This is interesting:
Increased Death Risk
After adjusting the figures to take into account factors such as age, body mass index and other illnesses, the researchers found men with low testosterone levels were 88% more likely to die than those with normal levels.
The researchers then removed the men who had died within one year of taking the second testosterone sample from their calculations, as critical illnesses can cause testosterone levels to dramatically decrease.
They still found men with low levels had a 68% increased mortality risk.
Molly Shores, the author of the study, wrote with colleagues: "The persistence of elevated mortality risk after excluding early deaths suggests that the association between low testosterone and mortality is not simply due to acute illness.
“Large prospective studies are needed to clarify the association between low testosterone levels and mortality.”
They pointed out their study might not be representative because it focused on military veterans, who had a higher risk of death than the normal population.