Similarities and differences in cardiometabolic risk factors among remote Aboriginal Australian and Canadian cohorts

Aim: Indigenous populations of Australia and Canada experience disproportionately high rates of chronic disease. We hypothesized that despite the common outcome of increased diabetes prevalence, differences in cardiometabolic risk profile may exist between these populations. Methods: We compared community-based data on cardiometabolic risks in Aboriginal Australians (n= 297 without, 45 with diabetes), and Aboriginal Canadians (n= 409 without, 87 with diabetes). Results: Despite strikingly lower weight (62 vs 83kg, p<0.0001) and body mass index (BMI, 22 vs 29kg/m ² , p<0.0001), Aboriginal Australians without diabetes had similar waist-hip ratio (WHR, 0.91 vs 0.91, p=0.732), lower HDL-cholesterol (0.97 vs 1.25mmol/L, p<0.0001) and higher HbA1c (5.4 vs 5.2%, p<0.0001) than Aboriginal Canadians without diabetes. Waist was the obesity measure most strongly related to diabetes or cardiometabolic risk in Australians while BMI performed similarly to other obesity measures only in Canadians. Multiple regression of HbA1c revealed age and fasting glucose as independent predictors in each study group, with the addition of WHR in Aboriginal Australians. Conclusion: The notable finding was that waist or WHR are preferred obesity measures to appropriately reflect cardiometabolic risk in Aboriginal Australians, who although leaner by BMI criteria, displayed a similarly adverse risk profile to Aboriginal Canadians. Waist or WHR should be routinely included in clinical assessment in these high-risk populations.