Are Socioeconomic Inequalities in Physical Health Mediated by Embodied Environmental Toxins?

Abstract

Although established theoretical models suggest that socioeconomic inequalities in physical health are partially mediated or explained by exposures to environmental toxins, there is little empirical evidence to support these processes. Building on previous research, we analyze data from the National Health and Nutrition Examination Surveys (2007–2008) to formally test whether associations between socioeconomic status and self-rated physical health are mediated by direct biological assessments of environmental toxins. We find that the embodiment of environmental toxins is disproportionate in individuals of lower socioeconomic status. Although toxins in general and lead in particular are unrelated to self-rated health, socioeconomic differences in self-rated physical health are partially mediated by embodied cadmium. Our mediation analyses suggest that education and income may promote physical health by reducing exposures to cadmium. This study contributes to previous work by bridging the fields of social epidemiology and environmental inequality and by formally testing established theoretical models.

Power, proximity, and physiology: does income inequality and racial composition amplify the impacts of air pollution on life expectancy in the United States?

“…Environmental justice and public health research suggest that segregation produces and reinforces structural inequities in the context of residential proximity to emitters of industrial pollution (Boyce and Pastor 2013, Mohai and Saha 2015, Ard 2016, Pulido 2016, Brailsford et al 2018, Mikati et al 2018. For example, Mikati and colleagues (2018) find that socioeconomically disadvantaged groups and neighborhoods are exposed to higher levels of PM 2.5 from facilities than wealthier communities, and this pattern is especially pronounced for black communities that are often socioeconomically disadvantaged.…”

Do exposure to heavy metals mediate the associations between socioeconomic indicators and self-rated health among the US adult Populations: A Weighted Quantile Sum Mediation Approach

“…Further research and longitudinal studies are needed to corroborate this study results and to make robust causal inferences. We suggest with reference to previous studies that neighborhoods with high concentration of poverty and people of low income and education are extremely vulnerable to the higher exposure to toxic heavy metals and their deleterious effects on SRH (Evans and Kantrowitz 2002;Evans and Kim 2010;Brender et al 2011;Morello-Frosch et al 2011;Tyrrell et al 2013;Ard et al 2016;Brailsford et al 2018). Thus, crafting public health interventions speci cally tailored to these disadvantaged communities (Evans and Kantrowitz 2002;Adler and Rehkopf 2008;Evans and Kim 2010;Brender et al 2011;Chakraborty et al 2011;Tyrrell et al 2013;Brailsford et al 2018) Mediation effect of WQS index of heavy metals mixtures on SRH…”

“…The observed association between SES and the combined effects of metals is often overlooked in previous studies (Mendy et al 2012;Tyrrell et al 2013;Awata et al 2017;Brailsford et al 2018). To our best knowledge, no study has examined both blood and urinary metal mixture effects on SRH and its mediating role in the associations between SES and SRH using the mixture approach.…”

“…Epidemiological studies have shown that people who are highly exposed to a range of environmental toxins tend to have poor health status, as indicated by higher prevalence of respiratory disease, obesity, hypertension, cardiovascular disease, diabetes, cancer, liver damage, kidney ailment, vision impairment, and lower cognitive function in adults (Evans and Kantrowitz 2002;Evans and Kim 2010;Mendy et al 2012;Cullati et al 2014;Chowdhury et al 2018). Two previous studies assessed the effects of toxic heavy metals on SRH and found that people with higher exposures to urinary heavy metals were more likely to rate their health as poor, fair, and good (Shiue 2015;Brailsford et al 2018). Hence, some scholars theoretically argued that non-social environmental factors, such as exposure to pollutants, may constitute a signi cant pathway connecting SES and SRH, which has not yet been measured and studied empirically (Evans and Kantrowitz 2002;Evans and Kim 2010;Chakraborty et al 2011).…”

The Toll of Inequality

“…And because of the economic vulnerability of low SES families, any single negative economic event (e.g., loss of employment) can also trigger a cascade of further stressful events (e.g., loss of income, eviction from one’s home, family conflict or dissolution), amplifying the negative health impact (Adler and Stewart, 2010; Evans and Kim, 2010; O’Rand and Lynch, 2018; Thoits 2010; Williams et al, 2010; Wolfe et al, 2012). Fourth, the health prospects of those with lower SES are chronically undermined by their greater exposure to a host of environmental hazards—chemical toxins and pollutants in their jobs and neighborhoods, unsafe working conditions, substandard housing, residential overcrowding, social disorder, criminal predation and violence, and poor access to healthy foods combined with commercial targeting by the purveyors of junk food, tobacco, alcohol, and illicit drugs (Bower et al, 2014; Brailsford et al, 2018; Cagney and York Cornwall, 2018; Clougherty et al, 2010; Diez Roux and Mair, 2010; O’Rand and Lynch, 2018; Sampson 2012; Wilkinson and Marmot, 2003; Williams et al, 2010). Finally, those with lower SES have less control or autonomy in both their work and personal lives, deficits that undermine personal efficacy and generate chronic stress (Lundberg 1999; Marmot et al, 1997; Marmot 2001; Matthews et al, 2010).…”