Introduction:
Male patients with type 2 diabetes (T2D) have a high prevalence of low testosterone (LT) or metabolic syndrome (MetS). While LT or MetS are associated with arterial stiffness, few studies have investigated the effect of these conditions when manifested together. Our study was performed to explore the influence of coexistence of LT and MetS on arterial stiffness in male patients with T2DM.

Material and methods:
We recruited 332 male patients with T2D at the endocrine and metabolic clinic of the Taitung branch of the Mackay Memorial hospital. Subjects were divided according to the presence of LT or MetS as follows: normal (neither condition present), LT only, MetS only and the coexistence of LT and MetS. All enrolled subjects consecutively underwent brachial-ankle pulse wave velocity (PWV) to evaluate arterial stiffness.

Results:
Patients with LT have a higher prevalence of MetS than those without LT (80.1% vs. 64.2%; P=0.03). Age, weight, triglycerides and PWV were significantly higher in patients with coexisting LT and MetS than in the groups with LT or MetS alone. Multiple linear regression analysis was performed to demonstrate that PWV was significantly positively associated with age (P <0.001), SBP (P=0.002) and triglycerides (P=0.001) and negatively associated with testosterone (P=0.039). ANCOVA analysis revealed that PWV remained highest in patients with coexisting MetS and LT compared to the other groups, even after adjusting for confounding factors.

Conclusions:
In our study, the coexistence of MetS and LT was significantly associated with a high risk of increased arterial stiffness in male patients with T2D.