Date of Award
College of Arts Humanities and Social Sciences, Psychology
Stress, Health, Cortisol, Child psychology
Early life stress is known to have an enduring impact on individuals’ health trajectories, however, some show greater resiliency to early life stress than others. The exploration of candidate genes and gene-environment interactions may be one promising window on risk versus resilience trajectories. However, prior work involving three polymorphisms (COMT Val158Met, MAOA-LPR, and 5-HTTLPR) has yielded well publicized but inconsistently replicated associations with mental health. Part of this inconsistency may be due to the limited exploration of mechanistic explanations for how these gene-environment interactions lead to variations in health. Thus, this dissertation examines gene-gene and gene-environment interactions in predicting basal cortisol at age eight (assayed from a single blood sample). Data for this project comes from 813 families participating in the Avon Longitudinal Study of Parents and Children (ALSPAC). Early environmental risk is characterized by three well-documented factors (maternal depression, maternal stress exposure, and child stress exposure) compiled across the developmentally salient 0-6 year age range. Contrary to expectation, genetic risk was not related to children’s basal cortisol in middle childhood, and neither were the tested gene-environment interactions. Most measures of environmental risk were also unrelated to children’s cortisol, however maternal stress exposure when the child was 48-61 months old was related to higher basal cortisol. Analyses and discussion describe patterns of environmental risk exposure across early childhood in an effort to better characterize risk trajectories in this sample. Although the current findings do not support HPA axis dysregulation as a mechanism by which gene-environment interactions impact health, methodological limitations likely contributed to these null findings. Future studies should continue to explore such mechanistic explanations in order to create effective interventions for children at high risk for stress related disease.
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Irena Y. Pikovsky
Received from author
Pikovsky, Irena Y., "Cortisol in Middle Childhood: Associations with Genetic Polymorphisms and Early Environmental Risk" (2012). Restricted Access ETDs. 81.