Lifecourse Traumatic Events and Cognitive Aging in the Health and Retirement Study.

INTRODUCTION: Much of the heterogeneity in the rate of cognitive decline and the age of dementia onset remains unexplained, and there is compelling data supporting psychosocial stressors as important risk factors. However, the literature has yet to come to a consensus on whether there is a causal relationship and, if there is, its direction and strength. This study estimates the relationship between lifecourse traumatic events and cognitive trajectories and predicted dementia incidence.

METHODS: Using data on 7,785 participants aged ≥65 years from the Health and Retirement Study, this study estimated the association between lifecourse experience of 10 traumatic events (e.g., losing a child) and trajectories of Telephone Interview for Cognitive Status from 2006 to 2016 using linear mixed-effects models and predicted incident dementia from 2006 to 2014 using cumulative incidence functions (data analysis was in 2020-2022). Inverse probability weights accounted for loss to follow-up and confounding by sex, education, race/ethnicity, and age.

RESULTS: Experiencing 1 or more traumatic events over the lifecourse was associated with accelerated decline compared with experiencing no events (e.g., β= -0.05 [95% CI= -0.07, -0.02] Health and Retirement Study-Telephone Interview for Cognitive Status units/year; 1 vs 0 events). In contrast, experiencing traumatic events was associated with better cognitive function cross-sectionally. Furthermore, the impact of trauma on cognitive decline was of greater magnitude when it occurred after the age of 64 years. However, the magnitude and direction of association varied by the specific traumatic event. There were no associations with predicted incident dementia.

CONCLUSIONS: These results suggest that researchers and clinicians should not aggregate traumatic events for understanding the risk of accelerated cognitive decline.