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Trajectories of cognitive activity from early to late life and risk of Alzheimer’s dementia in community‐dwelling older adults
Author(s) -
Dhana Klodian,
Rajan Kumar B,
Zammit Andrea R,
Wilson Robert S,
Liu Xiaoran,
Aggarwal Neelum T,
Leurgans Sue E,
Bennett David A,
Barnes Lisa L
Publication year - 2021
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.054375
Subject(s) - dementia , cognition , hazard ratio , cognitive decline , psychology , gerontology , confidence interval , cognitive reserve , proportional hazards model , effects of sleep deprivation on cognitive performance , medicine , psychiatry , disease
Background We used a life‐course approach to investigate the relationship between trajectories of cognitive activity from early to late‐life with the risk of Alzheimer’s dementia and elucidate a critical age window during which cognitive activities may exert most of their favorable effects. Method The investigation was based on 1,817 older persons without dementia participating in the Rush Memory and Aging Project, a community‐based clinical‐pathologic study. Participants underwent annual clinical evaluations including questions about cognitive activity over the life‐course. Latent class trajectory analyses were used to develop trajectories of cognitive activity from childhood (6‐12y), young adult (18y), middle‐adult‐life (30‐40y), to late‐life (>65y). Clinical diagnosis of Alzheimer’s dementia was determined using standard criteria. Multivariable adjusted Cox proportional hazard models were used to estimate the hazard ratio(HR) and 95% confidence interval (CI) of trajectories of cognitive activity and Alzheimer’s dementia. Result The average age of study participants was 80 years, 75% were women, and the mean education was 15 years. We identified three groups of participants with distinct trajectories of cognitive activity from early to late‐life. The largest group of individuals (n=1,614, 88.8%) showed steady cognitive activity levels over time – we named this group “stable‐high.” The second group comprised 131 (7.2%) individuals who experienced an increase in cognitive activities after the age of 40 years –‐ the “moderate‐progressive‐increase.” The third group included 72 (4%) individuals who initially engaged in high cognitive activities in early life but then experienced a substantial decrease during middle‐age – the “marked‐decrease” group. During 10 years of follow‐up, 358 (19.7%) of the participants were clinically diagnosed with Alzheimer’s dementia. Compared to individuals in the marked‐decrease group, the risk of Alzheimer’s dementia was 44% lower (HR 0.56, 95%CI 0.37‐0.86) among individuals in the stable‐high group and 53% lower (HR 0.47, 95%CI 0.27‐0.83) in those in the moderate‐progressive‐increase group. Conclusion Using the latent trajectory approach, we identified three distinct cognitive activity trajectories from early to late‐life. These trajectories were differently associated with the risk of Alzheimer’s dementia, suggesting that high cognitive activity starting in middle adult life is protective against Alzheimer’s dementia.