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Determinants of carotid intima-medial thickness in an urban Australian Aboriginal population

  • Pamela J. Bradshaw
    Affiliations
    School of Population Health University of Western Australia, Australia

    Heart Research Institute, Sir Charles Gairdner Hospital, Australia
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  • Edward T. Wilkes
    Affiliations
    Telethon Institute for Child Health Research, Australia

    Derbarl Yerrigan Health Service, Australia
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  • Peter L. Thompson
    Correspondence
    Correspondence to: Western Australia Heart Research Institute, First Floor, “C” Block, Sir Charles Gairdner Hospital, Nedlands, WA 6009, Australia. Tel.: +61 8 9346 2677; fax: +61 8 9346 2920.
    Affiliations
    School of Population Health University of Western Australia, Australia

    Heart Research Institute, Sir Charles Gairdner Hospital, Australia
    Search for articles by this author

      Abstract

      Introduction

      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.

      Keywords

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