The prevalence and the risk factors of testosterone deficiency in newly diagnosed and previously known type 2 diabetic men

Introduction: While the epidemiology of testosterone deficiency has been well described in men with previously known type 2 diabetes mellitus (T2DM), it was less reported in those with untreated, newly diagnosed T2DM.

Aim: The aim of this study was to investigate the prevalence and the risk factors of testosterone deficiency of men with newly diagnosed T2DM.

Methods: The cross-sectional study included 105 men (mean age: 61.2 ± 6.8 years) with previously known T2DM and another 81 (57.8 ± 8.8 years) with newly diagnosed T2DM. All received health checkup and sex hormone measurement at our institute in 2009.

Main outcome measures: We calculated the prevalence and explored the risk factors of low total (<300 ng/dL) and free (<6 ng/dL) testosterone in men with newly diagnosed and previously known T2DM.

Results: Men with previously known T2DM were older and had higher diastolic pressure and greater fasting glucose. There was no significant difference in total (358.0 [155.0] ng/dL vs. 363.0 [154.0] ng/dL, P=0.68) and free (7.2 [2.5] ng/dL vs. 7.4 [2.4]ng/dL, P=0.84) testosterone and sex-hormone binding globulin (SHBG) (27.3 [22.3]nmol/L vs. 28.7 [14.9]nmol/L, P=0.46). The prevalence of low total and free testosterone was 28.4% and 21.0%, respectively, in men with newly diagnosed T2DM, and was 26.7% and 19.0% in those with previously known T2DM. In men with previously known T2DM, better glycemic control (HbA1c <7%) was associated with a higher level of total testosterone and a lower risk of low total testosterone. Men with newly diagnosed and previously known T2DM shared similar risk factors of low total testosterone, including high HbA1c (≥ 7%), low SHBG (<20 nmol/L), obesity, hyperuricemia, hypertriglycemia, and metabolic syndrome. Elevated prostate-specific antigen was a protective factor of low total testosterone. However, none of these factors was associated with low free testosterone.

Conclusions: The prevalence and the risk factors of testosterone deficiency are similar between newly diagnosed and previously known type 2 diabetic men.