The impact of ethnicity on glucose regulation and the metabolic syndrome following gestational diabetes.

AIMS/HYPOTHESIS: We assessed the impact of ethnic origin on metabolism in women following gestational diabetes mellitus (GDM). MATERIALS AND METHODS: Glucose regulation and other features of the metabolic syndrome were studied at 20.0 (18.2-22.1) months (geometric mean [95% CI]) post-partum in women with previous GDM (185 European, 103 Asian-Indian, 80 African-Caribbean). They were compared with the same features in 482 normal control subjects who had normal glucose regulation during and following pregnancy. RESULTS: Impaired glucose regulation or diabetes by WHO criteria were present in 37% of women with previous GDM (diabetes in 17%), especially in those of African-Caribbean and Asian-Indian origin (50 and 44%, respectively vs 28% in European, p=0.009). BMI, waist circumference, diastolic blood pressure, fasting triglyceride and insulin levels, and insulin resistance by homeostatic model assessment (HOMA), were increased following GDM (p<0.001 for all, vs control subjects). Where glucose regulation was normal following GDM, basal insulin secretion (by HOMA) was high (p<0.001 vs control subjects). Irrespective of glucose regulation in pregnancy, Asian-Indian origin was associated with high triglyceride and low HDL cholesterol levels, and African-Caribbean with increased waist circumference, blood pressure, and insulin levels, together with insulin resistance and low triglyceride concentrations. Nonetheless, the GDM-associated features were consistent within each ethnic group. The metabolic syndrome by International Diabetes Federation criteria was present in 37% of women with previous GDM, especially in non-Europeans (Asian-Indian 49%, African-Caribbean 43%, European 28%, p=0.001), and in 10% of controls. CONCLUSIONS/INTERPRETATION: Following GDM, abnormal glucose regulation and the metabolic syndrome are common, especially in non-European women, indicating a need for diabetes and cardiovascular disease prevention strategies.

Women with a history of gestational diabetes of European and South Asian origin are shorter than women with normal glucose tolerance in pregnancy.

AIMS: It has been reported that short individuals are more likely to have abnormalities of glucose homeostasis. The aim of this study was to examine the relationship between adult height and gestational diabetes mellitus (GDM), taking into account possible artefactual or confounding explanations. METHODS: Three hundred and forty-six women with previous GDM (169 European, 102 South Asian, 75 Afro-Caribbean) and 470 control women with no previous history of GDM (282 European, 94 South Asian and 94 Afro-Caribbean) were studied. Post-partum glucose status and height were measured. RESULTS: European and South Asian women with previous GDM were shorter than control women from the same ethnic groups (European: (mean +/- SD) 162.9 +/- 6.1 vs. 165.3 +/- 6.8 cm, P < 0.0001; South Asian: 155.2 +/- 5.4 vs. 158.2 +/- 6.3 cm, P = 0.003, adjusted for age). A similar, but non-significant trend was observed among Afro-Caribbean women (162.2 +/- 6.2 vs. 163.7 +/- 6.1 cm, P = 0.1). Similar, significant height differences were observed in Europeans and South Asians when analysis was restricted to those GDM women who had received insulin during pregnancy. There was no association between height and glucose tolerance postpartum within the GDM group. CONCLUSIONS: European and South Asian women with previous GDM are shorter than control women from the same ethnic groups. The data demonstrate that this is unlikely to be an artefact resulting from the use of an fixed 75 g load in women of differing sizes, and suggest that there are likely to be common pathophysiological mechanisms underlying GDM and the determination of final adult height.

Implications of new diagnostic criteria for abnormal glucose homeostasis in women with previous gestational diabetes.

OBJECTIVE: To determine the consequences of applying revised American Diabetes Association (ADA) (1997) and World Health Organization (WHO) (1998) recommendations for the classification of glucose intolerance in women with previous gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: There were 192 women with previous GDM who took an oral glucose tolerance test (OGTT) 1-86 months after delivery and were classified by WHO (1985), ADA (1997, fasting glucose), and revised WHO (1998) guidelines. RESULTS: Among the 165 women without a preexisting diagnosis of diabetes, WHO-1985 and ADA-1997 provided similar estimates of diabetes prevalence (13.3% vs. 11.5%) but widely differing estimates of impaired glucose homeostasis (31.5% impaired glucose tolerance [IGT] by WHO-1985 vs. 10.9% impaired fasting glucose by ADA-1997 criteria). Overall, 56 women (34%) showed a classification discrepancy between WHO-1985 and ADA-1997 criteria, including 44 with normal fasting glucose by ADA-1997 criteria, but abnormal 2-h glucose by WHO-1985 criteria (40 IGT, 4 diabetes). The cardiovascular risk profile of these women was more favorable than that of 18 women with impaired fasting glucose. WHO-1998 recommendations reproduced ADA-1997 findings when used as a fasting screen, but behaved similarly to WHO-1985 criteria when 2-h glucose values were also analyzed. CONCLUSIONS: All criteria produced similar estimates of diabetes prevalence. However, analyses based on a single fasting glucose screen (and a threshold of 6.1 mmol/l) failed to identify 60% of women with abnormal 2-h glucose levels. Screening women with previous GDM (and by analogy, other groups at high risk of diabetes) with a single fasting glucose has low sensitivity for the detection of abnormal glucose tolerance. Recent guidelines recommending this approach require reevaluation.