Testosterone Related Diseases Alzheimers

Alzheimer’s disease is a form of age-related dementia caused by deteriorating brain tissue. Recent studies have found that declining levels of testosterone and other sex hormones may play a role in the development of Alzheimer’s.

Alzheimer's Disease and Testosterone - Testosterone Related Diseases

Symptoms and Causes of Alzheimer’s

Approximately half of all people over age 85 have Alzheimer’s, but the condition is not considered a natural or inevitable part of the aging process. For a person with early Alzheimer’s, symptoms can include:

  • Repeating the same statement multiple times in a conversation
  • Putting away household items in unreasonable places
  • Forgetting names of family and friends or of common objects (generally a symptom of more progressed Alzheimer’s).

Two key proteins are strongly associated with Alzheimer’s:

  • Beta-amyloid: In the brains of Alzheimer’s patients, beta-amyloid accumulates into clumps (called “plaques”) that may promote neuron death.
  • Tau: Tau, which normally functions as a support structure for brain cells, often forms twisted tangles in Alzheimer’s patients that may impair normal brain function.

The Link Between Testosterone and Alzheimer’s

Testosterone is a sex hormone found in relatively high amounts in men and comparatively low amounts in women. In men, testosterone levels escalate during puberty and then generally begin to decline sometime around age 40. Studies indicate that the more a man’s testosterone levels decline with age, the higher his risk for developing Alzheimer’s disease. The most recent data on the link between testosterone and Alzheimer’s indicate that low testosterone may contribute to the accumulation of beta-amyloid plaques in the brain.

The form of testosterone that appears to be associated with Alzheimer’s is “free testosterone,” which circulates in the blood. Free testosterone is not attached to a protein, making it available for use by the body’s cells.

General cognitive function may also be negatively impacted by the slow decline of testosterone that comes with age. These functions include memory retention and the ability to learn to new skills.

Testosterone Replacement Therapy and Alzheimer’s

Because decreasing testosterone is one of the risk factors for Alzheimer’s disease in men, researchers have been trying to determine if testosterone replacement therapy can alleviate or prevent Alzheimer’s in men with low testosterone levels. So far, the data are not conclusive.

In male mice with an Alzheimer’s-like disease, supplemental testosterone appears to have some benefits for cognitive function. In humans, the results have been mixed. A study conducted by the University of California at Los Angeles found that male Alzheimer’s patients given testosterone treatment reported some improvements to their caregivers in the parameters that measure quality of life. However, when these same patients were interviewed by clinicians involved in the study, no statistically significant improvement in cognitive function was measured. Even so, the possibility of using testosterone for treatment of Alzheimer’s remains an open question that is under investigation.

Resources

Mayo Foundation for Medical Education and Research staff. (2009). Alzheimer’s disease. Retrieved January 17, 2010 from the Mayo Clinic Web site: http://www.mayoclinic.com/health/alzheimers-disease/DS00161.

MediZine LLC staff. (2007). Men’s testosterone levels tied to Alzheimer’s disease risk. Retrieved January 17, 2010 from the Johns Hopkins Health Alerts Web site: http://www.johnshopkinshealthalerts.com/alerts/memory/JohnsHopkinsMemoryHealthAlert_310-1.html.

Pike, C. J., et. al. (2009). Protective actions of sex steroid hormones in Alzheimer’s disease. Frontiers in Neuroendocrinology, 30(2), 239-258.

ScienceDaily LLC staff. (2006). Alzheimer patients treated with testosterone in UCLA-led study show improved quality of life. Retrieved January 17, 2010 from the ScienceDaily Web site: http://www.sciencedaily.com/releases/2006/01/060110013237.htm.

ScienceDaily LLC staff. (2006). Testosterone therapy may prevent Alzheimer’s disease. Retrieved January 17, 2010 from the ScienceDaily Web site: http://www.sciencedaily.com/releases/2006/12/061219201939.htm.

Harvard University staff. (n.d.). Testosterone may improve mental function. Retrieved January 17, 2010 from the Harvard Health Web site: http://www.health.harvard.edu/press_releases/testosterone-and-memory.

WebMD, LLC staff. (2008). Testosterone. Retrieved January 14, 2010 from the WebMD Web site: http://men.webmd.com/testosterone-15738.