Low income children experience greater increases in ED visits at the same level of increase in pollutant exposure

Background: Previous studies have shown that air pollution exposures are related to ED visits. Additionally, low-income children have higher rates of emergency department (ED) visits. However, the questions remain: Do low-income children have greater exposure to ambient air pollutants, and do they experience greater air pollutant impacts due to interaction between their exposures and vulnerability factors? This study is designed to answer these questions, specifically to examine if low income children have a greater increase in ED visits at the same level of increase in pollutant exposure.

Methods: Using Geographic Information System (GIS) software, California Health Interview Survey (CHIS) 2003 children's home addresses were linked to government air monitoring data for NO2. Individual annual average pollutant exposure was estimated. Logistic regression analyses were performed to evaluate interactions between pollutant exposure with poverty level, controlling for race/ethnicity, age, and gender.

Results: Children with asthma living below 200% of the federal poverty level (FPL) had greater NO2 exposure (24.1 ppb vs. 20.2 ppb, respectively; p=<0.001) and a greater prevalence of ED visits (26.4% vs. 14.7%, respectively; p=<0.001). Children with asthma living below 200% of the FPL also experienced greater increases in emergency department (ED) visits than children living at ≥400% of the FPL with the same increase in NO2 exposure (p=0.01).

Conclusion: Low-income children have greater increases in ED visits at the same level of increase in pollutant exposure as high-income children. Health policy and community design should reflect the importance of protecting children from environmental exposures contributing to greater asthma burden within these vulnerable sub-populations.