Relevant factors influencing flatfoot in preschool-aged children.

The aim of this study was to discuss the influence of age, gender, obesity status, joint laxity, and the W-sitting habit on flatfoot in preschool-aged children. A total of 1,598 children (833 boys and 765 girls) between 3 and 6 years of age from kindergartens in the central area of Taiwan were studied. The children were divided into a normal group (n = 733), a unilateral flatfoot group (n = 266), and a bilateral flatfoot group (n = 599), and a multinomial logistic regression model was used to analyze the data. The prevalence of flatfoot decreased significantly with increasing age: 54.5% of 3-year-old but only 21% for 6-year-old children had bilateral flatfoot. In the bilateral flatfoot group, the risk decreased with increased age, increased with increasing weight beyond the normal range, and was higher for boys than girls. Age and obesity status were not significantly influential in the unilateral flatfoot group. Children with higher joint laxity and a habit of W-sitting also experienced higher risk in both flatfoot groups. In conclusion, this study demonstrates a significant association of age, gender, obesity status, joint laxity, and the W-sitting habit with the bilateral flatfoot in preschool-aged children. Children with unilateral flatfoot differ from those with normal feet and bilateral flatfoot. It is suggested that the unilateral flatfoot deserves special attention in future studies.