title: Relationship of the ApoE polymorphism to plasma lipid traits among South Asians, Chinese, and Europeans living in Canada.
abstract: BACKGROUND
  The prevalence of cardiovascular risk factors and atherosclerosis vary between ethnic groups. We examined the apolipoprotein E (ApoE) polymorphism, its association with lipid traits and atherosclerosis, and its influence on ethnic variations on lipid traits.
  
  
  METHODS
  In a randomly sampled cross-sectional study of 985 South Asian, Chinese, and European Canadians, three common isoforms of ApoE (E2, E3 and E4), plasma lipid concentrations and atherosclerosis of the carotid artery were measured.
  
  
  RESULTS
  The E2, E3 and E4 allele frequencies were 5.7%, 84.0%, and 10.2%, respectively, and differed significantly between ethnic groups. There was a strong, stepwise association between ApoE and each plasma lipid trait, except triglycerides. The E4 genotype was associated with higher low-density lipoprotein cholesterol (p for trend<0.001), ApoB (p<0.001), ApoB/ApoA ratio (p<0.001) and lipoprotein (a) (p<0.001), and lower ApoA (p<0.001) and high-density lipoprotein cholesterol (HDL-C) (p=0.005). A similar pattern of effects was observed across all ethnic groups. Ethnicity accounted for modest variation in ApoA, ApoB/ApoA ratio and HDL-C (4.2-5.0%), whereas ApoE isoforms explained only a small proportion of variability (0.3-1.4%). Dietary and lifestyle factors accounted for modest variation in several traits including HDL-C (5.6% and 5.0%, respectively). Carotid atherosclerosis was lower among individuals with E2 isoform in keeping with the effect of E2 on lipid levels.
  
  
  CONCLUSIONS
  The ApoE isoform is associated with plasma lipoproteins in all ethnic groups, yet explains only a small proportion of the inter-ethnic variation for most plasma lipoproteins. Additional genetic variants and/or health behaviors likely contribute to ethnic variations in plasma lipid traits.
authors.affiliation: Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, ON, Canada.
authors.forename: Debika
authors.initials: D
authors.lastname: Burman
authors.forename: Andrew
authors.initials: A
authors.lastname: Mente
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hegele
authors.forename: Shofiqul
authors.initials: S
authors.lastname: Islam
authors.forename: Salim
authors.initials: S
authors.lastname: Yusuf
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Anand
mesh_terms: D000328:Adult; D001057:Apolipoproteins E / Q000235:genetics*; D044466:Asian People; D002170:Canada; D002340:Carotid Artery Diseases / Q000097:blood* / Q000208:ethnology*; D004032:Diet; D005006:Ethnicity; D005260:Female; D006801:Humans; D008019:Life Style; D008055:Lipids / Q000097:blood*; D008075:Lipoproteins, HDL / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D044465:White People
chemical_list: D001057:Apolipoproteins E; D008055:Lipids; D008075:Lipoproteins, HDL