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Testosterone levels recover after obesity surgery

Obese men with low testosterone should lose weight, not take hormone replacement

Louise Prime

Tuesday, 06 October 2015

Obese men with low testosterone levels who had sleeve gastrectomy to lose weight had a significant increase in their serum testosterone levels as well as decrease in body mass index (BMI) over the following year, US researchers have found. They told colleagues at the 2015 Clinical Congress of the American College of Surgeons that their study* indicated that obese men with low levels of testosterone should lose weight, perhaps helped by bariatric surgery, rather than take hormone replacement.

The researchers, led from Stanford University in California, pointed out that low levels of testosterone increase men’s cardiovascular risk independently of other factors, and increase their risk of sarcopenia (muscle loss), as well as having a negative impact on their sexual quality of life. Low testosterone levels are more common in obese men because their fat produces oestrogen, which competes with testosterone, they added.

They investigated the effect of sleeve gastrectomy – a common type of bariatric surgery that since its introduction 10 years ago has largely replaced gastric bypass because it is a shorter and lower-risk operation – on hormone levels in 24 obese men. They measured the men’s serum levels of testosterone, DHEA (a precursor to testosterone), and prostate-specific antigen (PSA) before surgery and again three, six and 12 months later.

Before surgery, 63% of the men had low testosterone (defined as lower than 300ng/dl), and the mean was 295ng/dl; 12 months after surgery, only 41% of men had low levels of testosterone and the mean had risen to 423ng/dl. There were also improvements in DHEA, for which the mean rose from 12.8ng/dl to 39.6ng/dl. Mean serum concentrations of PSA rose from 0.62ng/dl to 0.75ng/dl but with no increase in PSA mass (a marker for prostate cancer progression). Over the year after surgery, the men’s mean BMI decreased from 46 to 31.

The researchers commented that far fewer men than women undergo bariatric surgery, even though they suffer similar levels of obesity. They said: “More men should seek surgical care for obesity as they carry more risk from their weight – low testosterone causes further weight gain, increases cardiac risk, and decreases quality of life. And sleeve gastrectomy can improve all of those comorbidities … The nice thing about what this process does is it creates an auto-transfusion of testosterone from yourself. This process occurs because you are losing weight, and therefore losing that oestrogen, causing your natural testosterone stores to rise.”

They concluded: “The take home message is that if you are an obese man with low testosterone your therapy should be weight loss not testosterone replacement, and a successful way to achieve meaningful weight loss is through a bariatric operation.

“This is a unique and beneficial finding for sleeve gastrectomy hasn't been studied before, demonstrating for the first time, that testosterone levels are improved in a group of obese male patients following sleeve gastrectomy.”

* Morton JM, Mokhrati T, Nair AA et al. Male sex hormones normalize after laparoscopic sleeve gastrectomy. American College of Surgeons 2015 Clinical Congress. Scientific Forum Session SF02, (Bariatric/Foregut I), Monday 5 October.

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