Large Waist but Low Body Mass Index: The Metabolic Syndrome in Australian Aboriginal Children

Objective

To describe the prevalence and clinical characteristics of the metabolic syndrome (MetS) in a cohort of Australian Aboriginal children.

Study design

Body mass index (BMI), waist circumference, skin fold thickness, body fat percentage, insulin resistance, and the prevalence of MetS were evaluated in 486 children age 9 to 14 years from the Darwin Health Region, Northern Territory, Australia.

Results

Using an age- and sex- specific definition, 14% of the children in the cohort had MetS, 6.4% were overweight, 4.9% were obese, and 26.2% had an elevated waist circumference. The mean percentage of body fat was 30.2%. The children with MetS had higher BMI and waist z-scores, percent body fat, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) score, and skin fold thickness compared with those without MetS (P < .001); however, >50% of those with MetS were neither overweight nor obese. Waist circumference was significantly associated with insulin resistance as measured by the HOMA-IR (P < .001).

Conclusions

MetS is common in our cohort despite low rates of overweight and obesity. A tendency for central adiposity is already evident in these young children. Measurement of waist circumference may help identify Aboriginal children at high risk for MetS.

Abbreviations: BMI, Body mass index, CVD, Cardiovascular disease, HDL-c, High-density lipoprotein cholesterol, HOMA-IR, Homeostasis Model Assessment of Insulin Resistance, LDL-c, Low-density lipoprotein cholesterol, MetS, Metabolic syndrome, NCEP III, Third National Cholesterol Education Program, T2DM, Type 2 diabetes mellitus