Does obesity influence foot structure in prepubescent children?

OBJECTIVE: This study examines the relationship between obesity and foot structure in prepubescent children. DESIGN: Field-based, experimental data on BMI (body mass index) and foot structure were collected for 431 consenting children from 18 randomly selected primary schools. SUBJECTS: Of the 431 participants, 62 obese (BMI > 95th percentile) and 62 non-obese (10th percentile < BMI > 90th percentile) children (age = 8.5 +/- 0.5 y) were selected. MEASUREMENTS: Height and weight were measured to calculate BMI. Static weight-bearing footprints for the right and left foot of each subject were then taken using a pedograph to calculate the Footprint Angle and the Chippaux-Smirak Index as representative measures of the surface area of the foot in contact with the ground. RESULTS: A significant difference was found between the Footprint Angle of the obese and non-obese subjects for both the left (t = 3.663; P < 0.001) and right (t = 3.742; P < 0.001) feet whereby obese subjects displayed a reduced angle. Chippaux-Smirak Index scores were also significantly different for both the left (t = - 6.362; P < 0.001) and right (t = - 5.675; P < 0.001) feet between the two subject groups where a greater score for the obese subjects was evident. A decreased footprint angle and an increased Chippaux-Smirak Index are characteristic of structural foot changes that have been associated with compromised foot function. CONCLUSIONS: Excess body mass appears to have a significant effect on the foot structure of prepubescent children whereby young obese children display structural foot characteristics which may develop into problematic symptoms if excessive weight gain continues. Further investigation into possible consequences, particularly any effects on foot function, is warranted.