Optimization of approaches to the assessment of some indicators of health condition of children of ethnic Khanties based on the development of standards adapted to them

Introduction

Individual and population assessments of children's health constitute an important section of pediatrics and are the subject of pediatricians' daily work. A comprehensive assessment of children's health includes, first of all, the analysis of indicators of physical and sexual development and blood pressure (BP), which are indicators of health in general, and their deviation from the norm requires further examination to make a nosological diagnosis [1]. These very parameters are determined during mass preventive examinations, which emphasizes the relevance of objectification of their evaluation, taking into account the individual characteristics of a particular child and the examined group as a whole.

Despite the availability of international standards for these indicators, including those recommended by the World Health Organization (WHO), most authors consider it necessary to develop regional standards, including those for a particular ethnic group.

The need for this is justified by the presence of climatic-geographical, social, and biological (including genetic) features that can directly or indirectly influence the rate of physical and sexual development and the level of BP [2][3][4]. The peculiarities of these indicators are most pronounced in ethnically isolated populations, which determines the greatest relevance of this problem for such cohorts of the child population [5][6].

Such populations include the small indigenous peoples of the North (IPNS), who have preserved their ethnic isolation and semi-nomadic way of life up to the present day to the maximum extent possible. Separate studies are devoted to the study of the anthropological features of IPNS [5][6]. The following anthropometric features were established, namely a high level of body density with well-developed muscular and skeletal systems. The cylindrical shape of the thorax, as well as the practical absence of asthenic physique, were characteristic of this group [6].

In the Khanty-Mansi Autonomous Area – Yugra, the IPNS representatives are mostly Khanty. Khanty children of school age stay with their parents in the summertime in the fields, raising reindeer, fishing, gathering taiga berries and mushrooms, and during their school years, they live in a boarding school.

The use of standards not developed on IPNS cohorts distorts the assessment of their health status. The absence of basic standards of their health status (physical, sexual development and BP) adapted for Khanty children was the basis for the development of such standards [7][8][9]. It is logical to ask about the effectiveness of their implementation in practice in terms of comparative analysis with the use of currently relevant other standards.

The aim of the study is to investigate the effectiveness of the assessment of physical, sexual development and BP parameters of ethnic Khanty school-age children when using the standards developed on this cohort in comparison with the use of non-adapted norms to them.

Materials and methods

A full cohort comparative study was conducted: the results of the assessment of physical, sexual development and BP of ethnic Khanty children were analyzed using various standards. The authors analyzed the results of the annual preventive examination in the boarding school for IPNS of the Russkinskiye settlement of the Surgut District of the Khanty-Mansi Autonomous Area –Yugra, conducted in accordance with the Order of the Ministry of Health of Russia of August 10, 2017 No. 514n (revised on November 19, 2020) "On the Order of Preventive Medical Examinations of Minors". Physical development and BP were assessed in 423 students aged 7–17 years (228 boys, 195 girls), sexual development was assessed in 284 of them aged 10–17 years (132 boys, 152 girls). Only those children whose parents were both members of that ethnic group were considered ethnic Khanty.

Two methods were used to assess physical development such as percentile and Z-score. All the examined children were distributed in the corridors of percentile values (≤ 3%; > 3 < 25%; 25–75%; > 75 < 97%; ≥ 97 %) and SDS (less than -2SDS; from -2 SDS to -1 SDS; from -1 SDS to +1SDS; from +1SDS to +2SDS; more than +2 SDS).

 Anthropometry was performed according to the standard technique. All children were divided into three groups when assessing their sexual development according to the Tanner method: passport age compliance, the advance of passport age, and lagging behind. BP was measured by Korotkov’s auscultatory method, and children were divided into the following groups: normal BP (systolic and diastolic BP between the 25th and 90th percentile for a given height, age, and sex); high normal BP (systolic and/or diastolic BP between the 90th and 95th percentile for a given height, age, and sex); arterial hypertension – AH (systolic and/or diastolic BP over the 95th percentile for a given height, age, and sex).

The structure of the obtained distributions was presented as a percentage. The authors compared the same type of relative indices in % when assessing them by three methods – using basic and the authors' standards (separately for the native and Khanty population).

The WHO standards [10], Tanner standards [11][12], and BP guidelines "Arterial hypertension in children and adolescents" of the Association of Pediatric Cardiologists and the Russian Union of Pediatricians [13], developed in 2004 by the National Educational Program Working Group on High Blood Pressure in Children and Adolescents [14] were used as basic guidelines for physical development assessment.

At the same time, to compare the results of the assessments, the authors used the standards developed and presented earlier for the children of the native population of the Khanty-Mansi Autonomous Area –Yugra and separately for ethnic Khanty [7][8][9].

This stage of the work was a test, the study was conducted on a separate group of ethnic Khanty whose data were not used for the development of standards (physical, sexual development and BP).

The statistical significance of intergroup differences in relative indices (%) was investigated by the Fisher angular transformation method. The threshold value of statistical significance was p = 0.05.

Results

The data presented in Table 1 testify to the presence of statistically significant differences in the results of the assessment of the physical development of ethnic Khanty children when using different standards.

Table 1

The use of norms not developed on the Khanty cohort significantly increases the number of children with low and very low height and body weight, both when assessed by centile tables and by the Z-score. At the same time, the evaluation according to the norms developed on the cohort of ethnic Khanty children distributes the surveyed people in proportion to the specified percentiles. The incomplete coincidence with the distribution of healthy people is due to the fact that the verification stage included an assessment of the indicators of all children in a continuous method, including those with deviations from health in terms of physical development, and the standards were developed on the cohort of children of health groups I–II.

The bodily structure of ethnic Khanty children according to the derivative index of body mass index (BMI) characterizing the nutritional status also depended on the standards used for this purpose. The most important thing should be considered the statistically significant lower proportion of overweight and obese children when using standards not adapted for ethnic Khanty, both according to the centile evaluation of the BMI and the Z-score.

The established patterns applied equally to boys and girls.

Table 2

The distribution of ethnic Khanty children according to the results of BP assessment into three groups (normal BP, high normal BP, and AH) was statistically significantly different when different standards were used (Table 2). The use of standards adapted to the cohort of ethnic Khanty children changes the specified structure in the direction of a greater share of children with BP abnormalities (AH and high normal BP).

 Table 3

Analysis of the results of the Tanner method of sexual development assessment (Table 3) also showed statistically significant differences when using different standards. The use of standards developed not on the ethnic Khanty cohort (Tanner standards and the authors' standards for children of the non-Russian population) significantly increases the proportion of Khanty children with delayed sexual development and decreases the proportion of children with advanced development. The established pattern is characteristic of both sexes of children.

Discussion

The data from this study show significant differences in the results of anthropometric data, BP, and sex development when using norms developed on different cohorts of children.

Previously, the authors described the phenotypic features of physical development indicators of ethnic Khanty children, characterized by lower height, body weight, and BMI [8]. Table 1 shows that the use of norms not developed on the Khanty cohort (WHO standards and the authors' norms for the indigenous population) can cause underdiagnosis of overweight and obesity in children of this IPNS cohort. Of 228 boys, the use of standards developed on the Khanty cohort revealed 9 cases of obesity (more than +2SDS), when using WHO standards, this figure was 2, the standards for the native population – only 1 case. Overweight (+1 ... +2 SDS) was diagnosed in 31, 13, and 3 boys, respectively. Of 195 girls, the use of standards adapted for Khanty people allowed identifying obesity in 9 people, the use of WHO standards proved to be the case in one, the standards for the native population of the North proved to be the case in none of the cases.

Overweight was diagnosed in 27, 18, and 17 girls, respectively. The established patterns were statistically significant.

The data presented by the authors earlier indicate statistically significant differences in the BP indices of ethnic Khanty children compared to the immigrant population of the North, in the direction of their lower systolic and diastolic BP [7]. Therefore, one can consider natural the smaller proportion of ethnic Khanty children with AH and high normal BP during mass regional examinations when using standards developed not on the Khanty cohort (Table 2). At the same time, the assessment of BP indicators using the standards developed on the cohort of ethnic Khanty children allowed establishing the prevalence of AH, more comparable with the literature data [13].

The higher prevalence of delay in sexual development when using standards not adapted for Khanty is associated with the previously presented features of the rates and some characteristics of sexual development of children in this cohort: a later debut of puberty and certain phenotypic features of secondary sexual characteristics (later completion of axillary hair formation in persons of both sexes, the absence of stage P5 of pubic hair formation and facial hair formation in young men) [9]. Application of the norms developed on the Khanty cohort allows statistically significant less often to diagnose their delay in sexual development and more often to diagnose its advancement.

Conclusion

The presence of peculiarities of physical and sexual development indicators and BP of Khanty children determines the necessity of using the standards developed on this ethnically isolated cohort of the child population for individual and population assessment of their health in the course of preventive examinations. Using different standards distorts the health assessment and contributes to the overdiagnosis of obesity, overweight, and AH, overdiagnosis of nanism, and delayed sexual development.

The implementation of these standards developed on ethnic Khanty children makes it possible to objectify the assessment of their health status, establish the true incidence and prevalence of various deviations in physical and sexual development and AH, and plan health care resources more effectively to provide medical care for this group of children.