title: Use of an online smoking cessation community promotes abstinence: Results of propensity score weighting.
abstract: OBJECTIVE
  We estimated the causal effects of use of an online smoking cessation community on 30-day point prevalence abstinence at 3 months.
  
  
  METHODS
  Participants (N = 492) were adult current smokers in the enhanced Internet arm of The iQUITT Study, a randomized trial of Internet and telephone treatment for smoking cessation. All participants accessed a Web-based smoking-cessation program that included a large, established online community. Automated tracking metrics of passive (e.g., reading forum posts, viewing member profiles) and active (e.g., writing forum posts, sending private messages) community use were extracted from the site at 3 months. Self-selected community use defines the groups of interest: "None," "Passive," and "Both" (passive + active). Inverse probability of treatment weighting corrected for baseline imbalances on demographic, smoking, psychosocial, and medical history variables. Propensity weights estimated via generalized boosted models were used to calculate Average Treatment Effects (ATE) and Average Treatment effects on the Treated (ATT).
  
  
  RESULTS
  Patterns of community use were: None = 198 (40.2%), Passive = 110 (22.4%), and Both = 184 (37.4%). ATE-weighted abstinence rates were: None = 4.2% (95% CI = 1.5-6.9); Passive = 15.1% (95% CI = 8.4-21.9); Both = 20.4% (95% CI = 13.9-26.8). ATT-weighted abstinence rates indicated even greater benefits of community use.
  
  
  CONCLUSIONS
  Community users were more likely to quit smoking at 3 months than nonusers. The estimated benefit from use of online community resources was even larger among subjects with high propensity to use them. No differences in abstinence emerged between passive and passive/active users. Results suggest that lurking in online communities confers specific abstinence benefits. Implications of these findings for online cessation communities are discussed.
authors.affiliation: Schroeder Institute for Tobacco Research and Policy Studies, American Legacy Foundation.
authors.forename: Amanda L
authors.identifier: 0000-0003-3036-9653
authors.initials: AL
authors.lastname: Graham
authors.affiliation: Center for Statistical Sciences, Brown University.
authors.forename: George D
authors.initials: GD
authors.lastname: Papandonatos
authors.affiliation: Center for Statistical Sciences, Brown University.
authors.forename: Bahar
authors.initials: B
authors.lastname: Erar
authors.affiliation: Westat.
authors.forename: Cassandra A
authors.initials: CA
authors.lastname: Stanton
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D020407:Internet / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D012111:Residence Characteristics; D012907:Smoking / Q000523:psychology* / Q000628:therapy*; D016540:Smoking Cessation / Q000379:methods / Q000523:psychology*; D013689:Telephone