Determinants of carotid intima-medial thickness in an urban Australian Aboriginal population.
BACKGROUND
We studied the determinants of carotid atherosclerosis in urban-dwelling Australian Aboriginals at high risk of atherosclerotic mortality and morbidity.


METHODS
Cross-sectional study of self-selected adult Australian Aboriginals. Participants (n=602) aged 18-74 years had risk factor assessment and carotid ultrasound to determine carotid intima-medial thickness (IMT) and the presence of plaque. The upper quartile (>0.71 mm in males and >0.62 mm in females) was used as a measure of increased carotid IMT.


RESULTS
Over 80% of participants were overweight or obese; the prevalence of diabetes was 25%. Age was the major predictor of thick IMT, OR 3.0 (95% CI 2.0-4.5) per decade for males and OR 6.3 (3.3-12.0) for females. Waist circumference and blood glucose were independent predictors of IMT for men, with hypertension, pack-years of smoking, diabetes, and cholesterol ratio additional predictors for women. Plaque was highly prevalent (>40%) in this relatively young population and was predicted by increasing age, a history of smoking and total cholesterol/HDL ratio, but not sex.


CONCLUSIONS
Urban-dwelling Aboriginal Australians are at increased risk for early atherosclerosis. In this study an excess of obesity-related cardiovascular risk factors were the important contributors to increased IMT carotid atherosclerosis, but not inflammatory markers or other novel risk factors.
Bradshaw
Pamela J
PJ
School of Population Health University of Western Australia, Nedlands, WA 6009, Australia.
Wilkes
Edward T
ET
Thompson
Peter L
PL
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001315:Australia; D001786:Blood Glucose; D001794:Blood Pressure; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology*; D002340:Carotid Artery Diseases / Q000453:epidemiology / Q000208:ethnology*; D002784:Cholesterol / Q000097:blood; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D012307:Risk Factors; D012907:Smoking; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography; D014505:Urban Population; D014904:Western Australia / Q000453:epidemiology
D001786:Blood Glucose; D002784:Cholesterol