Comparison of serum free testosterone, luteinizing hormone and follicle stimulating hormone levels in diabetics and non-diabetics men- a case-control study.

BACKGROUND Diabetic men have been claimed to have lower serum free testosterone (FT) concentrations than non-diabetic men. The aim of this study was to investigate if serum FT, luteinizing hormone (LH), and follicle stimulating hormone (FSH) concentrations are different in patients with type 2 diabetes mellitus compared with healthy men and to identify factors associated with low serum testosterone concentrations in men with type 2 diabetes. METHODS Serum FT, LH and FSH concentrations in 65 men with type 2 diabetes between 50 and 55 years compared with 65 non-diabetic men in Valye-Asr Hospital in Birjand, Iran during October 2009 to August 2010. In addition, the relationships between serum FT concentrations with LH and FSH concentrations as well as other factors including age, fast blood sugar and glycemic control (HbA1C) were investigated. RESULTS Serum FT concentrations were significantly lower in type 2 diabetic patients (2.53±1.68 pg/ml) than in healthy men (4.29±2.43 pg/ml) (P<0.001). There were not any significant differences in LH and FSH concentrations between the two groups. There was a significant negative relationship between serum FT and HbA1C, but this relation for LH and FSH was positive and non-significant (P<0.001). CONCLUSION Serum FT concentration is lower in type 2 diabetic patients compared with non-diabetic men suggesting further research to better understand the underlying biologic mechanisms.