Assessment of Body Fatness

  Do Skinfold Measurements Provide Additional Information to Body Mass Index in the Assessment of Body Fatness Among Children and Adolescents?

Zuguo Mei, MD (a), Laurence M. Grummer-Strawn, PhD (a), Jack Wang, MS (b), John C. Thornton, PhD (b), David S. Freedman, PhD (a), Richard N. Pierson, Jr, MD (b), William H. Dietz, MD, PhD (a) and Mary Horlick, MD (c)
a) Division of Nutrition and Physical Activity, Centers for Disease Control and Prevention, Atlanta, Georgia; b) Body Composition Unit, Department of Medicine, Obesity Research Center, St Luke's-Roosevelt Hospital, New York, New York; c) National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland

OBJECTIVES. The purpose of this work was to validate the performance of age- and gender-specific BMI, triceps, and subscapular skinfold for the classification of excess of body fat in children and adolescents and to examine how much additional information these 2 skinfold measurements provide to BMI-for-age.
METHODS. The receiver operating characteristic curve was used to characterize the sensitivity and specificity of these 3 indices in classifying excess body fat. Percentage of body fat was determined by dual-energy radiograph absorptiometry. Both 85th and 95th percentile of percentage of body fat were used to define excess body fat. Data from the New York Pediatric Rosetta Body Composition Project were examined (n = 1196; aged 5–18 years).
RESULTS. For children aged 5 to 18 years, BMI-for-age, triceps skinfold-for-age, and subscapular skinfold-for-age each performed equally well alone in the receiver operating characteristic curves in the identification of excess body fat defined by either the 85th or 95th percentile of percentage of body fat by dual-energy radiograph absorptiometry. However, if BMI-for-age was already known and was >95th percentile, the additional measurement of skinfolds did not significantly increase the sensitivity or specificity in the identification of excess body fat.
CONCLUSIONS. In contrast to the recommendations of expert panels, skinfold measurements do not seem to provide additional information about excess body fat beyond BMI-for-age alone if the BMI-for-age is >95th percentile.

Key Words: dual-energy radiograph absorptiometry • BMI • skinfold • anthropometry • receiver operating characteristic curve • sensitivity • specificity

Abbreviations: DXA—dual-energy radiograph absorptiometry • CDC—Centers for Disease Control and Prevention • %BF—percentage of body fat • CV—coefficient of variation • ROC—receiver operating characteristic

PEDIATRICS Vol. 119 No. 6 June 2007, pp. e1306-e1313