title: Low testosterone levels are common and associated with insulin resistance in men with diabetes.
abstract: BACKGROUND
  Low testosterone levels are common in men with type 2 diabetes and may be associated with insulin resistance.
  
  
  OBJECTIVE
  We investigated prevalence of testosterone deficiency and the relationship between testosterone and insulin resistance in a large cohort of men with type 2 and type 1 diabetes.
  
  
  METHODS
  The study was a cross-sectional survey of 580 men with type 2 diabetes and 69 men with type 1 diabetes. A subgroup of 262 men with type 2 diabetes was then reassessed after a median of 6 months.
  
  
  RESULTS
  Forty-three percent of men with type 2 diabetes had a reduced total testosterone, and 57% had a reduced calculated free testosterone. Only 7% of men with type 1 diabetes had low total testosterone. By contrast, 20.3% of men with type 1 diabetes had low calculated free testosterone, similar to that observed in type 2 diabetes (age-body mass index adjusted odds ratio = 1.4; 95% confidence interval = 0.7-2.9). Low testosterone levels were independently associated with insulin resistance in men with type 1 diabetes as well as type 2 diabetes. Serial measurements also revealed an inverse relationship between changes in testosterone levels and insulin resistance.
  
  
  CONCLUSIONS
  Testosterone deficiency is common in men with diabetes, regardless of the type. Testosterone levels are partly influenced by insulin resistance, which may represent an important avenue for intervention, whereas the utility of testosterone replacement remains to be established in prospective trials.
authors.affiliation: Department of Endocrinology and Medicine, University of Melbourne, Austin Health, Studley Road, Heidelberg, Victoria 3084, Australia. mathisg@unimelb.edu.au
authors.forename: Mathis
authors.initials: M
authors.lastname: Grossmann
authors.forename: Merlin C
authors.initials: MC
authors.lastname: Thomas
authors.forename: Sianna
authors.initials: S
authors.lastname: Panagiotopoulos
authors.forename: Ken
authors.initials: K
authors.lastname: Sharpe
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Macisaac
authors.forename: Sophie
authors.initials: S
authors.lastname: Clarke
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Zajac
authors.forename: George
authors.initials: G
authors.lastname: Jerums
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013739:Testosterone / Q000097:blood* / Q000172:deficiency
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone