title: Children's respiratory health and oxidative potential of PM2.5: the PIAMA birth cohort study.
abstract: BACKGROUND
  The oxidative potential (OP) of particulate matter (PM) has been proposed as a health-relevant metric, but currently few epidemiological studies investigated associations of OP with health. Our main aim was to assess associations of long-term exposure to OP with respiratory health in children. Our second aim was to evaluate whether OP is more consistently associated with respiratory health than PM mass, PM composition or nitrogen dioxide (NO2).
  
  
  METHODS
  For 3701 participants of a prospective birth cohort, annual average concentrations of OP (assessed by spin resonance (OP(ESR)) and dithiothreitol assay (OP(DTT))), PM with an aerodynamic diameter of less than 2.5 µm (PM2.5) mass, NO2, and PM2.5 constituents at the home addresses at birth and at all follow-up addresses were estimated by land-use regression. Repeated questionnaire reports of asthma and hay fever until age 14 years, and measurements of allergic sensitisation, lung function and fractional exhaled nitric oxide at age 12 years were linked with air pollution concentrations.
  
  
  RESULTS
  Asthma incidence, prevalence of asthma symptoms and rhinitis were positively associated with OP(DTT) (adjusted OR (95% CI) per IQR increase in exposure 1.10 (1.01 to 1.20), 1.08 (1.02 to 1.16), 1.15 (1.05 to 1.26), respectively). These associations persisted after adjustment for most co-pollutants. Forced expiratory volume in 1s and forced vital capacity were negatively associated with OP(DTT). These associations were sensitive to adjustment for NO2. Respiratory health was not significantly associated with PM2.5 mass and OP(ESR).
  
  
  CONCLUSIONS
  Respiratory health was more strongly associated with OP(DTT) than with PM2.5 mass; OP(DTT) associations with lung function, but not symptoms, were sensitive to adjustment for NO2.
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Aileen
authors.initials: A
authors.lastname: Yang
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Nicole A H
authors.initials: NA
authors.lastname: Janssen
authors.affiliation: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Bert
authors.initials: B
authors.lastname: Brunekreef
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Flemming R
authors.initials: FR
authors.lastname: Cassee
authors.affiliation: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Gerard
authors.initials: G
authors.lastname: Hoek
authors.affiliation: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Gehring
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000009:adverse effects; D000397:Air Pollution / Q000009:adverse effects*; D001249:Asthma / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D004229:Dithiothreitol; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D008297:Male; D009585:Nitrogen Dioxide / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D011446:Prospective Studies; D006255:Rhinitis, Allergic, Seasonal / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D001335:Vehicle Emissions; D014797:Vital Capacity
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions; D009585:Nitrogen Dioxide; D004229:Dithiothreitol