Print this page 
Testosterone Replacement Therapy in obese men
Summary
We are conducting studies of testosterone therapy in middle-aged and older men with an emphasis on its effects on visceral adiposity and markers of cardiovascular risk.
Description
We are conducting a major clinical study in the field of testosterone and the male ageing under the auspices of the Southern Health Human Ethics and Research Committee which is entitled "A 12-month Randomised, Placebo-controlled Trial of Testosterone Replacement Therapy and Lifestyle Modification Versus Lifestyle Modification Alone on Visceral Adiposity and Markers of Cardiovascular Risk in Obese Middle-Aged and Ageing Men".
As men age there is a small but progressive fall in serum testosterone levels, particularly in obese men. Increasingly, clinicians are consulted by ageing men with symptoms suggestive of testosterone deficiency. Symptoms include decreased sense of well-being, declining sexual performance, mood or memory changes. In these men a range of factors may be responsible, particularly obesity.
Testosterone replacement therapy (TRT) is increasingly used despite the lack of clear evidence for its benefits and safety.
Preliminary data suggests that TRT causes modest reductions in body fat, in particular abdominal fat, which may beneficially affect the development of cardiovascular disease through changes in several risk markers, such as cholesterol levels, insulin resistance and blood clotting factors.
It is suggested that those men who will benefit most from TRT are those who are obese and have lower testosterone levels but supportive evidence in this group is very limited. Importantly, obesity is associated with an increased risk of diabetes and cardiovascular disease.
We are investigating whether TRT, in combination with a programme of lifestyle management, especially diet and exercise, offers an advantage over lifestyle management alone in obese ageing men.
Men have been recruited into a 1 year placebo controlled trial of injectable testosterone therapy. Changes in total and abdominal body fat and its effects on risk factors for cardiovascular disease (blood tests and blood vessel ultrasound) are being studied. Effects on quality of life are being evaluated using questionnaires.
The safety profile of TRT in terms of prostate disease and sleep apnoea (abnormal sleep patterns are associated with an increased risk of cardiovascular disease), the latter being more common in obesity, are being monitored.
A favourable benefit versus risk profile in this study may prompt subsequent larger interventional trials focusing on men with the increasingly common problems of obesity, predisposition to cardiovascular disease and diabetes, and who are increasingly presenting with low testosterone levels.
Funding
Schering-Bayer-Pharma, Berlin
Outcomes
Data from our first study of testosterone therapy in ageing non-obese men continues to be published. Most recently those endpoints relating to body composition and sexual function have been reported (listed below).
Dr Allan received the Henry Burger Prize for Clinical Research, awarded by the Senior Medical Staff, Southern Health, for our work on testosterone and body composition in ageing men.
Prof McLachlan and Dr Allan have been invited to present at symposia at The Endocrine Society's annual meeting in Washington, June 2009.
In the study of testosterone therapy in obese men, as on December 2008, a total of 41 men had entered the study and study completion and data analyses will proceed during 2009.
Selected Publications
Allan CA, Forbes EA, Strauss BJ, McLachlan RI (2008). Testosterone therapy increases sexual desire in ageing men with low-normal testosterone levels and symptoms of androgen deficiency. Int J Impot Res. 20:396-401.
Allan CA, Strauss BJ, Burger HG, Forbes EA, McLachlan RI (2008). Testosterone therapy prevents gain in visceral adipose tissue and loss of skeletal muscle in non-obese aging men. J Clin Endocrinol Metab 93:139-146.
Allan CA, Strauss BJ, McLachlan RI (2007). Body composition, metabolic syndrome and testosterone in ageing men. Int J Impot Res 19:448-457.Allan CA, Strauss BJG, Burger HG, Forbes EA, McLachlan RI. The association between obesity and the diagnosis of androgen deficiency in symptomatic ageing men. Medical Journal of Australia 2006,185:424-7.
McLachlan RI and Allan CA. 2004 Defining the prevalence and incidence of androgen deficiency in aging men: where are the goal posts? Journal of Clinical Endocrinology and Metabolism 89(12):5916-5919.
Allan CA and McLachlan RI. 2004 Age-Related Changes in Testosterone and the Role of Replacement Therapy in Older Men. Clinical Endocrinology 60(6):653-670.