title: Changing Patterns of Tobacco and Alcohol Co-Use by Gender in the United States, 1976-2010.
abstract: BACKGROUND
  Smoking is a serious health concern both globally and in the U.S. Because drinking amplifies the negative health effects of smoking, the high association of these behaviors is an additional source of population morbidity. However, very little is known about trends in the co-use of smoking and drinking over time.
  
  
  OBJECTIVE
  To describe trends in tobacco use, alcohol use, and their co-use among U.S. youth, and to separate out trends in theassociationof smoking and drinking from trends in their marginal distributions.
  
  
  METHODS
  We use data on the smoking and drinking behaviors of 12thgraders from 1976 to 2010 in the Monitoring the Future study to examine trends in smoking, drinking, and co-use separately by gender. In each year we estimate the degree of co-use attributable to tobacco and alcohol use probabilities as well as the association between tobacco and alcohol use.
  
  
  RESULTS
  Although the prevalence of tobacco and alcohol co-use has declined over time, the association of the two has increased. This association accounts for an increasing proportion of the co-use of tobacco and alcohol.
  
  
  CONCLUSIONS
  We conclude that co-users of tobacco and alcohol are an increasingly select subpopulation. This suggests that continued decreases in the contribution of substance use to population health and mortality may not continue apace.
authors.affiliation: Department of Sociology, University of Alabama-Birmingham.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Daw
authors.affiliation: Department of Sociology and Institute of Behavioral Science, University of Colorado-Boulder.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Nowotny
authors.affiliation: Department of Sociology and Institute of Behavioral Science, University of Colorado-Boulder.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Boardman
keywords: Tobacco use; alcohol use; comorbidity; trends