More senior citizens in the United States, particularly women, are maintaining healthy brains, according to a new study.
According to a new study, the percentage of older Americans reporting serious memory and thinking problems has decreased in recent years, and higher education levels may be part of the reason.
Researchers discovered that between 2008 and 2017, the proportion of older U.S. adults reporting "serious cognitive problems" decreased from slightly more than 12% to 10%. The reasons are unknown, but an increase in educational attainment among Americans over time appeared to account for a portion of the trend.
As shown by lead researcher Esme Fuller-Thomson, director of the University of Toronto's Institute for Life Course and Aging, "many studies have linked higher education levels to a lower risk of impaired thinking and dementia."
Relative to one theory, people with more education are better able to withstand the pathological brain changes that characterize the dementia process. That is, they can function at a higher level for a longer period of time than their less-educated peers who have experienced the same brain changes.
Education can also be a predictor of other factors that influence dementia risk. People with higher levels of education are less likely to smoke, more likely to exercise and eat a healthy diet, have fewer chronic health conditions, and have better access to health care.
The current study did not look at actual dementia diagnoses, which is a limitation.
"We can't say this is a decline in dementia," Fuller-Thomson explained.
Instead, survey respondents were asked a yes/no question: "Does this person have serious difficulty concentrating, remembering, or making decisions due to a physical, mental, or emotional condition?"
However, Fuller-Thomson believes that this reflects how people were functioning in their daily lives, so the decrease in self-reported problems is encouraging. She believes it is unlikely that people in 2017 simply interpreted the question differently than those in previous years.
The study is not the first to show positive trends in the brain health of older Americans. Some studies have discovered a decrease in dementia diagnoses in recent decades. The Framingham Heart Study, which followed families for three generations, discovered that dementia diagnoses fell by 44% between 1977 and 2008.
According to Fuller-Thomson, the new findings are consistent with previous research and include more recent data.
Matthew Baumgart is the Alzheimer's Association's vice president of health policy. He agreed that the findings are consistent with some studies that track dementia incidence over time. However, as Baumgart pointed out, these patterns are not universal. They have been observed in some high-income Western countries with high levels of education.
And, as the elderly population in the United States and around the world grows, so does the prevalence of dementia (the number of people living with the disease).
"Even though some studies show a decrease in dementia incidence," Baumgart said, "the global Alzheimer's and dementia epidemic is growing."
Per the Alzheimer's Association, over 6 million Americans have Alzheimer's disease, the most common form of dementia. This figure is expected to nearly double to nearly 13 million by 2050.
The current findings are based on data from a 10-year Census Bureau survey. It affected 5.4 million Americans aged 65 and up in total.
In 2008, 13.6 percent of women reported serious cognitive problems; by 2017, that figure had dropped to just under 11 percent. Men, on the other hand, experienced a smaller relative decline, falling from 10.2 percent to 8.8 percent.
The survey did not collect data on lifestyle habits such as smoking, which has decreased in the United States over time. It also lacked information on physical health conditions and a number of other factors that may influence dementia risk.
However, changes in people's educational attainment appeared to explain a portion of the positive trend, according to Fuller-Thomson.
Other broad changes, she speculated, such as improved air quality and the removal of lead from gasoline in the 1970s, could also be potential contributors.
According to Baumgart, researchers are working to learn more about modifiable risk factors for dementia. A clinical trial funded by the Alzheimer's Association is testing whether a combination of lifestyle measures can slow cognitive decline in older adults at high risk. Exercise, better control of high blood pressure and diabetes, and mentally stimulating activities are among these measures.
For the time being, the group recommends all of those things for general brain health support.
When it comes to the burden of dementia on society, the rising prevalence figure is most important, according to Baumgart.
However, Fuller-Thomson believes that the decline in cognitive problems is encouraging for individuals. She pointed out that if 10% of older Americans reported such issues, that means 90% did not.
"Most older adults are functioning at a high level, contributing to society and thriving," she said.
The findings were recently published in the Journal of Alzheimer's Disease.