title: Lack of association of OPRM1 genotype and smoking cessation.
abstract: BACKGROUND
  Previous studies have reported an association between μ-opioid receptor (OPRM1) genotype and smoking cessation, with some evidence that the strength of this association depends on dose of nicotine replacement therapy (NRT). We examined whether a single-nucleotide polymorphism in the OPRM1 gene is associated with cessation and whether this variant moderates the effects of higher doses of NRT on abstinence.
  
  
  METHODS
  Participants were recruited from the practices of primary care physicians in the United Kingdom. Patients smoking an average of at least 10 cigarettes a day, who wanted to quit and were 18 years or older were eligible for inclusion. A total of N = 633 participants were recruited into the original trial, of whom complete data for pharmacogenetic analyses were available on n = 598. Logistic regression was used to test for the effects of OPRM1 genotype and NRT dose, including the genotype × dose interaction term, on smoking status at 4-week, and 26-week follow-up. Analyses were adjusted for potential confounders.
  
  
  RESULTS
  There was no evidence of a genotype effect at either follow-up, and no evidence of a genotype × dose interaction effect.
  
  
  CONCLUSIONS
  OPRM1 genotype may not affect the likelihood of smoking cessation, and it may not influence response to high- versus low-dose NRT. OPRM1 may have at most only a modest role in explaining cigarette smoking and cessation.
authors.affiliation: School of Experimental Psychology, University of Bristol, Bristol, UK. marcus.munafo@bristol.ac.uk
authors.forename: Marcus R
authors.initials: MR
authors.lastname: Munafò
authors.forename: Elaine C
authors.initials: EC
authors.lastname: Johnstone
authors.forename: Paul
authors.initials: P
authors.lastname: Aveyard
authors.forename: Theresa
authors.initials: T
authors.lastname: Marteau
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000008:administration & dosage*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D017450:Receptors, Opioid, mu / Q000235:genetics*; D012907:Smoking / Q000188:drug therapy* / Q000235:genetics; D016540:Smoking Cessation / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D006113:United Kingdom
chemical_list: C485764:OPRM1 protein, human; D017450:Receptors, Opioid, mu; D009538:Nicotine