Age, Sex, Body Mass Index, and Laterality in the Foot Posture of Adolescents: A Cross Sectional Study

Abstract

ObjectiveTo investigate the relationship between the right and left foot posture in terms of body mass index (BMI), sex, and age in adolescents aged 10 to 14. MethodsA total of 1400 adolescents were included. For assessment, the Foot Posture Index (FPI-6) was used. Each foot was assessed and ranked as supinated, normal, or pronated by the sum of the FPI-6 criteria. Each criterion was scored on a scale of –2 to +2, with negative for supinated and positive for pronated posture. A linear mixed model with repeated measures was used for statistical analysis. ResultsSex, BMI, and right and left foot are associated with FPI-6. The total score attributed for male sex (β = 0.29, P = .04) and the left foot (β = 0.73, P < .001) was higher (male right foot: mean ± standard deviation [SD], 3.09 ± 2.84, male left foot: 3.76 ± 2.80; female right foot: mean ± SD, 2.28 ± 2.61, female left foot: 3.45 ± 2.66; laterality for left foot: mean ± SD, 3.55 ± 2.71, laterality for right foot: mean ± SD, 2.82 ± 2.7). On the other hand, the correlation coefficient for the BMI was negative (β = -0.08, P = < .001), which means that the higher the BMI the lower the score attributed to the FPI-6. ConclusionsThe FPI-6 is positively related to the male sex and the left foot—that is, the predicted score is higher, so the feet tend to present with a tendency to pronation. Although BMI is associated with FPI-6, it was not possible to establish a relationship between high BMI and pronation of the feet.