Exposure to chronic stress in early childhood is associated with poor health and developmental outcomes that extend across the lifespan (McEwen, 2008). To better communicate this crucial link to policymakers and the public, researchers developed a metaphor to describe three types of stress response in early childhood: positive stress, tolerable stress, and toxic stress (Shonkoff et al., 2012). The most potent stress response, toxic stress, results from exposure to chronic stressors in childhood such as poverty, violence or parental mental illness. Without the protection of a nurturing adult, this exposure can result in persistent elevation of the child's stress response system, and over time may lead to impaired physical and mental health in both childhood and adulthood (Garner, 2013; Shonkoff, 2012). Given the detrimental effects of experiencing a toxic stress response, it is important to understand factors that may protect against this response in order to promote health and reduce disparities among vulnerable families at risk.
Although studies of animals and maltreated children demonstrate that supportive caregiving can buffer against a toxic stress response, the specific human caregiving patterns that best protect children are poorly understood (Hostinar, Sullivan, & Gunnar, 2014). Thus, this dissertation study addresses a critical gap in knowledge regarding the relationships among maternal characteristics, maternal caregiving, and indicators of exposure to chronic stress in children among multiethnic maternal-child dyads living in socioeconomically disadvantaged environments. An overview of the dissertation, three manuscripts prepared for publication, and a discussion of implications and next steps are presented in this document.
In the first manuscript (currently under peer review), I conducted a scoping study to explore sources of stress and strength for mothers who are vulnerable due to poverty, young maternal age, or ethnic minority status. Guided by Bronfenbrenner's bioecological model (Bronfenbrenner & Ceci, 1994), the results of this scoping study indicated that sources of stress and strength for vulnerable mothers are complex and transactional in nature. These results provided a framework for selecting key variables for inclusion in the dissertation study, and also highlighted a gap in the literature regarding a lack of research on protective caregiving patterns for vulnerable mothers. This served as an important foundation for the dissertation study aims.
In the second manuscript (accepted for publication in Biological Research for Nursing), I conducted a literature review to describe biomarkers of chronic stress and to review evidence of their use in pediatric research studies. I outlined biomarkers according to the allostatic load model and described primary mediators, secondary outcomes, and tertiary endpoints of the stress response (McEwen, 2008). I selected biomarkers for my dissertation study based on this review. I also discuss directions for future biobehavioral pediatric research studies, including recommendations for theoretically-based approaches to biomarker selection, measurement considerations, ethical issues, and potential moderators for consideration when collecting and analyzing biomarker data.
In the third manuscript (to be submitted to Nursing Research ), I present the methods and key findings from the dissertation study. The purpose of this cross-sectional exploratory study (N=54) was to describe variables of interest and examine associations among maternal characteristics (past maternal experiences and mental health), current caregiving, and children's physiological, health, and behavioral indicators of exposure to chronic stress in a multiethnic, urban sample of mothers and children at early school age (4 to 9 years). Results indicated that a mother's childhood history may have important implications for the health of her children, based on the finding that maternal history of childhood trauma was associated with less supportive and less reflective parenting, as well as increased blood pressure and reported behavioral problems in children. Maternal history of family strengths, however, was associated with higher levels of parental reflective functioning (PRF) and significantly lower body mass index and inflammatory markers in children. The results of this study also indicated that specific components of caregiving, such as PRF, may be protective against toxic stress, as high PRF was associated with lower inflammatory markers and fewer emergency department visits for children. While future research is necessary, the results of this study provide an important foundation for future research studies aiming to uncover the complex mechanisms that may protect against toxic stress among vulnerable families.
Identifying protective factors that may mitigate the effects of toxic stress and intervening with families at risk is critical for improving the health of children in vulnerable families. Given the multi-generational impact of early childhood experiences, the results of this study suggest that a two or three-generation approach is critical for interventions aiming to promote positive caregiving or otherwise strengthen vulnerable families living in environments of adversity. Informed by the results of this exploratory study, future research with large, diverse samples of caregivers and children may ultimately help to inform the development of interventions and policies aiming to promote health and reduce health disparities among children living in vulnerable families.
|Advisor:||Sadler, Lois S.|
|School Location:||United States -- Connecticut|
|Source:||DAI-B 79/12(E), Dissertation Abstracts International|
|Subjects:||Social research, Health sciences, Nursing|
|Keywords:||Biomarkers, Child Health, Cortisol, Mothers, Stress, Trauma|
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