title: Age-related differences in cigarette smoking among whites and African-Americans: evidence for the crossover hypothesis.
abstract: BACKGROUND
  Age crossover describes the age-related reversal in prevalence of current cigarette smoking among non-Hispanic whites and African-Americans, with prevalence higher among whites than African-Americans in adolescence but lower in adulthood. Prior studies have examined smoking patterns in separate adolescent and adult samples and have not sought to identify factors that could account for crossover. We conducted analyses using national samples to identify factors that account for crossover and estimate their impact on crossover age.
  
  
  METHODS
  Analyses are based on national samples of lifetime smokers 12-49 years old in the 2006-2008 aggregated National Surveys on Drug Use and Health (N=61, 757) (SAMHSA, 2007-2009) and on multiple birth cohorts followed over 21 cross-sectional surveys.
  
  
  RESULTS
  We identified crossover for cigarette smoking in the US population at about age 29. Crossover is partially explained by differences between whites and African-Americans in education and marital status, and more weakly by the opposite impact of age of smoking onset on persistence of smoking in the two groups. Controlling for smoking history, education and social role participation would raise crossover in current smoking by more than 14 years. Rates of current smoking among lifetime smokers at four different age categories in multiple birth cohorts followed from ages 12-17 to 35 and over in 21 surveys spanning 24 years confirm the age-related patterns observed cross-sectionally.
  
  
  CONCLUSIONS
  Age crossover for current smoking appears among whites and African-Americans. Efforts targeted toward improving educational levels of young people would have the strongest impact in decreasing persistent smoking, especially among African-Americans.
authors.affiliation: Columbia University, Department of Psychiatry, 1051 Riverside Drive Unit 20, New York, NY 10032, USA. dbk2@columbia.edu
authors.forename: Denise
authors.initials: D
authors.lastname: Kandel
authors.forename: Christine
authors.initials: C
authors.lastname: Schaffran
authors.forename: Mei-Chen
authors.initials: MC
authors.lastname: Hu
authors.forename: Yonette
authors.initials: Y
authors.lastname: Thomas
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D000367:Age Factors; D017668:Age of Onset; D002648:Child; D003430:Cross-Sectional Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012907:Smoking / Q000208:ethnology*; D044465:White People / Q000706:statistics & numerical data*