Monitoring childhood obesity: Assessment of the weight/height(2) index

The body mass index (BMI), defined as weight/height(2), is often used to mo nitor childhood obesity. BMI values for 979 children (438 White, 283 Black, and 258 Hispanic) aged 3-18 years living in the Houston, Texas, metropolit an area from 1994 to 1998 were compared with percentage of fat (%Fat) measu rements obtained by using dual-energy x-ray absorptiometry, The association s between %Fat and BMI were statistically significant (r(2) = 0.34-0.70, p < 0.0005) and were gender and ethnic dependent (p < 0.0005), indicating tha t BMI can provide a general description of the adiposity characteristics of a healthy pediatric population. However, BMI was a poor predictor for the individual child, with a standard error for %Fat of 4.7-7.3% of body weight . It is advantageous to identify accurately, as early as possible, those ch ildren who truly have excess adiposity, but this assessment should not be d one at the risk of falsely mislabeling a significant number of healthy chil dren as overweight or obese.