Testosterone & Blood Sugar: Unveiling the Unexpected Connection
Objective: The Pursuit of Knowledge
To determine if the impact of testosterone treatment on glucose levels is mediated by changes in factors such as total fat mass, abdominal fat mass, skeletal muscle mass, non-dominant handgrip, estradiol (E2), and sex hormone-binding globulin (SHBG).
Design: Laying the Groundwork
A randomized placebo-controlled trial of testosterone was conducted using a mediation analysis approach.
Methods: The Engine of Discovery
Six Australian tertiary care facilities recruited 1007 males, aged between 50-74 years, having a waist circumference ≥ 95 cm, lower serum testosterone levels, and either impaired glucose tolerance or newly diagnosed type 2 diabetes. Participants underwent a lifestyle program and were given testosterone injections or a placebo for two years at 3-month intervals. Data were complete for 709 participants (70%). The primary outcomes of type 2 diabetes at 2-years were assessed by changes in fat mass, % abdominal fat, skeletal muscle mass, non-dominant hand-grip strength, estradiol, and SHBG.
Results: Bringing Clarity to Complexity
The odds ratio (OR) for treatment was 0.53 for type 2 diabetes at 2-years, which became 0.48 after adjusting for covariates. However, including potential mediators attenuated the treatment effect (OR 0.77; direct effect), with 65% being mediated. Fat mass was the only factor remaining prognostic in the full model (OR: 1.23). **An odds ratio typically represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure**
Conclusion: Where We Stand
Part of the testosterone treatment effect on glucose was mediated by changes in fat mass, abdominal fat, skeletal muscle mass, grip strength, SHBG, and E2, with fat mass being the most significant factor.
Kristy P Robledo and others, Mediation analysis of the testosterone treatment effect to prevent type 2 diabetes in the T4DM trial., European Journal of Endocrinology, 2023;, lvad074,
We have been asked by our colleagues if it's the Testosterone or the weight loss that has improved my cholesterol which staved off diabetes. . . and our answer is YES to both!!. Jason & Rita.
