title: Assessment of neighbourhood-level socioeconomic status as a modifier of air pollution-asthma associations among children in Atlanta.
abstract: A broad literature base provides evidence of association between air pollution and paediatric asthma. Socioeconomic status (SES) may modify these associations; however, previous studies have found inconsistent evidence regarding the role of SES.
  
  
  
  Effect modification of air pollution-paediatric asthma morbidity by multiple indicators of neighbourhood SES was examined in Atlanta, Georgia. Emergency department (ED) visit data were obtained for 5-18 years old with a diagnosis of asthma in 20-county Atlanta during 2002-2008. Daily ZIP Code Tabulation Area (ZCTA)-level concentrations of ozone, nitrogen dioxide, fine particulate matter and elemental carbon were estimated using ambient monitoring data and emissions-based chemical transport model simulations. Pollutant-asthma associations were estimated using a case-crossover approach, controlling for temporal trends and meteorology. Effect modification by ZCTA-level (neighbourhood) SES was examined via stratification.
  
  
  
  We observed stronger air pollution-paediatric asthma associations in 'deprivation areas' (eg, ≥20% of the ZCTA population living in poverty) compared with 'non-deprivation areas'. When stratifying analyses by quartiles of neighbourhood SES, ORs indicated stronger associations in the highest and lowest SES quartiles and weaker associations among the middle quartiles.
  
  
  
  Our results suggest that neighbourhood-level SES is a factor contributing vulnerability to air pollution-related paediatric asthma morbidity in Atlanta. Children living in low SES environments appear to be especially vulnerable given positive ORs and high underlying asthma ED rates. Inconsistent findings of effect modification among previous studies may be partially explained by choice of SES stratification criteria, and the use of multiplicative models combined with differing baseline risk across SES populations.
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Cassandra R
authors.initials: CR
authors.lastname: O'Lenick
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Winquist
authors.affiliation: School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Mulholland
authors.affiliation: School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
authors.forename: Mariel D
authors.initials: MD
authors.lastname: Friberg
authors.affiliation: Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Howard H
authors.initials: HH
authors.lastname: Chang
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kramer
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Lyndsey A
authors.initials: LA
authors.lastname: Darrow
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Stefanie Ebelt
authors.initials: SE
authors.lastname: Sarnat
mesh_terms: D000293:Adolescent; D000397:Air Pollution / Q000032:analysis*; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D005845:Georgia / Q000453:epidemiology; D006801:Humans; D008297:Male; D012111:Residence Characteristics; D012307:Risk Factors; D012923:Social Class; D014505:Urban Population
keywords: AIR POLLUTION; ASTHMA; CHILD HEALTH; Environmental epidemiology; SOCIO-ECONOMIC