Agreement on the Prevalence of Body Mass Index (BMI) in Mexican Children and Adolescents Using Different International References.

(1) Background: Obesity and overweight are defined as an abnormal or excessive accumulation of fat that can be harmful to health. These are conditions that can lead to a lifetime of diseases, including cancer, diabetes, and heart disease. The diagnosis of overweight and obesity in children and adolescents depends on the international reference used. (2) Objectives: In this study aimed to determine the level of concordance of the prevalence of underweight, normal weight, overweight, and obesity were estimated with three international references in Mexican children and adolescents between 2 and 18 years of age. (3) Methods: We used specific the body mass index (BMI) cut-off points of the ENSANUT Continua 2022 database. The weight category was measured using the World Health Organization (WHO) criteria (<-2 standard deviation (SD), underweight; -2 and +0.99 SD, normal weight; +1 and +1.99 SD, overweight; and ≥+2 SD, obesity); Centers for Disease Control and Prevention (CDC) criteria (<percentile 5, underweight; percentile 5 and <percentile 85, normal weight; ≥percentile 85, overweight; and ≥percentile 95, obesity); and the Obesity Task Force (IOTF) criteria (specific limit values). To determine agreement among these three criteria, Cohen's Kappa index was used. (4) Results: There were differences in the estimation of weight categories according to the international reference used. Substantial (WHO-IOTF: 0.639; CDC-IOTF: 0.785) and almost perfect (WHO-CDC: 0.806) levels of agreement were found between the references used; however, agreement varied according to age. (5) Conclusions: The weight category depends on the reference used, so each one should be used with caution since the results inform our actions of prevention, surveillance, and the control of nutrition in childhood and adolescence for the timely detection of chronic health problems and effects of social deficiencies.