Six-minute walk distance equation in children and adolescents with obesity

Abstract

Aim: To develop a 6-minute walk-distance (6MWD) reference equation for children and adolescents with obesity, and to assess its determinant factors.

Methods: A cross-sectional study using mixed linear and multiple regression models was conducted in 497 children (235 girls and 262 boys) aged 6-18 years with a body mass index (BMI) greater than 97th percentile. Anthropometrics and a 6-minute walk test (6MWT) were performed.

Results: Mean 6MWD was 547 ± 86 m for girls and 575 ± 96 m for boys, which averaged ~80% of a reference normal-weight population matched for age and ethnicity. Age, weight and BMI were positively correlated with 6MWD whereas waist and hip circumferences (WC and HC, respectively) were negatively correlated with 6MWD for both genders. The combination of age, height, BMI and HC explained 69% of the 6MWD variability in the equation for the whole population. Moreover, the combination of age, height, HC as well as the combination of age, height, BMI and WC explained 67% and 75% of the variability in the girls' and boys' equations, respectively.

Conclusion: This 6MWD reference equation, which was influenced by abdominal obesity markers in a gender-specific way, extends and enhances scientific knowledge and provides useful predictive tools for the care of obese children.

Keywords: exercise testing; obesity; paediatric; walking.