Low testosterone levels are common and associated with insulin resistance in men with diabetes.
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.
Grossmann
Mathis
M
Department of Endocrinology and Medicine, University of Melbourne, Austin Health, Studley Road, Heidelberg, Victoria 3084, Australia. mathisg@unimelb.edu.au
Thomas
Merlin C
MC
Panagiotopoulos
Sianna
S
Sharpe
Ken
K
Macisaac
Richard J
RJ
Clarke
Sophie
S
Zajac
Jeffrey D
JD
Jerums
George
G
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
D012738:Sex Hormone-Binding Globulin; D013739:Testosterone