FALSE: In the 1940s it was observed that castration reduced the incidence of prostate cancer. From this observation, it was extrapolated that testosterone must play a role in the pathophysiology of prostate cancer. The testicle produces several hormones other than testosterone, and it is now believed that the improvement seen in those patients was due to a decrease in estrogen production rather than testosterone. Prostate cancer is uncommon in young men, who generally have higher levels of testosterone, and becomes more prevalent with age, as testosterone levels fall. Over the past decade or so, there have been many investigations that have disproven the link between testosterone and prostate cancer.
FALSE: As is typical with laboratory medicine, the reference range parameters don’t always equate with the optimal clinical outcomes. Studies indicate that men who maintain their testosterone levels in the mid to upper range have reduced incidence of cardiovascular events compared with those in the overtly low, or high ranges. The threshold of benefit appears to be greatest when levels are maintained above 500 ng/dL in serum.
FALSE: There were two articles published at the end of 2013 and in the early part of 2014 which purported that men on testosterone supplementation had an increased risk of heart attack, however neither of these studies was particularly well run. They were both observational and retrospective, which severely limits the ability to control variables and is not sufficient to establish causation.
Conversely there exists a multitude of studies that link LOW testosterone to increased cardiovascular disease, and furthermore that testosterone replacement improves cardiovascular and metabolic markers. The NIH conducted one of these studies for the express purpose of investigating the findings of the JAMA study that linked testosterone replacement to increased risk. This follow up study looked at over 24,000 patients and found no increased risk of heart attack in those treated with testosterone.
FALSE: Though low or suboptimal testosterone levels can contribute to changes in libido and the ability to achieve or maintain an erection, symptoms are varied and often include fatigue, apathy, difficulty concentrating, weight gain, depression, sleep disturbances and, most importantly, changes in metabolism including an increased risk for metabolic and cardiovascular disease.