title: CHRNA3 and CYP3A5*3 genotype, lung function and chronic obstructive pulmonary disease in the general population.
abstract: OBJECTIVE
  Genetic variations are most likely an additional risk factor besides tobacco smoking per se for the risk of chronic obstructive pulmonary disease (COPD). In this study, we compared genetic variants influencing the effect of smoking on COPD, that is, the effect of the well-known splicing defect polymorphism, CYP3A5*3 (rs776746), identified before genome-wide association studies, with the genome-wide association studies identified CHRNA3 (rs1051730) polymorphism on the risk of decreased lung function and COPD.
  
  
  METHODS
  In all, 10 605 participants from the general population were genotyped. Information on spirometry, hospital admissions and smoking behaviour was recorded. Endpoints were lung function and COPD.
  
  
  RESULTS
  For CHRNA3, the percentage of forced expiratory volume in 1 s (FEV1%) predicted was 89.3, 90.6 and 92.4% in homozygous, heterozygous and noncarrier ever-smokers (P-trend<0.001). The corresponding values for forced vital capacity percentage (FVC%) predicted were 94.5, 95.2 and 96.7% (P-trend<0.001), and for FEV1/FVC ratio, the values were 0.753, 0.760 and 0.764 (P-trend=0.008). The odds ratio for COPD in homozygous versus noncarrier ever-smokers was 1.5 [95% confidence interval (CI) 1.3-1.9] for COPD hospitalization, 1.3 (95% CI 1.1-1.6) for COPD defined as FEV1/FVC less than lower limit of normal, 1.3 (95% CI 1.0-1.5) for the Global Initiative for Chronic Obstructive Lung Disease category 1-4 (GOLD 1-4), 1.2 (95% CI 1.0-1.5) for GOLD 2-4 and 1.5 (95% CI 1.1-2.2) for GOLD 3-4. This association could not be found in never-smokers. No association was found for CYP3A5*3.
  
  
  CONCLUSIONS
  The CHRNA3 genotype is associated with decreased lung function and risk of COPD among ever-smokers, whereas this was not the case for CYP3A5*3.
authors.affiliation: aDepartment of Clinical Biochemistry, Herlev Hospital, Copenhagen University Hospital bCopenhagen City Heart Study, Frederiksberg Hospital, Copenhagen University Hospital cInstitute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Herlev, Denmark.
authors.forename: Diljit
authors.initials: D
authors.lastname: Kaur-Knudsen
authors.forename: Stig E
authors.initials: SE
authors.lastname: Bojesen
authors.forename: Børge G
authors.initials: BG
authors.lastname: Nordestgaard
mesh_terms: D000328:Adult; D000368:Aged; D051544:Cytochrome P-450 CYP3A / Q000235:genetics*; D003718:Denmark; D005541:Forced Expiratory Volume; D014644:Genetic Variation; D055106:Genome-Wide Association Study; D006801:Humans; D008168:Lung / Q000502:physiology*; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics*; D011978:Receptors, Nicotinic / Q000235:genetics*; D012907:Smoking / Q000009:adverse effects*
chemical_list: D051544:Cytochrome P-450 CYP3A; D011978:Receptors, Nicotinic; C510164:CYP3A5 protein, human