ABSTRACT
BACKGROUND: Obesity is associated with mobility reduction due to mechanical factors and excessive body fat. The six-minute walk test (6MWT) has been used to assess functional capacity in severe obesity. OBJECTIVE: To determine the association of BMI, total and segmental body composition with distance walked (6MWD) during the six-minute walk test (6MWT) according to gender and obesity grade. SETTING: University of São Paulo Medical School, Brazil; Public Practice. METHODS: Functional capacity was assessed by 6MWD and body composition (%) by bioelectrical impedance analysis in 90 patients. RESULTS: The mean 6MWD was 514.9 ± 50.3 m for both genders. The male group (M: 545.2 ± 46.9 m) showed a 6MWD higher (p = 0.002) than the female group (F: 505.6 ± 47.9 m). The morbid obese group (MO: 524.7 ± 44.0 m) also showed a 6MWD higher (p = 0.014) than the super obese group (SO: 494.2 ± 57.0 m). There was a positive relationship between 6MWD and fat free mass (FFM), FFM of upper limps (FFM_UL), trunk (FFM_TR) and lower limbs (FFM_LL). Female group presented a positive relationship between 6MWD and FFM, FFM_UL and FFM_LL and male group presented a positive relationship between 6MWD and FFM_TR. In morbid obese group there was a positive relationship between 6MWD with FFM, FFM_UL, FFM_TR and FFM_LL. The super obese group presented a positive relationship between 6MWD with FFM, FFM_TR and FFM_LL. CONCLUSIONS: Total and segmental FFM is associated with a better walking capacity than BMI.
Subject(s)
Body Composition/physiology , Exercise Tolerance/physiology , Obesity, Morbid/physiopathology , Walking/physiology , Adult , Brazil , Exercise Test/methods , Female , Humans , MaleABSTRACT
INTRODUÇÃO: A obesidade mórbida tornou-se um importante problema de saúde pública. A medida de massa corporal não é capaz de identificar deficiências ou excessos dos diferentes componentes corporais, surgindo a necessidade de se avaliar a composição corporal. Não há consenso sobre o melhor método para esse fim em obesos mórbidos. O Índice de Adiposidade Corporal (IAC) foi proposto para ser um método simples e preciso para uma população de diversificada quantidade de gordura corporal (GC). OBJETIVO: Avaliar a eficácia do IAC em determinar GC de adultos com obesidade mórbida. MÉTODOS: O IAC foi comparado à Bioimpedância (BIA) em 240 adultos obesos mórbidos (Grupo 1= G1), uma equação específica para determinar GC em obesidade mórbida foi desenvolvida e, posteriormente, validada em outra amostra de 158 indivíduos (Grupo 2 = G2). RESULTADOS: Observou-se diferença significativa entre os dois métodos (p=0,039). A quantidade média de GC no G1 foi 52,3±6,1% segundo a BIA e 51,6±8,1% segundo o IAC, com uma diferença de 0,6±5,1% entre os métodos. Algumas variáveis, como gênero, RCQ e gravidade da obesidade confundiram o IAC. Para minimizar esses erros uma equação (Índice de Adiposidade Corporal Modificado = IACM) foi desenvolvida por meio de regressão linear (IACM% = 23,6 + 0,5 x (IAC); somar 2,2 se IMC >= 50kg/m2 e 2,4 se RCQ >= 1,05). A equação foi aplicada no G2 e possibilitou a redução da diferença entre os métodos (1,2±5,9% para 0,4±4,0%) e o fortalecimento da correlação entre eles (0,6 para 0,7). CONCLUSÕES: O IAC apresenta limitações para determinar porcentagem de gordura corporal de obesos mórbidos, já a equação sugerida (IACM) foi eficaz, não se apresentando significativamente diferente da Bioimpedância e corrigindo as limitações anteriormente apresentadas pelo IAC.
BACKGROUND: Morbid obesity has become a public health problem. As body mass is not able to identify deficiencies or excesses of body components, the need to assess body composition emerged. There is no consensus of the best method to measure body composition in morbidly obese adults and a simple, accurate, reproducible and inexpensive method is desirable. The Body Adiposity Index (BAI) has been proposed to be a simple and accurate method for a population with a diverse amount of body fat (BF). OBJECTIVE: Evaluate the efficacy of BAI in determining BF of morbid obese adults. METHODS: BAI was compared to bioimpedance (BIA) in 240 morbidly obese adults (Group One= G1) and a specific equation for morbid obesity has been developed to determine BF and then validated on another sample of 158 subjects (Group Two= G2). RESULTS: There was a significant difference between the two methods (p=0,039). The average amount of BF in G1 was 52.3±6.1%, according to BIA and 51.6±8.1% according to BAI, with a difference of 0.6±5.1% between methods. Some variables, such as gender, WHR and severity of obesity mistook BAI. To minimize these errors an equation (Modified Body Adiposity Index = MBAI) was developed by linear regression (MBAI% = 23.6 + 0.5 x (BAI); add 2.2 if BMI >= 50kg/m2 and 2.4 if WHR >= 1.05). The equation was applied to G2 and resulted in a reduction in the difference between methods (1.2±5.9% to 0.4±4.12%) and strengthening of the correlation between them (0.6 to 0.7). CONCLUSIONS: BAI has limitations in determine BF in morbid obesity. The suggested equation (MBAI) was effective for predicting body fat in morbid obese adults; MBAI wasn't significant different from BIA and was able to correct BAI limitations.
