Validity of Body Mass Index in Assessing Adiposity in Latina/o Youth

Relatively few studies to date have examined the performance of BMI in detecting excess adiposity in Latina/o youth. The objective of the present study was to assess the validity of the Centers for Disease Control and Prevention’s (CDC’s) BMI 95th percentile to identify excess adiposity in a sample of rural Latina/o youth. Height and weight and anthropometric skinfold measures were obtained for 636 third through fifth grade Latina/o students. Approximately 41.5% of the sample fell within the obese BMI range. Receiver operating characteristic curves were utilized to assess the sensitivity and specificity of the CDC BMI 95th percentile in classifying excess percent body fat. For the total sample, the BMI 95th percentile showed a sensitivity of 0.84 and specificity of 0.80. The area under the curve (AUC) was 0.82 indicating fair to good discriminatory power. Subgroup analysis indicated high sensitivity (0.95) for Latina girls and high specificity (0.91) for Latino boys. Our findings suggest that rural Latino boys have a greater likelihood of being under identified as having excess adiposity when using BMI in isolation. These findings provide initial evidence for a need for racial/ethnic specific BMI norms for Latina/o youth.