Results
From 2013 to 2023, a total of 4,507,061 responses were included in the analysis. Apart from analyses focusing on strata of age, all estimates of cognitive disability were age-adjusted. Most respondents were aged 18–39 years (36.8%), identified as non-Hispanic White (60.9%), and had completed at least a high school education (87.3%). The age-adjusted self-reported cognitive disability prevalence in the United States rose from 5.3% (95% CI 5.1%–5.4%) in 2013 to 7.4% (95% CI 7.2%–7.6%) in 2023, with statistically significant increases beginning in 2016. The prevalence of cognitive disability among younger adults aged 18–39 years nearly doubled, increasing from 5.1% (95% CI 4.8%–5.3%) to 9.7% (95% CI 9.2%–10.2%), making this age group the primary driver of the overall rise in cognitive disability in the United States.
Discussion
The disproportionate growth in cognitive disability among younger adults seems to be the primary driver of the overall national trend. These findings warrant further investigation, given their potential long-term implications for population health, workforce productivity, and health care systems.

An article about the study: https://onepercentrule.substack.com/p/under-40s-declining-memory