Do reduced levels of sex hormones affect men’s risk for Alzheimer’s Disease?

A 2004 study found a link between low testosterone and Alzheimer’s Disease in older men. The study analysed the testosterone levels of 574 men between the ages of 32 and 87. Examining both ‘total’ and ‘free’ testosterone levels over an average of nineteen years in relationship to subsequent diagnosis of Alzheimer’s disease, this longitudinal study discovered that testosterone levels are lowere in men suffering from Alzheimer’s disease than in their peers without the disease.

The study found that ‘…men who were diagnosed with AD, on average, had about 1/2 the levels of circulating free testosterone as men who didn’t develop the disease. In some cases, the drop-offs in free testosterone levels associated with AD were detected up to 10 years before diagnosis.”

According to Professor Scott Moffat, head investigator on the study, “This is a big step forward in helping to understand how sex hormones affect the aging body and brain.”

So the logical question is “Would testosterone supplements given to such men help prevent Alzheimer’s disease?”

Unfotunately, this remains far from clear.

A 2005 study ‘Effects of Testosterone on Cognition and Mood in Male Patients with Mild Alzheimer’s Disease and Healthy Elderly Men” attempted to determine the “…effects of testosterone therapy on cognition, neuropsychiatric symptoms, and quality of life in male patients with mild AD and healthy elderly men.”

It’s conclusion indicated that while testosterone replacement therapy seemed to improve overall quality of life for Alzheimer’s sufferers, the therapy had minimal effects on improving cognition.”

A more recent ongoing Australian study is looking at the connection between testosterone levels and the protein beta amyloid, a key player in causing Alzheimer’s disease, and how testosterone replacement therapy might help.

You can listen to an interview about the study here. Or read the transcript here.