings.

Environmental Exposure to Perfluoroalkyl Substances in Early Pregnancy, Maternal Glucose Homeostasis and the Risk of Gestational Diabetes: A Prospective Cohort Study

Background: Humans are widely exposed to environmental perfluoroalkyl substances ( PFAS ), which may alter glucose homeostasis . However, research linking PFAS exposure to glucose tolerance during pregnancy is limited and the results were inconsistent. We aimed to investigate the association between PFAS exposure and glucose homeostasis in pregnancy in a large prospective cohort. Methods: A total of 2747 pregnant women who participated in the Shanghai Birth Cohort, had blood samples in early pregnancy and completed a 75 g oral glucose tolerance test (OGTT) at 24-28 gestational weeks were included. 10 PFAS were determined by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS-MS) in the plasma samples in early pregnancy. Logistic regression was used to explore the associations between PFAS concentrations and gestational diabetes mellitus (GDM), while multiple linear regression was used to model the associations between PFAS and OGTT fasting, 1-h and 2-h glucose levels. Potential confounders were adjusted. Bayesian kernel machine regression (BKMR) and a quantile-based g-computation approach were employed to explore the joint and independent effects of PFAS on glucose homeostasis. Findings: The incidence of GDM was 11·8%. One log-unit increment in plasma concentrations in early pregnancy was associated with an increased risk of GDM for perfluorobutane sulfonate (PFBS) [adjusted odd ratio (aOR)=1·23, 95% confidence interval (95% CI): 1·05,1·44] and perfluoroheptanoic acid (PFHpA) (aOR=1·25, 95% CI: 1·07,1·46). Perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorohexanesulfonate (PFHxS) and PFHpA were positively correlated with 1-h and 2-h glucose levels. Results of the mixed exposure model showed that the joint effects of PFAS were significantly associated with abnormal glucose homeostasis; PFOS, PFNA and PFHpA may be the main contributors. The above associations were more prominent among women with a normal prepregnant BMI. Interpretation: Environmental exposure to PFAS may affect glucose homeostasis in pregnancy and increase the risk of GDM, especially in normal weight women. Funding Statement: This study was funded by the National Nature Science Foundation of China (41991314 and 81530086) and the Collaborative Innovation Program of the Shanghai Municipal Health Commission (2020CXJQ01), the Ministry of Science and Technology of China (2019YFA0802501), and supported in part by the National Human Genetic Resources Sharing Service Platform (2005DKA21300). Declaration of Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Ethics Approval Statement: This project was approved by the Research Ethics Committees of Xinhua Hospital affiliated to Shanghai Jiao Tong University School of Medicine.

1385-P: Utility of Hemoglobin A1c for Predicting Adverse Pregnancy Outcomes in Women with Gestational Diabetes Mellitus

Aims: Despite current treatment strategies, gestational diabetes mellitus (GDM) remains a major risk factor for pregnancy complications. We examined whether the HbA1c measured at the time of oral glucose tolerance test (OGTT) predicts residual risk of adverse outcomes in women with treated GDM. Methods: Women with GDM (defined using the New Zealand criteria) enrolled in the Diabetes in Pregnancy Registry in South Auckland, New Zealand at ≥ 20 weeks gestation were included. Glycaemic targets used were fasting ≤5.0 mmol/l and 2-hour post-meal ≤6.7 mmol/l. Results: Of the 1403 women enrolled, 304 (21.7%) had an HbA1c 41-49 mmol/mol (5.9-6.6%). Women with higher HbA1c were significantly older, with higher BMI and fasting and 2-hour OGTT values. They were more likely to be multiparous, of Pacific ethnicity, and have a family history of diabetes. After adjusting for known risk factors, higher HbA1c was associated with increased risk of large for gestational age (LGA) babies (odds ratio (OR) 2.08 (1.47-2.93)) and preeclampsia (OR 2.09 (1.34-3.29)). The OGTT fasting glucose was predictive of LGA (OR 1.61 (1.17-2.21)), but not the 2-hour value (OR 1.12 (0.98-1.28)). The areas under the receiver operating characteristic curves for predicting LGA and preeclampsia by HbA1c, OGTT fasting, OGTT 2-hour, and 1-hour 50g polycose test were: LGA, 0.58 (0.51-0.65), 0.66 (0.59-0.73), 0.45 (0.37-0.52), and 0.59 (0.51-0.66) respectively; preeclampsia, 0.66 (0.57-0.75), 0.58(0.48-0.67), 0.46 (0.35-0.56), and 0.52 (0.42-0.62) respectively. Conclusions: HbA1c, fasting, and 1-hour glucose at GDM diagnosis predict residual adverse outcomes in treated women with late GDM. Studies are needed to test whether earlier treatment, or targeting the 1-hour post-prandial glucose can reduce this residual risk. Disclosure D. Simmons: None. J. Immanuel: None. C. Eagleton: None. J. Baker: None.

Evaluation of Gastric Emptying in Cystic Fibrosis Using Bedside Ultrasonography.

Although gastric emptying rate (GER) influences incretin response and nutrient absorption, both defective in people with cystic fibrosis (CF), there are few studies in this group, and the circadian rhythm is unknown. We employed an ultrasonographic technique to assess GER in people with CF following liquid and mixed meals and also evaluated the circadian rhythm, compared to normal controls. Thirteen pancreatic-insufficient adults with CF and 10 healthy controls underwent a fasting oral glucose tolerance test (OGTT; liquid meal) and on a second visit underwent a fasting mixed meal test (MMT) thrice on the same day. GER was measured during the OGTT and each MMT using a 3.5-MHz abdominal transducer probe at baseline and 30, 60, 90, and 120 minutes. Controls had normal GER for both OGTT and MMT. Compared to controls, people with CF had delayed GER60 for OGTT (mean 46%), which increased with time (P = .001), and also delayed GER90 for MMT in the morning (mean 56%), afternoon (58%), and evening (59%). The GER in the control group was better at all time points throughout the day compared to patients with CF. This is the first study to use ultrasonography, an inexpensive bedside technique, to assess GER in adults with CF. For the first time, we have shown that adults with CF have delayed GER for both liquid and mixed meals, and this delay continues throughout the day.

Almond "Appetizer" Effect on Glucose Tolerance Test (GTT) Results.

The extent to which glucose intolerance can be acutely improved with dietary modification is unclear. The purpose of this study was to test the effect of ingesting a low-calorie almond preload ("appetizer") 30 minutes before oral glucose tolerance testing in glucose-intolerant individuals without diabetes. Twenty adults with prediabetes or isolated 1-hour glucose ≥160 mg/dL underwent 2 fasting oral glucose tolerance tests (GTTs)-1 standard GTT and 1 GTT 30 minutes after eating a half ounce (12) of dry-roasted almonds. Fourteen participants met 1 or more prediabetes diagnostic criteria; 6 had only elevated 1-hour glucose ≥160 mg/dL. The mean 1-hour plasma glucose after the almond preload was 37.1 mg/dL (19.4%) lower (154.6 vs 191.7; P < .001) than in the standard GTT. The almond preload reduced the area under the glucose curve by 15.5% (P < .001). Eight individuals had a marked hypoglycemic effect (glucose reduced by 45 to 110 mg/dL); 4 had a moderate hypoglycemic effect (22-32 mg/dL). A low-calorie almond "appetizer" showed promise as an option for decreasing postprandial hyperglycemia in individuals with prediabetes or isolated 1-hour postprandial hyperglycemia. Further study is needed to confirm and refine the role of such a premeal appetizer in the self-care of prediabetes.

Association of temporal distribution of fine particulate matter with glucose homeostasis during pregnancy in women of Chiayi City, Taiwan

BackgroundTo investigate the effects of fine particulate matter (PM2.5) on the indicators of glucose homeostasis during pregnancy. Methods: A total of 3589 non-diabetic pregnant women who underwent a 3-h 100-g oral glucose tolerance test (OGTT) were enrolled from a tertiary teaching hospital in Chiayi City, Taiwan between 2006 and 2014. Fasting, 1-h, 2-h, and 3-h glucose levels after an OGTT were used as indicators of glucose homeostasis. PM2.5 and other air pollution data were obtained from one fixed-site monitoring station (Chiayi City station) operated by Taiwan Environmental Protection Administration (EPA). We used mixed models for indicators of glucose homeostasis to estimate the effects of PM2.5. The models were adjusted for individual-specific effects (nulliparous status, age, body mass index, season, and year) and the moving averages of temperature and relative humidity in the corresponding study period. ResultsThere were significant relationships between PM2.5 and the glucose homeostasis indicators, including fasting, 1-h, 2-h, and 3-h glucose levels in the single-pollutant covariate-adjusted model. The pre-screening 1-month to 1-year moving averages of IQR increases in PM2.5 were significantly associated with elevated fasting OGTT glucose levels (1.32–5.87mg/dL). The two-pollutant covariate-adjusted models had similar results. ConclusionsWe found positive associations between PM2.5 and OGTT glucose levels during pregnancy. The association was especially pronounced for the fasting and 1-h glucose levels. PM2.5 exposure in the second trimester may enhance this effect. Exposure to PM2.5 was associated with glucose homeostasis during pregnancy.