Hoping to counter the effects of aging, older men with low testosterone levels sometimes turn to testosterone replacement therapy. Might this hormone treatment put their cardiovascular health at risk?

THIS STUDY involved 308 men 60 and older (average age, 68) who had lower than normal testosterone levels. They were randomly assigned to use topical testosterone, in gel form, or a placebo gel daily for three years. Dosages were individually calibrated so that the men could attain a testosterone level in the middle of the normal range. Walls of their coronary arteries and the amount of calcium, or plaque, in those arteries were measured periodically to assess the presence or progression of atherosclerosis, sometimes called hardening of the arteries. Testosterone levels increased among the men using the testosterone gel, but no correlation was found between higher testosterone levels and changes in their arteries. Artery changes occurred at essentially the same rate whether the men did or did not use testosterone gel. Also, neither sexual desire and function nor physical functioning nor overall quality of life differed between men who used testosterone supplementation and those who did not.

WHO MAY BE AFFECTED? Older men. Levels of testosterone, the key male hormone, decline gradually as men age, usually starting at about age 40. Low testosterone also can occur at any age because of brain, testicle or pituitary gland disorders that cause the testicles to not produce enough of the hormone, a disease called hypogonadism. Testosterone supplementation has increased dramatically in the past decade, often prescribed to ease such symptoms as low sex drive and energy. The Food and Drug Administration has approved testosterone replacement therapy for hypogonadism but not for low testosterone levels that are a normal part of aging.

CAVEATS Data on sexual function, physical functioning and quality of life came from the men’s responses on questionnaires. The study did not determine the effect of any specific dosage of testosterone supplementation, nor did it test whether using testosterone gel had any effect on such cardiovascular events as heart attack and stroke.

FIND THIS STUDY Aug. 11 issue of JAMA (www.jama.com).

LEARN MORE ABOUT testosterone replacement therapy at www.mayoclinic.org and nlm.nih.gov (click on “Health Information,” then search for “testosterone”).

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.