Validity of body mass index compared with other body-composition screening indexes for the assessment of body fatness in children and adolescents.
BACKGROUND
Validation studies of height- and weight-based indexes of body fatness in children and adolescents have examined only small samples of school-age children.


OBJECTIVE
The objective was to validate the performance of age- and sex-specific body mass index (BMI) compared with the Rohrer index (RI) and weight-for-height in screening for both underweight and overweight in children aged 2-19 y.


METHODS
Data from the third National Health and Nutrition Examination Survey (n = 11096) and a pooled data set from 3 studies that used dual-energy X-ray absorptiometry (n = 920) were examined. The receiver operating characteristic curve was used to characterize the sensitivity and specificity of these 3 indexes in classifying both underweight and overweight. Percentage body fat and total fat mass were determined by dual-energy X-ray absorptiometry. Subcutaneous fat was assessed on the basis of the average of triceps and subscapular skinfold thicknesses.


RESULTS
For children aged 2-19 y, BMI-for-age was significantly better than were weight-for-height and RI-for-age in detecting overweight when average skinfold thicknesses were used as the standard, but no differences were found in detecting underweight. When percentage body fat or total fat mass was used as the standard, BMI-for-age was significantly better than was RI-for-age in detecting overweight in children aged 3-19 y. No differences were found between BMI-for-age and weight-for-height in detecting overweight or underweight.


CONCLUSIONS
For children and adolescents aged 2-19 y, the performance of BMI-for-age is better than that of RI-for-age in predicting underweight and overweight but is similar to that of weight-for-height.
Mei
Zuguo
Z
Division of Nutrition and Physical Activity, Centers for Disease Control and Prevention, Atlanta, GA 30341-3724, USA. zam0@cdc.gov
Grummer-Strawn
Laurence M
LM
Pietrobelli
Angelo
A
Goulding
Ailsa
A
Goran
Michael I
MI
Dietz
William H
WH
D015502:Absorptiometry, Photon / Q000379:methods; D000273:Adipose Tissue / Q000033:anatomy & histology; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001823:Body Composition / Q000502:physiology*; D001827:Body Height / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D002648:Child; D015362:Child Nutrition Disorders / Q000175:diagnosis; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D009748:Nutrition Disorders / Q000175:diagnosis*; D009749:Nutrition Surveys; D009765:Obesity / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors; D012885:Skinfold Thickness; D013223:Statistics as Topic; D014481:United States