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.
Based on the Hertzmann and Boyce article, I think that GxE interactions can contribute to major disparities along racial/ethnic, socioeconomic, and geographic dimensions, as it mentions that those from less privileged backgrounds tend to find themselves in risk-augmenting contexts in early childhood development, and that over time, this will drive the expression of socioeconomic gradients. The gene by environment argument suggests that specific genotypes may produce systematically different characteristics depending on the individual’s environment, rather than genetic or environmental influences serving as the main effect. Because of this, some individuals may be genetically predisposed to certain outcomes which are potentiated by the environment in which they grow and develop, and those with non-white race and ethnicities, low socioeconomic status, or from geographically disadvantaged neighborhoods may be disproportionately at risk.
With respect to interstitial lung disease, some of these diseases are suspected to have a genetic predisposition, and others are very heavily influenced by environmental exposures. Some, however, are thought to be influenced by the interaction between the two. One example includes the higher risk of interstitial lung disease in males with rheumatoid arthritis who smoke. There may be a genetic by environmental interaction such that growth and development in a low income neighborhood leads to an increased allostatic load, and in turn, higher rates of smoking. Because of this, these individuals may be at higher risk of developing interstitial lung disease.
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 Hertzmann and Boyce article calls attention to biological embedding that is likely to occur during sensitive periods in the development of neural circuitry. During these times, development is thought to be “maximally receptive to environmental tuning and input.” Because of this, epigenetic regulation can impact changes in gene expression. As discussed above, this contributes to disparities both at the structural and intermediary level, as those from less privileged backgrounds can find themselves in risk-augmenting contexts. This, in turn, leads to a socioeconomic gradient that can persist across generations due to intergenerational learning of experiences during growth and development that in turn, can be perpetuated when those individuals become adults.
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.
Allostatic load is a result of economic and social opportunities and resources, living and working conditions in homes and communities, behaviors, access to medical care, all of which impact health. In this particular paper, allostatic load was significantly higher in those who lived in neighborhoods that were perceived as unsafe even after adjusting for factors that encompassed neighborhood SES. Additionally, allostatic load has been showed to be elevated in those living in low income neighborhoods. Because of this chronic stress, the allostatic processes are continually activated which in turn, acts as an indicator of future risk for poor health and mortality.