Gene by Environment Interactions on Late-Life Cognitive Functioning: Integrative Roles of Polygenic Score, Early Life Trauma, and Psychological Resilience
BACKGROUND: Little is known about the integrative roles of genetic, environmental, and psychological factors on late-life cognitive functioning. This study investigated (a) whether early life trauma could moderate the effect of genetic predisposition on late-life cognitive functioning, and (b) whether psychological resilience could moderate the interactive effect of early life trauma and genetic predisposition on late-life cognitive functioning.METHODS: Growth curve modeling was conducted on a nationally representative sample of adults from the European ancestry group aged 50 or older (4,479 females and 3,502 males) from the 2004 – 2016 waves (7 waves) of the Health and Retirement Study. Global cognitive functioning was measured by a total cognition score, composed of fluid and crystallized intelligence. Genetic predisposition for cognitive functioning was measured by polygenic score for general cognition (PGS-gc), and early life trauma was measured by parental alcohol/drug use, physical abuse, and trouble with the police before the age of 18. Psychological resilience was measured as purpose in life and perceived control. RESULTS: After controlling for covariates, PGS-gc, purpose in life, and perceived control, respectively, were significantly and positively associated with global cognitive functioning. Moreover, a significant PGS-gc by early life trauma interaction existed on fluid intelligence. Parental alcohol/substance abuse for older females, and trouble with police for older males, respectively, were significant moderators which decreased the beneficial effect of high PGS-gc on fluid intelligence. Higher perceived control was associated with higher crystallized intelligence (a) among older females with a history of early life trauma and with high PGS-gc; and (b) among males with a history of early life trauma with low PGS-gc, respectively. IMPLICATIONS: The findings demonstrate a gene-by-environment interaction, as early life trauma serves as a significant moderator which attenuates the genetic benefits of PGS-gc on late-life cognitive functioning. Psychological resilience, such as perceived control, has a positive effect on cognitive functioning, and also moderates the interaction effect of PGS-gc and early life trauma on crystallized intelligence. These findings not only provide a clear rationale for trauma-informed care for geriatric populations but also highlight psychological resilience as a modifiable target for effective intervention to promote late-life cognitive health.