Testosterone and modifiable risk factors associated with diabetes in men

Objective: The role of endogenous testosterone in the pathogenesis of type 2 diabetes mellitus remains vague. We investigated whether associations between endogenous testosterone and diabetes prevalence in men could be partially explained by modifiable risk factors. Study design: A random population-based cross-sectional study of 1195 men aged 35-80 years living in the north-west regions of Adelaide, Australia. Data collections occurred between 2002 and 2005, and response rate was 45.1%. Materials and methods: Diabetes (non-specific) was classified by either: (1) self-report for doctor diagnosis of diabetes; (2) prescription medication for diabetes; (3) fasting plasma glucose ≥7 mmol/L; or (4) glycosylated haemoglobin ≥6.2%. Logistic regressions were used to estimate odds ratios (OR [with 95% confidence intervals]) for diabetes, with stepwise adjustments for demographic, lifestyle, and clinical factors. Results: Diabetes prevalence was positively associated with age groups 45-54 years (2.8 [1.4, 5.8]), 55-64 years (3.9 [1.9, 8.3]) and ≥65 years (4.0 [1.8, 8.9]), lowest income group (1.8 [1.0, 3.4]), ex-smoker (1.8 [1.2, 2.9]), lowest (3.2 [1.9, 5.5]) and middle (1.9 [1.1, 3.4]) alcohol tertiles, cardiovascular disease (1.9 [1.2, 2.8]), metabolic syndrome (4.0 [2.6, 6.1]), and lowest plasma total testosterone tertile (1.8 [1.1, 3.0]), but negatively associated with middle (0.5 [0.3, 0.8]) and highest (0.4 [0.3, 0.7]) sugar intake tertiles, arthritis (0.6 [0.3, 1.0]), and elevated LDL cholesterol (0.5 [0.3, 0.8]); ORs showed an inverted 'U' shape for middle and highest voiding lower urinary tract symptoms tertiles. Body composition, muscle strength, and cardio-metabolic factors partially explained the association between low plasma total testosterone and diabetes. Conclusions: Plasma total testosterone was inversely and independently associated with diabetes prevalence, that might have been partially explained by several modifiable risk factors.