Ethnic and Ecological Factors in the Formation of Health of Adolescents of the Republic of Sakha (Yakutia) in the Process of Their Growth and Development

The dissertation is devoted to a comprehensive study of ethnic and ecological factors influencing the formation of health of adolescents of the Republic of Sakha (Yakutia) in the process of their growth and development. The research encompasses physical and sexual development, functional activity of the endocrine system, immune status, and quality of life of adolescents of the indigenous (Sakha, Evens, Evenki, Chukchi, Yukaghirs, Dolgans) and incoming (Europoid) population living in different ecological zones of the republic. More than forty thousand adolescents aged 10 to 17 were examined during the work, including in-depth examination of more than 970 persons. Special attention was given to bronchial asthma as an ecologically conditioned disease, as well as the development of scientifically grounded regional norms of hormonal status and principles for the optimization of medical observation of the younger generation in the conditions of an extreme climato-ecological region.

Research Relevance. The problem of the formation, preservation, and improvement of the health of children of adolescent age is not only a priority socio-medical task of society but also an essential task of ensuring national security, since adolescents represent the nearest labour, reproductive, defence, and intellectual potential of the country's development [40, 41, 128, 259, 298].

The health of adolescents is formed from the level of physical, mental, and functional development, the state of neuroendocrine processes, immune protection, and adaptive-accommodative reactions in the process of growth, and is also subject to the influence of environmental factors and conditions of vital activity [157, 298, 436].

The impact of a complex of extreme climatographic, socio-economic, and ecological factors in the North is reflected in adverse dynamic shifts in the health of the younger generation [237, 332, 292, 338, 344]. Children and adolescents, by virtue of the incompleteness of growth and development processes, differ in heightened sensitivity to environmental pollution [38, 68, 180]. This is evidenced by the growth of environmentally dependent diseases in children and adolescents, one of which is bronchial asthma [35, 53, 55, 218].

During the period of socio-economic transformations, a negative trend was formed in the medico-demographic situation and in the state of health of adolescents, both in the Russian Federation as a whole [27, 200, 296] and at the regional level, including the Far Eastern Federal District [49, 158] and the Republic of Sakha (Yakutia) in particular [90, 292, 313, 337].

In the RS(YA), the number of adolescents decreased by 21.7% over 10 years (from 59.8 thousand in 2001 to 46.8 thousand in 2010), the mortality rate increased by 83% (from 0.6 to 1.1 per 1000), overall morbidity increased by 46.7% (from 1364.3 to 2001.6 per 1000), and primary morbidity increased by 74.8% (from 766.6 to 1339.9 per 1000). The increase in morbidity occurred in almost all disease classes. Morbidity of bronchial asthma among adolescents increased by 35% (from 5.7 to 7.7 per 1000). Reproductive health of adolescents also deteriorated.

Monitoring the health status of children and adolescents is impossible without observation of their growth and development [94, 357], and requires regular updating of regional standards and norms [195, 259, 358]. The role of the image and quality of life in the formation of physical and reproductive health of adolescents has significantly increased [69, 303]. The level of health of the population has regional specificity, determined by the distinctive nature of the relationship between man and the environment, and is considered as an integrated indicator of quality of life [68, 257].

Literature data attest to the contribution of the endocrine and immune systems to the processes of adaptation to various endogenous and exogenous factors, especially during the period of physical and sexual maturation [118, 141, 157, 273], to regional [205, 305], and ethnic [157, 317, 324] features of their functioning. Long-term adaptation is a factor of increasing the resistance of a healthy organism and the prevention of diseases [1, 11, 76, 141, 142, 206, 352]. In the adolescent period, the slightest disruption of adaptive mechanisms leads to the development of disease, and in the absence of timely measures, to its chronicity [439].

In the Republic of Sakha (Yakutia), research on the physical development and health status of children of indigenous peoples was conducted [18, 43, 197, 198, 267]; however, studies of the features of physical and sexual development of adolescents of different ethnic affiliation, the state of their reproductive health, the features of adaptation to external environmental conditions, the functional activity of various links of the endocrine system, and the analysis of quality of life have been conducted insufficiently and are fragmentary in nature [122, 213, 287].

In modern conditions of healthcare modernization, the development of new approaches to the preservation and strengthening of adolescent health is necessary [27]. In connection with this, the comprehensive study of the state of health and quality of life of adolescents of the RS(YA) from ecological and aetiological positions, the identification of weak links of protective-adaptive reactions, the specificity and directionality of functional and adaptive mechanisms, which determined the goal and objectives of the research.

Goal of the Research: An eco-physiological substantiation of the state of health, the formation of physical and sexual development, and hormonal mechanisms of adaptation of adolescents of the Republic of Sakha (Yakutia) of different ethnic affiliation, and the development of scientifically grounded recommendations for the preservation of the younger generation's health.

Tasks of the Research:

1. To conduct a comparative analysis of the health status of children and adolescents of the Republic of Sakha (Yakutia) for 2001–2010 depending on ethnic affiliation and ecological living conditions.

2. To analyze the quality of life of urban and rural adolescents.

3. To study the features of physical and sexual development of adolescents of different ethnic affiliation living in different ecological regions of the Republic of Sakha (Yakutia).

4. To provide a comparative assessment of the functional activity of the hypothalamic-pituitary-adrenal, hypothalamic-pituitary-thyroid, and hypothalamic-pituitary-gonadal systems in adolescents of the indigenous and incoming population of the Republic of Sakha (Yakutia) depending on sex, age, and ecological living conditions.

5. To study the features of immune status and immuno-endocrine relationships in healthy adolescents and adolescents with bronchial asthma.

6. To develop and implement scientifically grounded recommendations for the preservation and improvement of the health status of the younger generation of the Republic of Sakha (Yakutia).

Scientific Novelty

1. It has been demonstrated that the progressive deterioration of somatic and reproductive health of adolescents of the Republic of Sakha (Yakutia) over the last decade (2001–2010) is associated with unfavourable ecological and social conditions.

2. Based on a comprehensive examination of a representative number of adolescents of the Republic of Sakha (Yakutia), the ethnic determinacy of the physical and sexual development of adolescents under equal ecological living conditions has been demonstrated. It has been established that adolescents of the indigenous population of Yakutia — the Sakha and the indigenous small peoples of the North (Evens, Evenki, Chukchi, Yukaghirs, Dolgans) — more often have disharmonic mesomorphic development, lag behind in weight-height indicators and the degree of expression of secondary sexual characteristics compared with peers of the incoming population (Europoids).

3. It has been established that the functional activity of the hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, and hypothalamic-pituitary-gonadal systems in adolescents of the Republic of Sakha (Yakutia) has ethnic specificities and depends on climatographic and ecological living conditions. Age adaptation of the indigenous population and Europoids is achieved through the change in activity of different links of the endocrine system.

For the first time, the significant influence of sex, age, ecological living conditions, and ethnic affiliation on interhormonal interactions during the formation of stable long-term adaptation has been confirmed.

For the first time, regional norms of the hormonal status of adolescents of the Republic of Sakha (Yakutia) have been scientifically substantiated and developed.

4. The features of cellular immunity of adolescents of the Republic of Sakha (Yakutia) have been established — depression of immune reactivity, as well as dissonance of a high level of metabolic energy processes in cells of the macrophage line and low phagocytic activity of neutrophils of peripheral blood.

5. For the first time, a comprehensive study of the immune status and immuno-endocrine relationships in adolescents of the Republic of Sakha (Yakutia) with bronchial asthma has been conducted. Functional insufficiency and dysregulation of compartments of the immune system of adolescents have been identified, caused by climatographic features and the deterioration of the ecological situation, which, in combination with risk factors, further form the development and chronicity of allergic diseases.

6. Scientifically grounded principles for the optimization of medical observation of adolescents of the Republic of Sakha (Yakutia) have been developed.

Practical Significance of the Work

During the work, the physical development of more than 40 thousand adolescents aged 10 to 17 living in different regions of the Republic of Sakha (Yakutia) was examined, and more than 970 adolescents underwent comprehensive in-depth examination of somatic health.

The results of the work were presented in the State Reports "On the Situation of Children in the Republic of Sakha (Yakutia)" for 2009 and 2010, were implemented in the Healthcare Modernization Programme of the Republic of Sakha (Yakutia) for 2011–2012 in the section of paediatric service, republican target programmes on the development of medical care for the child population, and orders of the Ministry of Health of the Republic of Sakha (Yakutia) on the improvement of paediatric service.

Methodological recommendations and manuals have been published:

- methodological recommendations "Anthropometric Characteristics of Adolescents of the Republic of Sakha (Yakutia)", approved by the Scientific-Planning Committee of FGUP "Yakutian National Medical Centre" of the Siberian Branch of the Russian Academy of Medical Sciences (2012);

- methodological manual "Hormonal Status of Adolescents of the Republic of Sakha (Yakutia)", approved by the Scientific-Planning Committee of FGUP "Yakutian National Medical Centre" of the Siberian Branch of the Russian Academy of Medical Sciences (2012). The derived indicators of the hormonal status of adolescents of health groups I and II, taking into account ethnic affiliation, have been approved by the Ministry of Health of the Republic of Sakha (Yakutia) as reference standards for the RS(YA);

- a textbook "Bronchial Asthma in Children", approved by the Educational-Methodological Council of the Yakutian State University (2009);

- an educational-methodological manual "Nutrition of Children and Adolescents Studying in Educational Institutions of the Republic of Sakha (Yakutia)", approved by the Academic Council of FGNU "Institute of Health" and the Scientific-Methodological Council of the Medical Institute of the Yakutian State University (2009).

The results of the research have been introduced in the work of FGUB "Yakutian Scientific Centre of Complex Medical Problems" of the Siberian Branch of the Russian Academy of Medical Sciences, the Ministry of Health of the RS(YA), the Paediatric Centre of GBU RS(YA) "RB No. 1 — NCM", urban and central district hospitals, departments of the Medical Institute of the Federal State Budgetary Educational Institution of Higher Professional Education "North-Eastern Federal University named after M.K. Ammosov", and have been confirmed by implementation certificates.

Author's Contribution

The author conducted an analytical review of domestic and foreign literature on the studied problem, compiled a research programme, and developed a formalised examination map and an adolescent questionnaire. A clinical study and adolescent questioning were conducted, the author personally filled out 80% of the formalised cards, created an electronic database (100% personal participation), and conducted statistical processing of the material (90% personal participation).

Studies of the hormonal status were conducted in the laboratory of FSBE "Yakutian Scientific Centre of Complex Medical Problems" of the Siberian Branch of the Russian Academy of Medical Sciences, and the immune status — in the laboratory of the Far Eastern Branch of FSBE "Far Eastern Scientific Centre of Physiology and Pathology of Respiration" of the Siberian Branch of the Russian Academy of Medical Sciences. The analysis of the obtained data, formulation of conclusions, and practical recommendations were carried out personally.

Main Propositions to be Defended:

1. The negative trends in the state of somatic and reproductive health of adolescents of the RS(YA) are caused by socio-medical factors: residence in intensively deteriorating ecological conditions; low socio-economic status of families, especially in Arctic regions; insufficient accessibility of specialised medical care for adolescents of Arctic regions.

2. Among the risk factors in the lifestyle of adolescents of the RS(YA), such factors as residence in incomplete families, the spread of harmful habits among parents and adolescents themselves, poor material situation of the family, risky sexual behaviour, and low medical awareness are significant. The quality of life of adolescents in Arctic regions is significantly lower than in the city.

3. The physical and sexual development, hormonal and immune status indicators of adolescents of the RS(YA) are largely determined by their ethnic affiliation and ecological living conditions.

4. The improvement of the state of somatic and reproductive health of adolescents living in extreme climato-ecological conditions of Yakutia, and the increase in their quality of life, are possible through the development and implementation of comprehensive organisational and medical measures.

Presentation of the Work

The main results of the research were reported and discussed:

I. At congresses: the XVI Congress of Paediatricians "Actual Problems of Paediatrics" (Moscow, 2009); the I Congress of Paediatricians of the Republic of Sakha (Yakutia) (Yakutsk, 2010); the I and II Congresses of Paediatricians of the Far East (Khabarovsk, 2010, 2012).

II. At congresses, symposia, forums, conferences: the I Congress of the Federation of Paediatricians of the CIS Countries "Child and Society: Problems of Health, Development, and Nutrition" (Kyiv, 2009); the International Symposium "Actual Questions of Paediatrics in the Light of Evidence-Based Medicine" (Dalian, China, 2010); the I Paediatric Forum "Innovative Technologies in Paediatrics: Achievements and Prospects" (Yakutsk, 2011); the Scientific-Practical Conference with International Participation "Actual Problems of Paediatrics, Paediatric Surgery, and Orthopaedics at the Present Stage" (Khabarovsk, 2009); the All-Russian Scientific-Practical Conference with International Participation "Modern Problems of Paediatrics" (Yakutsk, 2011); interregional scientific-practical conferences: "Ecology and Human Health in the North" (Yakutsk, 2007), "Health of Children of the North" (Yakutsk, 2008), "Modern Factors of Formation, Methods of Assessment, and Forecasting of Public Health in the Territory of the Far Eastern Region" (Khabarovsk, 2008), "The State and Prospects of Development of Paediatric Service within the System of Municipal Healthcare" (Yakutsk, 2010); scientific-practical conferences "Clinical and Fundamental Aspects of Pulmonology of Paediatric Age" (Khabarovsk, 2009), "The State of Health of Children and Adolescents at the Present Stage" (Khabarovsk, 2011); the scientific-practical conference dedicated to the 10th Anniversary of the Paediatric Centre (Yakutsk, 2009); republican scientific-practical conferences: "Modern Problems of Paediatrics" (Yakutsk, 2007), "Children in the Modern Law-Protection Space" (Yakutsk, 2009), "Socio-Psychological Aspects of the Health of Adolescents and Youth of the Republic of Sakha (Yakutia): The State and Prospects" (Yakutsk, 2009), "Actual Questions of Infectious Pathology in Children" (Yakutsk, 2010), "Disability of the Child Population of the Republic of Sakha (Yakutia). Problems, Ways of Prevention, and Rehabilitation" (Yakutsk, 2012), "Modern Problems of Accessibility and Quality of High-Technology Medical Care to the Population of the Republic of Sakha (Yakutia)" (Yakutsk, 2012), "Improvement of Paediatric Service of the Republic of Sakha (Yakutia) within the Framework of the Implementation of the Healthcare Modernisation Programme of the RS(YA) for 2011–2012" (Yakutsk, 2012).

III. At annual meetings of district paediatricians of the Republic of Sakha (Yakutia) (2006–2011).

Publications

85 printed works have been published on the topic of the dissertation, including 19 publications in journals recommended by the VAK for the publication of works when defending a dissertation for the scientific degree of Doctor of Medical Sciences, and 3 methodological manuals.

Structure and Volume of the Dissertation

The dissertation is presented on 291 pages of typed text and consists of an introduction, a literature review, 5 chapters of original research, a discussion of results, conclusions, practical recommendations, and appendices. The bibliographic list includes 358 domestic and 120 foreign sources. The work is illustrated by 32 figures and 49 tables.