SEXUAL DIMORPHISM OF HEIGHT-WEIGHT INDICES AND BODY COMPOSITION IN RUSSIAN CHILDREN AND ADOLESCENTS AGED 5–18 YEARS: THE RESULTS OF MASS POPULATION SCREENING

Abstract

Background: Population screening in Health Centers (HCs) represents the only data source of mass anthropometric and body composition in Russia. Previously, an overview of the physical development and body composition of the population according to HCs’ data along with centile reference tables were published while a detailed analysis of sexual dimorphism was not carried out.Aims: The analysis of sexual dimorphism of height-weight indices and body composition data in modern Russian children and adolescents aged 5–18 years according to HCs data, as well as comparison of the dynamics of age-related changes in anthropometric data with the WHO growth references.Materials and methods: Non-clinical cross-sectional observational study was conducted using bioimpedance and related anthropometric HCs’ data over the period 2010–2012. The data was obtained according to Russian Health Ministry letter no. 14-1/10/2-3200 dated Oct. 24, 2012. The study sample included 268 153 subjects, 140 769 boys and 127 384 girls. Intergroup differences were evaluated with the Mann-Whitney test. The distributions of Ht, Wt, and BMI for age and sex were matched with the WHO reference data using LMS-transformation with the parameters from the WHO expanded tables with the subsequent calculation of 95% confidence intervals for median z-scores.Results: Availability of double crossing of growth curves in boys and girls for Ht and Wt during puberty is shown with a narrower double crossing interval for Wt as compared to conventional data. The relative annual growth rates for Ht and Wt were higher in females up to the age of 12 years, and in males older 12. Throughout the age range, median values of BMI in boys and girls were similar (with the differences in the range of 1 kg/m2); median values of FFM were significantly higher in males, and of BF and %BF in females. In most age groups, the median values of Ht and Wt in Russian children and adolescents were higher as compared to WHO reference data (with the maximal difference z=+0.74 for Wt in 10 years-old boys). The similar pattern was detected for BMI in boys aged 5–17 and girls aged 6–14.Conclusions: The narrower interval of double-crossing of growth curves for Wt may indicate adverse environmental effects associated with overnutrition and reduced physical activity which leads to elevated fatness in boys. Taking into account mass character of data, relatively broad coverage of regions, and the observed differences with the WHO growth references, the use of Health Centers’ data is advisable for the elaboration of the national standard of physical development in children and adolescents.