Flatfoot among school aged children in Bulgaria: An Epidemiological Overview and Analysis of Risk Factors

Abstract

This cross-sectional epidemiological study investigated the prevalence, morphological characteristics, and associated risk factors of pes planus in a cohort of 995 Bulgarian school-aged children (6–14 years). Standardized footprint-based diagnostics—including the Staheli Index, Chippaux–Smirak Index, and Chizhin Index—were employed via computerized plantography using the Zebris FDM platform. The aggregate prevalence of pes planus was 18.8%, with logistic regression modeling revealing statistically robust associations with chronological age, male sex, and overweight status. ROC analysis demonstrated excellent discriminative validity for the Staheli and Chippaux–Smirak indices (AUC = 0.91) and high diagnostic accuracy for the Chizhin Index (AUC = 0.87). Notably, a positive age-dependent trend in flatfoot prevalence was observed, diverging from normative developmental trajectories. The findings validate the clinical applicability of footprint-based indices and underscore the relevance of anthropometric and demographic variables in early screening and etiological profiling of pediatric pes planus.

Key words: pes planus, plantographic indices, anthropometric factors