Accuracy of alternative indexes for assessing the nutritional status of men and women / Acurácia de índices alternativos para avaliar o estado nutricional de homens e mulheres

Abstract A good evaluation of the nutritional status requires knowledge on body composition, casting doubts on the accuracy of some indexes. Therefore, the aim of this study was to analyze the accuracy of the following nutritional status indexes: Body Mass Index (BMI), BMI elevated to 2.5 (BMI2.5), Fat Mass Index (FMI) and BMI adjusted for fat mass (BMIfat). Participated of this study 280 subjects (aged 17-48 years), from which the results of BMI, BMI25, FMI and BMIfat indexes were analyzed, having the Hydrostatic Weighing method as reference. FMI presented the highest concordance value, but classified as discrete (k=0.21). he other indexes presented small concordance with results of the reference method (k<0.20). In conclusion, none of the indexes investigated has good accuracy in assessing the nutritional status of the study group, considering that, although they show results of correlation with the reference method, they do not reach the minimum agreement criterion.

Resumo Uma boa avaliação do estado nutricional requer o conhecimento da composição corporal, colocando em dúvida a acurácia de alguns índices. Dessa forma, o objetivo deste estudo foi analisar a acurácia dos seguintes índices de avaliação do estado nutricional: Índice de Massa Corporal (IMC), IMC elevado à 2,5 (IMC2,5), Índice de Massa Gorda (IMG) e IMC ajustado pela massa gorda (IMCgordura). Participaram do estudo 280 sujeitos (idade entre 17 e 48 anos), dos quais foram analisados os resultados dos índices IMC, IMC2,5, IMG e IMCgordura; tendo como método de referência a Pesagem Hidrostática. O IMG apresentou o maior valor de concordância, porém classificado como discreto (k = 0,21). Já os demais índices apresentaram concordância pequena com os resultados do método de referência (k<0,20). Em conclusão, nenhum dos índices investigados apresenta boa acurácia para avaliar o estado nutricional do público em questão, tendo em vista que, apesar de mostrarem resultados de correlação com o método de referência, não atingem o critério mínimo de concordância.

Validação de equações antropométricas específicas e generalizadas para estimativa do percentual de gordura corporal em estudantes de Educação Física do sexo masculino / Validation of generalized and specific equations anthropometric to estimate the percentage of body fat in male Physical Education students

O objetivo deste estudo foi verificar a validade das equações específicas de Guedes e Guedes(7) e das generalizadas de Petroski(9) em universitários do sexo masculino. A amostra foi constituída de 104 universitários de Educação Física com idade média de 21,7 ± 2,7 anos, submetidos à pesagem hidrostática (PH) e à antropometria (dobras cutâneas e perímetros corporais). Não foram observadas diferenças estatisticamente significativas entre as medidas de percentual de gordura pela PH e nove equações de Petroski(9). Todos os resultados obtidos pelas equações de Guedes e Guedes(7) apresentaram diferenças significativas quando comparados com os da PH. Entre as equações analisadas, oito desenvolvidas por Petroski(9) apresentaram validade concorrente na amostra estudada.

The objective of this study was to verify the validity of the specific equations Guedes and Guedes(7) and generalized by Petroski(9) in male college students. One hundred four students of Physical Education with a mean age of 21.7 ± 2.7 participated in the current study. They were submitted to the hydrostatic weighing (HW) and anthropometry (skinfolds and body circumferences). No statistically significant difference between measurements of fat percentage by PH and nine equations Petroski(9) was observed. All results obtained by equations Guedes and Guedes(7) showed significant differences when compared with the PH. Among the equations analyzed eight developed by Petroski(9) showed concurrent validity in the study sample.

Clinical performance of 3-body fat measurements in obese adolescents 15 to 18 years-old / Medidas da gordura corporal em adolescentes obesos de 15 a 18 anos

There is a lack of information about the performance and clinical use of body fat measurements in children and adolescents, particularly in obese people. Objective: the purpose of this study was to compare percentage body fat (%BF) among 3 different methodologies, including hydrostatic weighing (HW), dual energy x-ray absorptiometry (DXA) and air displacement plethysmography (ADP), in obese adolescents. Subjects: A total of 36 obese adolescents were evaluated, which 15 males (16.00 + 0.9 yrs, 105.0 + 10.9 kg, 179.9 + 7.2 cm, 34.9 + 4.4 kg/m2) and 21 females (16.5 + 1.5 yrs, 91.1 + 10.5 kg, 163.6 + 4.2 cm, 34.1 + 3.7 kg/m2). All of them performed HW, total body DXA and ADP. Results: For males, the means of %BF regarding HW, DXA and ADP were 45.7 + 9.0, 42.3 + 5.2 and 35.6 + 7.9, respectively. For females, the means of %BF were 47.7 + 6.8, 50.7 + 4 and 42.4 + 5.3, respectively. No significant difference was found between HW and DXA. In general, the %BF values provided by ADP measurements were lower than other two methods. Conclusion: There was a good agreement between DXA and HW methods, but ADP measurements can underestimate the %BF in obese adolescents.