title: Type 2 diabetes is associated with impaired endothelium-dependent, flow-mediated dilation, but impaired glucose metabolism is not; The Hoorn Study.
abstract: BACKGROUND
  Type 2 diabetes (DM2) and impaired glucose metabolism (IGM) are associated with an increased cardiovascular disease risk. Impaired endothelial synthesis of nitric oxide (NO) is an important feature of atherothrombosis and can be estimated from endothelium-dependent flow-mediated dilation (FMD). It is controversial whether or not FMD is impaired in DM2 and IGM. We investigated this issue in a population-based setting.
  
  
  RESULTS
  In the study population (n = 650; 246 with normal glucose metabolism (NGM), 135 with IGM and 269 with DM2; mean age: 67.6 years), FMD and endothelium-independent nitroglycerine-mediated dilation (NMD) were ultrasonically estimated from the brachial artery and expressed as the absolute change in diameter in mm. The increase in diameter (mean +/- standard deviation) in NGM, IGM and DM2 was 0.19 +/- 0.15, 0.19 +/- 0.18 and 0.13 +/- 0.17 MD and 0.45 +/- 0.21, 0.43 +/- 0.24 and 0.45 +/- 0.25 for NMD. After adjustment for age, sex, baseline diameter and percentage increase in peak systolic velocity, DM2, as compared to NGM, remained associated with impaired FMD (regression coefficient beta (95%CI)) as compared to NGM, -0.06 mm (-0.09 to -0.03). IGM was not associated with impaired FMD (beta, 0.01 mm (-0.02 to 0.04)). Additional adjustment for conventional cardiovascular risk factors did not alter these associations. Hyperglycemia or hyperinsulinemia explained 2% of the association between DM2 and FMD. NMD was not associated with glucose tolerance.
  
  
  CONCLUSIONS
  This study shows that DM2 is independently associated with impaired FMD. Hyperglycemia and hyperinsulinemia contribute minimally to this association. Impaired FMD may therefore, in part, explain the increased cardiovascular disease risk in DM2, whereas the normal FMD in IGM suggests that other forms of endothelial dysfunction are important in explaining the increased cardiovascular disease risk in IGM.
authors.affiliation: Institute for Research in Extramural Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Ronald M A
authors.initials: RM
authors.lastname: Henry
authors.forename: Isabel
authors.initials: I
authors.lastname: Ferreira
authors.forename: Piet J
authors.initials: PJ
authors.lastname: Kostense
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Dekker
authors.forename: Giel
authors.initials: G
authors.lastname: Nijpels
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Heine
authors.forename: Otto
authors.initials: O
authors.lastname: Kamp
authors.forename: Lex M
authors.initials: LM
authors.lastname: Bouter
authors.forename: Coen D A
authors.initials: CD
authors.lastname: Stehouwer
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000453:epidemiology*; D004108:Dilatation, Pathologic / Q000000981:diagnostic imaging; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D018149:Glucose Intolerance / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011336:Probability; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance