"There is a compelling need for therapies that prevent, defer the onset, slow the progression, or improve the symptoms of Alzheimer disease (AD)," the authors provide as background information in the article. They note that hormonal therapies have been the focus of research attention in recent years since male aging is associated with a gradual progressive decline in testosterone levels. "The gradual decline in testosterone level is associated with decreased muscle mass and strength, osteoporosis, decreased libido, mood alterations, and changes in cognition, conditions that may be reversed with testosterone replacement." The authors add that the age-related decline in testosterone is potentially relevant to AD as previous studies have found significantly lower concentrations of the hormone in middle-aged and elderly men who developed AD.
Po H. Lu, Psy.D., from the David Geffen School of Medicine, University of California, Los Angeles, and colleagues conducted a 24-week, randomized study to evaluate the effects of testosterone therapy on cognition, neuropsychiatric symptoms, and quality of life in 16 male patients with mild AD and 22 healthy elderly men who served as controls. The study participants were randomized to receive packets of gel to apply on their skin that either contained testosterone or a placebo. Standardized tests were administered at least twice (baseline and end) during the study for the assessment of cognitive functions and quality of life.
"For the patients with AD, the testosterone-treated group had significantly greater improvements in the scores on the caregiver version of the quality-of-life scale," the researchers report. "No significant treatment group differences were detected in the cognitive scores at end of study, although numerically greater improvement or less decline on measures of visuospatial functions was demonstrated with testosterone treatment compared with placebo. In the healthy control group, a nonsignificant trend toward greater improvement in self-rated quality of life was observed in the testosterone-treated group compared with placebo treatment. No difference between the treatment groups was detected in the remaining outcome measures."
"In conclusion, the present results should be considered preliminary and do not warrant routine treatment of AD and healthy control men with testosterone. Future studies with larger sample sizes are needed before clinical decisions regarding testosterone therapy can be rationally based. For men with compromised quality of life, as reflected on the type of measure employed in this study, and who suffer from low serum T [testosterone] levels, testosterone therapy may be a reasonable consideration."
(Arch Neurol. 2006;63:1-9. Available pre-embargo to the media at www.jamamedia.org)
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