Degree of Accuracy of the BMI Z-Score to Determine Excess Fat Mass Using DXA in Children and Adolescents

Obesity is caused by fat accumulation. BMI Z-score is used to classify the different degrees of weight status in children and adolescents. However, this parameter does not always express the true percentage of body fat. Our objective was to determine the degree of agreement between the fat mass perc...

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Detalles Bibliográficos
Autores: Monasor Ortola, David, Quesada-Rico, Jose Antonio, Nso-Roca, Ana Pilar, Rizo-Baeza, Mercedes, CORTÉS CASTELL, ERNESTO, Martínez-Segura, Asier, Sánchez Ferrer, Francisco
Tipo de recurso: artículo
Fecha de publicación:2021
País:España
Institución:Universidad Miguel Hernández de Elche
Repositorio:REDIUMH. Depósito Digital de la UMH
OAI Identifier:oai:dspace.umh.es:11000/30871
Acceso en línea:https://hdl.handle.net/11000/30871
Access Level:acceso abierto
Palabra clave:BMI Z-score
childhood obesity
body composition
fat mass
growth charts
Descripción
Sumario:Obesity is caused by fat accumulation. BMI Z-score is used to classify the different degrees of weight status in children and adolescents. However, this parameter does not always express the true percentage of body fat. Our objective was to determine the degree of agreement between the fat mass percentage measured by DXA and the stratification of weight according to BMI Z-score in the pediatric age group. We designed a descriptive cross-sectional study. The patients were classified as underweight/normal weight with Z-scores between 2 and +0.99, overweight from 1 to 1.99, obese from 2 to 2.99, and very obese 3. We included 551 patients (47% girls), with a mean age of 11.5 2.8 years (3.7–18 years). Higher BMI Z-scores were associated with a higher percentage of total fat (p < 0.001). However, there were important overlaps between both parameters, such that the BMI Z-score classified patients with the same percentage of total fat mass as having a different nutritional status classification. In conclusion, the stratification of weight status according to BMI Z-score revealed that 46.7% of patients had a fat percentage that did not correspond to their classification. For a more accurate weight assessment in clinical practice, we recommend combining anthropometric indices with diagnostic tools that better correlate with DXA, such as electrical bioimpedance.