The evidence of a close relationship between cardiovascular disease and erectile dysfunction (ED) is well documented. The aim of this study is to investigate whether there is an early asymptomatic impairment of the peripheral vasculature in young ED patients without obvious cardiovascular disease. We studied a total of 261 ED patients (19-40 years old) and 40 age-matched healthy controls. All participants received questionnaires of cardiovascular risk factors and erectile function assessment, were subjected to lab tests of fasting blood sample, and underwent the ultrasonographic examination of brachial artery flow-mediated dilation (FMD) and carotid intima-media thickness (c-IMT). Insulin resistance (IR) was measured by the homeostasis model assessment of insulin resistance (HOMA-IR). Compared with normal human controls, FMD was significantly lower, whereas the average c-IMT was significantly greater in ED patients. An inverse correlation was found between FMD and mean c-IMT. The ED patients had significantly higher levels of fasting glucose, fasting insulin and HOMA-IR index, but showed relatively lower total testosterone and prolactin levels than the controls. Both FMD and c-IMT showed a significant correlation with International Index of Erectile Function-5 questionnaire (IIEF-5) score, age and HOMA-IR. Multivariate stepwise regression analysis demonstrated that age, HOMA-IR and IIEF-5 score were the risk factors associated with FMD and c-IMT. In conclusion, young ED patients in association with IR display diminished FMD and increased c-IMT. Furthermore, ED, HOMA-IR and age are independent predictors of the two subclinical atherosclerotic markers.

Underlying endothelial dysfunction (EnD) may present in the early stage of ED or psychogenic ED. We retrospectively evaluated 191 ED patients with effective nocturnal penile tumescence and rigidity (NPTR) recording, including detailed medical and psychosexual history, International Index of Erectile Function-5 and vascular parameter. All patients were allocated into psychogenic and organic groups according to the NPTR test. Brachial artery flow-mediated dilation (FMD) was used to diagnose EnD, and ED patients were classified into two groups: non-EnD (FMDX10) and EnD (FMDo10). General and vascular parameters were compared between psychogenic and organic groups, and non-EnD and EnD groups with ED were compared in terms of NPTR parameters. In all, 48.7% and 51.3% patients were diagnosed as psychogenic and organic ED, respectively. 73.1% of the psychogenic patients had EnD and 39.8% organic patients had normal endothelial function. In all parameters, only the FMD value showed significant difference between psychogenic and organic ED groups (8.26±2.57 vs 9.16±2.76, P ¼ 0.020). No statistical difference was founded in NPTR parameters between non-EnD and EnD groups (P40.05). In conclusion, NPTR cannot effectively identify the underlying vasculogenic ED from psychogenic ED. Psychogenic causes may cause or aggravate EnD in these ED patients with normal NPTR.