title: Racial variation in lipoprotein-associated phospholipase A₂ in older adults.
abstract: BACKGROUND
  Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) is a predictor of cardiovascular events that has been shown to vary with race. The objective of this study was to examine factors associated with this racial variation.
  
  
  METHODS
  We measured Lp-PLA₂ mass and activity in 714 healthy older adults with no clinical coronary heart disease and not taking dyslipidemia medication. We evaluated the association between race and Lp-PLA₂ mass and activity levels after adjustment for various covariates using multivariable linear regression. These covariates included age, sex, diabetes, hypertension, body mass index, lipid measurements, C-reactive protein, smoking status, physical activity, diet, income, and education level. We further examined genetic covariates that included three single nucleotide polymorphisms shown to be associated with Lp-PLA₂ activity levels.
  
  
  RESULTS
  The mean age was 66 years. Whites had the highest Lp-PLA₂ mass and activity levels, followed by Hispanics and Asians, and then African-Americans; in age and sex adjusted analyses, these differences were significant for each non-White race as compared to Whites (p < 0.0001). For example, African-Americans were predicted to have a 55.0 ng/ml lower Lp-PLA₂ mass and 24.7 nmol/ml-min lower activity, compared with Whites, independent of age and sex (p < 0.0001). After adjustment for all covariates, race remained significantly correlated with Lp-PLA₂ mass and activity levels (p < 0.001) with African-Americans having 44.8 ng/ml lower Lp-PLA₂ mass and 17.3 nmol/ml-min lower activity compared with Whites (p < 0.0001).
  
  
  CONCLUSIONS
  Biological, lifestyle, demographic, and select genetic factors do not appear to explain variations in Lp-PLA₂ mass and activity levels between Whites and non-Whites, suggesting that Lp-PLA₂ mass and activity levels may need to be interpreted differently for various races.
authors.affiliation: Department of Health Research and Policy, Stanford University School of Medicine, HRP Redwood Building, Stanford, CA 94305-5405, USA. Keane.K.Lee@kp.org
authors.forename: Keane K
authors.initials: KK
authors.lastname: Lee
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Fortmann
authors.forename: Ann
authors.initials: A
authors.lastname: Varady
authors.forename: Joan M
authors.initials: JM
authors.lastname: Fair
authors.forename: Alan S
authors.initials: AS
authors.lastname: Go
authors.forename: Thomas
authors.initials: T
authors.lastname: Quertermous
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hlatky
authors.forename: Carlos
authors.initials: C
authors.lastname: Iribarren
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000097:blood*; D001741:Black or African American / Q000208:ethnology*; D000367:Age Factors; D000368:Aged; D001213:Asian / Q000208:ethnology*; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003327:Coronary Disease / Q000097:blood / Q000201:enzymology* / Q000208:ethnology; D005260:Female; D006630:Hispanic or Latino / Q000208:ethnology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D044465:White People / Q000208:ethnology*
chemical_list: D015415:Biomarkers; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase