title: Association between apolipoprotein A-IV concentrations and chronic kidney disease in two large population-based cohorts: results from the KORA studies.
abstract: BACKGROUND
  Apolipoprotein A-IV (apoA-IV) is an anti-atherogenic and antioxidative glycoprotein. Plasma apoA-IV levels are elevated in patients with primary chronic kidney disease (CKD) or renal failure. The association between apoA-IV and kidney function has not been investigated in the general population; therefore, we analysed this relationship in two large population-based cohorts.
  
  
  METHODS
  Plasma apoA-IV concentrations were measured in the Cooperative Health Research in the Region of Augsburg (KORA) F3 (n = 3159) and KORA F4 (n = 3061) studies. CKD was defined by the serum creatinine-estimated glomerular filtration rate (eGFR) and/or urine albumin-to-creatinine ratio.
  
  
  RESULTS
  Mean (±SD) apoA-IV concentration was 17.3 ± 4.7 mg dL(-1) in KORA F3 and 15.3 ± 4.3 mg dL(-1) in KORA F4. Fully adjusted linear mixed models revealed a significant association between apoA-IV concentration and lower eGFR in the third and fourth versus the first quartile of apoA-IV (β = -1.78 mL min(-1) /1.73 m², P = 0.0003 and β = -5.09 mL min(-1) /1.73 m², P = 2.83 × 10(-23) , respectively). ApoA-IV was significantly associated with an eGFR of <60 mL min(-1) /1.73 m², which was observed in 601 of the 6220 study participants [odds ratio (OR) 1.46, P = 0.03 and OR 3.47, P = 6.84 × 10(-15) for the third and fourth vs. the first quartile of apoA-IV, respectively]. Adding apoA-IV (fourth vs. first quartile) to the fully adjusted model significantly improved discrimination of eGFR <60 mL min(-1) /1.73 m² in KORA F3 [integrated discrimination improvement (IDI) 0.03, P = 1.30 × 10(-7) ] and KORA F4 (IDI 0.04, P = 1.32 × 10(-9) ) beyond classical risk factors for CKD.
  
  
  CONCLUSIONS
  The present analysis in two population-based cohorts revealed that high plasma apoA-IV concentrations are strongly associated with low kidney function defined by eGFR independent of major CKD risk factors. ApoA-IV appears to be an early marker of impaired kidney function.
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Stangl
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: B
authors.initials: B
authors.lastname: Kollerits
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Lamina
authors.affiliation: Institute of Epidemiology II, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Meisinger
authors.affiliation: Institute of Epidemiology II, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.|German Center for Diabetes Research (DZD), Neuherberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Huth
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Stöckl
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: D
authors.initials: D
authors.lastname: Dähnhardt
authors.affiliation: Department of Nephrology, University Hospital Regensburg, Regensburg, Germany.
authors.forename: C A
authors.initials: CA
authors.lastname: Böger
authors.affiliation: Vth Department of Medicine, Medical Faculty Mannheim of the University of Heidelberg, University Medicine Mannheim, Mannheim, Germany.
authors.forename: B K
authors.initials: BK
authors.lastname: Krämer
authors.affiliation: Institute of Epidemiology II, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Peters
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: F
authors.initials: F
authors.lastname: Kronenberg
mesh_terms: D001054:Apolipoproteins A / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000097:blood*
chemical_list: D001054:Apolipoproteins A; C022205:apolipoprotein A-IV
keywords: albuminuria; apolipoprotein A-IV; chronic kidney disease; glomerular filtration rate; kidney function impairment