The Relationship between Dementia, Parental Death, and Other Adverse Childhood Experiences: a Systematic Review and Meta-Analysis

Abstract Objective The objective of this review was to determine the association between adverse childhood experiences (ACEs) and dementia risk in older adults. Method Authors searched PubMed, Embase, and Web of Science, restricting to English articles with human subjects. The search syntax included several terms related to early life adversity and dementia, yielding 2677 papers. Following full-text review, references were searched for further relevant studies. We included peer-reviewed cohort and case–control studies involving adults exposed to ACEs as defined by the World Health Organization’s ACEs International Questionnaire with a comparison group of unexposed adults. The outcome of interest was dementia of any etiology based on clinical diagnosis or cognitive screening results. Two authors independently screened titles and abstracts according to a checklist, read full texts for inclusion, and performed data extraction. A third author resolved conflicts. Results Seventeen studies were included for systematic review, and 13 in the meta-analysis. We conducted meta-analyses for odds ratios (ORs) using a random-effects model and evaluated publication and reporting bias with funnel plots and Egger’s test. Initial evaluation covered all ACEs, followed by a separate analysis for parental death. ACE exposure (OR = 1.54; 95% CI 1.38–1.71) and parental death exposure in childhood (OR = 1.42; 95% CI 1.16–1.74; p < 0.0001) were associated with increased odds of developing dementia. Conclusion Although findings suggest that ACEs are associated with higher dementia odds, the limited number of studies, mostly of fair quality, necessitates caution in interpretation. High-quality cohort studies incorporating biomarkers into the outcome of interest are essential.