title: Parental stress increases the detrimental effect of traffic exposure on children's lung function.
abstract: BACKGROUND
  Emerging evidence indicates that psychosocial stress enhances the effect of traffic exposure on the development of asthma.
  
  
  OBJECTIVE
  We hypothesized that psychosocial stress would also modify the effect of traffic exposure on lung function deficits.
  
  
  METHODS
  We studied 1,399 participants in the Southern California Children's Health Study undergoing lung function testing (mean age, 11.2 yr). We used hierarchical mixed models to assess the joint effect of traffic-related air pollution and stress on lung function.
  
  
  RESULTS
  Psychosocial stress in each child's household was assessed based on parental response to the perceived stress scale (range, 0-16) at study entry. Exposures to nitric oxide, nitrogen dioxide, and total oxides of nitrogen (NOx), surrogates of the traffic-related pollution mixture, were estimated at schools and residences based on a land-use regression model. Among children from high-stress households (parental perceived stress scale > 4) deficits in FEV1 of 4.5 (95% confidence interval, -6.5 to -2.4) and of 2.8% (-5.7 to 0.3) were associated with each 21.8 ppb increase in NOx at homes and schools, respectively. These pollutant effects were significantly larger in the high-stress compared with lower-stress households (interaction P value 0.007 and 0.05 for residential and school NOx, respectively). No significant NOx effects were observed in children from low-stress households. A similar pattern of association was observed for FVC. The observed associations for FEV1 and FVC remained after adjusting for sociodemographic factors and after restricting the analysis to children who do not have asthma.
  
  
  CONCLUSIONS
  A high-stress home environment is associated with increased susceptibility to lung function effects of air pollution both at home and at school.
authors.affiliation: Department of Preventive Medicine, Keck School of Medicine, Los Angeles, CA 90033, USA. islam@usc.edu
authors.forename: Talat
authors.initials: T
authors.lastname: Islam
authors.forename: Robert
authors.initials: R
authors.lastname: Urman
authors.forename: W James
authors.initials: WJ
authors.lastname: Gauderman
authors.forename: Joel
authors.initials: J
authors.lastname: Milam
authors.forename: Fred
authors.initials: F
authors.lastname: Lurmann
authors.forename: Ketan
authors.initials: K
authors.lastname: Shankardass
authors.forename: Ed
authors.initials: E
authors.lastname: Avol
authors.forename: Frank
authors.initials: F
authors.lastname: Gilliland
authors.forename: Rob
authors.initials: R
authors.lastname: McConnell
mesh_terms: D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D002140:California / Q000453:epidemiology; D002648:Child; D016241:Child of Impaired Parents; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D012111:Residence Characteristics; D012129:Respiratory Function Tests; D012306:Risk; D012907:Smoking / Q000523:psychology; D013315:Stress, Psychological; D014028:Tobacco Smoke Pollution / Q000009:adverse effects / Q000032:analysis; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D014028:Tobacco Smoke Pollution; D001335:Vehicle Emissions