Association between impaired glucose tolerance and carotid atherosclerosis: a study in 64-year-old women and a meta-analysis.

BACKGROUND AND AIMS: Impaired glucose tolerance (IGT) is regarded as a transient metabolic state leading to type-2 diabetes, and is known to predict future risk of cardiovascular disease. This study was designed to investigate if IGT is associated with subclinical atherosclerosis. METHODS AND RESULTS: In a population-based cohort of 64-year-old women, a group with IGT determined by repeated oral glucose tolerance tests (n=205) was compared with healthy women with normal glucose tolerance (NGT, n=188). Intima-media thickness (IMT) and plaques in the common carotid arteries (CCA) and bulbs were measured by ultrasound. The 95% confidence interval (CI) of the difference between the IGT and NGT groups was -0.03 to 0.03mm. There was no difference in carotid bulb IMT or in the occurrence, size, and characteristics of plaques between the IGT and NGT groups. A meta-analysis was used to calculate summary measures of 12 reviewed studies showing a difference of 0.030 (95% CI 0.012-0.048) mm in carotid IMT between IGT and NGT groups. Heterogeneity in IMT differences between studies was shown. CONCLUSIONS: In our population-based cohort of 64-year-old women, IGT was not associated with increased occurrence of subclinical atherosclerosis. However, a meta-analysis of 12 studies, including our current study, showed that IGT was associated with a small increase in the CCA IMT.

Are serum adiponectin concentrations in a population sample of 64-year-old Caucasian women with varying glucose tolerance associated with ultrasound-assessed atherosclerosis?

OBJECTIVE: To examine whether serum adiponectin concentrations were associated with subclinical atherosclerosis assessed as intima media thickness (IMT) in the carotid arteries in Caucasian women with varying degrees of glucose tolerance. RESEARCH DESIGN AND METHODS: From a population-based cohort of 64-year-old Swedish women, 533 subjects with type 2 diabetes (DM2, n=177), impaired glucose tolerance (IGT; n=178) or normal glucose tolerance (NGT, n=178) were recruited. Anthropometrics, usual cardiovascular risk factors were examined and ultrasound examination of the carotid arteries was performed. RESULTS: Women with low adiponectin concentrations were characterized by thick IMT, higher prevalence of DM2, history of previous myocardial infarction, angina pectoris, anti-hypertensive treatment and high body mass index (BMI), waist circumference, plasma insulin, serum triglycerides, fasting glucose, HbA1c, and low serum HDL cholesterol levels. Carotid IMT correlated with HbA1c (r=0.24, P<0.001), waist circumference (r=0.22, P<0.001), plasma insulin (r=0.19, P<0.001), BMI (r=0.18, P<0.001), DM2 (r=0.16, P<0.001), systolic blood pressure (r=0.16, P<0.001), blood glucose (r=0.16, P<0.001), triglycerides (r=0.15, P<0.001), and reversely to adiponectin (r=-0.11, P=0.01), HDL cholesterol (r=-0.13, P=0.004), and alcohol intake (r=-0.087, P<0.05). A more detailed analysis of underlying associations was difficult due to a high co-linearity between these variable. CONCLUSIONS: Low serum adiponectin concentrations were associated with increased carotid artery IMT, and several risk factors for cardiovascular diseases, mainly those constituting the metabolic syndrome.

Carotid artery intima-media thickness in patients with Type 2 diabetes mellitus and impaired glucose tolerance: a systematic review.

AIMS: To review the difference in carotid artery intima media thickness (IMT) between patients with Type 2 diabetes (DM) or impaired glucose tolerance (IGT), and control subjects. METHODS: Systematic reviews were made in order to identify cross-sectional studies using the ultrasound method. The differences between IMT in DM or IGT and control subjects were calculated. Meta-analysis using random-effects modelling was used to calculate summary measures. RESULTS: Twenty-three studies included 24,111 subjects; 4019 with DM and 1110 with IGT. In 20 of 21 studies, the diabetic patients had greater carotid artery IMT than the subjects in the control groups. The estimated mean difference in IMT was 0.13 (95% CI: 0.12-0.14) mm. Heterogeneity was observed and likely sources of variation were study size, diabetes duration, and ultrasound method. In three out of nine studies, the IGT patients had significant greater carotid artery IMT than the subjects in the control groups. The estimated mean difference in IMT was 0.04 (95% CI: 0.014-0.071) mm. CONCLUSIONS: Type 2 diabetes was associated with an 0.13 mm increase in IMT compared with control subjects. In patients with IGT, the increase in IMT was about one-third of that observed in diabetes. The observed difference in IMT can be interpreted as if the diabetes patients were more than 10 years older than the control groups, and that the relative risks of myocardial infarction and stroke were increased by almost 40%, respectively.