title: Low testosterone in men predicts impaired arterial elasticity and microvascular function.
abstract: BACKGROUND
  A low testosterone level in men is associated with increased adiposity, insulin resistance, and dyslipidemia. Whether low testosterone level is associated with arterial stiffness and endothelial and microvascular dysfunction remains unknown and was investigated in this study.
  
  
  METHODS
  Serum testosterone was measured in 237 healthy men aged 50 years (SD 12). Endothelial and microvascular function were assessed as brachial artery flow-mediated dilation (FMD) and digital reactive hyperemia index (RHI), respectively. Arterial stiffness was evaluated by tonometry-derived pulse wave velocity (PWV) and central augmentation index (AIX).
  
  
  RESULTS
  Mean total testosterone level was 16.3 nmol/L (SD 6.11) and 25% of subjects had low levels (<12.0 nmol/L). Testosterone level correlated positively with RHI (r=0.24, p<0.001) and inversely with AIX (r=-0.14, p=0.033) but not with FMD or PWV, indicating impaired microvascular hyperemia and arterial elasticity with lower testosterone levels. After multivariate adjustment for the Framingham Risk Score and weight, testosterone level remained an independent predictor of RHI and AIX (β=0.23, -0.13; p=0.001, 0.04, respectively).
  
  
  CONCLUSIONS
  In men with few co-morbidities, lower serum testosterone level is associated with microvascular dysfunction and increased pulse wave reflections, mechanisms by which lower testosterone levels may confer increased cardiovascular risk. Whether normalization of low testosterone level improves vascular function needs further investigation.
authors.affiliation: Emory University School of Medicine, Department of Medicine, Division of Cardiology, Atlanta, GA, USA. Electronic address: fcorrig@emory.edu.
authors.forename: Frank E
authors.initials: FE
authors.lastname: Corrigan
authors.affiliation: Emory University School of Medicine, Department of Medicine, Division of Cardiology, Atlanta, GA, USA.
authors.forename: Ibhar
authors.initials: I
authors.lastname: Al Mheid
authors.affiliation: Emory University School of Medicine, Department of Medicine, Division of Cardiology, Atlanta, GA, USA.
authors.forename: Danny J
authors.initials: DJ
authors.lastname: Eapen
authors.affiliation: Emory University School of Medicine, Department of Medicine, Division of Cardiology, Atlanta, GA, USA.
authors.forename: Salim S
authors.initials: SS
authors.lastname: Hayek
authors.affiliation: Emory University School of Medicine, Department of Medicine, Division of Cardiology, Atlanta, GA, USA; Emory-Georgia Tech Predictive Health Institute, Atlanta, GA, USA.
authors.forename: Salman
authors.initials: S
authors.lastname: Sher
authors.affiliation: Emory-Georgia Tech Predictive Health Institute, Atlanta, GA, USA; Emory University School of Medicine, Department of Medicine, Division of Pulmonary and Critical Care Medicine, Atlanta, GA, USA.
authors.forename: Greg S
authors.initials: GS
authors.lastname: Martin
authors.affiliation: Emory University School of Medicine, Department of Medicine, Division of Cardiology, Atlanta, GA, USA; Emory-Georgia Tech Predictive Health Institute, Atlanta, GA, USA.
authors.forename: Arshed A
authors.initials: AA
authors.lastname: Quyyumi
mesh_terms: D000328:Adult; D001741:Black or African American / Q000208:ethnology; D002318:Cardiovascular Diseases / Q000097:blood / Q000208:ethnology; D004548:Elasticity; D006801:Humans; D008297:Male; D055806:Microvessels / Q000502:physiology*; D008875:Middle Aged; D012307:Risk Factors; D013739:Testosterone / Q000097:blood*; D059289:Vascular Stiffness / Q000502:physiology*; D044465:White People / Q000208:ethnology
chemical_list: D013739:Testosterone
keywords: Arterial stiffness; Reactive hyperemia index; Testosterone