Inverse Association Between Serum Testosterone and Glycaemic Control in Men with Type 2 Diabetes Mellitus: A Hospital-Based Cross-Sectional Study.
Background: Testosterone deficiency is an increasingly recognised but under-investigated complication of type 2 diabetes mellitus (T2DM), arising from a bidirectional interplay between insulin resistance, visceral adiposity and suppression of the hypothalamic–pituitary–gonadal axis. Population-specific data on how closely testosterone tracks glycaemic control remain limited, particularly in Indian tertiary-care settings. We examined the association between serum total testosterone and glycaemic control, and assessed the impact of glycaemic status on testosterone, in men with T2DM. Methods: In this single-centre, hospital-based cross-sectional study, 150 men aged above 18 years with T2DM were enrolled by simple random sampling from outpatient and inpatient services. Fasting serum total testosterone, HbA1c, fasting blood glucose, lipid profile and anthropometric measures were assessed. Associations were tested using Pearson correlation, one-way ANOVA, the independent-samples t test and the chi-square test, with p < 0.05 considered significant. Results: Mean age was 53.1 ± 13.3 years, mean HbA1c 8.31 ± 1.22%, and mean serum total testosterone 421.3 ± 212.1 ng/dL; hypogonadism was present in 47.3% of participants. Serum testosterone correlated inversely with HbA1c (r = −0.53, 95% CI −0.63 to −0.40; p < 0.0001), independent of age, body mass index, diabetes duration and total cholesterol. Testosterone declined stepwise across worsening glycaemic strata, from 599.3 ng/dL in optimal control to 285.9 ng/dL in very poor control (ANOVA F = 22.49, p < 0.0001), with hypogonadism prevalence rising from 18.8% to 78.6%. Hypogonadal men had significantly higher HbA1c and fasting glucose than eugonadal men (both p < 0.0001), and hypogonadism was strongly associated with glycaemic-control category (χ² = 30.67, p < 0.0001). Conclusions: Lower serum testosterone is robustly and independently associated with poorer glycaemic control in men with T2DM, with hypogonadism concentrated among the most poorly controlled patients. These findings support routine androgen screening in diabetic men with suboptimal glycaemic control.