Testosterone replacement improved the quality of life for men with Alzheimer's disease and low serum testosterone levels in a small preliminary study, reported Po H. Lu, PsyD., and associates at the University of California, Los Angeles, David Geffen School of Medicine.
Testosterone therapy has been shown to improve mood, muscle mass, strength, bone density, libido, and certain cognitive functions in hypogonadal men who are otherwise healthy, but this is the first study to report that testosterone may exert positive effects in Alzheimer's disease (AD), the researchers said (Arch. Neurol. 2006;63:1–9).
They assessed testosterone's effects on a variety of cognitive, behavioral, mood, and quality of life (QOL) measures in 16 men with mild to moderate AD and 22 healthy elderly men who served as control subjects. The study subjects were randomly assigned to apply either testosterone patches (7 patients and 10 controls) or placebo patches (9 patients and 12 controls) every day for 6 months.
Five of the AD patients and six of the control subjects were hypogonadal at baseline, with serum testosterone levels below 298 ng/dL.
As a group, AD patients who received testosterone showed a significantly better QOL, as assessed by their caregivers using the 13-item Quality of Life-Alzheimer's Disease scale, than AD patients who received placebo. This effect occurred because the testosterone recipients showed a nonsignificant trend toward improved QOL over the 6-month study period, while the placebo group showed significant declines.
Similarly, the AD patients who received testosterone showed either greater improvement or less decline in three measures of visual-spatial cognitive functioning, compared with the AD placebo group and the control groups.
Both the improved QOL and the improved cognitive functioning were correlated with increased serum testosterone levels.
Two AD patients and four control subjects withdrew from the study because of adverse effects, including skin rash at the testosterone patch application site. None of the AD patients who received testosterone showed more aggression or agitation than placebo subjects, and caregivers did not observe any marked changes in patients' sexual behavior.