title: Association between ethnicity and obesity with high-density lipoprotein (HDL) function and subclass distribution.
abstract: BACKGROUND
  Obesity and low high-density lipoprotein-cholesterol (HDL-C) levels are associated with cardiovascular risk. Surprisingly, despite a greater prevalence of obesity and lower HDL concentrations than white women, black South African women are relatively protected against ischaemic heart disease.
  
  
  METHODS
  We investigated whether this apparent discrepancy may be related to different HDL function and subclass distribution in black and white, normal-weight and obese South African women (n = 40). HDL functionality was assessed by measuring paraoxonase (PON) activity, platelet activating factor acetylhydrolase (PAF-AH) activity, Oxygen Radical Absorbance Capacity (ORAC) and quantification of the expression of vascular cell adhesion molecule in endothelial cells. PON-1 and PAF-AH expression was determined in isolated HDL and serum using Western blotting. Levels of large, intermediate and small HDL subclasses were measured using the Lipoprint® system.
  
  
  RESULTS
  PON activity was lower in white compared to black women (0.49 ± 0.09 U/L vs 0.78 ± 0.10 U/L, p < 0.05), regardless of PON-1 protein levels. Obese black women had lower PAF-AH activity (9.34 ± 1.15 U/L vs 13.89 ± 1.21 U/L, p <0.05) and HDL-associated PAF-AH expression compared to obese white women. Compared to normal-weight women, obese women had lower large HDL, greater intermediate and small HDL; an effect that was more pronounced in white women than black women. There were no differences in antioxidant capacity or anti-inflammatory function across groups.
  
  
  CONCLUSIONS
  Our data show that both obesity and ethnicity are associated with differences in HDL functionality, while obesity was associated with decreases in large HDL subclass distribution. Measuring HDL functionality and subclass may, therefore, be important factors to consider when assessing cardiovascular risk.
authors.affiliation: Department of Medicine, Hatter Institute for Cardiovascular Research in Africa and South African Medical Research Council Inter-University Cape Heart Group, Faculty of Health Sciences, University of Cape Town, Chris Barnard Building, Anzio Road, Observatory, 7925, Cape Town, Western Cape, South Africa. nicholaswoudberg@gmail.com.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Woudberg
authors.affiliation: Non-Communicable Disease Research Unit, South African Medical Research Council, Cape Town, South Africa.|Department of Human Biology, University of Cape Town, Cape Town, South Africa.
authors.forename: Julia H
authors.initials: JH
authors.lastname: Goedecke
authors.affiliation: Division of Chemical Pathology, Department of Pathology, University of Cape Town, Cape Town, South Africa.
authors.forename: Dee
authors.initials: D
authors.lastname: Blackhurst
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Miguel
authors.initials: M
authors.lastname: Frias
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Richard
authors.initials: R
authors.lastname: James
authors.affiliation: Department of Medicine, Hatter Institute for Cardiovascular Research in Africa and South African Medical Research Council Inter-University Cape Heart Group, Faculty of Health Sciences, University of Cape Town, Chris Barnard Building, Anzio Road, Observatory, 7925, Cape Town, Western Cape, South Africa.
authors.forename: Lionel H
authors.initials: LH
authors.lastname: Opie
authors.affiliation: Department of Medicine, Hatter Institute for Cardiovascular Research in Africa and South African Medical Research Council Inter-University Cape Heart Group, Faculty of Health Sciences, University of Cape Town, Chris Barnard Building, Anzio Road, Observatory, 7925, Cape Town, Western Cape, South Africa.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lecour
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000378:metabolism; D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D043303:Aryldialkylphosphatase / Q000097:blood; D044383:Black People; D005260:Female; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood*; D017202:Myocardial Ischemia / Q000097:blood* / Q000208:ethnology; D009765:Obesity / Q000097:blood / Q000208:ethnology*; D012307:Risk Factors; D013019:South Africa / Q000208:ethnology; D044465:White People
chemical_list: D000975:Antioxidants; D008075:Lipoproteins, HDL; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human
keywords: Cardiovascular risk; Ethnicity; High-density lipoprotein; Obesity