Older men with moderate natural testosterone levels may be more likely to live longer than those with the highest and lowest levels, a new study suggests.
The researchers of the study measured testosterone, dihydrotestosterone, and estradiol levels in men 70 to 89 years of age and assessed the risks for all-cause and ischemic heart disease mortality. Baseline blood samples were collected in the morning between 2001 and 2004 and were analyzed using liquid chromatography-tandem mass spectrometry.
The researchers followed 3690 men, recording deaths until December 2010. The results were published online on November 20, 2013, in The Journal of Clinical Endocrinology & Metabolism
Overall, 26.4% of participants died throughout the study period. When separated into 4 groups based on testosterone levels, 23.3% to 25.1% of men in the middle quartiles died, compared with 30.8% of men with the lowest levels and 26.5% of men with the highest levels.
After other risk factors were adjusted for, both testosterone and dihydrotestosterone were associated with all-cause mortality. Higher levels of dihydrotestosterone were associated with a reduced risk for death caused by ischemic heart disease. There was not a relationship between estradiol and all-cause or heart disease mortality.
The study did not include men taking testosterone supplements, and the authors note that more research is needed to study the effects of hormone therapy in men.