Low Testosterone in Aging Men

Joggers near the Washington Monument, an obelisk at the National Mall in Washington, DC. (Dr. Noorali Bharwani)
Joggers near the Washington Monument, an obelisk at the National Mall in Washington, DC. (Dr. Noorali Bharwani)

After the age of 40, testosterone levels in men go down by 1% each year. Testosterone boosts mood, libido and muscle mass. It’s a $2 billion industry in the US, with millions of men buying testosterone gel, pills or getting injections.

Clinically, there is only one indication for prescribing testosterone. A man suffering from hypogonadism. Examples of this include failure of the testicles to produce testosterone because of genetic problems, or damage to the testicles from chemotherapy or infection.

Hypogonadism is a medical term for a defect of the reproductive system resulting in loss of function of the gonads. In men, it is the testes. The testicles have two functions: to produce hormones (testosterone) and to produce sperm.

Many men have been prescribed testosterone to boost sexual performance. A blood test will tell when testosterone is low. But doctors do not know what is a normal level for that individual or when the individual is getting too much testosterone.

The concern is that high testosterone level can cause heart attacks. Recently, the Food and Drug Administration (FDA) in the US has stepped up warnings for testosterone and other steroid drug prescribers and users. Testosterone is approved to treat men with medically diagnosed low levels of testosterone. The FDA does not approve the use of testosterone to treat the effects of aging.

The FDA says, “Not only can the drugs cause heart attacks, personality changes and infertility, but people can easily abuse them.”

There is a long list of reported serious adverse side effects including heart attack, heart failure, stroke, depression, hostility, aggression, liver toxicity, kidney failure, baldness and male infertility from shrinking testicles.

Individuals abusing testosterone have also reported withdrawal symptoms, such as depression, fatigue, irritability, loss of appetite, decreased libido and insomnia. It can also raise the risk of blood clots.

An article “Predicting low testosterone in aging men: a systematic review,” by Adam C. Millar and colleagues published in the Canadian Medical Association Journal (CMAJ June 20, 2016) says in men over 40, clinical signs and symptoms thought to be associated with low testosterone correlate poorly with testosterone levels.

Miller and his colleagues conducted a systematic review to estimate the accuracy of clinical symptoms and signs for predicting low testosterone among aging men. They found among 6053 articles identified, 40 met the inclusion criteria. The prevalence of low testosterone ranged between two per cent and 77 per cent. Threshold testosterone levels used for reference standards also varied substantially.

Authors of the CMAJ article found weak correlation between signs, symptoms and testosterone levels.

CMAJ editor’s comment: Until we know more about hypogonadism in older men, it’s prudent to be cautious in making the diagnosis and initiating treatment in this group.

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