Saliva Test Might Determine Alzheimer’s Risk in Elderly People

A new research claims examining the saliva of healthy elderly people could assist recognize those who are at danger for cognitive decrease.

This new study published in journal Neurology mentions that, elderly people with great amounts of the stress hormone “cortisol” in their saliva had smaller brain volumes, which was connected with lesser performance on tests of memory and thinking.

Research co-author Dr. Lenore J. Launer and colleagues think their results could pave way for a saliva examination that would easily help identify individuals who may be at a higher risk of developing Alzheimer’s  and other dementias. Earlier research has recommended that depression increases the threat of dementia for older population but Dr. Launer and colleagues say it the reason for this is still unclear.

“Greater levels of the stress hormone cortisol have been identified in individuals with depression, and the concept is that cortisol has a toxic impact on the hippocampus region of the brain, which performs an essential role in memory.”

The investigators determined to examine this concept further, analyzed the cortisol levels, brain volumes and intellectual skills of 4,244 people of an average age of 76 who were free from dementia.

Brain volume about 16 millimeters lesser in people with high cortisol levels

Individuals’ cortisol levels were calculated from saliva samples that were obtained on a single day – 45 minutes after waking up in the morning and once again in the evening. Based upon on their cortisol levels, individuals were designated to one of 3 groups: high, medium or low.

Individual’s brains were examined using magnetic resonance imaging (MRI), enabling investigators to evaluate brain volume.

Additionally, subjects were needed to take part in assessments that assessed memory and thinking abilities.

In comparison with participants in the lower cortisol group, those with higher cortisol levels were identified to have entire brain volumes about 16 millimeters smaller. The variation in brain volume size was especially visible in gray matter areas instead of white matter areas.

What is more, subjects with higher cortisol levels performed worse on memory and thinking assessments than those with lower levels of the hormone.

The scientists admit that due to the fact that their research only viewed at a short time period, they are not able to identify whether higher levels of cortisol or reduction of brain volume will take place first, but Dr. Launer has a concept:

“It’s quite possible that the reduction of brain volume that can take place with aging results in a lesser capability of the brain to stop the negative effects of cortisol, which consequently results in additional loss of brain cells. Understanding these connections may assist us develop methods to decrease the consequences of cortisol on the brain and thinking abilities.”

According to author, the fact that saliva samples were only received on one day is a restriction of the investigation, as it raises risk for cortisol measurement errors. However, they say their huge sample size counteracts this restriction.

This study uses another study presented previous month that suggested an individual’s possibility of Alzheimer’s and mild cognitive impairment (MCI) might be estimated through a saliva check that measures specific substances that are more pronounced in individuals with such problems. This study was presented in Clinical Research Society with title Simple Saliva Test May Identify Alzheimer’s Risk