Social inequities are strongly associated with health disparities. Research shows that chronic and traumatic social inequities can be epigenetic and complicate the health risks of inflammatory illnesses such as type 2 diabetes, cardiovascular disease, and depression. Linda D. Oakley, PhD, University of Wisconsin, Madison, Wisconsin, USA, presented the findings of this study, conducted with Rick P. Voland, PhD, University of Wisconsin, Madison, Wisconsin, USA which tested basic assumptions of the epigenetic biological link between social inequities and health disparities in African Americans living in the United States.

The study design was guided by an upstream socialecological model of race as a potential mediator of the relationship between social inequities and health disparities (Figure 1).

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Figure 1.

Social-Ecological Model of African American Population: Effects on SES and Health

AA, African American; HS, high school; SES, socioeconomic status.Reproduced with permission from LD Oakley, PhD.

The study sample was collected from US population data aggregated by county [University of Wisconsin Population Health Institute. 2014 County Health Rankings. 2014]. The mediators tested were African American total population, density, and percentage; level of black-white population segregation; and nonracial fragmentation of municipal infrastructures. Socioeconomic status (SES) was defined as the percentage of county adults who had a high school diploma with or without some years of college, were unemployed, lacked support, and had children living in poverty. Health outcome variables were premature mortality, fair or poor health, number of days of poor physical health, and number of days of poor mental health. Premature mortality was defined as mean years of life lost before age 65. Fair-poor health was defined as mean adult self-ratings of fair or poor health. A poor physical health day was defined as mean days lost in the past month due to poor physical health. A poor mental health day was defined as mean days lost in the past month due to poor mental health.

The total county population was 233 584 (11.1%) African Americans, with a mean African American density per square mile of 4993. The mean number of premature deaths in years per 100 000 was 7273. The percentages of African Americans with fair or poor health, poor physical health days per month, and poor mental health days per month were 15.2%, 3.6%, and 3.4%, respectively. The high school graduation rate was 81.7%, and 60.2% attended some college. Almost 20% of African American children were living in poverty. The percentages of African Americans with no socioeconomic support or employment were 19.3% and 9.2%, respectively.

The African American percentage of the total county population was the only mediator associated with both SES and health outcome variables (Table 1). The impact indices for all but 1 health outcome were significantly (β ≥ 0.1, 95% CI) associated with the African American population percentage.

The African American total number, the African American county density, the black-white segregation level, and municipal fragmentation were not associated with either SES or county health outcomes.

Poor mental health days had the largest (16.7%) mediating effect with respect to race. The association of SES with poor mental health days was negatively mediated by the population percentage of African Americans. This mediation effect decreased as the population percentage of African Americans increased. Psychiatric nursing assessment of poor mental health in persons coping with comorbid illnesses and problems with education, employment, social support, and poverty should include the social-ecological effects of race.