title: Effect of exposure to traffic on lung development from 10 to 18 years of age: a cohort study.
abstract: BACKGROUND
  Whether local exposure to major roadways adversely affects lung-function growth during the period of rapid lung development that takes place between 10 and 18 years of age is unknown. This study investigated the association between residential exposure to traffic and 8-year lung-function growth.
  
  
  METHODS
  In this prospective study, 3677 children (mean age 10 years [SD 0.44]) participated from 12 southern California communities that represent a wide range in regional air quality. Children were followed up for 8 years, with yearly lung-function measurements recorded. For each child, we identified several indicators of residential exposure to traffic from large roads. Regression analysis was used to establish whether 8-year growth in lung function was associated with local traffic exposure, and whether local traffic effects were independent of regional air quality.
  
  
  RESULTS
  Children who lived within 500 m of a freeway (motorway) had substantial deficits in 8-year growth of forced expiratory volume in 1 s (FEV(1), -81 mL, p=0.01 [95% CI -143 to -18]) and maximum midexpiratory flow rate (MMEF, -127 mL/s, p=0.03 [-243 to -11), compared with children who lived at least 1500 m from a freeway. Joint models showed that both local exposure to freeways and regional air pollution had detrimental, and independent, effects on lung-function growth. Pronounced deficits in attained lung function at age 18 years were recorded for those living within 500 m of a freeway, with mean percent-predicted 97.0% for FEV1 (p=0.013, relative to >1500 m [95% CI 94.6-99.4]) and 93.4% for MMEF (p=0.006 [95% CI 89.1-97.7]).
  
  
  CONCLUSIONS
  Local exposure to traffic on a freeway has adverse effects on children's lung development, which are independent of regional air quality, and which could result in important deficits in attained lung function in later life.
authors.affiliation: Department of Preventive Medicine, University of Southern California, 1540 Alcazar Street, Suite 220, Los Angeles, CA 90033, USA. jimg@usc.edu
authors.forename: W James
authors.initials: WJ
authors.lastname: Gauderman
authors.forename: Hita
authors.initials: H
authors.lastname: Vora
authors.forename: Rob
authors.initials: R
authors.lastname: McConnell
authors.forename: Kiros
authors.initials: K
authors.lastname: Berhane
authors.forename: Frank
authors.initials: F
authors.lastname: Gilliland
authors.forename: Duncan
authors.initials: D
authors.lastname: Thomas
authors.forename: Fred
authors.initials: F
authors.lastname: Lurmann
authors.forename: Edward
authors.initials: E
authors.lastname: Avol
authors.forename: Nino
authors.initials: N
authors.lastname: Kunzli
authors.forename: Michael
authors.initials: M
authors.lastname: Jerrett
authors.forename: John
authors.initials: J
authors.lastname: Peters
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000009:adverse effects*; D002140:California; D002648:Child; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000187:drug effects / Q000254:growth & development*; D008297:Male; D008450:Maximal Midexpiratory Flow Rate; D012923:Social Class; D001335:Vehicle Emissions; D014797:Vital Capacity
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions