Comparison of methods to assess body fat in non-obese six to seven-year-old children

Background & aim Different non-invasive methods exist to evaluate total body fat in children. Most methods have shown to be able to confirm a high fat percentage in children with overweight and obesity. No data are available on the estimation of total body fat in non-obese children. The aim of this study is to compare total body fat, assessed by different methods in non-obese children. Methods We compared total body fat, assessed by isotope dilution, dual energy X-ray, skinfold thickness, bioelectrical impedance analysis, combination of these methods as well as BMI in 30 six to seven-year-old children. Results The children had a mean BMI of 16.01 kg/m2 (range 13.51–20.32) and five children were overweight according to international criteria. Different methods showed rather different absolute values for total body fat. Bland–Altman analysis showed that the difference between the DEXA method and isotope dilution was dependent on the fat percentage. Children with the same BMI show a marked variation in total body fat ranging from 8% to 22% as estimated from the isotope dilution method. Conclusion Non-invasive methods are presently not suited to assess the absolute amount of total body fat in 6–7 years old children.