RESUMEN
Abstract Objective: To estimate the accuracy of neck circumference measurement as a method of diagnosing excess weight of six and seven-year-old children. Methods: 1026 six and seven-year-old children were included and anthropometric data were collected using cut-off points for the Body Mass Index (BMI) Z-score, in addition to the measurement of their neck circumference in centimeters. Pearson's correlation coefficient was used to assess the correlation between neck circumference and BMI. Sensitivity, specificity, positive and negative predictive values were calculated. The Receiver Operating Characteristic curve was used to measure the accuracy of neck circumference as a diagnostic method for excess weight. Results: A positive linear correlation value was observed between neck circumference and BMI 0.572 (p < 0.001). The accuracy value of the global ROC curve was 0.772 (p < 0.001). Sensitivity and specificity showed low values, but high positive predictive values were observed, especially between measures of 30 and 31 cm. Conclusion: Neck circumference showed accuracy of 77.2% as a diagnostic method for overweightness in six and seven-year-old children.