Fat mass index (FMI) or body mass index (BMI): which is more accurate in diagnosing childhood obesity?

Mehnoosh Samadi; Amir Bagheri

doi:10.21767/2471-8203-C1-009

Fat mass index (FMI) or body mass index (BMI): which is more accurate in diagnosing childhood obesity?

7^th European Congress on Obesity and Eating Disorder
April 12-13, 2018 Amsterdam, Netherlands

Mehnoosh Samadi and Amir Bagheri

Kermanshah University of Medical Sciences, Iran

Posters & Accepted Abstracts: J Obes Eat Disord

DOI: 10.21767/2471-8203-C1-009

Abstract

As for increasing prevalence of obesity in children, it is essential to use a measure that accurately diagnoses obesity in children. The purpose of this study was to determine the sensitivity and specificity of body mass index (BMI) compared to fat mass index (FMI) as a measure of child actual obesity. In this study, obesity in children was compared on the basis of two criteria. This cross-sectional study was conducted in 580 girls, aged 8–10. Height and weight were measured and BMI was calculated. Body fat using the body composition analyzer (BCA) was measured and FMI was calculated by fat mass in kilogram divided by height in meters squared. In this study, FMI at or above 90th percentile of age specific data (FMI 6.9 kg/m2) are known as obese and FMI less than 90th percentile are known as normal weight. ROC curves to evaluate performance BMI against FMI were used to determine the actual obesity. The kappa test was used to determine whether the two criteria were used to define obesity in children. Mean and SD BMI and FMI in children was 19.4±3 (kg/m2) and 6±2.1 (kg/m2), respectively. The area under the ROC curve 83% was calculated and the sensitivity and specificity and cut-off point of BMI compared with FMI was calculated to be 21.2 kg/m2, 59% and 97%. The agreement between BMI=21.2 kg/m2 and FMI=6.9 kg/m2 in determining obesity was 0.5. In this study, the BMI sensitivity was poor and only 59% of the children who were obese based on FMI, were also obese based on BMI and 3% of the children, who were identified as non-obese based on FMI, were obese based BMI. FMI seems a more accurate measure of obesity than BMI is, however, more research is needed in this area.