1 University of Alabama at Birmingham, USA; 2 Medical Nutrition Research Unit - Mexican Institute of Social Security, México.
National data from the United States has shown weight stabilization in children in the past decade. However, weight stabilization does not necessarily reflect potential changes in body composition. This study created reference tables for waist circumference (WC) percentiles in a 2014 nationally representative data set and identified changes in WC percentiles across a decade. Data from the National Health and Nutrition Examination Survey (NHANES) was used to evaluate WC measured at the right iliac crest among non-institutionalized US children and adolescents self-classified as African Americans (AA, n=3498), European Americans (EA, n=3686) and Mexican Americans (MA; n=3549). Percentile regression was used to model the regression lines of the 10th, 25th, 50th, 75th, 85th, 90th and 95th percentiles of the distribution of WC according to race/ ethnicity and sex for age 2 - 18. Descriptive trends in WC percentile distributions across time were identified by comparing present study data with previously reported (2004) data for boys and girls at every age. WC increased in a monotonic fashion in all children with significant differences in the slope trajectory across age among AA, EA and MA boys and girls. When changes across a decade were evaluated, a clear left shift of percentile categories was observed such that values that used to be in the 90th percentile are now in the 85th percentile. AA and MA girls exceeded the WC cutoff value for obesity-related disease risk in adults at as early as 11 years of age. In conclusion, WC has increased in the past decade in the US pediatric population. Given that no increase in the prevalence of pediatric obesity in the US has been reported, our data raises the potential concern of having stable-weight children with a distribution of body composition that places them at risk of disease.