1. Hertzmann and Boyce argue that “it is not genes or environment, nor is it genes and environment, but rather it is gene-by-environment interactions that influence developmental trajectories.” To what extent do you think that GxE interactions can contribute to major disparities along racial/ethnic, socioeconomic, or geographic dimensions? Please consider this both in general and in respect to your particular area of interest.
As is the case with the majority of theories and models we have reviewed so far, I think that gene by environment interactions are important to keep in mind as a model that contributes to disparities but not the only way in which disparities may manifest or can be explained. With respect to organ allocation and access to liver transplantation, there are several common etiologies of liver disease (Hepatitis C, alcoholic liver disease, and non-alcoholic steatohepatitis) that are exacerbated by health-related behaviors in which genetic predispositions and risk factors are well-established (substance abuse, alcohol use, obesity, respectively). In this regard, patients who are genetically “at risk” and subsequently experience events in their environment that contribute to the development of these habits in the future are probably more at risk for major disparities.
2. Discuss implications of epigenetic mechanisms of disease for intergenerational effects on health disparities, as well as for interventions designed to address health disparities.
The data presented in the Barcelona de Mendoza paper underscores the concept above that gene by environment interactions have a quantifiable impact on individuals. This association of gene methylation with Major Life Discrimination scores suggests that those experiencing major discrimination events are biologically altered, which is compelling evidence of the biologic consequences of health disparities. I thought it was interesting that the RES scale did not show any significant associations with gene methylation. Drawing from the Hartzmann and Boyce paper, the RES scale seems more geared towards identifying cumulative relationships between race-related adverse experiences, while the MLD scale is more focused on singular, formative events. My gestalt was that cumulative exposures might have a more robust relationship with genetic modifications, but these results seem to suggest otherwise. This discrepancy in findings also highlights the importance of careful and specific instrument choices when evaluating the perception of racism/discrimination.
3. Discuss how the findings in the Robinette paper relate to socioecological model we are using in this course – e.g. briefly describe how the different levels displayed in this model are related to each other in this paper.
Robinette et al re-demonstrate that allostatic load is higher in low income neighborhoods and further identify that anxiety, exercise habits, smoking, and fast food consumption partially account for this relationship, while gender, age, and individual income do not. The levels in our socioeconomic model include economic and social opportunities, living and working conditions, behaviors, medical care, and interaction with genetics as factors that contribute to overall health. The Robinette paper categorizes the following pathways: psychological, affective, and behavioral, but in the end they are all shown to contribute to increased allostatic load, which in turn impacts overall health. This interconnected framework is similar to the RWJ model we are utilizing.