Introduction

Obesity is a civilization disease of the 21st century. The prevalence of obesity and overweight among children and adolescents is constantly increasing. BMI (body mass index) and WHR (waist to hip ratio) are methods of obesity assessment recommended by the WHO. Also, the WtHR (waist to height ratio), which takes into account height, is one of the most popular methods of diagnosing childhood obesity. A more recent diagnostic indicator is the FMI (fat mass index), which considers the percentage of the patient's body fat.

The aim of the study

was to compare the methods of assessing obesity in children and adolescents using the following indicators: BMI, WHR, WtHR, and FMI and to determine the consistency of the results obtained with them.

Material and methods

The study included 195 children aged 11–18 years, from whom the following data were collected: height, weight, waist circumference, and percentage of body fat. The calculated indices (BMI, WHR, WtHR, FMI), expressed in SDS, were compared using the Bland-Altman test, Passing-Bablok regression, and the slope chart.

Results

The fewest diagnoses of obesity were shown by FMI SDS (15.9%) and the highest by WHR SDS (28.7%). WHR SDS showed the least consistent results with BMI SDS. Significant statistical differences were found between BMI SDS and both FMI SDS and WtHR SDS.

Conclusions

BMI, as the most acceptable obesity indicator, can be used as a screening method for assessing obesity. However, patients with boundary BMI values should be examined more precisely, using more than one index. FMI is recommended.