title: Socioeconomic inequalities in childhood exposure to secondhand smoke before and after smoke-free legislation in three UK countries.
abstract: BACKGROUND
  Secondhand smoke (SHS) exposure is higher among lower socioeconomic status (SES) children. Legislation restricting smoking in public places has been associated with reduced childhood SHS exposure and increased smoke-free homes. This paper examines socioeconomic patterning in these changes.
  
  
  METHODS
  Repeated cross-sectional survey of 10 867 schoolchildren in 304 primary schools in Scotland, Wales and Northern Ireland. Children provided saliva for cotinine assay, completing questionnaires before and 12 months after legislation.
  
  
  RESULTS
  SHS exposure was highest, and private smoking restrictions least frequently reported, among lower SES children. Proportions of saliva samples containing <0.1 ng/ml (i.e. undetectable) cotinine increased from 31.0 to 41.0%. Although across the whole SES spectrum, there was no evidence of displacement of smoking into the home or increased SHS exposure, socioeconomic inequality in the likelihood of samples containing detectable levels of cotinine increased. Among children from the poorest families, 96.9% of post-legislation samples contained detectable cotinine, compared with 38.2% among the most affluent. Socioeconomic gradients at higher exposure levels remained unchanged. Among children from the poorest families, one in three samples contained >3 ng/ml cotinine. Smoking restrictions in homes and cars increased, although socioeconomic patterning remained.
  
  
  CONCLUSIONS
  Urgent action is needed to reduce inequalities in SHS exposure. Such action should include emphasis on reducing smoking in cars and homes.
authors.affiliation: DECIPHer, School of Social Sciences, Cardiff University, 1-3 Museum Place, Cardiff, Wales CF10 3BD, UK. mooreg@cardiff.ac.uk
authors.forename: Graham F
authors.initials: GF
authors.lastname: Moore
authors.forename: Dorothy
authors.initials: D
authors.lastname: Currie
authors.forename: Gillian
authors.initials: G
authors.lastname: Gilmore
authors.forename: Jo C
authors.initials: JC
authors.lastname: Holliday
authors.forename: Laurence
authors.initials: L
authors.lastname: Moore
mesh_terms: D002648:Child; D003367:Cotinine / Q000032:analysis*; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000331:legislation & jurisprudence* / Q000517:prevention & control / Q000706:statistics & numerical data; D005260:Female; D006798:Housing / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D009660:Northern Ireland / Q000453:epidemiology; D010290:Parents; D011203:Poverty / Q000706:statistics & numerical data; D011633:Public Facilities / Q000331:legislation & jurisprudence / Q000706:statistics & numerical data; D012463:Saliva / Q000737:chemistry; D012606:Scotland / Q000453:epidemiology; D012923:Social Class; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000331:legislation & jurisprudence* / Q000517:prevention & control / Q000706:statistics & numerical data; D014852:Wales / Q000453:epidemiology
chemical_list: D014028:Tobacco Smoke Pollution; D003367:Cotinine