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Examining the role of environmental quality in asthma-related hospitalizations
Citation:
Gray, C., S. Grabich, L. Messer, J. Jagai, K. Rappazzo, AND D. Lobdell. Examining the role of environmental quality in asthma-related hospitalizations. Society for Epidemiologic Research, Denver, CO, June 16 - 19, 2015.
Impact/Purpose:
This abstract demonstrates the utility of the Environmental Quality Index in assessing environmental exposures related to asthma hospitalizations.
Description:
Asthma prevalence in the U.S. increased 12.3% from 2001 to 2009, causing 479,300 hospitalizations and 1.9 million emergency room visits in 2009 alone. Environmental quality is of particular concern: air pollution and low socioeconomic status have been associated with asthma, while exposure to green space has been linked to reductions in atopic sensitization, an asthma precursor. We linked the Environmental Quality Index (EQI), which represents 5 environmental domains (air, water, land, built, and sociodemographic) for all US counties (N=3,141) from 2000—2005 to county-level, age-adjusted asthma-related hospitalizations from 2005—2010 using data from the Environmental Public Health Tracking Network (N=1,150 counties). We used random intercept multi-level linear regression clustered by state to estimate fixed effects of quintiles of the EQI on asthma hospitalization rates. We stratified models by 4 rural-urban continuum codes (RUCC) ranging from most urban (RUCC1) to rural (RUCC4). Prevalence differences (PD) and 95% confidence intervals (CI) comparing the highest quintile (worst quality) to lowest quintile (best quality) are reported. For the overall EQI, we observed negative associations across strata (RUCC1: -0.52(-2.67, 1.63); RUCC2: -6.36(-9.42, -3.29), RUCC3: -1.75(-4.76, 1.25), RUCC4: -2.36(-7.83, 3.10)); as environmental quality worsened, asthma hospitalizations decreased. We further examined domain-specific EQIs. Results varied by RUCC strata; key associations were: in RUCC1, the air (5.88(3.97, 7.79)) and sociodemographic (9.011(7.36, 10.66)) domains; for RUCC2, the air (3.64(0.89, 6.40)) and land (-5.81(-8.77, -2.85)) domains; in RUCC3, the sociodemographic (-5.61(-8.23, -2.97)) domain; and for RUCC4, the air (4.16(-0.93, 9.23)) and water (-3.96(-7.30, -0.61)) domains. Environmental quality is associated with asthma-related hospitalizations, but is driven by different domains depending on urbanicity. This abstract does not necessarily reflect EPA policy.