Ethnicity influences BMI as evaluated from reported serum lipid values in Inuit and non-Inuit: raised upper limit of BMI in Inuit?

Objective: To identify thresholds of BMI at which similar levels of serum lipids occur in Inuit and in non-Inuit as the impact of obesity on metabolic risk factors differ in Inuit compared to other ethnic groups.

Design: Published comparative data among Inuit and non-Inuit whites on BMI and HDL-cholesterol and triglyceride were identified for analysis.

Methods: A literature search was done for BMI, lipids, Inuit and Greenland or Canada. Studies with data on triglycerides and HDL-cholesterol in Inuit and non-Inuit Caucasians were selected and data were retrieved.

Main Outcome Measures: Regression equations were computed for BMI and HDL-cholesterol and BMI and triglycerides. BMI for similar levels of lipids in Inuit and non-Inuit and ratios of Inuit/non-Inuit BMI's were calculated.

Results: At BMI 25 kg/m2 HDL-cholesterol was 1.7/1.6 mM in Greenland Inuit/non-Inuit women and 1.7/1.5 mM in men in a major comparative study. HDL cholesterol decreased by 0.09 for each 1 kg/m2 increase in BMI. Serum triglycerides were 1.0/1.1 mM for Greenland Inuit/non-Inuit women and 0.9/ 1.4 mM for men at BMI 25 kg/m2. Slopes were around 0.1. A comparative study in Canadian Inuit/non-Inuit gave similar results. The BMI levels required for similar HDL-cholesterol or triglycerides were around 27.5 kg/m2, and Inuit/non-Inuit BMI-ratios were around 1.1.

Conclusion: The same degree of dyslipidaemia was seen when Inuit had a 10% higher BMI compared to non-Inuit. This may support the establishment of Inuit-specific BMI cut-offs for the purposes of health screening and population health surveillance.