Childhood asthma disparities: Race, place or not keeping pace?

Asthma remains the leading chronic disease of childhood in the US and the annual incidence is increasing, most rapidly among children under five years of age.¹ Studies have well documented the strong association between race/ethnicity and asthma prevalence,² and the increased asthma morbidity among children from lower SES neighborhoods.³

In this issue of the Journal, Zanobetti and colleagues investigate the interaction of race/ethnicity with neighborhood-level physical, social and economic variables, and the effect of these exposures on early childhood wheeze and the age of asthma onset in children. Study data was drawn from ten birth cohorts participating in the Children’s Respiratory and Environmental Workgroup (CREW) Consortium. The cohorts represented children living in neighborhoods of varying population density and economic advantages from four census years between 1980 and 2010. The chronologic span of the birth cohort, a particular strength of this study, captured children born across a wide variance of social economic change and collated information from three major regions of the United States. As a result, the study paints a nationally representative picture over time. This work will make a significant contribution to guiding future research, policies, and interventions targeting reduction in asthma disparities.

Key findings in this article confirm the significance of ethnic and economic contributors to the prevalence of asthma and wheezing among children.^1,3,4 Importantly, they confirm what community providers have voiced experiencing in clinical practice for years.

The authors conclude that Black and Hispanic children have an increased incidence of asthma and an earlier asthma onset relative to White children. Further, children born in socioeconomic tracts with a greater proportion of low-income households, higher population density and greater poverty also experienced a higher incidence of asthma.

Most notably, assessment of effect modification revealed that census variables did not significantly alter the association between race/ethnicity and the risk for increased asthma incidence. Regardless of neighborhood-level socioeconomic variables, Black and Hispanic children remained at increased risk for asthma compared to White children with similar socioeconomic exposures.

These important findings of Zanobetti and colleagues underscore the well-documented evidence^1,4 that racial disparities are not simply the result of socioeconomic disparities. As with every other health outcome for which racial disparities have been documented, racial disparities in asthma risk reflect the reality that race is a social construct that serves as a proxy for complex interactions between genetic ancestry, and environmental and social factors ⁵ related to structural and interpersonal racism. For instance, an emerging body of literature has linked the historical practice of redlining to ongoing increased risk of asthma diagnosis and severity ⁶. One weakness of this article is that the authors did not look at the age or condition of housing stock which may be an important contributor to their findings.

There should now be sufficient evidence to allow us to more resolutely fund and conduct fourth generation health equity research focused on remediating racial disparities in asthma risk.⁷ Importantly, this work must not simply focus on factors modifiable on the individual level. As Zanobetti et al and others’ work shows, mitigating racial disparities in asthma risk will require structural solutions and policy changes. For instance, dollars previously invested in large observational cohort studies could be channeled to quasi-experimental trials that evaluate interventions aimed at mitigating the ongoing impact of historical redlining on modern-day housing quality, home ownership and environmental pollutants on asthma risk and disease. Potential interventions might include housing policy changes, tenant or environmental regulation reform, or prescription drug reform, given the financial stress that chronic asthma medications can impart on families.

In short, to really move towards equity for racial minoritized children at risk of, or suffering from asthma, research priorities must shift. We must undertake rigorous scientific evaluation and dissemination of programmatic and legislative policies and interventions that target the now very well documented root causes of racial disparities in asthma.