Scientists have been studying testosterone’s role in dementia for some time.
Research has shown that men appear to be more likely to develop dementia if they have low testosterone levels.
In 2010, researchers from the United States and Hong Kong studied a group of 47 older Chinese men with mild cognitive impairment (MCI). People with this condition have slight changes in memory and cognitive skills, but can usually still manage life on their own, unlike people with dementia. MCI is a risk factor for developing Alzheimer’s disease later.
The men’s testosterone levels were measured at the start of the study. One year later, the men were assessed for dementia. Ten of them were diagnosed with Alzheimer’s disease. These men had all had low levels of free testosterone in their earlier blood tests.
In 2013, a study by French researchers found that low testosterone levels were associated with increased dementia risk in men. This risk was greater in men over age 80. It was also higher in men with higher levels of education.
Scientists have also investigated testosterone and dementia risk in women.
In 2013, researchers from Monash University in Australia presented the results of their study involving 90 healthy postmenopausal women at the Endocrine Society’s 95th Annual Meeting.
The women underwent cognitive testing and were then assigned to one of two groups. One group was given a testosterone gel to apply to the upper arm each day. The other group used a placebo gel.
After 26 weeks of treatment, the women’s cognitive skills were tested again. Those who had used the testosterone gel showed significant improvement in verbal learning and memory.
While their testosterone levels were higher, they were still in a normal female range.
Scientists suggest a few ways that testosterone affects the brain.
First, low testosterone might be associated with vascular (blood vessel) problems. If blood cannot flow to the brain properly, dementia can develop.
Second, low testosterone has been linked to heart disease and stroke, which can be risk factors for dementia.
Finally, it’s possible that testosterone can protect the brain, especially the areas that are prone to dementia.
However, more research is needed to determine if testosterone therapy is appropriate for people showing symptoms of cognitive decline.