Environmental justice index and prevalence of asthma and COPD in US neighborhoods- a population-based study

Abstract

Background: The independent effects of social and environmental factors on asthma and chronic obstructive pulmonary disease (COPD) are well-documented, but less is known about their combined impact across US neighborhoods. This study aimed to determine the combined and individual associations of neighborhood-level social vulnerability and environmental burden with the prevalence of asthma and COPD.

Methods: This cross-sectional study analyzed 71,677 US census tracts, linking the 2022 CDC Environmental Justice Index (EJI) rankings and its subcomponents (environmental burden module [EBM] and social vulnerability module [SVM]) to the 2023 CDC PLACES dataset. Multivariable quasi-Poisson regression with an offset function was used to compare covariate-adjusted risk ratios of health indicators across quartiles of neighborhood socio-environmental burden.

Findings: Among the 71,677 neighborhoods studied, the median proportion of females was 50.90%. The median proportions of individuals aged 18 to 44, 45 to 64, and ≥65 were 30.6%, 26.7%, and 15.3%, respectively, with 22.6% of the Hispanic population. Asthma and COPD prevalence rates increased with increasing EJI and EBM quartiles. Neighborhoods with the highest socio-environmental burden (Q4 EJI) had significantly higher rates of asthma (RR:1.102, 95% CI: 1.087-1.117, p < 0.001) and COPD (RR:1.156, 95% CI:1.141-1.172, p < 0.001) compared to neighborhoods with the lowest burden (Q1 EJI), after adjusting for covariates. Similarly, neighborhoods with the highest environmental burden (Q4 EBM) had higher rates of asthma (RR: 1.091, 95% CI: 1.064-1.118, p < 0.001) and COPD (RR:1.099, 95% CI: 1.070-1.129, p < 0.001) compared with Q1 EBM, after adjusting for SVM and other covariates.

Interpretation: A higher prevalence of obstructive lung disease is associated with neighborhoods experiencing high cumulative socio-environmental burden. Environmental burden showed an independent association with asthma and COPD prevalence, even after adjusting for social vulnerability and other factors.

Funding: None.

Keywords: Asthma and COPD; Environmental burden index; Environmental justice index (EJI); Social determinants of health (SDOH); Social vulnerability index.

Fig. 1

Choropleth maps of the Environmental Justice Index across census tracts. Abbreviation: EJI: Environmental Justice Index; COPD: Chronic obstructive pulmonary disease. EJI categories were defined based on ranked percentile scores: low (<25th percentile), medium (51st–75th percentile), and high (76th–100th percentile). EJI combines both environmental and social vulnerability measures.

Fig. 2

Choropleth maps of environmental burden, social vulnerability, and pulmonary outcomes across the US Census tracts. a) the US choropleth map of environmental burden at the census tract level. b) the US choropleth map of social vulnerability at the census tract level. c) the US choropleth map of the prevalence rate of asthma at the census tract level. d) the US choropleth map of COPD prevalence at the census tract level. Created using R programming. Source: CDC PLACES database. Abbreviation: EBM: Environmental burden module; SVM: Social vulnerability module; COPD: Chronic obstructive pulmonary disease. Environmental burden categories were defined based on ranked percentile scores of the Environmental Burden Module (EBM): low medium (25th–50th percentile), medium (51st–75th percentile), and high (76th–100th percentile). EBM includes measures of air quality, built environment, and other environmental hazards. Social vulnerability categories were defined based on ranked percentile scores of the Social Vulnerability Module (SVM): low medium (25th–50th percentile), medium (51st–75th percentile), and high (76th–100th percentile). SVM includes measures of socioeconomic status, minority status, housing, and transportation. Table represents two distinct analyses: (1) Association of environmental burden module (EBM) quartiles with asthma and COPD prevalence, adjusted for social vulnerability module (SVM) in three scenarios: unadjusted, adjusted for age categories only, and fully adjusted for multiple covariates; (2) Association of social vulnerability module (SVM) quartiles with asthma and COPD prevalence, adjusted for environmental burden module (EBM) in the same three scenarios. EBM-SVM interaction was tested in all models. Fully adjusted models include age category, healthcare visits, gender percentage, smoking status, and rurality as covariates. RR = relative risk; CI = confidence interval.