Impact of dyslipidaemia on arterial structure and function in urban Indigenous Australians

Background: Premature cardiovascular disease (CDV) is highly prevalent in urban Indigenous Australians. We studied arterial structure and function in 144 volunteers aged 15-66 years to assess the role of dyslipidaemia and other traditional vascular risk factors on cardiovascular risk in young and older urban Indigenous Australians. Methods: We assessed carotid intima-media thickness (CIMT) by high-resolution B-mode ultrasound imaging of the common carotid artery and peripheral wave reflection using applanation tonometry to obtain the aortic augmentation index (AI) in Indigenous Australian participants of the Darwin Region Urban Indigenous Diabetes (DRUID) study. Results: Participants aged 15-24 years demonstrated fewer cardiovascular risk factors than the older group (25-66 years) and predictors of CIMT and AI differed between younger and older groups. CIMT was higher in the older group (0.67 mm vs. 0.61 mm, p = 0.004) and in those with diabetes (0.81 mm vs. 0.67 mm, p < 0.001). AI was higher in the older group (24% vs. 0%, p < 0.001), but was not affected by diabetes status. On multivariate regression analysis, low HDL-cholesterol was the only independent predictor of CIMT in the younger group; triglycerides, heart rate (inverse) and height (inverse) were independent predictors of AI in the same group. Conclusion: Dyslipidaemia (low HDL-cholesterol or elevated triglycerides) is independently associated with non-invasive measures of cardiovascular disease in a relatively healthy and young subgroup of this high-risk population. We propose that triglycerides and low HDL-cholesterol may represent the most useful commonly measured clinical indicators of cardiovascular risk in young, urban Indigenous Australians.