Weight-for-stature compared with body mass index-for-age growth charts for the United States from the Centers for Disease Control and Prevention.

BACKGROUND The 2000 Centers for Disease Control and Prevention growth charts for the United States include population reference data for body mass index (BMI)-for-age (ages 2-19 y) and weight-for-stature (from 77 to 121 cm). For younger children, either set of reference data could be used. OBJECTIVE The objective of this study was to compare BMI-for-age with weight-for-stature. DESIGN We used data for 4348 children (aged 2-5 y) from the third National Health and Nutrition Examination Survey. Weight-for-stature and BMI-for-age percentiles were calculated for each child. The 10th and 85th percentiles of weight-for-stature at selected ages were also reexpressed as BMI-for-age percentiles. RESULTS More than 63% of children had lower weight-for-stature than BMI-for-age percentiles. Children were more likely to be classified as < or = 10th percentile by weight-for-stature than by BMI-for-age, but less likely to be classified as > or = 85th percentile. Differences in classification by the 2 measures varied with age and stature and were greater for shorter children. The 10th and 85th percentiles of weight-for-stature corresponded to BMI-for-age percentiles from the 3rd to the 21st percentile and from the 74th to the 92nd percentile, respectively, depending on age and stature. CONCLUSIONS Weight-for-stature is easier to use than BMI-for-age. However, BMI-for-age captures changes in the weight-height relation with age and can be used continuously up to the age of 20 y. BMI-for-age is recommended in most situations. BMI-for-age and weight-for-stature will not give identical results and are not interchangeable.