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.