Assessment of body mass formation in schoolchildren aged 7–17 in forty subjects of the Russian Federation

Background

Body weight is a key indicator of physical development in children, reflecting the development of the musculoskeletal system, subcutaneous adipose tissue, and internal organs [1-5].

Objective

To assess the body weight formation in schoolchildren aged 7-17 years across forty constituent entities of the Russian Federation.

Materials and Methods

The selection of regions was based on the specific geographical characteristics of the Russian Federation. The country spans a vast territory from west to east and from north to south, features diverse topography, and is located within four climatic zones (Arctic, subarctic, temperate, and subtropical). The constituent entities differ not only in climatic and geographical conditions and socio-economic status but also in the ethnic composition of their populations (over 190 ethnic groups reside within the country).

Inclusion criteria: Schoolchildren from general education institutions in the Moscow region, who are indigenous to the region, with a completed voluntary informed consent form signed by parents/legal representatives, including the schoolchild's assent; availability of health data; and belonging to health groups I-III.

Exclusion criteria: Other age groups; absence of a completed voluntary informed consent form from parents/legal representatives, including the schoolchild's assent; lack of health data; belonging to health groups IV-V; and being part of the "migrant" population.

The study was approved by the Local Ethics Committee of the N.I. Pirogov Russian National Research Medical University (Protocol No. 239, dated April 15, 2024).

Statistical analysis was performed using Microsoft Office Excel and Statistica 13.0 (StatSoft, USA) software packages.

Results and Discussion

For 40 regions, the mean (M), standard error of the mean (m), and sample standard deviation (σ) for body weight (kg) were calculated for boys and girls aged 7-17 years.

The assessment of body weight formation was based on the analysis of age- and sex-specific body weight curves (see Fig. 1-8).

Fig. 1. Body weight curves of schoolchildren aged 7-17 years living in the Central Federal District

Fig. 2. Body weight curves of schoolchildren aged 7-17 years living in the Northwestern Federal District

Fig. 3. Body weight curves of schoolchildren aged 7-17 years living in the Southern Federal District

Fig. 4. Body weight curves of schoolchildren aged 7-17 years living in the North Caucasus Federal District

Fig. 5. Body weight curves of schoolchildren aged 7-17 years living in the Volga Federal District

Fig. 6. Body weight curves of schoolchildren aged 7-17 years living in the Ural Federal District

Fig. 7. Body weight curves of schoolchildren aged 7-17 years living in the Siberian Federal District

Fig. 8. Body weight curves of schoolchildren aged 7-17 years living in the Far Eastern Federal District

Analysis of the age- and sex-specific body weight curves revealed a gradual increase in body weight with age in both boys and girls in almost all 40 regions. This pattern is consistent with fundamental biological principles such as directionality, graduality, irreversibility, heteromorphy, and heterochrony. In almost all age groups and at the completion of growth, body weight indicators were significantly higher (p≤0.05) in boys compared to girls, which aligns with the pattern of sexual dimorphism in growth and development.

Conclusions

Thus, the processes of growth and development in schoolchildren aged 7-17 years residing in various constituent entities of the Russian Federation were assessed. The findings indicate harmonious growth and development processes in the analyzed regions.