Comparison of Body Composition and Body Mass Index in the Determination of Obesity in Schoolchildren

OBJECTIVE: The determination of obesity that develops with an increase in the percentage of fat in the body may not always be possible in the real sense with body mass index, which is frequently used in practice. This study aimed to compare the results obtained from body mass index and bioelectrical impedance analysis measurements in evaluating obesity in Turkish school-aged children using age-related percentile curves. MATERIALS AND METHODS: The study included 1127 children (604 boys and 523 girls) recruited from a screening of the schools in the city center of Isparta between May 20 and June 20, 2014. Body mass index was calculated, and the variables of fat mass, body fat percentage, fat-free body mass, and total body water were measured with a Tanita BC-418 MA device. RESULTS: According to the body mass index values, 23.8% of the study sample was overweight/obese, and according to bioelectrical impedance analysis, this rate was 14.7%. When examined by gender, males’ overweight/obese ratio was 19.9% (overweight 11.3% and obese 8.6%) according to body mass index and 12.9% (overweight 7.1% and obese 5.8%) using the bioelectrical impedance analysis method. In females, the overweight/obese ratio was 19% (overweight 9.4%, obese 9.6%) according to body mass index and 16.7% (overweight 9.6% and obese 7.1%) using the bioelectrical impedance analysis method. CONCLUSION: The results obtained from the weight-based body mass index method were not consistent with the body fat percentage results obtained with the bioelectrical impedance analysis method. Since the fat ratio is also crucial in evaluating obesity, care should be taken when diagnosing obesity using body mass index only.