Recent trends in waist circumference and waist-height ratio among US children and adolescents.

OBJECTIVES: Abdominal obesity may be a better predictor than overall obesity for the risk of cardiovascular disease and type 2 diabetes. Waist circumference and waist-height ratio are 2 simple, yet effective, surrogate measures of abdominal obesity. We sought to examine the recent trends in mean waist circumference and waist-height ratio and prevalence of abdominal obesity among children and adolescents aged 2 to 19 years in the United States.

METHODS: Representative samples of the civilian, noninstitutionalized US population from the National Health and Nutrition Examination Survey conducted during 4 time periods, 1988-1994 (ie, National Health and Nutrition Examination Survey III), 1999-2000, 2001-2002, and 2003-2004, were examined to estimate the mean waist circumference and waist-height ratio of boys and girls in 4 different age groups. Data from the 3 most recent National Health and Nutrition Examination Surveys were combined to establish a National Health and Nutrition Examination Survey 1999-2004 category.

RESULTS: Categorized by age group, the unadjusted mean waist circumference for boys increased between National Health and Nutrition Examination Survey III and National Health and Nutrition Examination Survey 1999-2004 from 50.7 cm (aged 2-5 years), 61.9 cm (aged 6-11 years), 76.8 cm (aged 12-17 years), and 81.3 cm (aged 18-19 years) to 51.9, 64.5, 79.8, and 86.6 cm, respectively. During the same time periods and within the same age groups, the unadjusted mean waist circumference for girls increased from 51.0, 61.7, 75.0, and 77.7 cm to 51.8, 64.7, 78.9, and 83.9 cm, respectively. The relative change in waist-height ratio was similar to waist circumference at each age group for both boys and girls. Using the 90th percentile values of waist circumference for gender and age, the prevalence of abdominal obesity increased by 65.4% (from 10.5% to 17.4%) and 69.4% (from 10.5% to 17.8%) for boys and girls, respectively.

CONCLUSIONS: Mean waist circumference and waist-height ratio and the prevalence of abdominal obesity among US children and adolescents greatly increased between 1988-1994 and 1999-2004.