title: Haemoglobin A1c is associated with carotid intima-media thickness in a Chinese population.
abstract: BACKGROUND
  The association between haemoglobin A1c (HbA1c) levels and subclinical atherosclerosis in carotid arteries in Chinese populations is unknown. AIM, DESIGN AND METHODS: The objective of this study was to investigate this relationship and evaluate the ability of HbA1c levels to predict carotid atherosclerosis in a Chinese population. This was a cross-sectional study, which included 541 subjects without known diabetes (Taiwan Lifestyle Study). About 67 (9·2%) subjects were newly diagnosed with diabetes during the study. Carotid intima-media thickness (IMT) and the presence of carotid plaques were determined using ultrasonography.
  
  
  RESULTS
  The HbA1c level in all subjects was positively correlated with carotid IMT (β = 0·018, P = 0·03) after being adjusted for age, gender, smoking, low-density lipoprotein cholesterol level, hypertension and body mass index. HbA1c level was higher in subjects with plaques in carotid arteries (P = 0·01). There was a positive and linear relationship between HbA1c levels and the probability of having plaques, thickened carotid IMT or both (P for all comparisons, <0·05). The ability of HbA1c levels to predict thickened carotid IMT or the presence of plaques was only modest {the optimal cutoff of HbA1c level [5·7%] was determined from the receiver operating characteristic (ROC) curve (sensitivity = 67%, specificity = 61%) and the area under the ROC curve [0·666]}.
  
  
  CONCLUSIONS
  Thus, HbA1c level is associated with subclinical atherosclerosis in carotid arteries in a Chinese population. The relationship is linear without an inflection point. However, HbA1c criterion is not a useful marker for the identification of subclinical atherosclerosis.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan.
authors.forename: Chi Sheng
authors.initials: CS
authors.lastname: Hung
authors.forename: Po-chu
authors.initials: PC
authors.lastname: Lee
authors.forename: Hung-Yuan
authors.initials: HY
authors.lastname: Li
authors.forename: Wen-Ya
authors.initials: WY
authors.lastname: Ma
authors.forename: Mao-Shin
authors.initials: MS
authors.lastname: Lin
authors.forename: Jung-Nan
authors.initials: JN
authors.lastname: Wei
authors.forename: Shyang-Rong
authors.initials: SR
authors.lastname: Shih
authors.forename: Cyue-Huei
authors.initials: CH
authors.lastname: Hua
authors.forename: Lee-Ming
authors.initials: LM
authors.lastname: Chuang
authors.forename: Ming-Fong
authors.initials: MF
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People / Q000706:statistics & numerical data; D058070:Asymptomatic Diseases / Q000453:epidemiology; D002340:Carotid Artery Diseases / Q000097:blood / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000208:ethnology; D059168:Carotid Intima-Media Thickness / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011153:Population; D015995:Prevalence; D012372:ROC Curve
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human