Declining testosterone levels is a reality every man must face as he gets older. The majority of men worry about their libido and the possibility of erectile dysfunction. However, evidence has also linked a drop in testosterone to more severe complications, including Type 2 diabetes, osteoporosis, and heart problems. As with any condition, low testosterone levels cannot be properly treated until identified, which is problematic in this case.

In a recent study, published in the Canadian Medical Association Journal, researchers from Mount Sinai Hospital, University Health Network, Women's College Hospital, and the University of Toronto suggest that the standard method for identifying low testosterone may work better for younger men than older ones.

"These results suggest that it is difficult to extrapolate the way we diagnose pathologic hypogonadism in younger men to older men who have age-related declines in testosterone levels," said Dr. Allan Detsky, a professor at the University of Toronto and a physician at Mount Sinai Hospital, in a statement.

In men with hypogonadism, the body is incapable of producing enough testosterone, has an impaired ability to produce sperm, or both. Testosterone is the hormone responsible for masculine growth and development during puberty.

Doctors generally divide those with the condition into two groups: one has specific symptoms, including delayed sexual development, impaired sexual function, less facial and body hair, small testes, and low bone mineral density, and other signs that result from an underlying disease. A second group has more general symptoms, such as lower energy and motivation, depressed mood, poor concentration, and loss of muscle mass that result from developing hypogonadism at an older age as opposed to being born with it.

Detsky and his colleagues set out to determine the accuracy of using signs and symptoms to predict low testosterone in older men. They conducted a systematic review of 40 studies on hypogonadism among aging men, collecting data on a total of 37,565 male patients at an average age of 40. All studies included in the analysis featured a measurement of serum testosterone.

The research team discovered a staggering variation in the number of men dealing with low testosterone. The prevalence of hypogonadism in the studies ranged between 2 percent and 77 percent, and its signs and symptoms didn’t always predict low testosterone levels. Lastly, there was rampant uncertainty among the studies about what should be deemed low testosterone in older men.

"Our extensive review of all clinical studies published to date shows that in men over the age of 40, the symptoms and physical signs that are classically found in young men who suffer from pathological hypogonadism, caused by disease in the testes or pituitary gland, correlate poorly with their testosterone levels,"

In 2007, the Centers for Disease Control and Prevention announced a $1.7 million grant to help improve and standardize hormone measurements, specifically testosterone, and investigators have been working to improve the science ever since. The research carried out by Detsky’s team could help doctors prescribe a more effective prevention and treatment strategy that would combat dropping testosterone levels.

Source: Millar A, Lau A, Detsky A, et al. Predicting Low Testosterone in Aging Men: A Systematic Review. Canadian Medical Association Journal . 2016.