Agreement between anthropometric indicators in the identification of high adiposity in schoolchildren

The objective of this study was to evaluate the agreement between the use of body mass index (BMI), the conicity index (CI), the waist-to-height ratio (WHtR), and body fat percentage (%BF), estimated via the Deurenberg equation, in the diagnosis of excess adiposity in schoolchildren. This cross-sectional study took place in 2023, with an anthropometric assessment of 1,459 kindergarten and elementary school students from municipal schools and municipal early childhood education centers in the municipality of Diamantina, Minas Gerais. Anthropometric diagnoses obtained through BMI, CI, WHtR, and %BF were compared to verify possible agreement between them according to sex and age group. For this analysis, Cohen's kappa and Fleiss tests were applied. A p value less than 5% was considered significant. Excess adiposity was identified in 9.5% of the schoolchildren by BMI, in 11.7% by WHtR, in 16.7% by CI, and in 20% by %BF. Regardless of sex, the WHtR showed moderate agreement with BMI (Cohen's kappa: 0.426 for girls and 0.425 for boys; p value <0.001) and with %BF (kappa: 0.515 for girls and 0.494 for boys; p value <0.001). WHtR, regardless of age, showed moderate agreement with %BF (<6 years - Cohen's kappa= 0.527, ≥6 years - 0.502; p value <0.001) and weak agreement with CI and BMI among those under six years of age. However, it was strongly correlated with BMI among schoolchildren ≥6 years (Kappa: 0.619; p value <0.001). The results of this study show that the WHR, regardless of sex and age over six, showed moderate agreement with BMI and %BF different from the CI; thus, it can be an option for use in studies in which the aim is to evaluate adiposity and the risk of cardiometabolic diseases.