Role of the waist/height ratio in the cardiometabolic risk assessment of children classified by body mass index

Objectives: The aim of this study was to determine the utility of waist/height ratio (WHtR) in the specification of cardiometabolic risk in children already stratified by body mass index (BMI). Background: Reflective of its association with cardiometabolic risk, BMI is a commonly used indirect indicator of adiposity in children. The WHtR, a marker of central adiposity, has been advocated as a possibly superior indicator of cardiometabolic risk. Methods: Cross-sectional analysis of 5 National Health and Nutrition Examination Surveys from 1999 to 2008 (ages 5 to 18 years of age). The BMI percentile categories (normal, overweight, and obese) were further stratified on the basis of WHtR (<0.5, 0.5 to <0.6, ≥0.6). Outcome measures were lipid and glycemic profiles, C-reactive protein, liver transaminases, prevalence of hypertension, and metabolic syndrome. Results: Data were available for 14,493 subjects. Overweight and obese subjects with a WHtR <0.5 had a cardiometabolic risk approaching that of subjects with a normal BMI percentile category. Increasing WHtR was significantly associated with increased cardiometabolic risk in overweight and obese subjects, with the greatest associations observed in the obese population. Of obese subjects with WHtR ≥0.6, 26% had elevated non-high-density lipoprotein levels, 18% had elevated C-reactive protein levels, 69% had an elevated homeostatic model assessment-insulin resistance, and 32% had metabolic syndrome. Conclusions: The WHtR further specifies cardiometabolic risk within classifications stratification on the basis of BMI percentile. A significant proportion of obese children with increased WHtRs have abnormal cardiometabolic risk factor levels. The WHtR should be included in the routine screening and assessment of overweight and obese children, and those with an elevated WHtR should undergo a further cardiometabolic risk assessment.