title: Retrospective analysis of changing characteristics of treatment-seeking smokers: implications for further reducing smoking prevalence.
abstract: The goal of the current study was to empirically compare successive cohorts of treatment-seeking smokers who enrolled in randomised clinical trials in a region of the USA characterised by strong tobacco control policies and low smoking prevalence, over the past three decades.
  
  
  
  Retrospective treatment cohort comparison.
  
  
  
  Data were collected from 9 randomised clinical trials conducted at Stanford University and the University of California, San Francisco, between 1990 and 2013.
  
  
  
  Data from a total of 2083 participants were included (Stanford, n=1356; University of California San Francisco, n=727).
  
  
  
  One-way analysis of variance and covariance, χ(2) and logistic regression analyses were used to examine relations between nicotine dependence, cigarettes per day, depressive symptoms and demographic characteristics among study cohorts.
  
  
  
  Similar trends were observed at both settings. When compared to earlier trials, participants in more recent trials smoked fewer cigarettes, were less nicotine-dependent, reported more depressive symptoms, were more likely to be male and more likely to be from a minority ethnic/racial group, than those enrolled in initial trials (all p's<0.05). Analysis of covariances revealed that cigarettes per day, nicotine dependence and current depressive symptom scores were each significantly related to trial (all p's<0.001).
  
  
  
  Our findings suggest that more recent smoking cessation treatment-seeking cohorts in a low prevalence region were characterised by less smoking severity, more severe symptoms of depression and were more likely to be male and from a minority racial/ethnic group.
authors.affiliation: Department of Psychology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Leyro
authors.affiliation: Department of Medicine, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford University, Stanford, California, USA.
authors.forename: Erin E
authors.initials: EE
authors.lastname: Crew
authors.affiliation: Stanford Prevention Research Center, Stanford University, Palo Alto, California, USA.
authors.forename: Susan W
authors.initials: SW
authors.lastname: Bryson
authors.affiliation: Department of Psychiatry, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Lembke
authors.affiliation: Department of Family Medicine, Oregon Health & Sciences University, Portland, Oregon, USA.
authors.forename: Steffani R
authors.initials: SR
authors.lastname: Bailey
authors.affiliation: Department of Medicine, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford University, Stanford, California, USA.
authors.forename: Judith J
authors.initials: JJ
authors.lastname: Prochaska
authors.affiliation: Department of Medicine, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford University, Stanford, California, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Henriksen
authors.affiliation: Department of Medicine, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford University, Stanford, California, USA Kaiser Permanente Center for Health Research, Northwest, Portland, Oregon, USA.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Fortmann
authors.affiliation: Department of Medicine, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford University, Stanford, California, USA.
authors.forename: Joel D
authors.initials: JD
authors.lastname: Killen
authors.affiliation: Department of Medicine, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford University, Stanford, California, USA.
authors.forename: Diana T
authors.initials: DT
authors.lastname: Killen
authors.affiliation: Department of Psychiatry, San Francisco Treatment Research Center, University of California, San Francisco, California, USA.
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Hall
authors.affiliation: Department of Medicine, Division of General Medical Disciplines, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: David
mesh_terms: D000293:Adolescent; D000328:Adult; D005006:Ethnicity; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care / Q000523:psychology; D015995:Prevalence; D011634:Public Health; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D012495:San Francisco / Q000453:epidemiology; D000074285:Smokers / Q000193:education / Q000523:psychology*; D012907:Smoking / Q000009:adverse effects*; D016540:Smoking Cessation / Q000523:psychology / Q000706:statistics & numerical data*
keywords: PUBLIC HEALTH