Modified Body Adiposity Index to determine body fat in morbid obese adults

Author(s)

Aline Biaseto Bernhard

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2015-01-14

Examining board members

Roberto de Cleva; Carlos Alberto Malheiros; Marco Aurelio Santo

• Advisor: Roberto de Cleva

Abstract

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 (AU)

• FAPESP's process: 12/22159-9 - Modified Body Adiposity Index to determine body fat in morbid obese adults
• Grantee: Aline Biaseto Bernhard
• Support Opportunities: Scholarships in Brazil - Master