title: IGF-1 and NT-proBNP in a black and white population: The SABPA study.
abstract: BACKGROUND
  Black populations exhibit lower concentrations of the cardioprotective peptide, insulin-like growth factor-1 (IGF-1), and are more prone to develop hypertensive heart disease than whites. We therefore determined whether lower IGF-1 in black individuals relates to a marker of cardiac overload and systolic dysfunction, namely N-terminal prohormone B-type natriuretic peptide (NT-proBNP).
  
  
  METHODS
  We included 160 black and 195 white nondiabetic South African men and women (aged 44·4 ± 9·81 years) and measured ambulatory blood pressure, NT-proBNP, IGF-1 and insulin-like growth factor-binding protein-3 (IGFBP-3).
  
  
  RESULTS
  Although the black group presented elevated ambulatory blood pressure accompanied by lower IGF-1 compared to the white group (all P < 0·001), we found similar NT-proBNP concentrations (P = 0·72). Furthermore, in blacks we found a link between NT-proBNP and systolic blood pressure (SBP) (R(2) = 0·37; β = 0·28; P < 0·001), but not with IGF-1. In the white group, NT-proBNP was inversely associated with IGF-1 (R(2) = 0·39; β = -0·22; P < 0·001) after adjusting for covariates and potential confounders. As IGF-1 is attenuated in diabetes, we added the initially excluded patients with diabetes (n = 38), and the aforementioned associations remained robust.
  
  
  CONCLUSIONS
  Contrary to the white group, we found no association between NT-proBNP and IGF-1 in black adults. Our findings suggest that SBP and other factors may play a greater contributory role in cardiac pathology in blacks.
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.
authors.forename: Anna S E
authors.initials: AS
authors.lastname: Koegelenberg
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.
authors.forename: Wayne
authors.initials: W
authors.lastname: Smith
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.|Postgraduate Medical Institute, Faculty of Medical Science, Anglia Ruskin University, Chelmsford, UK.
authors.forename: Rudolph
authors.initials: R
authors.lastname: Schutte
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.|MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
authors.forename: Aletta E
authors.initials: AE
authors.lastname: Schutte
mesh_terms: D000328:Adult; D044383:Black People; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D013019:South Africa; D044465:White People
chemical_list: C583557:IGF1 protein, human; C515497:IGFBP3 protein, human; D018972:Insulin-Like Growth Factor Binding Protein 3; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D007334:Insulin-Like Growth Factor I
keywords: Insulin-like growth factor-1; N-terminal prohormone B-type natriuretic peptide, ethnicity, race, African; insulin-like growth factor-binding protein-3