Nutritional status in children with cancer: comparison of deuterium oxide dilution with bioelectric impedance analysis and anthropometry / Estado nutricional em crianças com câncer: comparação entre diluição de deutério, impedância bioelétrica e antropometria

ABSTRACT Objective: To explore changes in the nutritional status of pediatric cancer patients before and after chemotherapy and evaluate the correlation between deuterium oxide dilution, bioelectric impedance analysis, and anthropometry for assessment of body composition. Methods: This study included 14 children (aged 5.6 to 13.6 years) and classified them as having hematologic or solid tumors. They had their body composition analyzed according to deuterium oxide, bioelectric impedance, and anthropometric measurements before the first chemotherapy cycle and after three and six months of therapy. Results: The patients in the hematologic tumor group had an increase in weight, height, body mass index, waist, hip, and arm circumference, subscapular skinfold thickness, and fat mass with the isotope dilution technique during chemotherapy. In the solid tumor group, the children showed a reduction in fat-free mass when assessed by bioimpedance analysis. We found a positive correlation between the triceps skinfold thickness and fat mass determined by bioimpedance analysis and deuterium oxide. The arm muscle circumference correlated with the fat-free mass estimated by bioimpedance analysis and deuterium oxide. Conclusions: Patients with hematologic tumors had an increase in body weight, height, and fat mass, which was not identified in the solid tumor group. The positive correlation between anthropometry (triceps skinfold thickness and arm muscle circumference), deuterium oxide dilution, and bioelectric impedance analysis shows the applicability of anthropometry in clinical practice.

RESUMO Objetivo: Verificar mudanças no estado nutricional de crianças com câncer antes e após o tratamento quimioterápico e avaliar a correlação entre diluição de óxido de deutério, análise de impedância bioelétrica (BIA) e dados antropométricos. Métodos: Quatorze crianças (entre 5,6 e 13,6 anos de idade) foram incluídas e classificadas como tendo tumores hematológicos ou sólidos. A composição corporal foi medida pelo óxido de deutério, impedância bioelétrica e medidas antropométricas antes da primeira quimioterapia e após três e seis meses de terapia. Resultados: Os pacientes do grupo de tumores hematológicos aumentaram o peso, a estatura, o índice de massa corporal, a circunferência da cintura, quadril e braço, dobra cutânea subescapular e a massa gorda com a técnica de diluição isotópica durante o tratamento quimioterápico. No grupo de tumores sólidos, as crianças mostraram uma redução na massa magra quando avaliadas por análise de impedância. Houve uma correlação positiva entre a dobra cutânea tricipital e a massa gorda determinadas pela análise de impedância e pelo óxido de deutério. A circunferência muscular do braço correlacionou-se com a massa magra estimada pela análise de impedância e pelo óxido de deutério. Conclusões: Pacientes com tumores hematológicos tiveram aumento no peso corporal, estatura e massa gorda, o que não foi observado naqueles com tumores sólidos. A boa correlação entre a antropometria (dobra cutânea tricipital e circunferência muscular do braço), a diluição do óxido de deutério e a análise da impedância bioelétrica mostra a aplicabilidade da antropometria na prática clínica.

Validez del porcentaje de grasa corporal por pliegues cutáneos comparado con la dilución de óxido de deuterio en escolares costarricenses / Validity of percent body fat by skinfold thickness comparated with deuterium oxide dilution in Costa Rican school children

El objetivo del estudio fue determinar la validez del porcentaje de grasa corporal (% GC) estimado por la ecuación de Slaughter en escolares costarricenses. Participaron 54 niños y 49 niñas con una edad promedio 7.8 ± 1.0 años. El óxido de deuterio (D2O) fue el método de referencia para determinar la masa grasa (FM) expresada como % GC. Se utilizó un análisis de regresión lineal y prueba t para determinar la asociación y las diferencias entre el %GC por la ecuación de Slaughter y D2O. La concordancia entre métodos se determinó por el coeficiente de correlación de concordancia (CCC) de Lin. La medición de acuerdo entre los métodos se analizó mediante el procedimiento de Bland-Altman. El % GC entre métodos fue significativamente diferente en niños (26.3 ± 7.4% vs 22.4 ± 7.0%) y niñas (33.2 ± 5.7% vs 26.1 ± 5.7%). La asociación entre métodos no fue significativa en niños (R2 = 0.76, p <0.0001) y niñas (R2 = 0.24, p <0.0001). Los gráficos de Bland-Altman mostraron que la ecuación de Slaughter subestimó el % GC en 6,0% en niños y 3,5% en niñas, en comparación con D2O. El CCC de Lin identificó una fuerza de concordancia pobre entre métodos, niños ρc= 0.87 y niñas ρc= 0.56. Con los resultados se concluye que la ecuación de Slaughter registró baja concordancia del % GC en comparación con el D2O en escolares costarricenses(AU)

The aim of the study was to determine the validity of the body fat percentage (% GC) estimated by the Slaughter equation in Costa Rican school children. The sample consisted of 54 male and 49 female, mean age 7.8 ± 1.0 years. Deuterium oxide dilution (D2O) was the reference method to determine the fat mass (FM) expressed as BF%. Linear regression analyses and paired sample t-tests were used to test association and mean differences between Slaughter equation and D2O BF%. Concordance between Slaughter equation and D2O BF% was determined by Lin's concordance correlation coefficient (CCC). Measurement of agreement between the two methods was analyzed using the Bland-Altman procedure. Measurements of BF% by Slaughter equation and D2O were significantly different for boys (26.3 ± 7.4% vs 22.4 ± 7.0%) and for girls (33.2 ± 5.7% vs 26.1 ± 5.7%). Non-significant association between methods was found in males (R2 = 0.76, p <0.0001) and females (R2 = 0.24, p <0.0001). Bland-Altman plots showed that Slaughter equation underestimated the %BF in a 6.0% for boys and in a 3.5% for girls compared with D2O. Lin's CCC identified poor strength of concordance between the two methods, for boys ρc= 0.87 and for girls ρc= 0.56. With the results we conclude that the Slaughter equation registered low agreement of BF% compared against the one obtained by D2O in Costa Rican school children(AU)