To determine if women with previous gestational diabetes mellitus (pGDM), a population at high risk for type 2 diabetes and metabolic syndrome (1), have signs of subclinical atherosclerosis, we measured carotid intimal-medial thickness (IMT) and multiple cardiovascular risk factors in 28 women with and 24 without pGDM (control group) 2 years after delivery. A 75-g 2-h oral glucose tolerance test was performed for assessment of glucose tolerance, area under the glucose curve (AUCgluc), insulin sensitivity index, homeostasis model assessment of insulin resistance (HOMA-IR), lipid profile, oxidized LDL (oxLDL), C-reactive protein (CRP), adiponectin, and fibrinogen. Family history, anthropometric parameters, and blood pressure were recorded. IMT was measured at four segments of the left and right common carotid artery and bulb level mean IMT values were calculated with the upper limit of normal set at 1.0 mm.
Positive family history of type 2 diabetes and cardiovascular disease were more frequent in subjects with pGDM than in control subjects (all P < 0.05). Subjects with pGDM were older (38.1 ± 4.1 vs. 34.2 ± 3.2 years) and had larger waist circumference (86.9 ± 9.7 vs. 79.6 ± 9.7 cm) and higher systolic (110.4 ± 12.7 vs. 103.7 ± 8.3 mmHg) and diastolic blood pressure (71.9 ± 8.1 vs. 66.6 ± 5.6 mmHg) (all P < 0.01) but had similar BMI (25.7 ± 8.9 vs. 23 ± 3.4 kg/m2). Only four women (three control, one with pGDM) were currently smoking. Based on the oral glucose tolerance test, nine women with pGDM had impaired glucose tolerance and/or impaired fasting glucose and all control subjects had normal glucose tolerance. Fasting plasma glucose (84.3 ± 9.6 vs. 79.5 ± 4.3 mg/dl), AUCgluc (873.5 ± 147.4 vs. 690.6 ± 114.4 mg/dl/min), and HOMA-IR (1.9 ± 1.08 vs. 1.39 ± 0.7) were all greater in subjects with pGDM (P < 0.05 or less), while insulin sensitivity index (6.4 ± 4 vs. 11.7 ± 10, P < 0.01) and adiponectin concentrations (3.54 ± 1.7 vs. 4.71 ± 1.8 μg/ml, P < 0.04) were lower. Serum triglycerides (91.28 ± 67 vs. 62.7 ± 21 mg/dl), oxLDL (58.54 ± 15 vs. 44.06 ± 9.8 units/l), fibrinogen (356.7 ± 69 vs. 298.4 ± 60 mg/dl), and CRP (1.7 ± 1.7. vs. 0.8 ± 0.92 mg/l) were all increased in subjects with pGDM (P < 0.05).
Mean common carotid IMT (CC-IMT) was higher in subjects with pGDM than in control subjects (0.57 ± 0.058 vs. 0.51 ± 0.051 mm, P < 0.01); no difference was observed at bulb level. On simple regression analysis, CC-IMT was related with age, BMI, waist circumference, systolic and diastolic blood pressure, HOMA-IR, AUCgluc, oxLDL, and CRP and inversely related with adiponectin. However, when these variables were introduced in a multiple regression analysis, only oxLDL remained significantly associated with CC-IMT.
In conclusion, the increased carotid IMT, a marker of preclinical atherosclerosis (2), shows that young women with pGDM have an early sign of vessel involvement, although within the upper limit of normal. These alterations were present in spite of the fact that no woman had diabetes, only one met the criteria for metabolic syndrome, and no difference was apparent in BMI between the two groups. Although increased IMT can be supported by multiple metabolic alterations, interestingly, on multiple regression analysis, only the levels of oxLDL remained independent predictors.
