title: Medical marijuana legalization and cigarette and marijuana co-use in adolescents and adults.
abstract: Medical marijuana legalization is associated with a higher prevalence of marijuana use which may affect cigarette use and nicotine dependence in co-users. In the present study, we examined relationships between statewide legalization of medical marijuana and prevalence of cigarette and marijuana co-use and nicotine dependence in co-using adolescents and adults.
  
  
  
  Data were analyzed from the 2013 National Survey on Drug Use and Health. We compared cigarette and marijuana co-use in the past 30days across age categories (12-64 years) by statewide medical marijuana legalization. Logistic regression models were used to estimate the odds of having nicotine dependence among current cigarette smokers who also reported past 30-day marijuana use and "ever but not current" marijuana use (vs. "never" use) adjusting for covariates including statewide legalization of medical marijuana.
  
  
  
  Overall, 5.1% of the sample reported past 30-day cigarette and marijuana co-use and a higher proportion of co-users resided in states where medical marijuana was legal compared to illegal (5.8% vs. 4.8%; p=0.0011). Co-use was associated with greater odds of having nicotine dependence compared to cigarette-only use across age categories. Odds were highest and up to 3-times higher in adolescents aged 12-17 years (OR=3.54; 95%CI: 1.81-6.92) and adults aged 50-64 years (OR=3.08; CI: 1.45-6.55).
  
  
  
  Marijuana policy could inadvertently affect cigarette and marijuana co-use and pose challenges to tobacco cessation.
authors.affiliation: Center for Tobacco Control Research and Education, Cardiovascular Research Institute, University of California, San Francisco, 530 Parnassus Avenue, San Francisco, CA 94143, USA. Electronic address: julie.wang@ucsf.edu.
authors.forename: Julie B
authors.initials: JB
authors.lastname: Wang
authors.affiliation: Center for Tobacco Control Research and Education, Cardiovascular Research Institute, University of California, San Francisco, 530 Parnassus Avenue, San Francisco, CA 94143, USA; Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, 401 Parnassus Avenue, Box RAM 0984, San Francisco, CA 94143, USA.
authors.forename: Danielle E
authors.initials: DE
authors.lastname: Ramo
authors.affiliation: Center for Tobacco Control Research and Education, Cardiovascular Research Institute, University of California, San Francisco, 530 Parnassus Avenue, San Francisco, CA 94143, USA.
authors.forename: Nadra E
authors.initials: NE
authors.lastname: Lisha
authors.affiliation: Center for Tobacco Control Research and Education, Cardiovascular Research Institute, University of California, San Francisco, 530 Parnassus Avenue, San Francisco, CA 94143, USA; Department of Physiological Nursing, University of San Francisco, 2 Koret Way, Box 0610, San Francisco, CA 94143, USA.
authors.forename: Janine K
authors.initials: JK
authors.lastname: Cataldo
mesh_terms: D000293:Adolescent; D000328:Adult; D002188:Cannabis; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007880:Legislation, Drug / Q000639:trends; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology* / Q000331:legislation & jurisprudence* / Q000639:trends; D064086:Medical Marijuana / Q000008:administration & dosage*; D008875:Middle Aged; D012907:Smoking / Q000453:epidemiology* / Q000639:trends; D062789:Tobacco Products; D055815:Young Adult
chemical_list: D064086:Medical Marijuana
keywords: Cigarette; Co-use; Marijuana; Medical marijuana policy; Nicotine dependence; Tobacco control