Characteristics of Informativity of Methods for Indication of Overweight and Obesity in Schoolchildren 12-16 Years of Age and Results of Comparative Assessment of Component Body Composition among Children with Normal Weight, Overweight and Obesity

Introduction: The high prevalence of overweight and obesity among the child and adolescent population and the serious negative consequences associated with the diseases caused by this factor dictate the necessity of a serious approach to methods of mass index evaluation in order to detect deviations early and develop measures of prevention of the diseases associated with them. Objective of the study: To study the features of excessive body weight among schoolchildren of different age and sex groups by the example of the Novosibirsk region using different methods of BMI estimation as well as to study the component composition of the body by bioimpedance analysis among children with normal and excessive body weight. Materials and Methods: Materials of work were the results of experimental research conducted on the basis of Novosibirsk Research Institute of Hygiene in accordance with the program of monitoring of nutrition and health of schoolchildren, carried out within the framework of the national project “Demography”. During the work hygienic, clinical-diagnostic, analytical and statistical methods of research were used. Body mass index (BMI) and bioimpedance results were used to assess and indicate excess body weight and obesity. Parametric methods were used in statistical analysis, because the data obtained had a normal distribution. The data were presented as M±Se, where M is the sample mean, Se is the standard error of the average. The level of statistical significance p was assumed to be 0.05. Results of the Study: Comparative analysis of the prevalence of obesity by Body Mass Index revealed statistically significantly (p≤0,05) higher rates in the whole observation cohort and in the age groups 12-14 and 15-16 years old, compared to the assessment by bioimpedance measurement. We have revealed gender differences: young males showed higher indices of obesity when estimated by WHO method (6,6 times higher in the 12-14 age group and 2,5 times higher in the 15-16 age group). Girls, in contrast, showed higher indices when estimated by bioimpedance spectrometry (in the 12-14 age group - 71,7%, in the 15-16 age group - by 17,2%). Bioimpedansometry revealed statistically significantly higher values of water content, intracellular and extracellular fluid, fat mass and percentage of fat in children with obesity compared with children with normal body weight in all age groups. Conclusions: The found significant and multidirectional differences in assessing the prevalence of obesity in children aged 12-16 years in the compared methods of assessment by BMI and bioimpedance as well as differences in the studied body composition in children with obesity compared to children with normal body weight indicate the low information significance of the body mass index method and the need to use bioimpedance analysis to assess the body weight of 12-16-year-old schoolchildren with excess body weight and consider the findings when developing interventions to prevent obesity.