title: Significant associations between lipoprotein(a) and corrected apolipoprotein B-100 levels in African-Americans.
abstract: OBJECTIVE
  Lipoprotein(a), Lp(a), represents an apolipoprotein (apo) B-carrying lipoprotein, yet the relationship between Lp(a) and apoB levels has not been fully explored.
  
  
  METHODS
  We addressed the relationship between Lp(a) and apoB-containing lipoprotein levels in 336 Caucasians and 224 African-Americans. Our approach takes unique molecular properties of Lp(a) as well as contribution of Lp(a) to the levels of these lipoproteins into account.
  
  
  RESULTS
  Levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), apoB and apoB/apoA-1 did not differ across ethnicity. African-Americans had higher levels of Lp(a) and high-density lipoprotein cholesterol and lower triglyceride levels compared to Caucasians. Lp(a) levels were correlated with levels of TC (p < 0.005), LDL-C (p < 0.001), apoB (p < 0.05) or apoB/apoA-1 (p < 0.05) in both ethnic groups. These associations remained significant only in African-Americans after adjustments for the contribution of Lp(a)-cholesterol or Lp(a)-apoB. Furthermore, taking Lp(a)-apoB into account, allele-specific apo(a) levels were significantly associated with apoB levels and the apoB/apoA-1 ratio in African-Americans. The latter associations in African-Americans remained significant for allele-specific apo(a) levels for smaller apo(a) sizes (<26 K4 repeats), after controlling for the effects of age, sex, and BMI.
  
  
  CONCLUSIONS
  Although TC, LDL-C, and apoB levels were comparable between African-Americans and Caucasians, the associations of these parameters with Lp(a) and allele specific apo(a) levels differed between these two ethnic groups. In African-Americans, apoB and apoB/apoA-1 remained consistently and positively associated with both Lp(a) and allele-specific apo(a) levels after adjustments for the contribution of Lp(a)-apoB. The findings suggest an interethnic difference with a closer relationship between Lp(a) and apoB among African-Americans.
authors.affiliation: Department of Internal Medicine, University of California, Davis, CA, USA.
authors.forename: Byambaa
authors.initials: B
authors.lastname: Enkhmaa
authors.affiliation: Department of Internal Medicine, University of California, Davis, CA, USA.
authors.forename: Erdembileg
authors.initials: E
authors.lastname: Anuurad
authors.affiliation: Department of Internal Medicine, University of California, Davis, CA, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Internal Medicine, University of California, Davis, CA, USA; Department of Veterans Affairs, Northern California Health Care System, Sacramento, CA, USA. Electronic address: lars.berglund@ucdmc.ucdavis.edu.
authors.forename: Lars
authors.initials: L
authors.lastname: Berglund
mesh_terms: D001741:Black or African American / Q000235:genetics*; D000368:Aged; D000483:Alleles; D053299:Apolipoprotein B-100 / Q000097:blood* / Q000235:genetics; D050197:Atherosclerosis / Q000097:blood / Q000208:ethnology* / Q000235:genetics; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D006801:Humans; D017270:Lipoprotein(a) / Q000097:blood* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms; D018570:Risk Assessment; D012307:Risk Factors; D044465:White People
chemical_list: D053299:Apolipoprotein B-100; D008078:Cholesterol, LDL; D017270:Lipoprotein(a); D020033:Protein Isoforms; D002784:Cholesterol
keywords: Apo(a) sizes; Corrections for the contribution of Lp(a); Ethnicity; K4 repeats; Plasma lipids