Vascular disease risk in type 2 diabetes: high sugars, fluctuating sugars, both?

Abstract

Optimal glucose control is important for the prevention of the microvascular complications in type 1 and type 2 diabetes (T2D). Although hyperglycemia is associated with oxidative stress, studies in adults have demonstrated that increased blood glucose variability can magnify this effect and may be as important or potentially, even more important, than the degree of blood glucose control in increasing the risk of microvascular and macrovascular disease. As the TODAY study demonstrated, youth with T2D have earlier appearance and more rapid progression of complications than do adults with T2D; it is important to determine if adolescents have the same effect of glycemic variability on oxidative stress as do adults. In this issue of The Journal, Dasari et al evaluated the mean amplitude of glycemic excursion (MAGE) using continuous glucose monitoring in normal weight (n = 12), normoglycemic obese (n = 10), and adolescents with T2D (n = 12). The authors quantified MAGE and counted the number of glucose excursions, calculating the mean and standard deviation for each set of glucose values. All subjects wore a continuous glucose monitor and step activity monitor for 5 days. Markers of oxidative stress were correlated with MAGE, with oxidized low density lipoprotein, an inflammatory marker of atherosclerotic risk, having the highest correlation. Traditional cardiovascular risk factors moderately to strongly associated with MAGE were body mass index, body fat, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, C-reactive protein, and nonesterified fatty acids. The vascular inflammatory biomarkers, E-selectin and intercellular adhesion molecule 1, also correlated with MAGE. This study demonstrates the significance of glycemic variability in inducing oxidative stress in youth with T2D. Although diabetologists typically have patients measure blood glucose values before meals, at bedtime, and occasionally at 2:00 a.m., glycemic variability is not assessed routinely. Pre- and postprandial blood glucose concentrations are usually measured only when adjusting insulin doses in an effort to improve glycemic control. Because this study indicates that glycemic variability is at least as important as blood glucose concentrations as a risk for endothelial dysfunction, clinicians should consider asking patients to monitor both pre- and postprandial blood glucose levels routinely and to adjust bolus insulin doses to attempt to minimize pre- and postprandial glucose excursions. Article page 47▶ Glycemic Variability Is Associated with Markers of Vascular Stress in AdolescentsThe Journal of PediatricsVol. 172PreviewWe used continuous glucose monitoring to test the hypothesis that mean amplitude of glycemic excursions (MAGE) is associated with circulating markers of oxidative and vascular stress in adolescents with habitually low physical activity classified as healthy weight, healthy obese, or obese with type 2 diabetes mellitus (T2DM). Full-Text PDF