Weight status of indigenous youth in Oaxaca, southern Mexico: concordance of IOTF and WHO criteria

Purpose: To compare the prevalence of thinness, overweight and obesity with IOTF and WHO criteria among indigenous school youth from the state of Oaxaca, southern Mexico. Methods: The sample included 11 454 indigenous youth (6216 boys, 5238 girls) 6-14 years of age. Heights and weights were measured in 2007 by trained staff. BMIs were calculated and classified as severely thin, moderately thin, normal, overweight or obese using age- and sex-specific IOTF and WHO cut-offs. Prevalence, percentage agreement between classifications, Spearman rank order correlations and Kappa coefficients were calculated. Results: Prevalence of overweight and obesity was higher with WHO than IOTF criteria, while prevalence of severe and moderate thinness did not appreciably differ between criteria. Weight status with the two criteria was discordant in 839 boys (13.5%) and 383 girls (7.3%) and more often for overweight and obesity than thinness. Percentage agreement, correlations and Kappa coefficients were moderate-to-high and were higher in girls than boys. Conclusion: Prevalence of overweight and obesity among indigenous youth in Oaxaca was higher with WHO than IOTF criteria, whereas prevalence of severe and moderate thinness was similar. Differences in estimates for overweight and obesity have implications for surveillance.