Relationship between lower-extremity defects and body mass among polish children: a cross-sectional study

Lower extremity defects in healthy children raises interest of researchers as confirmed by numerous published original and review articles. The relationship between lower extremity postural defects and body mass are unclear as published data are inconclusive. The aim of the present cross-sectional study was to analyse the prevalence of lower extremity defects in a large group of 8- to 12-year-old children; and further to assess the probability of defects associated with values of body mass variables.

The study included prospective anthropometric measurements data of 6992 children (3476 boys and 3516 girls) from Gdansk (Northern Poland). Standard screening test used in Poland for assessment of lower limb defects were used (intermalleolar or intercondylar distance for knee alignment, linear vertical compass for valgus heel, computer podoscope or classical footprint and measuring the Sztriter-Godunow index for flatfeet). Body mass was assessed with local centile charts and IOTF cutoffs. Prevalence of postural defects was compared with an aid of Pearson's chi-squared test and Fisher's exact test. Probability of lower extremities postural defect was estimated on the basis of logistic regression analysis, and expressed as an odds ratio (OR) and its 95.0% CI.

The study demonstrated that cumulative prevalence of lower extremity defects (31.5%) was lower than reported in most published studies, most common defects were valgus heel (21.8%) and valgus knee (14.5%). Boys were significantly more frequently diagnosed with lower limb defects overall (p < 0.001), as well as with varus knee, valgus heel, flatfoot of any degree. Limb defects were found in 90,2% of obese children, 25,7% of normal weight and 15,1% of underweight children.

Prevalence of some lower extremities defects seems to be sex specific. Prevalence varied across body weight categories and was rising with the increase of BMI. Increased body mass is correlated with a higher risk of developing lower extremity postural defects in children.