People who can't read and write are three times likely to develop dementia, says study
Nearly 32 million people in the US, who have not learned to read or write, may have a higher risk of developing dementia. They are three times more likely to develop the condition, according to a new study.
Even with a few years of education, people may enjoy lifelong advantages over people who have never learned to read or write, explains Jennifer J Manly from Columbia University Vagelos College of Physicians and Surgeons in New York.
"Being able to read and write allows people to engage in more activities that use the brain, like reading newspapers and helping children and grandchildren with homework. Our study also found that literacy was linked to higher scores on memory and thinking tests overall, not just reading and language scores. These results suggest that reading may help strengthen the brain in many ways that may help prevent or delay the onset of dementia," says Manly, one of the authors of the study.
According to the US Centers for Disease Control and Prevention (CDC), the burden of Alzheimer’s disease and related dementias in 2014 was five million people, which is 1.6 percent of the US population in 2014—319 million people. This burden is projected to grow to 13.9 million, nearly 3.3 percent of the population in 2060–417 million people.
Earlier, scientists have shown that education keeps the brain engaged and sharp. In the 1930s, researchers studied people who were mostly illiterate or with one or two years of formal education in Uzbekistan in Central Asia. When the researchers compared illiterates with the educated group, they saw that the latter performed better in tasks of reasoning, suggesting that literacy had something to do with it. Building on this, several studies have suggested that illiteracy is a risk factor for dementia.
"Previous research has shown such activities may reduce the risk of dementia. Our new study provides more evidence that reading and writing may be important factors in helping maintain a healthy brain," says Manly.
The current study included 983 people, averaging 77 years, and residing in northern Manhattan. The researchers divided them into two groups: 237 people were illiterate and 746 people were literate. The participants were given medical exams, memory and thinking tests. The same participants were tested again during follow-up appointments that occurred every 18 months to two years.
They further divided the participants into two groups: those who had dementia and those who did not have the condition at the start of the study.
Of the people who had dementia at the start of the study, 35% were illiterates and 18% were literates. After further analysis, they found that illiterates had nearly a three times greater chance of having dementia at the start of the study.
To test those who did not have dementia at the start of the study, the team conducted tests after four years. The results showed that dementia incidence was lower among literates: 48% of the illiterates and 27% of the literates had dementia. The researchers add that people who could not read and write were twice as likely to develop dementia during the study.
Based on the current findings, Manly says future studies directed towards understanding whether teaching people to read and write could lower the risk of dementia.