More Evidence That Education May Protect Against Dementia
Not everyone who becomes forgetful as they age develops dementia, and a new study suggests that those with college degrees and advanced language skills are likely to get better.
Mild cognitive impairment (MCI) is an early stage of memory loss marked by lapses in memory and thinking problems that don't interfere with everyday life. While people with MCI are more likely to develop dementia than folks who don't have these early memory lapses, some improve and return to normal.
"Although many people assume that if they develop mild cognitive impairment they will inevitably progress to dementia, we found encouraging evidence that this is not so," said study author Suzanne Tyas, an associate professor of public health sciences at the University of Waterloo in Ontario, Canada.
Education and language skills can help predict who will go on to develop dementia and who won't, the study found.
"These factors reflect exercise for the brain, and our work suggests they may be indicators of cognitive reserve," Tyas said. But exactly how cognitive reserve helps protect from dementia is not fully understood yet.
"One possible mechanism is neural compensation, where the brains of those individuals with higher levels of cognitive reserve may, by using alternate brain networks, be more able to compensate for the brain changes that originally led to mild cognitive impairment," Tyas explained.
The researchers analyzed data on 619 U.S. Catholic nuns, age 75 and up, in a long-running study of aging and Alzheimer's disease.
The nuns took tests measuring memory and other mental skills for up to 12 years or until they died.
A total of 472 women were diagnosed with MCI during the study, and about a third (143) regained their normal memory level at least once during an average 8.5 years after diagnosis. Nearly 84% of these 143 nuns never developed dementia.
Another third did progress to dementia without ever reverting to normal thinking and memory skills, while 3% stayed in the MCI stage, and 36% of the nuns died.
The participants who earned a bachelor's degree had more than double the chances of getting their memory back compared to those with a grade school or high school education. Nuns who had a master's degree or more advanced education were even more likely to regain their normal thinking skills after an MCI diagnosis, the study found.
The findings also offer reassurance for folks without such high levels of formal education, Tyas said.
Language skills, including those reflected in high grades in English class or in strong writing skills, also protected against dementia, the study found.
Those who had high grades in English but not in other subjects were almost twice as likely to improve after MCI as to develop dementia. What's more, participants with strong writing skills based on number of ideas expressed were four times more likely to improve than progress to dementia, the study showed. This effect was even stronger for those whose writing used complex grammatical structure, Tyas said.
"Language is a complex function of the brain, so it makes sense that strong language skills were also protective, and this effect was even stronger than for education," Tyas said.
In addition to having high levels of education and solid language skills, nuns who were younger than 90 and didn't carry certain genetic risk factors associated with Alzheimer's disease, the most common type of dementia, were also more likely to see a return of their memory.
The bottom line? "It's encouraging that our findings show there are multiple factors that improve your chance of regaining cognitive function after experiencing mild cognitive impairment," Tyas said.
The findings were recently published online in the journal Neurology.
Dr. Kenneth Langa, a dementia researcher at the University of Michigan in Ann Arbor, called the study "interesting and well-done."
Many people with MCI will get better on their own, said Langa, who was not part of the study.
"These findings are in line with other studies, but this study's careful measurement and long period of follow-up provide additional confidence in the results," he said.
These findings should be taken into account when considering treatment, Langa said.
"The fact that a significant number of individuals with MCI will not go on to dementia, even in the absence of any treatment, increases the risk for overdiagnosis and potential overtreatment among those with MCI," he said.
The Alzheimer's Association has information about reducing your risk for Alzheimer's disease.
SOURCES: Suzanne Tyas, PhD, associate professor, public health sciences, University of Waterloo, Ontario, Canada; Kenneth Langa, MD, PhD, professor, medicine, University of Michigan, Ann Arbor; Neurology, Feb. 4, 2022