title: PCSK9 R46L, low-density lipoprotein cholesterol levels, and risk of ischemic heart disease: 3 independent studies and meta-analyses.
abstract: OBJECTIVE
  The aim of this study was to examine the effect of PCSK9 R46L on low-density lipoprotein cholesterol (LDL-C), risk of ischemic heart disease (IHD), and mortality.
  
  
  BACKGROUND
  The 46L allele has been associated with reductions in LDL-C and risk of IHD, but results vary between studies.
  
  
  METHODS
  We determined the association of R46L genotype with LDL-C, risk of IHD, myocardial infarction (MI), and mortality in the prospective CCHS (Copenhagen City Heart Study) (n = 10,032) and validated the results in: 1) the cross-sectional CGPS (Copenhagen General Population Study) (n = 26,013); and 2) the case-control CIHDS (Copenhagen Ischemic Heart Disease Study) (n = 9,654). We also performed meta-analyses of present and previous studies (n = 66,698).
  
  
  RESULTS
  In carriers (2.6%) versus noncarriers, the 46L allele was associated with reductions in LDL-C of 0.35 to 0.55 mmol/l (11% to 16%) from 20 to 80+ years in the general population (CCHS and CGPS; p values <0.0001). Observed risk reductions for IHD in 46L allele carriers were: 6% in the CCHS study (hazard ratio [HR]: 0.94; 95% confidence interval [CI]: 0.68 to 1.31), 46% in the CGPS study (odds ratio [OR]: 0.54; 95% CI: 0.39 to 0.77), 18% in the CIHDS study (OR: 0.82; 95% CI: 0.55 to 1.21), and 30% in the studies combined (OR: 0.70; 95% CI: 0.58 to 0.86). In the CCHS study, HR for mortality was 1.18 (95% CI: 0.93 to 1.50). In meta-analyses, 46L allele carriers had a 12% (0.43 mmol/l) reduction in LDL-C and a 28% reduction in risk of IHD (HR: 0.72; 95% CI: 0.62 to 0.84), similar to results in the CCHS, CGPS, and CIHDS studies combined. However, the observed 12% (0.43 mmol/l) reduction in LDL-C theoretically predicted an only 5% reduction in risk of IHD (HR: 0.95; 95% CI: 0.92 to 0.97).
  
  
  CONCLUSIONS
  The PCSK9 46L allele was associated with reductions in LDL-C from 20 to 80+ years in the general population. The reduction in risk of IHD was larger than predicted by the observed reduction in LDL-C alone. This could be because genotype is a better predictor of lifelong exposure to LDL-C than LDL-C measured in adult life.
authors.affiliation: Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Marianne
authors.initials: M
authors.lastname: Benn
authors.forename: Børge G
authors.initials: BG
authors.lastname: Nordestgaard
authors.forename: Peer
authors.initials: P
authors.lastname: Grande
authors.forename: Peter
authors.initials: P
authors.lastname: Schnohr
authors.forename: Anne
authors.initials: A
authors.lastname: Tybjaerg-Hansen
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D008078:Cholesterol, LDL / Q000235:genetics* / Q000378:metabolism; D002986:Clinical Trials as Topic; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D014644:Genetic Variation; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D016016:Proportional Hazards Models; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D018570:Risk Assessment; D012697:Serine Endopeptidases / Q000235:genetics*; D012720:Severity of Illness Index; D016019:Survival Analysis
chemical_list: D008078:Cholesterol, LDL; C472125:PCSK9 protein, human; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D012697:Serine Endopeptidases