Risk factors for gestational diabetes in black population

Can we really diagnose diabetes during pregnancy?

OBJECTIVE

To identify the accuracy of diagnosing postpartum diabetes and glucose intolerance using antepartum glycosylated hemoglobin (HbA1c) and fasting glucose values.

STUDY DESIGN

A retrospective Hawaiian cohort of women with gestational diabetes during 2004-2011 were evaluated. Antepartum HbA1c and postpartum 75-g glucose tolerance tests were obtained.

RESULTS

An antepartum HbA1c value of ≥6.5% had a 45.7% sensitivity, a 96% specificity and a 40% positive predictive value (PPV) for predicting postpartum diabetes. An antepartum HbA1c value of ≥6.5% had a 6.6% sensitivity, a 94.2% specificity and a 27% PPV for predicting postpartum impaired glucose tolerance. An antepartum HbA1c value of ≥6.5% had a 10.3% sensitivity, a 95.7% specificity and a 33.3% PPV for predicting postpartum impaired fasting glucoses.

CONCLUSION

We could not demonstrate a clinically useful PPV for diagnosing postpartum diabetes or glucose intolerance using an antepartum elevated HbA1c value of ≥6.5% or a fasting glucose level of ≥90 mg/dL.

Gestational diabetes: risk factors and recent advances in its genetics and treatment

The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study of over 23000 diabetes-free pregnancies has shown that at a population level an unequivocal linear relationship exists between maternal glucose concentrations around the beginning of the third trimester of pregnancy and the risk of their baby being born above the ninetieth centile for weight. With the rising incidence of gestational diabetes (GDM) across the developed world, largely paralleling the increased prevalence of obesity, there has been a sharp increase in the risk of pregnancy complications developing related to the birth of macrosomic babies. The associated additional long-term complications of GDM pregnancies means that in the future there is likely to be a large increase in the incidence of type 2 diabetes and associated conditions in both the mothers and their affected offspring. The present review seeks to highlight recent advances and remaining gaps in knowledge about GDM in terms of its genetics (where some of the recently discovered polymorphic risk factors for type 2 diabetes have also proved to be risk factors for GDM) and its treatment by diet, exercise and drugs.

Onset of autoimmune type 1 diabetes during pregnancy: Prevalence and outcomes

Although this has been recently challenged, gestational diabetes mellitus (gestational diabetes) is still defined as an "impairment of glucose tolerance with onset or first recognition during pregnancy". According to this definition, all pathophysiological conditions leading to beta cell deficiency may reveal as gestational diabetes, due to the physiological insulin resistance associated with pregnancy. In rare patients, gestational diabetes is associated with the presence of islet autoantibodies and with a high risk of progression to overt type 1 diabetes after delivery. This condition has often been compared to the Latent Autoimmune Diabetes in Adults. The frequency of islet autoantibodies in gestational diabetes has been assessed in many studies, but data about the clinical presentation of this subtype and about its prognosis are few. We review these studies and discuss the links of autoimmune gestational diabetes with type 1 diabetes mellitus.

Diabetes related autoimmunity in gestational diabetes mellitus: is it important?

Some GDM women show autoantibody positivity during and after pregnancy and pancreatic autoantibodies can appear for the first time in some patients after delivery. Autoantibody positivity is often accompanied by a high frequency of DR3 and DR4 alleles, which are classically related to the development of type 1 diabetes and, although not all studies agree on this point, by an immunological imbalance expressed by the behaviour of the lymphocyte subpopulation, which can be seen as diabetic anomalies overlapping with the immunological changes that occur during pregnancy. It is worth emphasizing that such patients may develop classical type 1 diabetes during and/or after their pregnancy or they may evolve, often some years after their pregnancy, into cases of latent autoimmune diabetes of adulthood (LADA). Autoimmune GDM accounts for a relatively small number of cases (about 10% of all GDM) but the risk of these women developing type 1 diabetes or LADA is very high, so these patients must be identified in order to prevent the severe maternal and fetal complications of type 1 diabetes developing in pregnancy, or its acute onset afterwards. Since women with autoimmune GDM must be considered at high risk of developing type 1 diabetes in any of its clinical forms, these women should be regarded as future candidates for the immunomodulatory strategies used in type 1 diabetes.

Prevention of T2DM in women with a previous history of GDM

Women with a history of gestational diabetes mellitus (GDM) have a high risk of progression to type 2 diabetes mellitus (T2DM). Risk factors are similar for GDM and T2DM and include, among others, obesity, family history, and ethnic background. GDM is also associated with the metabolic syndrome. Women with impaired glucose tolerance or "prediabetes" postpartum have the highest risk of progression. In women with impaired glucose tolerance, lifestyle modification or pharmacologic therapy may prevent or delay the onset of T2DM.

Insulin resistance syndrome, pre-diabetes, and the prevention of type 2 diabetes mellitus

Insulin resistance syndrome (IRS), also known as the metabolic syndrome, is now well recognized as a distinct pathological and clinical entity, with multiple significant ramifications for both the high-risk individual as well as the public health system. The primary contributory cause is obesity. Common manifestations associated with IRS may include atherosclerotic heart disease, hypertension, impaired glucose tolerance, dyslipidemia, polycystic ovary syndrome, and hypercoagulability. This review will present the features associated with the disorder, the accepted clinical diagnosis, available and potential treatment modalities, and ongoing or completed trials which suggest that progression from IRS to type 2 diabetes mellitus and early coronary heart disease may be prevented in adolescents and adults.

Autoimmune gestational diabetes mellitus: a distinct clinical entity?

This review gives an update of the present knowledge on what is defined here as autoimmune gestational diabetes mellitus (GDM). Autoimmune phenomena associated with type 1 diabetes mellitus (DM) can be detected in a subgroup of women with GDM. Islet autoantibodies are present in sera from women with GDM with variable frequency. Distinct phenotypic and genotypic features may be recognised in this subset of women with GDM, which are representative of a distinct clinical entity. Furthermore, these women are at increased risk of developing type 1 DM after pregnancy. However, the eventual progression of the autoimmune destruction of beta-cells in these subjects may follow different time-course patterns thus leading to variable forms of presentation of autoimmune DM. As a high-risk group for type 1 diabetes, women with previous autoimmune GDM may be candidates for potential immune intervention strategies.

Prevalence and risk factors of microalbuminuria in a cohort of African-American women with gestational diabetes

OBJECTIVE

To study the prevalence of microalbuminuria (MA) in African-American women with a history of gestational diabetes (GDM) who are at high risk for insulin resistance and renal dysfunction and to study MA's relation to insulin resistance, type 2 diabetes, and hypertension.

RESEARCH DESIGN AND METHODS

MA was assessed using 24-h, timed, and/or random urine samples in a cross-sectional sample (n = 289) from a cohort of African-American women with a history of GDM and followed for a median of 11 years (range 3.0-18.4) since their diabetic pregnancy. Subjects with a urine albumin excretion rate of 30-300 g/24 h or 30-300 microg/mg creatinine in a random sample were classified as having MA if two of three samples over a 3- to 6-month period were positive. These women were evaluated for family history of diabetes, smoking and alcohol use, BMI, diabetes, hypertension, and lipid abnormalities. Insulin sensitivity was determined using the homeostasis model assessment (HOMA) estimates, which used fasting insulin and glucose measurements obtained at the same time as the MA urine sample.

RESULTS

At MA assessment, the women ranged in age from 22 to 57 years, with a median of 39 years. The overall prevalence of MA was 20%; 36% in those with diabetes. Those women with MA had higher rates of diabetes (63.8 vs. 28.6%, odds ratio [OR] = 4.4, P < 0.05), hypertension (82.8 vs. 42.9%, OR = 6.4, P < 0.05), and family history of diabetes (85.7 vs. 61.7%, OR = 3.7, P < 0.05). The proportion of subjects with MA with a family history of hypertension was nonsignificantly increased (92.9 vs. 82.4%). Subjects with MA were more obese (BMI 37.2 +/- 8.9 vs. 34.4 +/- 8.6 kg/m(2)) and had higher levels of HbA(1c) (8.8 +/- 3.3 vs. 6.6 +/- 1.8%, P < 0.001) and systolic (144.3 +/- 25.9 vs. 122.8 +/- 17.2 mmHg, P < 0.0001) and diastolic (95.1 +/- 15.4 vs. 82.5 +/- 11.9 mmHg, P < 0.0001) blood pressures. Lipid fractions were similar in those with and without MA. Although fasting glucose was much higher in subjects with MA (10.3 +/- 5.8 vs. 7.1 +/- 4.2 mmol/l, P = 0.0002), insulin levels were not significantly higher in subjects with MA (17.4 +/- 21.2 vs. 15.2 +/- 12.4 pmol/l). Insulin sensitivity, as measured using log HOMA, was similar (1.5 +/- 0.6 vs. 1.6 +/- 0.6) in women with and without MA, respectively. Multivariable logistic regression analyses indicated that HbA(1c), OR = 1.16 (1.07, 1.27), and systolic blood pressure, OR = 1.27 (1.14, 1.41), were independent risk factors for MA. In those with diabetes, the subjects with MA had higher rates of hypertension-83.8 vs. 56.1%, OR = 4.1 (1.5, 11.10)-which was reflected by their higher systolic and diastolic blood pressures, 146.1 mmHg (P = 0.001) and 94.8 mmHg (P = 0.002), respectively, and lower levels of VLDL (0.45 +/- 0.22 vs. 0.61 +/- 0.33 mmol/l, P = 0.021). In the multivariable analyses of those with diabetes, the two independent risk factors for MA were similar: HbA(1c), OR = 1.13 (1.01, 1.28), and systolic blood pressure, OR = 1.21 (1.04, 1.41).

CONCLUSIONS

African-American women with a history of GDM have one of the highest rates for MA. Presence of MA was not associated with insulin resistance but was significantly independently associated with HbA(1c) levels and hypertension. These results, taken in context of the literature, suggest that hypertension and glucose intolerance, in part, influence MA through different mechanisms. Because of the high prevalence of MA in this population and MA's relation to all-cause and cardiovascular mortality, screening for MA should be considered.

A multiethnic study of the predictors of macrosomia

PURPOSE

This study examined predictors of macrosomia in a multiethnic sample of 213 low-income women diagnosed with gestational diabetes mellitus (GDM) after week 24 of their pregnancy.

METHODS

Medical records were reviewed retrospectively. Variables examined were mother's height, weight history, educational level, age at diagnosis, weeks at diagnosis and delivery, type of diabetes, mean fasting blood glucose (FBG), and infant's weight, sex, and Apgar scores.

RESULTS

Fifty-one percent of babies were macrosomic. Weight gain, nonpregnant weight, weight at delivery, FBG, and Apgar scores at 1 minute were associated with macrosomia, especially in Hispanic women. Logistic regression revealed that nonpregnant weight was the strongest predictor of macrosomia.

CONCLUSIONS

Nonobese GDM mothers with optimal weight gain but with high FBG levels > 90 mg/dL may be at risk for macrosomia. The major concerns with obese GDM mothers are nonpregnant weight and high blood glucose levels, in this order. Education for women with GDM should target these risk factors to decrease macrosomia.

Do sociodemographics and economic status predict risks for type II diabetes in African Americans?

The prevalence of type II diabetes and the metabolic characteristics in high-risk African Americans were examined to determine whether certain socioeconomic and demographic characteristics (SED) increase the risk for type II diabetes in this population. Study participants were high-risk African Americans between the ages of 25 and 64 years. Glucose tolerance status was assessed and questionnaires were completed to obtain information regarding SED, hypertension, and physical activity. The majority of patients had normal glucose tolerance; undiagnosed type II diabetes was identified in 36 of 164 patients. Questionnaire data revealed that, in highly selected African Americans at risk for type II diabetes, there was a higher rate of obesity, prior gestational diabetes, and undiagnosed type II diabetes despite higher educational and income levels and greater access to health care and recreational facilities. Findings indicate that African Americans may be at higher risk for type II diabetes, regardless of socioeconomic status, due to genetic inheritance and other unknown environmental determinants. Further studies are needed to characterize SED and metabolic profiles that confer a high risk for type II diabetes in this population.

Islet cell antibodies and beta-cell function in gestational diabetic women: comparison to first-degree relatives of type 1 (insulin-dependent) diabetic subjects

In order to further characterize women with islet cell antibodies (ICA) at the diagnosis of gestational diabetes (GDM), we aimed to compare titres and persistence as well as B-cell function with those of ICA+ first-degree relatives of Type 1 (insulin-dependent) diabetic subjects. Titres at detection of ICA were compared between 69 women with GDM and 53 relatives. Persistence of ICA positivity was investigated in 33 ICA+ gestational diabetic women and 39 relatives (mean follow-up: 13 months). Assessment of the acute insulin response, through an intravenous glucose tolerance test (IVGTT), was carried out in 9 ICA+ women with previous GDM and normal oral glucose tolerance, and their results were compared to those of a control group (9 women) and a group of 12 adult ICA+ relatives. In comparison with first-degree relatives, women with GDM had a higher ICA prevalence, especially with titres of < 20 JDF, and a similar persistence at follow-up. Women with ICA at diagnosis of GDM and normal oral glucose tolerance after pregnancy showed a decreased insulin response to glucose as compared to the control group. Results of the IVGTT closely paralleled those from adult ICA+ relatives. It is concluded that ICA+ gestational diabetic women share with ICA+ first-degree relatives of Type 1 diabetic subjects metabolic and immunologic disturbances.