title: Vitamin B status in patients with type 2 diabetes mellitus with and without incipient nephropathy.
abstract: OBJECTIVE
  To investigate the vitamin B status, with particular focus on vitamin B6, in adults with and without incipient nephropathy secondary to type 2 diabetes mellitus.
  
  
  METHODS
  Plasma and/or urine concentrations of vitamins B₆, B₁, B₁₂, related vitamers and biomarkers (including total homocysteine, methylmalonic acid) were measured in 120 adults with type 2 diabetes (including 46 patients with microalbuminuria) and 52 non-diabetic control subjects.
  
  
  RESULTS
  Plasma concentrations of pyridoxal 5'-phosphate (PLP) were significantly lower in patients with type 2 diabetes than in control subjects (median: 22.7 nmol/L, diabetes with microalbuminuria; 26.8 nmol/L, diabetes without microalbuminuria; 39.5 nmol/L, non-diabetic control; p<0.0001). The prevalence of low PLP (<30 nmol/L) was 63%, 58%, and 25% in the diabetes groups with and without microalbuminuria and the control group, respectively. Plasma levels of pyridoxine and pyridoxal were also lower (p<0.0001), but levels of pyridoxamine, pyridoxamine 5'-phosphate, and pyridoxic acid were higher in both groups with diabetes compared to the control group (p<0.001). Thiamine deficiency was highly prevalent in all groups, whereas low vitamin B₁₂ and elevated methylmalonic acid were rare. Increased levels of C-reactive protein and soluble vascular cell adhesion molecule-1 were observed in the groups with diabetes (p<0.05, versus healthy control).
  
  
  CONCLUSIONS
  Deficiency of vitamin B₆ (PLP, pyridoxine, pyridoxal) and vitamin B₁ (thiamine) was prevalent in type 2 diabetes. Incipient nephropathy was associated with more pronounced alterations in vitamin B₆ metabolism and stronger indications of endothelial dysfunction and inflammation.
authors.affiliation: Akademie für Ärztliche Fortbildung in Rheinland-Pfalz, Mainz, Germany. Electronic address: nix@arztkolleg.de.
authors.forename: Wilfred A
authors.initials: WA
authors.lastname: Nix
authors.affiliation: Private Practice, Daun, Germany.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Zirwes
authors.affiliation: Private Practice, Daun, Germany.
authors.forename: Volkhard
authors.initials: V
authors.lastname: Bangert
authors.affiliation: Private Practice, Kelberg, Germany.
authors.forename: Raimund Peter
authors.initials: RP
authors.lastname: Kaiser
authors.affiliation: Private Practice, Wittlich, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schilling
authors.affiliation: Merck KGaA, Darmstadt, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hostalek
authors.affiliation: Aarhus Institute of Advanced Studies, Aarhus University, D-8000, Aarhus C, Denmark.
authors.forename: Rima
authors.initials: R
authors.lastname: Obeid
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000419:Albuminuria / Q000097:blood / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D003928:Diabetic Nephropathies / Q000097:blood* / Q000209:etiology; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011735:Pyridoxic Acid / Q000097:blood; D013831:Thiamine / Q000097:blood*; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000453:epidemiology; D025101:Vitamin B 6 / Q000097:blood*; D026681:Vitamin B 6 Deficiency / Q000453:epidemiology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D011735:Pyridoxic Acid; D025101:Vitamin B 6; D014805:Vitamin B 12; D013831:Thiamine
keywords: Microalbuminuria; Pyridoxal 5′-phosphate; Type 2 diabetes; Vitamin B deficiency