Aim of the study was to investigate the effects of testosterone replacement therapy on components of metabolic syndrome, vascular function and morphology, grade of non-alcoholic fatty liver disease (NAFLD), bone mineral density (BMD) and health-related quality of life.

Studies have shown that approximately 50 % of older obese males, who are being treated for diabetes mellitus type 2, also exhibit low testosterone levels. Hypogonadism negatively affects glycemic control, exacerbates early cardio-vascular disease, causes osteoporosis, erectile disfunction, reduces lean body mass, accelerates the accumulation of visceral fat and leads to obesity.

Patients with diabetes mellitus type 2 and confirmed hypogonadism were enrolled into this randomized, double-blind, placebo-controlled clinical study. Placebo group patients were receiving placebo throughout the first year of this study and Testosterone group patients were receiving testosterone undecanoate during first year. Both groups were receiving testosterone undecanoate throughout the second year of this study.

Inclusion Criteria:

• men aged > 35 years
• body mass index > 30 kg/m2
• confirmed hypogonadism
• type 2 diabetes mellitus treated with non-insulin therapy

Exclusion Criteria:

• previously treated hypogonadism
• the 2 diabetes mellitus treated with insulin therapy
• a history of current prostate or breast cancer
• severe benign prostatic hyperplasia
• elevated prostate-specific antigen (PSA > 4.0 lg/l)
• severe heart failure
• acute coronary event or procedure during the six months leading up to the study
• chronic obstructive lung disease
• hypothyroidism
• severe obstructive sleep apnea (OSA)
• active infection
• rheumatoid arthritis