Childhood Adversity and Cognitive Impairment in Later Life

Background and Purpose: The life course perspective suggests that the effects of adverse early life events on health can track across the life span. Many studies have shown that childhood adversity affects cognitive function in early childhood. However, whether the detrimental impact persists into older adulthood is unclear. This study examined the association between childhood adversity and incident cognitive impairment in later life and explored the potential moderation effect by sex, race, and education.

Methods: The study sample includes 15,133 participants of the Health and Retirement Study (1998-2016 surveys) who had complete data on key study measures and were over age 50 at baseline. The outcome variable is a dichotomous indicator of cognitive impairment as assessed by the Telephone Interview for Cognitive Status for self-respondents and the 16-item Informant Questionnaire on Cognitive Decline in the Elderly for proxies. Six childhood adversity indicators included grade retention, parental substance abuse, physical abuse, trouble with the police, move due to financial hardship, and receipt of help due to financial hardship in early life. Estimation of the association between childhood adversity and cognitive impairment involved Cox proportional hazards regression.

Results: About half of the study sample reported at least one childhood adversity, with a mean count of 0.8 (SD=1.06). The most prevalent childhood adversity was parental alcohol/drug problems or parental substance abuse (19.2%), followed by financial difficulties that caused a move (16.6%), repeated a year of school or grade retention (16.5%), and receipt of help from relatives due to financial difficulties (14.5%). Grade retention had the largest effect on incident cognitive impairment (HR=1.3, 95% CI=1.23-1.38, p<.001), followed by physical abuse by a parent (HR=1.10, 95% CI=1.00-1.20, p=.001). The impact of grade retention was more detrimental to women than men (HR=0.89, 95% CI=0.80-1.00, p=.048, female as the reference). Parental substance abuse was associated with a lower risk of incident cognitive impairment for most racial groups (HR=0.89, 95% CI=0.83-0.95, p=.001), but this association was reversed in the “non-Hispanic other,” consisted mainly of Asians (HR=1.54, 95% CI=1.05-2.26, p=.025).

Conclusions and Implications: Some aspects of childhood adversity continue to harm cognitive functioning in later life, whereas some events may have the opposite effect, with evidence of heterogeneity across sex and race. Future inquiries into the long-term impact of childhood adversity on cognition should consider individual adverse events in addition to aggregate scores of adverse events. More research is needed to explore mechanisms and mediating factors underlying the gender and racial disparities in associations between early life experiences and cognition in later life.