Obesity in Adolescents: Assessment by DXA Scan and Skinfold Thickness Equations

Aim: This study aimed to compare obesity, estimated percentage of fat in adolescents in Brazil, using Dual-Energy X-Ray Absorptiometry (DXA) with skinfold data that were entered into mathematical models.

Study Design: This research is a cross-sectional, descriptive study.

Place and Duration of Study: Participants were randomly selected from a pool of 525 students. It was conducted employing a sample with students from elementary and high schools in Curitiba - Paraná – Brazil (December – 2013 to December 2014).

Methodology: Two hundred seventy two adolescents were evaluated (199 males and 73 females), ages 12 to 17.9 years. The percentage of body fat (%BF) has been calculated using five skinfold thickness equations: Slaughter; Boileau, Lohman and Slaughter; Durnin and Rahaman; Parizkova; Deurenberg, Weststrate and Seidell. They have been specifically applied to each gender, and compared to the reference method, DXA.

Results: The results show that despite all equations producing statistically significant correlations, none demonstrated agreement with DXA in a Bland-Altman plot. Sensitivity analyses showed a range of 37.3 to 77.7 for males and 21.2 to 69.2% for females, The Parizkova equation presented the best results in both genders.

Conclusion: It was concluded that mathematical modeling for skinfold-thickness among Brazilian adolescents for estimate %BF must be improved.