title: Mediation of smoking consumption on the association of perception of smoking risks with successful spontaneous smoking cessation.
abstract: BACKGROUND
  The perception of smoking risks has positive and smoking consumption has negative effects on successful smoking cessation, but no information is now available for what is the role of smoking consumption on the relationship between perception of smoking risks and successful smoking cessation.
  
  
  OBJECTIVE
  To assess the mediation of smoking amount on the association of perception of smoking risks with successful spontaneous smoking cessation.
  
  
  METHODS
  A community-based case-control study was conducted with 294 adult spontaneous successful smoking quitters who have been quitting smoking consecutively for more than 2 years as the cases, and 347 adult failed spontaneous smoking quitters who quitted but relapsed or have been quitting smoking continuously equal to or less than 2 years as the controls. The smoking amount was evaluated by pack-year that was categorized into tertiles and scored inversely. The score of perception of smoking risks was also categorized into tertiles. Propensity score as the covariate in the regression model was used to adjust the potential confounding. The total effect was decomposed into direct effect and indirect (mediating) effect by using logistic regression based on the KHB method proposed by Karlson, Holm, and Breen. The proportion of mediating effect among the total effect is calculated as the indirect effect divided by the total effect.
  
  
  RESULTS
  After adjusting age, profession, education, marital status, and reasons for quitting smoking by using propensity score, the small mediating effect of smoking amount on the association of perception of smoking risks with successful spontaneous smoking cessation was observed, and the mediating effect of smoking amount was 23.75% among the total effect. The dose-response analysis showed that the mediating effect of smoking amount in the groups with middle and high score of perception of smoking risks were 10.15 and 37.84% among their total effect, respectively.
  
  
  CONCLUSIONS
  This study reveals that smoking amount has only small mediating effect among the total effect of perception of smoking risks on the successful spontaneous smoking cessation; enhancing the smokers' perception of smoking risks could promote their attempt to reduce smoking, so as to increase the probability of successful smoking cessation.
authors.affiliation: Department of Epidemiology and Biostatistics, Shandong University, Jinan, 250012, Shandong, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yanxun
authors.initials: Y
authors.lastname: Liu
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Chongqi
authors.initials: C
authors.lastname: Jia
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010465:Perception; D012306:Risk; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology / Q000523:psychology*; D016540:Smoking Cessation / Q000523:psychology*; D014029:Tobacco Use Disorder / Q000523:psychology / Q000534:rehabilitation*