The risk factors and incidence of type 2 diabetes mellitus and metabolic syndrome in women with previous gestational diabetes

The association between food desert severity, socioeconomic status, and metabolic state during pregnancy in a prospective longitudinal cohort

Poor metabolic health during pregnancy is associated with health concerns for pregnant individuals and their offspring. Lower socioeconomic status (SES) is one risk factor for poor metabolic health, and may be related to limited access to healthful and affordable foods (e.g., living in a food desert). This study evaluates the respective contributions of SES and food desert severity on metabolic health during pregnancy. The food desert severity of 302 pregnant individuals was determined using the United States Department of Agriculture Food Access Research Atlas. SES was measured using total household income adjusted for household size, years of education, and amount of reserve savings. Information about participants' glucose concentrations one hour following an oral glucose tolerance test during the second trimester was extracted from medical records and percent adiposity during the second trimester was assessed using air displacement plethysmography. Information about participants' nutritional intake during the second trimester was obtained by trained nutritionists via three unannounced 24-h dietary recalls. Structural equation models showed that lower SES predicted higher food desert severity (β = - 0.20, p = 0.008) and higher adiposity (β = - 0.27, p = 0.016) and consumption of a more pro-inflammatory diet (β = - 0.25, p = 0.003) during the second trimester of pregnancy. Higher food desert severity also predicted higher percent adiposity during the second trimester (β = 0.17, p = 0.013). Food desert severity significantly mediated the relationship between lower SES and higher percent adiposity during the second trimester (βindirect = - 0.03, 95% CI [- 0.079, - 0.004]). These findings indicate that access to healthful and affordable foods is a mechanism by which SES contributes to adiposity during pregnancy and may inform interventions intended to improve metabolic health during pregnancy.

Nonlinear association between changes in fasting plasma glucose and the incidence of diabetes in a nondiabetic Chinese cohort

BACKGROUND

Limited data show that changes in fasting plasma glucose (FPG changes) are related to the incidence of type 2 diabetes (T2D). We aimed to correlate FPG changes with incident diabetes and evaluate FPG changes as a marker to screen participants at high risk of T2D in China.

METHODS

A total of 116,816 individuals were followed during a median follow-up of 3.10 years by secondary analysis in a nondiabetic Chinese cohort. The turning points were derived from a receiver operating characteristic curve. Hazard ratios (HRs) were evaluated by Cox proportional hazards models.

RESULTS

A total of 2669 cases of T2D were identified (788 women and 1881 men). The age-standardized incidence of diabetes was 12.87 per 1000 person-years (women: 11.04; men: 14.69). A nonlinear relationship between FPG changes and incident diabetes is shown by the fitting curves. The curves were categorized into three stages by two turning points (-0.04 and 1.25 mmol/L) and conformed to the hook-like pattern: an initial decrease (stage-1), then a transient sharp elevation (stage-2), followed by a slow increase (stage-3). HRs per SD of FPG changes on incident diabetes varied with stage: stage-1: 0.16 (0.12, 0.23), stage-2: 0.20 (0.15, 0.28) and stage-3: 0.22 (0.16, 0.31). Compared with stage-1, the HR in stage-3 was significantly higher at 28.05 (23.99, 32.79), while the increase in stage-2 was slight at 2.16 (1.79, 2.61), and the HR in stage-3 rose to 30.09 (25.02, 36.19).

CONCLUSIONS

FPG changes had a strong correlation with the incidence of T2D and was a steady indicator that was used to distinguish the participants at high risk of diabetes.

Gestational Diabetes Mellitus Among Asians - A Systematic Review From a Population Health Perspective

OBJECTIVE

Since Asians are particularly vulnerable to the risk of gestational diabetes mellitus (GDM), the lifecourse health implications of which are far beyond pregnancy, we aimed to summarize the literature to understand the research gaps on current GDM research among Asians.

METHODS

We systematically searched the articles in PubMed, Web of Science, Embase, and Scopus by 30 June 2021 with keywords applied on three topics, namely "GDM prevalence in Asians", "GDM and maternal health outcomes in Asians", and "GDM and offspring health outcomes in Asians".

RESULTS

We observed that Asian women (natives and immigrants) are at the highest risk of developing GDM and subsequent progression to type 2 diabetes among all populations. Children born to GDM-complicated pregnancies had a higher risk of macrosomia and congenital anomalies (i.e. heart, kidney and urinary tract) at birth and greater adiposity later in life.

CONCLUSION

This review summarized various determinants underlying the conversion between GDM and long-term health outcomes in Asian women, and it might shed light on efforts to prevent GDM and improve the lifecourse health in Asians from a public health perspective.

SYSTEMATIC REVIEW REGISTRATION

Prospero, CRD42021286075.

Impact of Risk Factors on Short and Long-Term Maternal and Neonatal Outcomes in Women With Gestational Diabetes Mellitus: A Prospective Longitudinal Cohort Study

AIMS

Universal screening of gestational diabetes mellitus (GDM) in women with no risk factors (RF) for GDM remains controversial. This study identified the impact of the presence of RF on perinatal and postpartum outcomes.

METHODS

This prospective cohort study included 780 women with GDM. GDM RF included previous GDM, first grade family history of type 2 diabetes, high-risk ethnicity and pre-pregnancy overweight/obesity (OW/OB). Outcomes included obstetrical, neonatal and maternal metabolic parameters during pregnancy and up to 1 year postpartum.

RESULTS

Out of 780 patients, 24% had no RF for GDM. Despite this, 40% of them needed medical treatment and they had a high prevalence of glucose intolerance of 21 and 27% at 6-8 weeks and 1-year postpartum, respectively. Despite similar treatment, women with RF had more neonatal and obstetrical complications, but they had especially more frequent adverse metabolic outcomes in the short- and long-term. The most important RF for poor perinatal outcome were previous GDM and pre-pregnancy OW/OB, whereas high-risk ethnicity and pre-pregnancy OW/OB were RF for adverse postpartum metabolic outcomes. Increasing number of RF were associated with worsened perinatal and long-term postpartum outcomes except for pregnancy-induced hypertension, C-section delivery and neonatal hypoglycaemia.

CONCLUSION

Women with no RF had a high prevalence of adverse perinatal and postpartum outcomes, while the presence of RF particularly increased the risk for postpartum adverse metabolic outcomes. This calls for a RF-based long-term follow-up of women with GDM.

Progression to Abnormal Glucose Tolerance and Its Related Risk Factors Among Women with Prior Gestational Diabetes in Rural Communities of China

BACKGROUND

The purpose of this study was to describe the status of abnormal glucose tolerance with a longer duration after delivery among women with prior gestational diabetes mellitus (GDM) in a rural community of China, and to explore the influence of socio-demographic factors, GDM-related factors (family history of diabetes, number of children, receipt of treatment for GDM), psychosocial factors (perceived stress, self-efficacy, and social support), lifestyle behaviors (physical activity, sedentary activity, fruit or vegetables intake), and obesity indicators (body mass index and waist circumferences) on abnormal glucose tolerance.

PATIENTS AND METHODS

A cross-sectional descriptive survey was conducted among women with prior GDM in two county-level hospitals in Western and Eastern Hunan, China from November 2017 to June 2018. Under the guidance of life course theory, data were collected using self-report measures of socio-demographic and GDM-related factors as well as psychosocial factors (perceived stress, self-efficacy, and social support) and postpartum lifestyle behaviors (physical activity, sedentary activity, and fruit and vegetable intake). Additionally, a 75-g oral glucose tolerance test was conducted, and weight, height, and waist circumference were measured on site.

RESULTS

A total of 425 women were included in this study, with an average postpartum duration of 18.04 months. Of these women, 20.9% had abnormal glucose tolerance (AGT). A multivariate analysis indicated that the proportion of abnormal glucose tolerance increased with increased age (OR = 2.13; 1.27-3.57, p=0.004), ethnic minority (OR: 1.62, 95% CI: 0.96-2.72, p=0.069), lower educational levels (OR:0.58, 95% CI: 0.33-1.02, p=0.057), receipt of treatment for GDM during pregnancy (OR =1.93; 1.11-3.37, p=0.020) and larger waist circumference (OR = 1.08; 1.05-1.12, p=0.000).

CONCLUSION

More than one-fifth of the women with GDM in rural China had progression to AGT. More postpartum programs aimed at reducing waist circumference are warranted to delay or prevent progression to type 2 diabetes mellitus for rural Chinese women with prior GDM.

Type 2 diabetes and pre-diabetes mellitus: a systematic review and meta-analysis of prevalence studies in women of childbearing age in the Middle East and North Africa, 2000-2018

BACKGROUND

Investing in women's health is an inevitable investment in our future. We systematically reviewed the available evidence and summarized the weighted prevalence of type 2 diabetes (T2DM) and pre-diabetes mellitus (pre-DM) in women of childbearing age (15-49 years) in the Middle East and North African (MENA) region.

METHODS

We comprehensively searched six electronic databases to retrieve published literature and prevalence studies on T2DM and pre-DM in women of childbearing age in the MENA. Retrieved citations were screened and data were extracted by at least two independent reviewers. Weighted T2DM and pre-DM prevalence was estimated using the random-effects model.

RESULTS

Of the 10,010 screened citations, 48 research reports were eligible. Respectively, 46 and 24 research reports on T2DM and pre-DM prevalence estimates, from 14 and 10 countries, were included. Overall, the weighted T2DM and pre-DM prevalence in 14 and 10 MENA countries, respectively, were 7.5% (95% confidence interval [CI], 6.1-9.0) and 7.6% (95% CI, 5.2-10.4). In women sampled from general populations, T2DM prevalence ranged from 0.0 to 35.2% (pooled, 7.7%; 95% CI, 6.1-9.4%) and pre-DM prevalence ranged from 0.0 to 40.0% (pooled, 7.9%; 95% CI, 5.3-11.0%). T2DM was more common in the Fertile Crescent countries (10.7%, 95% CI, 5.2-17.7%), followed by the Arab Peninsula countries (7.6%, 95% CI, 5.9-9.5%) and North African countries and Iran (6.5%, 95% CI, 4.3-9.1%). Pre-DM prevalence was highest in the Fertile Crescent countries (22.7%, 95% CI, 14.2-32.4%), followed by the Arab Peninsula countries (8.6%, 95% CI, 5.5-12.1%) and North Africa and Iran (3.3%, 95% CI, 1.0-6.7%).

CONCLUSIONS

T2DM and pre-DM are common in women of childbearing age in MENA countries. The high DM burden in this vital population group could lead to adverse pregnancy outcomes and acceleration of the intergenerational risk of DM. Our review presented data and highlighted gaps in the evidence of the DM burden in women of childbearing age, to inform policy-makers and researchers.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017069231.

A systematic review on costs and cost-effectiveness of screening and prevention of type 2 diabetes in women with prior gestational diabetes: Exploring uncharted territory

AIMS

Women with gestational diabetes mellitus (GDM) are more likely to develop type 2 diabetes mellitus (T2DM) as compared to women with normoglycemic pregnancies. This study aims to explore the literature on cost(-effectiveness) of screening and prevention of T2DM in women with prior GDM.

METHODS

Five databases were systematically searched, inclusion criteria were: (1) women with (prior) GDM; (2) post-partum screening or prevention of T2DM; and (3) health-economic evaluations. No year limits were applied. English, Dutch, French or German publications were included. Quality was assessed using the Consensus Health Economic Criteria checklist.

RESULTS

Two cost-effectiveness analyses and two cost analyses were found. One study evaluated nine screening strategies. Three studies evaluated one prevention strategy each: intensive diet and behavioural modification; annual counseling; and an annual dietary consultation. Methodological quality was poor. Perspectives were unclear, time horizons were too short, and no incremental analyses were performed.

CONCLUSION

An oral glucose tolerance test per three years leads to the lowest cost per case detected, and prevention is potentially cost-effective or cost-saving. More health economic evaluations are needed that compare all relevant alternatives, including 'doing nothing'.

Relationship maternal subcutaneous adipose tissue thickness and development of gestational diabetes mellitus

Objective

We investigated whether the ultrasonographic measurement of maternal subcutaneous adipose tissue (SAT) thickness in the second trimester played a role in predicting gestational diabetes.

Materials and methods

This was a prospective cross-sectional study in which 223 women were classified as healthy (n = 177) or as gestational diabetes (n = 46) on the basis of a negative or positive two-step oral Glucose Challenge Test (GCT), respectively. The depth of the abdominal SAT was evaluated by two-dimensional ultrasonography. Body mass index (BMI), waist circumference (WC), and waist/hip ratio were determined.

Results

There was a positive strong significant correlation between a 50-g GCT level and BMI, WC, and SAT thickness (p < 0.001). Receiver-operating characteristic curve analysis showed SAT thickness above 16.75 mm predicted gestational diabetes mellitus (GDM) with a sensitivity of 71.7%, a specificity of 57.1%, a positive predictive value of 32.3%, and a negative predictive value of 87.6%. There was a good correlation between SAT, BMI, and WC.

Conclusion

Increased SAT, BMI, and WC measurements may be helpful in predicting the risk of the development of GDM in pregnant women.

Long-Term Effects of Pregnancy Complications on Maternal Health: A Review

Background: Most pregnancy-related medical complications appear to resolve at delivery or shortly thereafter. Common examples are preterm labor, placental abruption, preeclampsia, and gestational diabetes. Women who developed such complications are known to be at increased risk of developing similar complications in future pregnancies. It has recently become evident that these women are at an increased risk of long term medical complications. Methods: A search through scientific publications in English regarding the association of obstetric complications and long-term maternal illness. Results: There is a clear association between various obstetric complications and long-term effects on maternal health. Conclusions: Women with a history of adverse pregnancy outcomes are at increased risk of cardiovascular and metabolic diseases later in life. Data increasingly links maternal vascular, metabolic, and inflammatory complications of pregnancy with an increased risk of vascular disease in later life.

Effect of exercise during pregnancy to prevent gestational diabetes mellitus: a systematic review and meta-analysis

INTRODUCTION

Exercise showed some potential in preventing gestational diabetes mellitus. However, the results remained controversial. We conducted a systematic review and meta-analysis to evaluate the impact of exercise during pregnancy on gestational diabetes mellitus.

METHODS

PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases were systematically searched. Randomized controlled trials (RCTs) assessing the influence of exercise during pregnancy on gestational diabetes mellitus were included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. The primary outcome was the incidence of gestational diabetes mellitus. Meta-analysis was performed using random-effect model.

RESULTS

Six RCTs involving 2164 patients were included in the meta-analysis. Compared with control intervention, exercise intervention was associated with significantly decreased incidence of gestational diabetes mellitus (Std. mean difference = 0.59; 95%CI = 0.39-.88; p = .01), but had no effect on gestational age at birth (Std. mean difference = -0.03; 95%CI = -0.12 to 0.07; p = .60), the number of preterm birth (OR = 0.85; 95%CI = 0.43-1.66; p = .63), glucose 2-h post-OGTT (Std. mean difference = -1.02; 95%CI = -2.75 to 0.71; p = .25), birth weight (Std. mean difference = -0.13; 95%CI = -0.26 to 0.01; p = .06), and Apgar score less than 7 (OR = .78; 95%CI = 0.21-2.91; p = .71).

CONCLUSIONS

Compared to control intervention, exercise intervention could significantly decrease the risk of gestational diabetes mellitus, but showed no impact on gestational age at birth, preterm birth, glucose 2-h post-OGTT, birth weight, and Apgar score less than 7.

A randomized clinical trial of exercise during pregnancy to prevent gestational diabetes mellitus and improve pregnancy outcome in overweight and obese pregnant women

BACKGROUND

Obesity and being overweight are becoming epidemic, and indeed, the proportion of such women of reproductive age has increased in recent times. Being overweight or obese prior to pregnancy is a risk factor for gestational diabetes mellitus, and increases the risk of adverse pregnancy outcome for both mothers and their offspring. Furthermore, the combination of gestational diabetes mellitus with obesity/overweight status may increase the risk of adverse pregnancy outcome attributable to either factor alone. Regular exercise has the potential to reduce the risk of developing gestational diabetes mellitus and can be used during pregnancy; however, its efficacy remain controversial. At present, most exercise training interventions are implemented on Caucasian women and in the second trimester, and there is a paucity of studies focusing on overweight/obese pregnant women.

OBJECTIVE

We sought to test the efficacy of regular exercise in early pregnancy to prevent gestational diabetes mellitus in Chinese overweight/obese pregnant women.

STUDY DESIGN

This was a prospective randomized clinical trial in which nonsmoking women age >18 years with a singleton pregnancy who met the criteria for overweight/obese status (body mass index 24≤28 kg/m²) and had an uncomplicated pregnancy at <12⁺⁶ weeks of gestation were randomly allocated to either exercise or a control group. Patients did not have contraindications to physical activity. Patients allocated to the exercise group were assigned to exercise 3 times per week (at least 30 min/session with a rating of perceived exertion between 12-14) via a cycling program begun within 3 days of randomization until 37 weeks of gestation. Those in the control group continued their usual daily activities. Both groups received standard prenatal care, albeit without special dietary recommendations. The primary outcome was incidence of gestational diabetes mellitus.

RESULTS

From December 2014 through July 2016, 300 singleton women at 10 weeks' gestational age and with a mean prepregnancy body mass index of 26.78 ± 2.75 kg/m² were recruited. They were randomized into an exercise group (n = 150) or a control group (n = 150). In all, 39 (26.0%) and 38 (25.3%) participants were obese in each group, respectively. Women randomized to the exercise group had a significantly lower incidence of gestational diabetes mellitus (22.0% vs 40.6%; P < .001). These women also had significantly less gestational weight gain by 25 gestational weeks (4.08 ± 3.02 vs 5.92 ± 2.58 kg; P < .001) and at the end of pregnancy (8.38 ± 3.65 vs 10.47 ± 3.33 kg; P < .001), and reduced insulin resistance levels (2.92 ± 1.27 vs 3.38 ± 2.00; P = .033) at 25 gestational weeks. Other secondary outcomes, including gestational weight gain between 25-36 gestational weeks (4.55 ± 2.06 vs 4.59 ± 2.31 kg; P = .9), insulin resistance levels at 36 gestational weeks (3.56 ± 1.89 vs 4.07 ± 2.33; P = .1), hypertensive disorders of pregnancy (17.0% vs 19.3%; odds ratio, 0.854; 95% confidence interval, 0.434-2.683; P = .6), cesarean delivery (except for scar uterus) (29.5% vs 32.5%; odds ratio, 0.869; 95% confidence interval, 0.494-1.529; P = .6), mean gestational age at birth (39.02 ± 1.29 vs 38.89 ± 1.37 weeks' gestation; P = .5); preterm birth (2.7% vs 4.4%, odds ratio, 0.600; 95% confidence interval, 0.140-2.573; P = .5), macrosomia (defined as birthweight >4000 g) (6.3% vs 9.6%; odds ratio, 0.624; 95% confidence interval, 0.233-1.673; P = .3), and large-for-gestational-age infants (14.3% vs 22.8%; odds ratio, 0.564; 95% confidence interval, 0.284-1.121; P = .1) were also lower in the exercise group compared to the control group, but without significant difference. However, infants born to women following the exercise intervention had a significantly lower birthweight compared with those born to women allocated to the control group (3345.27 ± 397.07 vs 3457.46 ± 446.00 g; P = .049).

CONCLUSION

Cycling exercise initiated early in pregnancy and performed at least 30 minutes, 3 times per week, is associated with a significant reduction in the frequency of gestational diabetes mellitus in overweight/obese pregnant women. And this effect is very relevant to that exercise at the beginning of pregnancy decreases the gestational weight gain before the mid-second trimester. Furthermore, there was no evidence that the exercise prescribed in this study increased the risk of preterm birth or reduced the mean gestational age at birth.

High Incidence of Diabetes Mellitus Among a Middle-Aged Population in Iran: A Longitudinal Study

OBJECTIVES

There are few data concerning the incidence rates of diabetes in Iran. This study aimed to determine the incidence of diabetes and its risk factors in a middle-aged population in Iran.

METHODS

All of the people who participated in the first phase of the Shahroud eye cohort study were invited to the study in 2014; after signing informed consent forms, a total of 4737 people 45 to 69 years of age were enrolled in the second phase of the study (participation rate: 91.3%). The 5-year incidence rate of diabetes was determined by age and sex, and we used the binomial logistic regression model to calculate the risk ratio.

RESULTS

The prevalence of diabetes in the second phase was 20.19% in men, 26.45% in women and 23.89% in the total group. The 5-year incidence of diabetes was 11.19% in men, 15.55% in women and 13.73% in both sexes. With increases in age, the incidence of diabetes rose in both sexes. Age (risk ratio [RR]: 1.02; CI 95%: 1.01 to 1.03) hypertension (RR: 1.41; CI 95%: 1.15 to 1.74), being overweight (RR: 2.17; CI 95%: 1.64 to 2.88) and obesity (RR: 3.4; CI 95%: 2.53 to 4.41) were associated with increased risks for the incidence of diabetes.

CONCLUSIONS

This study is 1 of the few studies in Iran that has reported the incidence of diabetes. Because the incidence of diabetes was high in the studied population, it is necessary for the health system to design and implement emergency intervention to prevent further spread of diabetes and its complications.

The Impact of Vitamin D Supplementation on Post-Partum Glucose Tolerance and Insulin Resistance in Gestational Diabetes: A Randomized Controlled Trial

BACKGROUND

Hypovitaminosis D has been associated with the development of gestational diabetes mellitus (GDM) in many observational studies.

OBJECTIVES

We report the first study of the impact of prenatal vitamin D supplementation on postpartum dysglycemia in GDM patients in a randomized clinical trial.

PATIENTS AND METHODS

Women with GDM at 12 - 32 weeks of gestation were assigned randomly to either the intervention group (in which serum 25-hydroxy vitamin D [25OHD] levels were measured immediately, n = 48) or the control group (in which the serum was stored and assayed at 6 - 12 weeks post-partum, n = 48). Participants with initial serum 25OHD < 30 ng/mL in the intervention group were instructed to take a total of 700,000 IU vitamin D3 during pregnancy. The primary outcomes were fasting plasma glucose (FPG), insulin, 2-h post 75 g glucose load plasma glucose (2-hPLG), homeostasis model assessment of insulin resistance (HOMA-IR), HbA1C, and 25 OHD at 6 - 12 weeks after delivery.

RESULTS

The mean ± SD of serum 25OHD in the intervention group raised dramatically from 14.6 ± 6.3 to 32.4 ± 14.4 ng/mL, whereas no significant change occurred in the control group (from 17.7 ± 6.1 to 19.3 ± 9.6 ng/mL, P < 0.001). Thirteen participants developed dysglycemia in each group. Mean FPG, 2-hPLG, and HOMA-IR were not significantly different between the groups. There was no significant difference between the groups for maternal and neonatal outcomes.

CONCLUSIONS

Although the high vitamin D supplementation dose in the present study (compared to the 400 IU/day dose usually recommended for pregnancy) safely increases the serum 25OHD, in GDM cases, the higher dose does not affect the plasma glucose level or insulin resistance at short term follow-up after delivery.

Impact of ATM and SLC22A1 Polymorphisms on Therapeutic Response to Metformin in Iranian Diabetic Patients

Metabolic syndrome and its pathological sequel, type 2 diabetes are considered as important global health problems. Metformin is the most common drug prescribed for patients with this disorder. Consequently, understanding the genetic pathways involved in pharmacokinetics and pharmacodynamics of this drug can have a considerable effect on the personalized treatment of type 2 diabetes. In this study, we evaluated the association between rs11212617 polymorphism of ATM gene and rs628031 of SLC22A1 gene with response to treatment in newly diagnosed type 2 diabetes patients. We genotyped rs11212617 and rs628031 polymorphism by PCR based restriction fragment length polymorphism (RFLP) and assessed the role of this polymorphisms on response to treatment in 140 patients who have been recently diagnosed with type 2 diabetes and were under monotherapy with metformin for 6 months. Response to metformin was defined by HbA1c and fasting blood sugar (FBS) values. Based on such evaluations, patients were divided into two groups: responders (n= 63) and non-responders (n= 77). No significant association was found between these polymorphisms and response to treatment (OR= 0.86, [95% CI 0.52-1.41], P= 0.32) for rs11212617 and (OR= 0.45, [95% CI 0.64-1.76], P= 0.45) for rs 628031. The reported gene variants in ATM and SLC22A1 are not significantly associated with metformin treatment response in type 2 diabetic patients in an Iranian population.

β-Cell death is decreased in women with gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) affects approximately 7-17 % of all pregnancies and has been recognized as a significant risk factor to neonatal and maternal health. Postpartum, GDM significantly increases the likelihood of developing type 2 diabetes (T2D). While it is well established that insulin resistance and impaired β-cell function contribute to GDM development, the role of active β-cell loss remains unknown. Differentially methylated circulating free DNA (cfDNA) is a minimally invasive biomarker of β-cell loss in type 1 diabetes mellitus. Here we use cfDNA to examine the levels of β-cell death in women with GDM.

METHODS

Second to third-trimester pregnant women with GDM were compared with women with normal pregnancy (PRG), women at postpartum (PP), and non-pregnant (NP) women. Fasting glucose levels, insulin, and C-peptide levels were measured. Serum samples were collected and cfDNA purified and bisulfite treated. Methylation-sensitive probes capable of differentiating between β-cell-derived DNA (demethylated) and non-β-cell-derived DNA (methylated) were used to measure the presence of β-cell loss in the blood.

RESULTS

GDM was associated with elevated fasting glucose levels (GDM = 185.9 ± 5.0 mg/dL) and reduced fasting insulin and c-peptide levels when compared with NP group. Interestingly, β-cell derived insulin DNA levels were significantly lower in women with GDM when compared with PRG, NP, and PP groups (demethylation index: PRG = 7.74 × 10(-3) ± 3.09 × 10(-3), GDM = 1.01 × 10(-3) ± 5.86 × 10(-4), p < 0.04; NP = 4.53 × 10(-3) ± 1.62 × 10(-3), PP = 3.24 × 10(-3) ± 1.78 × 10(-3)).

CONCLUSIONS

These results demonstrate that β-cell death is reduced in women with GDM. This reduction is associated with impaired insulin production and hyperglycemia, suggesting that β-cell death does not contribute to GDM during the 2nd and 3rd trimester of pregnancy.