October 31, 2011
Stuart Weinerman, MD
Older men with higher testosterone levels lose less lean muscle mass as they age, according to a recent study accepted for publication in the Endocrine Society's Journal of Clinical Endocrinology and Metabolism. In the study of 1,183 men aged 65 years or older, higher testosterone levels were also associated with less loss of lower body strength.
While the study confirms that higher blood levels of testosterone in older men is associated with less of the loss of muscle mass that occurs with aging, there are several qualifications in the interpretation of the data. It was a prospective epidemiological study, which means it followed the group over time to address this specific question--so other variables may exist. For example, patients with low testosterone were more likely to have diabetes. Also, there was very little correlation with functional outcomes such as measures of strength, except in subgroup analysis conducted afterward.
Finally, this study should not be interpreted as evidence that men who have a decline or deficiency in testosterone production should begin testosterone replacement. The risks and benefits of testosterone replacement can only be studied in larger, randomized controlled trials, which are the most rigorous way to determine whether a cause/effect relation exists between treatment and outcome.