Testosterone may reduce risk of type 2 diabetes

Thursday, 18 June 2020

The world’s largest study on testosterone suggests it may play a role in decreasing the risk of type 2 diabetes in men, following two years of treatment with the hormone.

The results of the Australia-wide study were recently presented at the Annual Scientific Sessions of the American Diabetes Association conference.

In the study, 1000 men at high risk of diabetes were enrolled in a diet and exercise program provided by WW (formerly Weight Watchers). Half were given testosterone injections and half placebo injections.

At the end of the study, those on testosterone were 40 per cent less likely to have diabetes.

Although the study showed that the development of diabetes among overweight or obese men aged 50 to 74 can be prevented and that newly diagnosed diabetes can be reversed with testosterone, the authors warn it is not a quick fix.

“It was only a two-year study and we don’t not know either the durability of the effect or the long-term safety of testosterone for preventing type 2 diabetes,” said study leader Gary Wittert, Director of the Freemasons Foundation Centre for Men’s Health at Adelaide University.

“I want to emphasise this is not a signal to rush for the script pad. It is far more important to deal with the basic underlying issues of shedding excess weight, eating well and doing resistance and aerobic activity to build muscle.

“During the study I discovered how few men had been thoroughly assessed and provided with appropriate advice about preventing diabetes and its associated conditions, such as sleep apnoea.”

The study had encouraging and discouraging aspects. Encouragingly, both groups lost an average of four kilograms of weight but men on testosterone gained muscle mass while losing fat. They also gained small improvements in sexual function.

While fasting blood glucose was, on average, lower at the end of the study for both groups, the decrease was greater in the testosterone group.

Discouragingly, the most common side effect of testosterone was an increase in red blood cells, potentially leading to sludgy blood and clots. This occurred in 22 per cent of men on testosterone.

At the end of the study, 21 percent of men on placebo had diabetes, compared with 12 per cent on testosterone.

About 20 per cent had begun the study with newly diagnosed diabetes.

“While testosterone therapy might be an option for some, this should never be a substitute for a thorough physical and mental health assessment, and support to adopt and maintain a healthy lifestyle,” Professor Wittert said.

Study participants received injections every three months. Those who engaged more with the WW program lost more weight and did better.

On average, over the two years about 30 percent of the men in each treatment group attended WW and 70 per cent overall achieved the recommended amount of exercise.

“The standard of care for preventing or reversing diabetes is a program of healthy eating, physical activity which includes strength and aerobic training, and moderate weight loss,” Professor Wittert said.

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