To examine influence of insulin resistance and other clinical risk factors for the MetS (metabolic syndrome) on vascular structure and function in young adults. This cross-sectional study was conducted in a cohort of young adults (mean age 22 years) and their siblings participating in a longitudinal study of cardiovascular risk ( n =370). Insulin sensitivity was determined by euglycaemic insulin clamp. EDD (endothelium-dependent dilation) was determined by flow-mediated dilation using high-resolution ultrasound imaging of the brachial artery. EID (endothelium-independent dilation) was determined by NTG (nitroglycerine)-mediated dilation. The diameter and cIMT (intima–media thickness) of the carotid artery were also measured. There was no significant difference between males and females for age or body mass index. However, males had significantly higher glucose and triacylglycerol (triglyceride) levels, while the females had significantly higher HDL-C (high-density lipoprotein-cholesterol) and insulin sensitivity (13.00±0.33 compared with 10.71±0.31 mg·kg −1 of lean body mass·min −1 , P <0.0001). Although peak EDD was significantly lower (6.28±0.26 compared with 8.50±0.28%, P <0.0001) in males than females, this difference was largely explained by adjustment for brachial artery diameter ( P =0.15). Peak EID also was significantly lower in males than females (20.26±0.44 compared with 28.64±0.47%, P <0.0001), a difference that remained significantly lower after adjustment for brachial artery diameter. Males had a significantly greater cIMT compared with females (females 0.420±0.004 compared with males 0.444±0.004 mm, P =0.01), but when adjusted for carotid diameter, there was no significant difference ( P =0.163). Although there were gender differences in vascular function and structure in the young adult population examined in this study, many of the differences were eliminated simply by adjusting for artery diameter. However, the lower EID observed in males could not be explained by artery diameter. Future studies need to continue to examine influence of gender on EID and other measures of vascular function.

The aim of the present study was to investigate the impact of acute hyperglycaemia on endothelial function in both normal-weight and overweight children. A total of 16 overweight [BMI (body mass index) ≥85th percentile] and 15 normal-weight (BMI <85th percentile) children were evaluated for FMD (flow-mediated dilation) at baseline and 30, 60 and 120 min after glucose ingestion. At 15 min following the measurement of the final FMD, 0.3 mg of sublingual nitroglycerine was administered and the brachial artery was imaged in order to assess endothelium-independent dilation. By design, the overweight children were significantly heavier (63.2±4.6 compared with 41.3±2.5 kg; P =0.0003) and had a greater percentage body fat (43.9±1.8 compared with 23.8±2.05%; P <0.0001) than the normal-weight children. The area under the curve in response to glucose administration was significantly ( P <0.0001) greater in the overweight group for both glucose and insulin. The FMD area under the curve was not significantly different at baseline or between time points after glucose ingestion, nor was there a difference in response between the two groups. Endothelium-independent dilation in the normal-weight group was significantly greater compared with the overweight group (26.7±1.6 compared with 20.2±2.0% respectively; P =0.019). In conclusion, these results suggest that acute elevation of glucose and insulin in overweight and normal-weight children are not associated with impairment in endothelial function.