"Finally, Nissen urged caution and common sense, pointing out that a "fall in hormone levels in both men and women is a normal part of aging; it is not necessarily a disease. Making it into a disease may end up causing more harm than good."
This may be so, but at 42 when my T level should be around 500-600 Ng/dl, and the reality is that it's at 198 Ng/dl; this is not normal.
I did not see any mention of "normalized" T levels for their age after therapy. Their TRT could have been ineffective or their levels could have been higher than the normal range, thus putting them at higher risk of coronary artery disease, myocardial infarction, and cerebrovascular accident.
Other studies have shown low T levels put men at greater risk for heart disease / heart attack.
In my opinion, genetics and obesity play a greater role in predicting cardiac disease.
I've seen young, fairly fit men (40-50) who have terrible heart problems due to bad family history of heart disease. I've also known of 40-50 year old distance runners who are extremely cardiovascularly fit drop dead of myocardial infarction. If TRT gives me more energy to do cardio and lift weights, and I can keep losing weight, I think I'm at lower risk of cardiac disease, diabetes, or stroke.
The one problem that does seem related to TRT is prostate cancer, which even then, is statistically low incidence.