Illiteracy Linked to Higher Risk of Dementia
Illiteracy may increase the risk of developing dementia, according to a new study from researchers at Columbia University Vagelos College of Physicians and Surgeons.
The researchers found that among a group of 983 people over age 65 who enrolled in an aging study, about 35% of those who could not read or write had dementia at the beginning of the study. Approximately half of the illiterate participants who entered the study without dementia developed it about four years later.
The study is one of many over the past two decades that suggest that education—either formal or informal—may protect the brain against dementia.
The CUIMC Newsroom spoke with the study’s senior author, Jennifer Manly, PhD, a neuropsychologist at Columbia whose research focuses on disparities in Alzheimer’s disease, about the link between education and brain health and the potential of education to prevent dementia.
How does education decrease dementia risk?
We don’t really know what it is about education that seems to protect against cognitive decline and dementia, but evidence has shown that the risk is lower for those who attended more years of school.
For example, a recent study found that people with college degrees tend to develop dementia later than those with high school degrees. Another study showed that the overall rate of dementia across the U.S. decreased between 2000 and 2012, while the average amount of education increased over the same period.
It’s possible that educational experience fosters neuron growth and builds a healthier brain that’s more resistant to the damage our brains sustain as we age.
We know that the brain is pretty resilient. Some people have early evidence of Alzheimer’s in their brains but never develop cognitive impairment. We’re looking at what aspects of education may be a factor that promotes resilience. And we’re looking in different ethnic, racial, and cultural groups because we know that access to schooling, and quality of education, varies widely across these groups.
But the link between education and brain health could also be explained by the opportunities afforded by having a degree. People who attain higher levels of education may avoid exposure to toxic environments or harsh working conditions, for example, that are more frequently faced by people whose jobs do not require high school or college degrees.
Why did your recent study focus on literacy?
We tried to isolate the effects of literacy from the effects of being in a classroom. In the study, led by my colleague Miguel Arce, PhD, none of the participants had more than four years of school. But some of them had learned to read and write anyway.
Being able to read and write allows people to engage in more activities that engage the brain, and previous research has shown that these activities—like reading a newspaper, helping grandchildren with homework—may reduce dementia risk, though the mechanism isn’t known.
In future research, we plan to analyze brain images from the same group of participants to see if we can isolate those brain mechanisms in the illiterate group.
Ultimately, we want to be able to make some recommendations about how to maintain brain health and prevent dementia as we age.
Can we use education to prevent Alzheimer’s?
It’s possible that spending more years in the classroom may buffer genetic risk for Alzheimer’s. One of my postdoctoral fellows recently published a study showing that having more than a high school degree buffered the risk of cognitive decline among older African Americans who carry a gene that raises Alzheimer’s risk.
Since racial and ethnic disparities seem to be best explained by early life educational factors, we need to look more closely at how those experiences may reduce risk.
I’m starting to appreciate the importance of educational policy in shaping opportunities and health throughout life. Education isn’t just an individual’s responsibility—we need national and local policies that promote access to high-quality education for everyone.
Many of the people from our study grew up with very few educational opportunities. We've seen that people around the world who had more opportunities to attend high-quality schools are healthier overall.
In the U.S., school quality varies widely from community to community, leading to differences in educational opportunity across racial, ethnic, and social status. We hope to learn how those different educational pathways relate to brain health later on because educational policy can be changed to improve public health.
Jennifer Manly, PhD, is professor of neuropsychology in the Department of Neurology, the Gertrude H. Sergievsky Center, and the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain at Columbia University Vagelos College of Physicians and Surgeons.
Miguel Arce, PhD, is a postdoctoral research scientist in the Gertrude H. Sergievsky Center.
The paper, published in Neurology, is titled “Illiteracy, dementia risk, and cognitive trajectories among older adults with low education.” The study was funded by the National Institute on Aging (RF1AG054023). The other authors are listed in the paper.
The Washington Heights-Inwood Columbia Aging Project (WHICAP) is a community-based, prospective study of dementia in the ethnically diverse neighborhoods of northern Manhattan. The study includes three cohorts of more than 6,500 people.