Foot structure in overweight and obese children

OBJECTIVE. To analyse the association between overweight and obesity and foot structure in children older than 9 years of age, whose longitudinal medial arch (MLA) should be practically established. DESIGN, SETTING AND SUBJECT. A cross-sectional study of 245 children (age: 13.22±1.8 years) from four randomly selected schools (Zaragoza, Spain). Body mass index (BMI) was calculated and normal-weight, overweight and obese groups were defined. Footprints for both feet were collected. MEASUREMENTS. Foot angle (FA) and Chippaux-Smirak index (CSI) were calculated from the footprints. Height and body mass were measured to calculate the BMI. RESULTS. Mean values of FA and CSI in the normal-weight group indicated the presence of a normal MLA; however, in the overweight they indicated an intermediary MLA and in the obese group, a low MLA. Comparison among the groups showed a decrease of FA (p<0.01) and an increase of CSI (p<0.01) with increasing weight associated with a lower MLA. A low but significant correlation (p<0.0001) was found between the z-score BMI and footprint parameters. CONCLUSIONS. In children aged 9 to 16.5 years, the increase of body mass is related to a lower MLA. The MLA is lower in these obese children than in the younger ones studied in previous works probably due to the continuous bearing of excessive mass from childhood. A lower MLA could cause health problems. An assessment of foot structure in these children is recommended as the classification of the foot arch type can help decide if treatment to avoid these problems is necessary.