Study Uncovers Early Alzheimer's Risk Factors Affecting Cognition in Young Adults

A recent investigation conducted by researchers at Columbia University's Mailman School of Public Health, in collaboration with the Columbia Butler Aging Center, indicates that Alzheimer's disease risk factors may begin to influence cognitive abilities in individuals as young as 24. This groundbreaking study emphasizes the significance of identifying these risk factors early to enhance preventative measures.

Published in The Lancet Regional Health Americas, this study represents the first systematic examination of Alzheimer's disease risk factors and biomarkers associated with cognitive decline in a sizable cohort of generally healthy middle-aged adults in the United States. Previous research primarily focused on individuals aged 50 and older, leaving a gap in understanding the early signs of cognitive impairment linked to Alzheimer's.

Dr. Allison Aiello, a professor of epidemiology at the Butler Aging Center, highlighted the importance of these findings, stating that recognizing risk factors earlier in life could drastically alter how clinicians and researchers approach Alzheimer's disease. The study revealed a clear connection between various established risk factors and cognitive performance, suggesting that the trajectory of cognitive decline can be predicted well before midlife.

The research utilized the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) score, which takes into account numerous health factors such as age, education, gender, systolic blood pressure, body mass index (BMI), cholesterol levels, physical activity, and the presence of the apolipoprotein E ?4 allele (APOE ?4), a genetic risk factor for Alzheimer's disease. Data were analyzed from Waves IV and V of the National Longitudinal Study of Adolescent to Adult Health (Add Health), which has tracked a representative group of adolescents since the mid-1990s.

In particular, Wave IV comprised data from approximately 11,449 participants aged 24 to 34. Researchers conducted in-home interviews, cognitive assessments, physical examinations, and collected blood samples from over 4,500 individuals. In Wave V, participants aged 34 to 44 were invited to participate in both in-person and online surveys.

Cognitive tasks administered included immediate and delayed word recall, as well as backward digit span tasks. The results indicated significant correlations between the CAIDE score and cognitive performance, particularly among those under 50.

Moreover, the study highlighted the relevance of biological markers--such as genetic, neurological, immune, and inflammatory indicators--in assessing Alzheimer's disease risk. The amyloid (A), tau (T), and neurodegeneration (N) biomarkers, collectively referred to as ATN, were found to have associations with cognitive function prior to reaching midlife. However, the APOE genetic risk factor did not show an impact until later in life.

Overall, the findings suggest that blood-based biomarkers associated with Alzheimer's disease reflect differences in cognitive functioning decades before clinical symptoms emerge. This underscores the critical need for early intervention strategies to mitigate the anticipated rise in Alzheimer's disease prevalence in future decades.

Co-authors of the study included researchers from the University of North Carolina at Chapel Hill and other affiliated institutions, contributing to a comprehensive understanding of Alzheimer's disease risk factors across different demographics.