title: Residential proximity to a major roadway is associated with features of asthma control in children.
abstract: BACKGROUND
  While several studies suggest that traffic-related air pollutants are detrimental for respiratory health, few studies have examined relationships between residential proximity to a major roadway and asthma control in children. Furthermore, a major limitation of existing research is reliance on self-reported outcomes. We therefore determined the spatial relationship between the distance from a major roadway and clinical, physiologic and inflammatory features of asthma in a highly characterized sample of asthmatic children 6-17 years of age across a wide range of severities. We hypothesized that a closer residential proximity to a major roadway would be associated with increased respiratory symptoms, altered pulmonary function and a greater magnitude of airway and systemic inflammation.
  
  
  RESULTS
  224 children 6-17 years with confirmed asthma completed questionnaires and underwent spirometry, plethysmography, exhaled nitric oxide determination, exhaled breath condensate collection and venipuncture. Residential distance from a major roadway was determined by mapping the geographic coordinates of the residential address in Geographic Information System software. The distance between the home address and the nearest major roadway was calculated according to the shortest distance between the two points (i.e., "as the crow flies"). Asthmatic children living in closer proximity to a major roadway had an increased frequency of wheezing associated with increased medication requirements and more hospitalizations even after controlling for potential confounders. These children also had increased airway resistance, increased airway inflammation reflected by a lower breath condensate pH, and higher plasma EGF concentrations.
  
  
  CONCLUSIONS
  These findings suggest that closer residential proximity to a major roadway is associated with poorer asthma control in school-age children. Assessment of residential proximity to major roadways may be useful in the clinical evaluation of asthma in children.
authors.affiliation: Department of Pediatrics, Emory University School of Medicine, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Meredith S
authors.initials: MS
authors.lastname: Brown
authors.forename: Stefanie Ebelt
authors.initials: SE
authors.lastname: Sarnat
authors.forename: Karen A
authors.initials: KA
authors.lastname: DeMuth
authors.forename: Lou Ann S
authors.initials: LA
authors.lastname: Brown
authors.forename: Denise R
authors.initials: DR
authors.lastname: Whitlock
authors.forename: Shanae W
authors.initials: SW
authors.lastname: Brown
authors.forename: Paige E
authors.initials: PE
authors.lastname: Tolbert
authors.forename: Anne M
authors.initials: AM
authors.lastname: Fitzpatrick
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000506:poisoning*; D000397:Air Pollution / Q000706:statistics & numerical data; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D002648:Child; D045853:Exhalation / Q000502:physiology; D005260:Female; D040362:Geographic Information Systems; D006798:Housing; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D012129:Respiratory Function Tests / Q000379:methods; D012135:Respiratory Sounds / Q000502:physiology; D001335:Vehicle Emissions / Q000506:poisoning*
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D009569:Nitric Oxide