Rates of self-reported cognitive disability among U.S. adults are on the increase, driven largely by a surprising jump among young adults ages 18 to 39, according to a new Yale study.
The study drew on data from the U.S. Centers for Disease Control and Prevention's (CDC) Behavioral Risk Factor Surveillance System, an annual phone survey of U.S. adults. The survey asks respondents how often they experienced serious trouble with memory, concentration, or decision-making, conditions which the CDC labels as "cognitive disability."
In their analysis of the findings, researchers examined more than 4.5 million survey responses from 2013 to 2023, skipping 2020 when pandemic-related restrictions disrupted survey participation.
Few prior studies have tracked responses to this survey and how they've evolved over time.
Researchers found the percentage of overall adults reporting cognitive disability increased from 5.3% in 2013 to 7.4% in 2023, with young adults (ages 18 to 39) seeing the biggest rise. Their rates nearly doubled from 5.1% to 9.7%, driving most of the overall increase.
"What stood out was the surprising rise among young adults," said study author Adam de Havenon, an associate professor of neurology term at the Yale School of Medicine.
Kevin Sheth, professor of neurology and neurosurgery and founding director of the Yale Center for Brain & Mind Health, also took part, along with researchers from the University of Utah and from the Mass General Brigham health system.
The study appears in the journal Neurology.
While the findings raise concerns, de Havenon stressed that they don't mean a public health tsunami of dementia cases is on the horizon.
"This isn't a diagnosis of dementia or even of cognitive impairment," he explained. "It's a subjective report of people saying they're having serious difficulty concentrating, remembering, or making decisions. With dementia, there's a structural brain disease and a specific pathology that's injuring the brain and leading to cognitive impairment."
That said, the findings do warrant further investigation, as growing cognitive problems among the population can pose future health care and workplace consequences.
"It's important to highlight that impairment in cognition is a problem in the adult population of the United States," de Havenon said. "It's something that I think we'll be paying more and more attention to in the years to come."
Of course, the study is not without its limitations. Although researchers eliminated responses from people reporting depression, dementia, and other cognitive disabilities, self-reported data is still based on subjective perception.
Furthermore, growing public awareness of cognitive health - what constitutes it and what threatens it - could be prompting rising self-reported rates. Are more people reporting impairment simply because they can now recognize it?
"I'd argue that we can't answer that question, but the fact that more people are reporting this as a disability means we should be paying more attention to it," de Havenon said. "Because either people are better at reporting it or we're underdiagnosing it, and it's occurring for reasons that we don't understand yet."
The study also yielded demographic correlations, showing that cognitive problems afflict communities unevenly.
Adults who identified as American Indian, Alaska Native, and Hispanic reported the highest rates of cognitive disability, while Asian adults reported the lowest. Lower income and lower educational rates were strongly linked to higher rates of cognitive disability, as were geographic differences: the South and Midwest regions had higher rates, while the Northeast had the lowest.
And people with chronic health problems (such as diabetes or high blood pressure) were much more likely to report cognitive disability.
"These are already well-known phenomena: Cognitive impairment follows social determinants of health," said de Havenon, who has a specializes in vascular neurology conditions that involve blood vessels in and around the brain. The study is part of his ongoing investigation into the epidemiology of cognitive impairment in the U.S.
"A lot of work has been done in small cohorts looking at very specific disease pathology like the plaques that cause certain dementia," de Havenon said. "My goal is to start talking about how vascular interventions at a population level could improve not only stroke and cardiovascular disease rates, but also cognition."
