Increased arterial stiffness in remote Indigenous Australians with high risk of cardiovascular disease

OBJECTIVE: To assess central and peripheral arterial stiffness in Indigenous and European Australians with and without type 2 diabetes using applanation tonometry to obtain the augmentation index (AI) and pulse wave velocity (PWV). METHODS: AI was assessed in 162 Indigenous Australians (60 with type 2 diabetes) participating in a population-based study and 121 Australians of European ancestry (38 with diabetes) of similar age and sex. PWV was assessed in a subgroup: n = 62 indigenous, n = 118 European participants. RESULTS: The indigenous group had higher AI than the European group [mean (SD) 32 (12) versus 24 (12)%, P < 0.0001] and carotid-femoral PWV [8.4 (1.8) versus 7.1 (2.2) ms(-1), P < 0.0001]. There were no significant differences between groups regarding blood pressure and total cholesterol; however, indigenous individuals had higher fasting glucose, insulin, haemoglobin A1c, triglycerides, waist circumference (despite lower body mass index), and a higher prevalence of cigarette smoking. Fifty-five per cent of the variance in AI was explained on multiple regression analysis by age, sex, indigenous participant, heart rate, mean arterial pressure, height, triglycerides and waist circumference. Age, indigenous participant, heart rate, mean arterial pressure and antihypertensive medication explained 56% of the variance in PWV. Variables of the metabolic syndrome and smoking, C-reactive protein (CRP), homocysteine and heart rate clustered with indigenous status on factor analysis. CONCLUSIONS: Indigenous Australians have higher indices of peripheral and central arterial stiffness than European Australians of similar age and sex. Factor analysis revealed that metabolic syndrome variables, smoking, CRP, homocysteine and heart rate clustered with 'indigenous participant' and may explain increased arterial stiffness in this group.