title: Risk factors for cardiovascular disease do not fully explain differences in carotid intima-media thickness between Indigenous and European Australians without diabetes.
abstract: OBJECTIVE
  To investigate whether cardiovascular risk factors can explain the higher carotid intima-media thickness (CIMT) in Indigenous compared with European Australians.
  
  
  METHODS
  Cross-sectional study in three subgroups.
  
  
  METHODS
  Non-diabetic urban European (n = 86), urban Indigenous (n = 69), and remote Indigenous (n = 60) Australians aged 25-64 years.
  
  
  METHODS
  CIMT, age, sex, anthropometry, blood pressure, smoking status, fasting glucose and insulin, haemoglobin (Hb)A1c, homocysteine, C-reactive protein (CRP), lipids, urinary albumin and creatinine.
  
  
  RESULTS
  CIMT and levels of risk factors, except fasting glucose and total cholesterol, worsened across the three groups. Log(n) fasting insulin [beta = 0.022, 95% confidence interval (CI) 0-0.0439], age (beta = 0.006, 95% CI 0.004-0.007), gender (female beta = -0.005 vs. male, 95% CI -0.084 to -0.026), mean arterial pressure (MAP) (beta = 0.001, 95% CI 0.001-0.002) and ethnicity/location [urban Indigenous (beta = 0.027, 95% CI -0.010 to 0.064 vs. European); remote Indigenous (beta = 0.083, 95% CI 0.042-0.123 vs. European)] explained 41% of variance in CIMT. Significant interactions were seen for ethnicity/location with age (P = 0.014) and MAP (P = 0.018). Age was consistently associated with CIMT across the three populations, and was associated with larger increments in CIMT for the Indigenous subgroups (beta = 0.007, 95% CI 0.005-0.009 urban; beta = 0.007, 95% CI 0.004-0.010 remote) compared with Europeans (beta = 0.003, 95% CI 0.002-0.006) in models including age, sex and MAP. MAP was only associated with CIMT in the remote Indigenous subgroup.
  
  
  CONCLUSIONS
  After adjusting for selected risk factors, CIMT in remote Indigenous participants was still higher than in Europeans. The slope of the association between age and CIMT steepened from urban Europeans to remote Indigenous.
authors.affiliation: Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Maple-Brown
authors.forename: A
authors.initials: A
authors.lastname: Hodge
authors.forename: J
authors.initials: J
authors.lastname: Cunningham
authors.forename: D S
authors.initials: DS
authors.lastname: Celermajer
authors.forename: K
authors.initials: K
authors.lastname: O'Dea
mesh_terms: D000328:Adult; D001315:Australia / Q000208:ethnology; D001786:Blood Glucose; D002097:C-Reactive Protein / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000208:ethnology / Q000378:metabolism; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000378:metabolism; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D017539:Tunica Intima / Q000000981:diagnostic imaging*; D017540:Tunica Media / Q000000981:diagnostic imaging*; D014463:Ultrasonography
chemical_list: D001786:Blood Glucose; D008055:Lipids; D002097:C-Reactive Protein