The relationship between cognitive abilities in youth and dementia risk in older age has been explored in an NIA-funded study, recently published in “Alzheimer’s & Dementia.” The investigation reveals that cognitive performance in adolescence may serve as a predictor for later dementia risk, tied in part to its correlation with levels of educational achievement. These findings emphasize the enduring impact of early life cognitive faculties on long-term neurological health.
Prior studies have confirmed that lower educational levels increase susceptibility to dementia. Other research has also indicated a connection between the cognitive capabilities displayed in younger years and the likelihood of developing dementia. Building upon these insights, researchers at the University of Southern California conducted an in-depth analysis using data from the Project Talent Aging Study (PTAS). Project Talent is a comprehensive, decades-spanning study that began in 1960 with 377,015 high school students across the nation. The PTAS zooms in on a subset of the initial cohort, extending its focus to encompass the aging process and health evolution.
The original Project Talent participants were evaluated for cognitive abilities while in high school in 1960. Fast forward to 2018, a cohort of 22,584 of these individuals was invited to join the follow-up PTAS. The selection process for the PTAS gave priority to those from racially diverse and predominantly Black schools. Efforts were made to include twins and siblings in the sample, as well as to bolster the representation of individuals from varied ethnic backgrounds. The evaluations administered to the PTAS participants aimed to measure cognitive functions and proficiency in memory and cognition-related tasks, acting as indicators of possible dementia or mild cognitive impairment.
The investigation commenced with a dual-phase approach. In its inaugural phase, an extensive cohort of 6,491 individuals engaged with a detailed postal survey probing into their educational background, vocational history, and an array of demographic factors including age, gender, race, and socioeconomic status benchmarks as of 1960. Subsequent to this initial phase, only those who duly completed the survey were extended the opportunity to partake in the following phase. This second segment of the study, which witnessed the participation of 2,411 individuals, incorporated telephonic cognitive assessments and an online questionnaire delving into aspects concerning memory, lifestyle, familial history, and health status.
Within their analytical pursuit, the researchers discerned that cognitive prowess in adolescence serves as a harbinger for cognitive deficits and dementia in the twilight years. To further elucidate this connection, they employed statistical models to unearth not only the direct impact of adolescent cognitive abilities on dementia risk but also their indirect influence via the attainment of higher education and subsequent immersion in complex occupational roles, both of which could potentially mitigate this risk. Notably, results indicated that heightened cognitive capabilities in early life coupled with advanced educational achievement correlated with a diminished likelihood of later life cognitive impairment. While the duration of educational engagement emerged as a formidable predictor of the participants’ chosen vocations, the occupational complexity was found to have no additional bearing on cognitive impairment or dementia, beyond the paramount influence of adolescent cognitive abilities.
This evidence gained extra credence from the analysis of twin dyads, which inherently exhibit comparable levels of cognitive abilities. Scrutinizing 82 twin pairs with discordant cognitive outcomes—one twin with cognitive impairment or dementia, the other devoid of such ailments—revealed that despite analogous scores in adolescent cognitive abilities, variances in educational pursuits were predictive of their existing cognitive status. This underlines that the association between early cognitive faculties and later life cognitive deficits is not solely pinned on genetic determinants or a collective familial milieu.
The results of the study indicate a notable link between cognitive abilities in adolescence and the risk of dementia and cognitive impairment in later life. Furthermore, the research revealed that lower levels of educational attainment emerge as a risk factor for dementia, potentially due to the interplay between education and early-life cognitive abilities.