Associação entre a circunferência do punho e o escore Z do índice de massa corporal em escolares do primeiro ano do ensino fundamental da rede pública municipal de São Carlos - SP

Abstract

This undergraduate thesis comprises two main components: an undergraduate research project and a reflection on the author’s journey as a medical student, from admission to graduation, exploring how curricular and extracurricular experiences shaped his education. The research project aimed to assess the correlation between wrist circumference (WrC) and body mass index (BMI) z-score in elementary schoolchildren, with analyses stratified by sex and age, as an exploratory step for studies on the use of this measurement in the nutritional assessment of children. Childhood obesity is a major public health concern, and there is interest in simple, low-cost anthropometric measures that may complement its assessment. This cross-sectional, descriptive, quantitative study used a pre-existing database of 286 children of both sexes, aged 6–7 years, enrolled in municipal public schools in São Carlos, SP, Brazil. After excluding three children with WrC measurement errors and three with BMI z-scores above +5 (the WHO AnthroPlus flag limit), 280 were analyzed. The correlation between WrC and BMI z-score was estimated with Spearman’s coefficient. A statistically significant positive correlation of moderate to strong magnitude was observed in the total sample (ρ = 0.754) and in all subgroups (ρ = 0.692 to 0.811; p < 0.001). WrC thus showed a consistent anthropometric association with BMI z-score. However, because WrC was compared only with BMI, without a gold-standard measure of adiposity, metabolic outcomes, cut-off values or diagnostic accuracy analysis, the study cannot validate WrC as a screening tool for excess weight or metabolic risk; its findings support future studies with that purpose.