Effect of Testosterone Therapy Combined with a Very Low Caloric Diet on Fat Mass in Obese Men with a Low- to Low-Normal Testosterone Level: A Randomized Controlled Trial

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 134-160-Male Reproductive Endocrinology and Male Reproductive Tract (posters)
Bench to Bedside
Saturday, April 2, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SAT 158
Mark Ng Tang Fui*1, Rudolf Hoermann1, Philippe Dupuis2, Manjri Raval1, Jeffrey D Zajac1 and Mathis Grossmann1
1The University of Melbourne, Heidelberg, Australia, 2Department of Medicine Austin Health, University of Melbourne, Sainte-Foy, QC, Canada
Effect of Testosterone Therapy Combined with a Very Low Caloric Diet on Fat Mass in Obese Men with a Low- to Low-Normal Testosterone Level: A Randomized Controlled Trial

Context

In men, obesity is strongly associated with low testosterone levels. Weight loss due to caloric restriction is associated with increases in circulating testosterone, and testosterone treatment reduces fat mass. However, whether combining testosterone treatment with caloric restriction reduces fat mass more so than caloric restriction alone is not known.

Objective

We hypothesised that testosterone treatment will reduce body fat mass more so than caloric restriction alone.

Design, setting and participants
We conducted a 56-week double-blind randomised placebo-controlled trial at a tertiary referral centre.  We recruited 100 obese men (BMI > 30 kg/m2) aged 18-75 years with a low- to low-normal serum total testosterone level (average of 2 consecutive morning fasting levels of <12nmol/L [<346ng/dL]).

Intervention

All men underwent a weight-loss phase with a very low-calorie diet (providing approximately 600 kcal/ d) for 10 weeks followed by reinstitution of normal foods with the aim of weight maintenance for the next 46 weeks.  In addition, men were randomised in a concealed 1:1 allocation to receive 10-weekly intramuscular 1000 mg testosterone undecanoate or placebo injections for the 56-week duration of the study. 

Main outcome measures:

The primary outcome was fat mass measured by DEXA. Secondary outcomes were visceral fat mass by abdominal CT and lean body mass by DEXA.

Results

Baseline characteristics of the 100 men were as follows: median [interquartile range] age 53.2 y [47.4-59.9y], BMI 37.4 kg/m2 [34.7-41.2kg/m2], fat mass 45.1kg [37.8-51.9kg] and total testosterone 7.1nmol/L [6.1-8.2nmol/L] (204ng/dL [175-237ng/dL]) by LCMS-MS. The study will be completed by November 2015 and results will be reported at the meeting

Conclusions

There is an epidemic of obesity and related functional hypogonadism yet testosterone treatment remains controversial.  This trial will assess whether in middle-aged obese men with a low to low-normal testosterone, testosterone treatment has fat lowering effects beyond that achieved by caloric restriction alone.

Nothing to Disclose: MN, RH, PD, MR, JDZ, MG

*Please take note of The Endocrine Society's News Embargo Policy at https://www.endocrine.org/news-room/endo-annual-meeting/pr-resources-for-endo

Sources of Research Support: MNTF was supported by a postgraduate scholarship (1055305) and MG by a Career Development Fellowship (1024139) both from the National Health and Medical Research Council (Australia). Bayer Pharma AG (Berlin, Germany) provided testosterone, placebo and financial support to conduct investigations, but had no role in trial design, data analysis or writing the manuscript.