title: Circulating vitamin D metabolites and subclinical atherosclerosis in type 1 diabetes.
abstract: OBJECTIVE
  People with type 1 diabetes are at high risk of premature atherosclerosis. Existing evidence suggests that impaired vitamin D metabolism may contribute to the development of atherosclerosis. We tested associations of circulating vitamin D metabolite concentrations with subclinical atherosclerosis among 1,193 participants with type 1 diabetes in the DCCT/EDIC study.
  
  
  METHODS
  We measured plasma concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D, and 24,25-dihydroxyvitamin D by mass spectrometry at the end of the DCCT. In a staggered cross-sectional design, we tested associations with coronary artery calcium (CAC), measured by computed tomography a median of 10 years later, and with common and internal carotid intima-media thickness (IMT), measured by B-mode ultrasonography on two occasions a median of 4 years later and a median of 10 years later. We hypothesized that lower concentrations of each vitamin D metabolite would be associated with increased risk of CAC and greater carotid IMT. RESULTS At the time metabolites were measured, mean age was 32.4 years and mean duration of diabetes was 7.5 years. The prevalence and severity of CAC tended to be lower-not higher-with lower concentrations of each vitamin D metabolite. For instance, in a fully adjusted multinomial logistic model, a 25 nmol/L lower 25-hydroxyvitamin D was associated with a 0.8-fold decrease in the odds of having higher CAC (95% CI 0.68-0.96, P = 0.01). No vitamin D metabolite was associated with either common or internal mean IMT.
  
  
  CONCLUSIONS
  We did not find evidence linking impaired vitamin D metabolism with increased subclinical atherosclerosis in type 1 diabetes.
authors.affiliation: University of Washington, Seattle, Washington, USA. sachsmc@u.washington.edu
authors.forename: Michael C
authors.initials: MC
authors.lastname: Sachs
authors.forename: John D
authors.initials: JD
authors.lastname: Brunzell
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Cleary
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Hoofnagle
authors.forename: John M
authors.initials: JM
authors.lastname: Lachin
authors.forename: Mark E
authors.initials: ME
authors.lastname: Molitch
authors.forename: Michael W
authors.initials: MW
authors.lastname: Steffes
authors.forename: Bernard
authors.initials: B
authors.lastname: Zinman
authors.forename: Ian H
authors.initials: IH
authors.lastname: de Boer
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3 / Q000097:blood*; D000328:Adult; D050197:Atherosclerosis / Q000209:etiology*; D002118:Calcium / Q000032:analysis; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging; D059168:Carotid Intima-Media Thickness; D003324:Coronary Artery Disease / Q000209:etiology; D003331:Coronary Vessels / Q000737:chemistry / Q000000981:diagnostic imaging; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D061205:Vascular Calcification / Q000097:blood / Q000000981:diagnostic imaging; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; D015650:24,25-Dihydroxyvitamin D 3; C097949:1,25-dihydroxyvitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium