title: Secondhand smoke exposure in cars and rooms: trend comparisons among subpopulations of nonsmoking U.S. middle and high school students.
abstract: BACKGROUND
  Young people in the United States are exposed to secondhand smoke (SHS) primarily in 2 settings: homes and cars. Recently, researchers reported that the prevalence of U.S students exposed to SHS in cars decreased from 2000 to 2009; however, comparisons of trends across school levels, gender, and racial/ethnic groups were not assessed. Moreover, no studies have examined trends of exposure to SHS in rooms.
  
  
  METHODS
  We used data from the 2000, 2002, 2004, 2006, and 2009 waves of the National Youth Tobacco Survey, a nationally representative cross-sectional survey of U.S. middle and high school students. For SHS in cars and rooms, we identified exposure trends among nonsmokers from 2000 to 2009 and compared trends across subpopulations with binary logistic regression.
  
  
  RESULTS
  We identified significant downward linear trends in SHS in cars and rooms for nearly all measured subpopulations of nonsmoking students from 2000 to 2009. SHS exposure in cars and rooms declined at a significantly greater rate for males than for females. SHS exposure in cars declined at a significantly greater rate for non-Hispanic (NH) Blacks than for NH Whites. SHS exposure in rooms declined at a significantly greater rate for NH Whites than for Hispanics and Native Hawaiians/Pacific Islanders.
  
  
  CONCLUSIONS
  Although prevalence of exposure to SHS in cars and rooms among nonsmoking U.S. middle and high school students has declined from 2000 to 2009, the rates of decline were not equal across genders and racial/ethnic groups. Identification of these differing rates of exposure can help the public health community advocate for interventions focused on reducing adolescent SHS exposure.
authors.affiliation: Department of Applied Health Science, Indiana University School of Public Health-Bloomington, Bloomington, IN;
authors.forename: Russell K
authors.initials: RK
authors.lastname: McIntire
authors.forename: Jonathan T
authors.initials: JT
authors.lastname: Macy
authors.forename: Dong-Chul
authors.initials: DC
authors.lastname: Seo
authors.forename: Ashlyn A
authors.initials: AA
authors.lastname: Nelson
authors.forename: Lloyd J
authors.initials: LJ
authors.lastname: Kolbe
mesh_terms: D000293:Adolescent; D001336:Automobiles; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D044469:Racial Groups; D012574:Schools; D012907:Smoking / Q000639:trends*; D013334:Students / Q000706:statistics & numerical data*; D014028:Tobacco Smoke Pollution / Q000706:statistics & numerical data*; D014481:United States
chemical_list: D014028:Tobacco Smoke Pollution