Air Pollutants and Asthma Hospitalization in the Medicaid Population

• Published in: American journal of respiratory and critical care medicine 2022-05, Vol.205 (9), p.1075-1083
• Main Authors: Wei, Yaguang, Qiu, Xinye, Sabath, Matthew Benjamin, Yazdi, Mahdieh Danesh, Yin, Kanhua, Li, Longxiang, Peralta, Adjani A, Wang, Cuicui, Koutrakis, Petros, Zanobetti, Antonella, Dominici, Francesca, Schwartz, Joel D
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Air Pollutants - toxicity; Air pollution; Air Pollution - adverse effects; Air Pollution - analysis; Airborne particulates; Asthma; Asthma - chemically induced; Asthma - epidemiology; Environmental Exposure - adverse effects; Environmental Exposure - analysis; Hospitalization; Humans; Medicaid; Nitrogen Dioxide - adverse effects; Original; Ozone - adverse effects; Ozone - analysis; Particulate Matter - adverse effects; Particulate Matter - analysis; Population density; Socioeconomic factors; United States - epidemiology
• ISSN: 1073-449X; 1535-4970
• DOI: 10.1164/rccm.202107-1596OC

Risk of asthma hospitalization and its disparities associated with air pollutant exposures are less clear within socioeconomically disadvantaged populations, particularly at low degrees of exposure. To assess effects of short-term exposures to fine particulate matter (particulate matter with an aerodynamic diameter of ⩽2.5 μm [PM ]), warm-season ozone (O ), and nitrogen dioxide (NO ) on risk of asthma hospitalization among national Medicaid beneficiaries, the most disadvantaged population in the United States, and to test whether any subpopulations were at higher risk. We constructed a time-stratified case-crossover dataset among 1,627,002 hospitalizations during 2000-2012 and estimated risk of asthma hospitalization associated with short-term PM , O , and NO exposures. We then restricted the analysis to hospitalizations with degrees of exposure below increasingly stringent thresholds. Furthermore, we tested effect modifications by individual- and community-level characteristics. Each 1-μg/m increase in PM , 1-ppb increase in O , and 1-ppb increase in NO was associated with 0.31% (95% confidence interval [CI], 0.24-0.37%), 0.10% (95% CI, 0.05 - 0.15%), and 0.28% (95% CI, 0.24 - 0.32%) increase in risk of asthma hospitalization, respectively. Low-level PM and NO exposures were associated with higher risk. Furthermore, beneficiaries with only one asthma hospitalization during the study period or in communities with lower population density, higher average body mass index, longer distance to the nearest hospital, or greater neighborhood deprivation experienced higher risk. Short-term air pollutant exposures increased risk of asthma hospitalization among Medicaid beneficiaries, even at concentrations well below national standards. The subgroup differences suggested individual and contextual factors contributed to asthma disparities under effects of air pollutant exposures.