快樂小藥師 Im pharmacist nichts glücklich

Higher testosterone levels might be associated with better physical performance, but supplementation is recommended only for alleviation of sexual symptoms.

Testosterone levels decline as men age, but how often this decrease produces symptoms that are correctable by testosterone supplementation is unclear. Several studies and guidelines published in 2010 shed some light on these questions but also leave many questions unresolved.

Do testosterone levels affect physical performance? A cross-sectional longitudinal analysis of 1445 men from the Framingham Offspring Study showed that men with repeatedly higher free testosterone levels had better physical performance scores and walking speed and lower risk for poor subjective health than men with lower levels. Men with low baseline free testosterone levels were more likely to report mobility limitations, but no clear correlation was established between low total testosterone levels and mobility limitation or physical performance (JW Gen Med Jul 15 2010).

What symptoms are caused by low levels of testosterone? A study of 3369 community-dwelling men (age range, 40–79) showed a clear correlation between low morning levels of total testosterone (<317 ng/dL [11 nmol/L]) or free testosterone (<64 pg/dL [220 pmol/L]) and three sexual symptoms — poor morning erection, low sexual desire, and erectile dysfunction. Importantly, low testosterone levels were not correlated with various psychological and physical symptoms (JW Gen Med Jul 15 2010).

Does testosterone supplementation alleviate symptoms in older men with low testosterone levels? In a randomized trial of 209 community-dwelling men (age, ≥65) with low total testosterone levels (100–350 ng/dL [3.5–12.1 nmol/L]) or free testosterone levels (<50 pg/mL [173 pmol/L]), participants received transdermal testosterone gel or placebo for 6 months. Many participants had hypertension, diabetes, or hyperlipidemia, or were obese. Although the treatment group had greater improvements in strength tests and stair climbing, they also experienced more adverse cardiovascular events: 23 occurred in the treatment group versus just 5 in the placebo group (JW Gen Med Jul 15 2010). However, a randomized trial from the U.K. showed that testosterone supplementation improved performance on just one of several strength tests (JW Gen Med Mar 9 2010).

So, based on these and previous studies, should we consider testosterone supplementation in older men? Guidelines from the Endocrine Society published this year recommended supplementation only in men with low testosterone levels and "classical androgen deficiency symptoms" — which presumably refers to only sexual symptoms and not other less-specific symptoms (JW Gen Med Jul 15 2010). The question, however, is whether cardiovascular risk might be incurred by supplemental testosterone treatment.

— Anthony L. Komaroff, MD