title: Youth exposure to in-vehicle second-hand smoke and their smoking behaviours: trends and associations in repeated national surveys (2006-2012).
abstract: OBJECTIVE
  To extend the limited international evidence on youth in-vehicle second-hand smoke (SHS) exposure by examining trends in New Zealand, a country with a national smoke-free goal and indoors smoke-free environment legislation.
  
  
  METHODS
  We tracked exposure rates and explored the associations between in-vehicle SHS exposure and smoking behaviours. In-home exposure was also examined for comparative purposes. Data were collected in annual surveys of over 25 000 year 10 school students (14-15-year olds) for a 7-year period (2006-2012). Questions covered smoking behaviour, exposure to smoking and demographics.
  
  
  RESULTS
  Youth SHS exposure rates in-vehicle and in-home trended down slightly over time (p<0.0001 for both) with 23% exposed in-vehicle in the previous week in 2012. However, marked inequalities in exposure between ethnic groups, and by school-based socioeconomic position, persisted. The strongest association with SHS exposure was parental smoking (eg, for both parents versus neither smoking in 2012: in-vehicle SHS exposure adjusted OR: 7.4; 95% CI: 6.5 to 8.4). After adjusting for seven other factors associated with initiation, logistic regression analyses revealed statistically significant associations of in-vehicle SHS exposure with susceptibility to initiation and smoking.
  
  
  CONCLUSIONS
  The slow decline in SHS exposure in vehicles and the lack of progress in reducing relative inequalities is problematic. To accelerate progress, the New Zealand Government could follow the example of other jurisdictions and prohibit smoking in cars carrying children. Other major policy interventions, beside enhanced smoke-free environments, will also likely be required if New Zealand is to achieve its 2025 smoke-free nation goal.
authors.affiliation: Department of Public Health, University of Otago, Wellington, New Zealand.
authors.forename: Benjamin
authors.identifier: http://orcid.org/0000-0002-9637-6058
authors.initials: B
authors.lastname: Healey
authors.affiliation: Department of Marketing, University of Otago, Dunedin, New Zealand.
authors.forename: Janet
authors.initials: J
authors.lastname: Hoek
authors.affiliation: Department of Public Health, University of Otago, Wellington, New Zealand.
authors.forename: Nick
authors.initials: N
authors.lastname: Wilson
authors.affiliation: Department of Public Health, University of Otago, Wellington, New Zealand.
authors.forename: George
authors.initials: G
authors.lastname: Thomson
authors.affiliation: School of Public Health and Psychosocial Studies, AUT University, Auckland, New Zealand.
authors.forename: Steve
authors.initials: S
authors.lastname: Taylor
authors.affiliation: Department of Public Health, University of Otago, Wellington, New Zealand.
authors.forename: Richard
authors.initials: R
authors.lastname: Edwards
mesh_terms: D000293:Adolescent; D001336:Automobiles; D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D005006:Ethnicity; D005260:Female; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008297:Male; D009520:New Zealand; D016017:Odds Ratio; D010290:Parents; D012574:Schools; D061845:Smoke-Free Policy; D012907:Smoking / Q000639:trends; D012959:Socioeconomic Factors; D013334:Students; D014028:Tobacco Smoke Pollution
chemical_list: D014028:Tobacco Smoke Pollution
keywords: Disparities; Environment; Public policy; Secondhand smoke