title: Ambient particulate pollution and the world-wide prevalence of asthma, rhinoconjunctivitis and eczema in children: Phase One of the International Study of Asthma and Allergies in Childhood (ISAAC).
abstract: OBJECTIVE
  To investigate the effect of ambient particulate matter on variation in childhood prevalence of asthma, rhinoconjunctivitis and eczema.
  
  
  METHODS
  Prevalences of asthma, rhinoconjunctivitis and eczema obtained in Phase One of the International Study of Asthma and Allergies in Childhood (ISAAC) were matched with city-level estimates of residential PM(10) obtained from a World Bank model. Associations were investigated using binomial regression adjusting for GNP per capita and for clustering within country. For countries with more than one centre, a two stage meta-analysis was carried out. The results were compared with a meta-analysis of published multi-centre studies.
  
  
  RESULTS
  Annual concentrations of PM(10) at city level were obtained for 105 ISAAC centres in 51 countries. After controlling for GNP per capita, there was a weak negative association between PM(10) and various outcomes. For severe wheeze in 13-14-year-olds, the OR for a 10 microg/m(3) increase in PM(10) was 0.92 (95% CI 0.84 to 1.00). In 24 countries with more than one centre, most summary estimates for within-country associations were weakly positive. For severe wheeze in 13-14-year-olds, the summary OR for a 10 microg/m(3) increase in PM(10) was 1.01 (0.92 to 1.10). This result was close to a summary OR of 0.99 (0.91 to 1.06) obtained from published multi-centre studies.
  
  
  CONCLUSIONS
  Modelled estimates of particulate matter at city level are imprecise and incomplete estimates of personal exposure to ambient air pollutants. Nevertheless, our results together with those of previous multi-centre studies, suggest that urban background PM(10) has little or no association with the prevalence of childhood asthma, rhinoconjunctivitis or eczema either within or between countries.
authors.affiliation: Division of Community Health Sciences, MRC-HPA Centre for Environment and Health, St George's, University of London, Cranmer Terrace, London SW17 0RE, UK. r.anderson@sgul.ac.uk
authors.forename: H Ross
authors.initials: HR
authors.lastname: Anderson
authors.forename: Ruth
authors.initials: R
authors.lastname: Ruggles
authors.forename: Kiran D
authors.initials: KD
authors.lastname: Pandey
authors.forename: Venediktos
authors.initials: V
authors.lastname: Kapetanakis
authors.forename: Bert
authors.initials: B
authors.lastname: Brunekreef
authors.forename: Christopher K W
authors.initials: CK
authors.lastname: Lai
authors.forename: David P
authors.initials: DP
authors.lastname: Strachan
authors.forename: Stephan K
authors.initials: SK
authors.lastname: Weiland
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D003233:Conjunctivitis, Allergic / Q000453:epidemiology*; D004485:Eczema / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D015995:Prevalence; D012221:Rhinitis, Allergic, Perennial / Q000453:epidemiology*; D014504:Urban Health
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter