Washington DC: A recent study suggests the people who cannot read and write are at nearly three times higher risk of developing dementia than people who can read and write.
The study is published in an online issue of Neurology, the medical journal of the American Academy of Neurology.
According to the United States Department of Education, approximately 32 million adults in the country are illiterate.
"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," says study author Jennifer J Manly, PhD, of Columbia University Vagelos College of Physicians and Surgeons in New York.
"Previous research has shown that 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," adds Manly.The study has looked at the people with low levels of education, who lived in northern Manhattan.
Researchers asked each person, "Did you ever learn to read or write?"Researchers then divided the people into two groups -- 237 people were illiterate and 746 people were literate.
Participants had medical exams and took memory and thinking tests at the beginning of the study and at follow-up appointments that occurred every 18 months to two years.
Testing included recalling unrelated words and producing as many words as possible when given a category like fruit or clothing.Researchers found the people who were illiterate, 83 of 237 people, or 35 per cent, had dementia at the start of the study.
Of the people who were literate, 134 of 746 people, or 18 per cent, had dementia.
After adjusting for age, socioeconomic status and cardiovascular disease, people who could not read and write had nearly a three times greater chance of having dementia at the start of the study.
Among participants without dementia at the start of the study, during follow-up an average of four years later, 114 of 237 people who were illiterate, or 48 per cent, had dementia.
Of the people who were literate, 201 of 746 people, or 27 per cent, had dementia. After adjusting for age, socioeconomic status and cardiovascular disease, researchers found that people who could not read and write were twice as likely to develop dementia during the study.
When researchers evaluated language, speed, spatial, and reasoning skills, they found that adults who were illiterate had lower scores at the start of the study.
But their test scores did not decline at a more rapid rate as the study progressed."Our study also found that literacy was linked to higher scores on memory and thinking tests overall, not just reading and language scores," said Manly.
"These results suggest that reading may help strengthen the brain in many ways that may help prevent or delay the onset of dementia," added Manly.
"Even if they only have a few years of education, people who learn to read and write may have lifelong advantages over people who never learn these skills," continued Manly.