You might think that more testosterone means greater vitality and wellbeing, but it’s more complicated than that says Professor Bu Yeap, consultant endocrinologist at Fiona Stanley Hospital, WA.
According to results from the Western Australian Health In Men Study (HIMS) of men aged 70 and older, there’s an optimal amount of testosterone for good health outcomes.
“You are at greater risk of dying if your testosterone is low. But if it’s really high, your risk is going up again – there’s actually a ‘U’ shape association of testosterone with mortality risk in older men,” Professor Yeap says.
In the HIMS study, the optimal range of circulating total T was approximately 10 to 15 nmol/L and was associated with improved survival independent of risk factors such as age and obesity.
A new international meta-analysis led by the University of Western Australia shows that in healthy men, testosterone levels are generally stable until they reach their 70s. After that, testosterone levels decrease with increasing age, while luteinising hormone levels rise. However, healthy men aged 40-69 years maintain stable testosterone levels for some time, according to the UWA research which followed men for 4.3 years.
“The healthier you are, the better you maintain your testosterone production. When you hit your 70s, testosterone production from the testes begins to decrease, so you want to be in the best possible situation leading up to then,” Professor Yeap explains.
The T4DM study of approximately 1,000 Australian men aged 50-74 years, all with central obesity and impaired glucose tolerance or newly diagnosed type 2 diabetes, highlighted the benefits of maintaining lean mass – something made easier with testosterone.
All participants received a Weight Watchers program with half the group randomised to receive testosterone and the other half assigned to placebo. The men who were given testosterone gained lean mass (0.4 kg) and lost fat (4.6 kg), while the placebo group lost lean mass (1.3 kg) and didn’t lose as much fat (1.9 kg). At two years, the testosterone group had a 40% lower risk of type 2 diabetes than the placebo group (P=0.0007).
“We randomised men to testosterone or placebo for two years, and guess what, at the end of two years, if you had received testosterone, your risk of having type 2 diabetes was 40% lower. This is a really robust result,” Professor Yeap says.
However, testosterone treatment is not without risks, such as an increase in haemoglobin concentrations, and the need for prostate assessments—there are no specific recommendations for the frequency of assessments, as these need to be individualised according to age and risk factors, Professor Yeap adds.
“Therefore, if you can achieve those changes in body composition some other way, for instance healthy lifestyle behaviours including resistance exercise, that could be a preferred course of action,” he says.
A recent study of 25,000 men found that many factors are associated with lower testosterone levels, including:
It’s important to consider such factors when interpreting testosterone results.
“There are sociodemographic, lifestyle and medical factors that influence testosterone concentrations. Of these, the top four are age, BMI, diabetes and cancer —when you look at a testosterone result, you should be thinking about all these factors that might influence it,” Professor Yeap says.
In men with symptoms suggestive of androgen deficiency, it is essential to determine whether hypothalamic-pituitary-testicular (HPT) disease exists or not.
When HPT disease is present, preventing the production of testosterone, and the patient has signs and symptoms of androgen deficiency, testosterone treatment is warranted.
Contraindications for testosterone treatment would include presence of polycythaemia or prostate cancer.
“If a man comes to you and they’re worried, or someone’s done a testosterone test and it’s a little low, this is what I do: I ask myself, does this man have hypothalamic, pituitary or testicular disease that’s causing him to be androgen deficient? If the answer is yes, he should be treated, provided there are no contraindications and that’s what he really wants,” Professor Yeap says.
In other men who do not have HPT disease, he recommends a holistic approach, addressing lifestyle behaviours, especially exercise, and managing any risk factors or medical comorbidities that may be present.
“We really need to be encouraging men to take an interest in their health, and testosterone is a great conversation starter. Because if they have HPT axis disease, we can treat them really effectively; if they don’t, there’s all these other things we can do to improve their health,” Professor Yeap says.
For more information on assessment and indications for testosterone therapy, Professor Yeap recommends this position statement from the Endocrine Society of Australia.
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