Oral Presentation The Joint Annual Scientific Meetings of the Endocrine Society of Australia and the Society for Reproductive Biology 2017

The effects of testosterone treatment on body composition in obese men are not sustained after cessation of therapy (#59)

Mark Ng Tang Fui 1 2 , Rudolf Hoermann 2 , Jeffrey D Zajac 1 2 , Mathis Grossmann 1 2
  1. Austin Health, Heidelberg, Victoria, Australia
  2. Medicine, University of Melbourne, Heidelberg, Victoria, Australia

Background:Testosterone treatment in obese dieting men augments the diet-associated loss of fat mass, but protects against loss of lean mass. We assessed whether body composition changes are maintained following withdrawal of testosterone treatment

Methods:We conducted a pre-specified double-blind randomised placebo-controlled observational follow-up study of a randomized controlled trial (RCT).Participants were men with baseline obesity (body mass index >30kg/m2) and a repeated total testosterone level <12nmol/L,previously enrolled in a 56-week testosterone-treatment trial combined with a weight loss program.Main outcome measures weremean adjusted differences (MAD) (95% confidence interval), in body composition between testosterone and placebo-treated men at the end ofthe observation period.

Results:Of the 100 randomised men, 82 completed the RCT, and 64 the subsequent observational study. Median[IQR] observation time after completion of the RCT was 82 weeks [74; 90]in men previously receiving testosterone (cases) and 81 weeks [67; 91]in men previously receiving placebo (controls), p=0.51. At end of the observation period, circulating total testosterone levels were no different between cases and controls, MAD -0.4nmol/L (-2.5, 1.7) p=0.71. Similarly, there were no between group differences in fat mass,MAD
-0.8kg,  (-3.6, 2.0), p=1.0, in lean mass, MAD-1.3kg (-3.0, 0.5), p=0.39, and in appendicular lean mass, MAD-0.1kg/m2 (-0.3, 0.1), p=0.45. During observation, cases lost more lean mass, MAD-3.7kg (-5.5, -1.9), p=0.0005 and appendicular lean mass, MAD-0.5kg/m2 (-0.8, -0.3), p<0.0001 compared to controls.

Conclusions:The favourable effects of testosterone therapy on body composition in men subjected to a concomitant weight loss program were not maintained at 82 weeks after treatment cessation.