The importance of the compartment model of body composition analysis in women with severe obesity

Abstract

Introduction. Obesity is usually diagnosed based only on body mass index (BMI), which may lead to an unreliable body composition analysis. Objective: To analyze the body characteristics of morbidly obese (class III) women referred to bariatric surgery using the compartment model of body composition analysis. Materials and methods: Cross-sectional study conducted in 2017 in 14 morbidly obese women aged between 25 and 51 years, who attended clinical and physical therapy assessment prior to undergoing bariatric surgery at a university hospital in Rio de Janeiro, Brazil. Body composition analysis was performed using an octopolar bioimpedance scale. The Pearson’s correlation coefficient was used to analyze the correlation between variables, with a significance level of p<0.05. Results: A high mean percentage of fat body was observed (51.2%), mainly in the trunk. BMI was correlated with total fat in kilograms (r=0.93), total body fat percentage (TBF%) (r=0.67), total body water (r=0.63), and muscle mass (r=0.60); besides, a moderate correlation with the waist-to-hip ratio (WHR) was found (r=0.55). WHR showed a correlation with TBF% (r=0.60) and a moderate correlation with total fat in kilograms (r=0.57). Moreover, the sarcopenia index was correlated with muscle mass (r=0.79) and total body water (r=0.78). All these correlations were statistically significant (p<0.05). There were no sarcopenia cases. Conclusion: A higher concentration of fat in the trunk and the upper limbs was observed in the study population; however, none of the participants had sarcopenia. On the other hand, BMI showed a stronger correlation with both total fat (kg) and TBF% than with WHR. Such findings suggest that assessing these patients based only on BMI or WHR may hinder the development individualized treatment strategies.