Study on serum free testosterone level and its relevant factors in adult male patients with type 2 diabetes mellitus

Abstract:

Objective: To evaluate the level of serum free testosterone (FT) and to investigate the relevant factors of FT in male patients with type 2 diabetes mellitus (T2DM) . Methods: A retrospective study was conducted on 303 male patients with T2DM aged between 18-70 years and another age-matched 303 healthy individuals were selected as controls. We compared the difference of demographic and clinical indicators in different FT levels. According to the serum FT level, T2DM patients were divided into Q1 group, Q2 group,Q3 group and Q4 group by quartile method. Spearman rank correlation analysis and logistic regression analysis was conducted to analyze the revalent factors of the decrease of serum FT in T2DM patients. Results: The level of serum FT in men with T2DM was significantly lower than that in control group, and decreased with age. Spearman rank correlation analysis showed that FT was negatively correlated with age (r=-0.402, P<0.001) , BMI (r=0.215, P=0.001) , duration of diabetes (r=-0.121, P=0.035) , and positively correlated with total cholesterol (TC) (r=0.115, P=0.049) , 25- (OH) D₃ (r=0.340, P<0.001) , and thyroid-stimulating hormone (TSH) (r=0.231, P=0.025) . Multivariate logistic regression analysis showed that after adjustment for age, distribution, history of diabetes, smoking and alcohol consumption, high BMI (OR=1.101, 95%CI=1.023-1.183, P=0.009) , high HbA1c (OR=1.175, 95%CI=1.060-1.302, P=0.002) , low 25- (OH) D₃ (OR=0.937, 95%CI=0.900-0.975, P=0.001) , and low TSH (OR=0.838, 95%CI=0.710-0.989, P=0.037) were closely related to low FT level. Conclusion: T2DM patients have lower level of FT than healthy men and the low of serum FT level may be related to high BMI, high HbA1c, low 25- (OH) D₃and low TSH.