Characteristics of Physical and Sexual Development of Girls and Adolescent Girls in the Conditions of Yakutia

The dissertation is devoted to the study of the characteristics of the health status, physical and sexual development of girls and adolescent girls aged 9–17 residing in various climatic-geographic regions of the Republic of Sakha (Yakutia). The research was conducted under conditions of a sharply continental climate and against the background of extreme ecological factors, including atmospheric, water, and soil pollution associated with the development of diamond mining and processing industries. The work is aimed at identifying patterns of somatic, sexual, and endocrine development depending on region of residence, ethnic affiliation, and age.

During the research, a comparative analysis of the health status, physical and sexual development of girls of indigenous and non-indigenous populations of the Northern, Vilyuysk, and Central regions of Yakutia was conducted. Indicators of somatic and gynecological morbidity, functional activity of the hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, and hypothalamic-pituitary-ovarian systems were assessed, as well as the age dynamics of secondary sexual characteristic development and hormonal status during the pre-pubertal and pubertal periods of development.

Relevance of the problem: Issues concerning the protection of the somatic and reproductive health of adolescent girls are a pressing problem of modern medicine. It is now beyond doubt that the state of female reproductive function is largely determined by development during childhood and adolescence. The formation of the sexual system of girls during puberty is interrelated with physical development. It has been established that unfavorable factors, regardless of their nature, cause impairment of reproductive function. Early detection of these impairments and timely correction constitutes a controllable factor for the preservation of reproductive health during puberty (Bogdanova E. A., 1993; Ushakova G. A., 1994; Baranov A. N., 1997, 2002; Gurkin Yu. A., 1993, 2000). Accurate diagnosis of these deviations is possible only under the condition of knowledge of the patterns of growth and development of the organism during puberty. During this period, there occurs a relatively rapid growth of the sexual organs, the appearance and establishment of menstrual function, occurring under the influence of the cyclic secretion of hypothalamic releasing factors, pituitary gonadotropic hormones, and ovarian steroid hormones (Kobozeva N. V., 1988; Vikhlyaeva E. M., 1997; Kokolina V. F., 2001). In the establishment of reproductive system function, the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid systems play an important role (Sukhanov S. G., 1993; Tkachyov A. V., 1988).

The literature contains data on the formation of physical and sexual development of children in various climatic-geographic zones of the country, including ecologically unfavorable ones, reflecting an unfavorable trend in their health status, manifested by a decrease in the proportion of healthy children at birth, an increase in the number of children with disabilities, and patients with chronic pathology. In the Northern regions of the Russian Federation, as a whole across the country, there is observed a negative environmental impact on human health associated with the increase in the volume and expansion of the spectrum of environmental pollution (Narzullaev S. B. et al., 1997; Tyomdaya V. I., 1999). This manifests itself in unsatisfactory indicators of somatic and reproductive health and physical development (V. K. Yuryev, 1994, 1998; Yu. A. Gurkin, 2000, V. A. Trufakina, V. T. Manchuk, 1997).

The territory of the Republic of Sakha (Yakutia) is located in a zone of extreme climatic factors. Its development led to the formation of several zones of potential environmental contamination: Group 1 — arctic, Group 2 — agricultural, Group 3 — industrial. Unfavorable meteorological conditions (air stagnation, low wind speed, frost fogs) exacerbate atmospheric pollution during the winter period. In the republic, contamination of water and soil by human waste products is noted, including heavy metal salts. In recent years, the priority industry in the republic is diamond mining and processing, at all stages of which a large quantity of dust is released into the working zone air. According to the State Epidemiological Surveillance (Republic of Sakha), at many diamond-cutting plants of the republic, the concentration of carbon dust exceeds the maximum permissible level several times (Savvin D. D., 1992; Agadzhanian, Petrova P. G., 1996).

Despite industrial development, all uluses are characterized by a relatively low level of socio-economic development and a high cost of the consumer basket and essential goods.

In the Republic of Sakha (Yakutia), a number of studies have been conducted devoted to the study of the influence of individual socio-hygienic, medico-biological, and ecological factors on the health, physical, and sexual development of children (A. G. Egorova, 1995; Naumova A. A., 1996; M. V. Khandy, 1997; L. V. Aleksandrova, 1998; S. V. Markova, 2002, N. M. Zakharova, 2002). Despite this, the region lacks normative indicators of sexual development of girls and adolescent girls aged 9–17, taking into account ethnic composition and reflecting belonging to indigenous and non-indigenous populations of the republic. There are also insufficient studies that, from a clinical-endocrinological standpoint, would allow characterizing the contemporary level of health, physical, and sexual development, and assessing the functional activity of the main links of the endocrine system regulating growth and the establishment of reproductive function in girls with varying health status during the pre-pubertal and pubertal periods.

It has been observed that over the past 15 years in the republic there has been a decline in the birth rate, an increase in overall mortality, and a decrease in the natural population growth rate. The gynecological morbidity of adolescent girls increases annually — 171.6 per 1,000 girls examined.

From this standpoint, scientific research into the somatic and reproductive health of contemporary girls and adolescent girls is highly relevant and should contribute to a reduction in morbidity and the preservation of the reproductive potential of the nation as a whole. To date, no such comprehensive studies have been conducted in the conditions of Yakutia.

The present work was carried out within the framework of regional programs "Children of the Arctic" and "Medical-Ecological Monitoring of the Health Status of the Population in the Diamond Mining Region (on the example of the Nyurba Ulus) of the Republic of Sakha (Yakutia)," aimed at identifying causal relationships between the level of health and external environmental factors.

Goal of the research.

To study the characteristics of the health status, physical and sexual development, and hormonal status of girls and adolescent girls in the conditions of the sharply continental climate of Yakutia.

Research objectives:

1. To analyze certain socio-economic and medico-biological aspects of the health of girls and adolescent girls of the Republic of Sakha (Yakutia).

2. To study the somatic health of girls and analyze the structure and prevalence of diseases depending on ecological conditions of residence.

3. To conduct a comparative analysis of the physical and sexual development of girls and adolescent girls residing in the Northern, Vilyuysk, and Central regions of Yakutia.

4. To study the age dynamics of the development of secondary sexual characteristics in girls of indigenous and non-indigenous populations.

5. To study the hormonal status indicators of girls during the pre- and pubertal periods of development.

Scientific novelty. For the first time in the Republic of Sakha (Yakutia), a comprehensive study of the health status, physical and sexual development of girls and adolescent girls aged 9–17 residing in various climatic-geographic regions of the Republic of Sakha (Yakutia) has been conducted. Characteristics have been revealed of the health status, physical and sexual development of schoolgirls depending on age, duration of residence in the region (indigenous and non-indigenous populations), and ecological conditions of residence.

It has been established that in the age group of 9–17 years, 4.9% of all examined children can be considered healthy, of whom indigenous children — 4.2%, non-indigenous — 7.4%. Of the examined girls, 52.5% have functional deviations in health status, and 42.6% have chronic diseases. With age, an increase in the number of illnesses contracted by girls is noted, along with a transition from functional impairments to chronic pathology. The lowest indicators of somatic health were recorded among residents of the Northern and Vilyuysk regions; Group I health was identified in 1.9% and 2.2% of observations, respectively. The structure of somatic pathology depends on the region of residence. Among urban children, orthopedic pathology occupies the first place in the morbidity structure regardless of ethnic affiliation, in the Central and Vilyuysk uluses — diseases of the digestive organs, and in the Northern regions — endocrine diseases.

The structure of gynecological diseases in girls differs across different age periods. In girls under 14 years of age, the following predominate: inflammatory diseases of the external genitalia, disorders of the tempo of sexual development; in adolescent girls aged 15–17, the following prevail: menstrual cycle disorders and inflammatory diseases of the internal reproductive organs.

The physical development of girls in Yakutia conforms to general anatomical-physiological patterns of development, yet possesses its own characteristics. The physical development of 79.2% of schoolgirls in Yakutia can be assessed as corresponding to age. Deviations from the age norm are present in 20.8% of the examined girls. In the assessment of physical development, advancement beyond the age norm was identified in 11.2% of the examined children, and delay in 9.6%. The lowest indicators of physical development were noted among girls of the Northern region, with sharply disharmonic physical development identified in 0.9% of cases. Among rural residents, delayed physical development was registered three times more frequently.

The age dynamics of the development of secondary sexual characteristics in Yakut girls have their own characteristics. Schoolgirls of the indigenous population lag significantly behind their European peers in the degree of development of pubic and axillary hair. The average age of menarche was 12.6 years. A comparative analysis of the sexual development of girls in Yakutia showed that in recent years a shift toward an earlier age of menarche has occurred, on average by 1.1 years, the appearance of signs of breast development by 4.4 years, pubic hair growth by 2.3 years, and axillary hair growth by 1.8 years.

The study of the level of functional activity of the endocrine system of girls during puberty showed that hormonal regulation of physical and sexual development in Yakutia occurs within reduced timeframes. The functional activity of the endocrine system in children of the indigenous population depends on age, region of residence, and season of examination.

Practical significance of the work: The obtained results characterize the regional features of the health status, growth processes, and physical and sexual development of girls and adolescent girls of school age in the conditions of Yakutia. Based on the dissertation materials, methodological guidelines have been developed for pediatric physicians "Sexual Development of Girls and Adolescent Girls Aged 9–17 of Indigenous and Non-Indigenous Populations of Yakutia." The results of the research will allow a more objective assessment of the level of physical and sexual development of girls in the region, timely identification of groups of children at risk of impaired physical and sexual development, during the All-Russian dispensary examination of children and adolescents in 2003–2005. Hormone levels obtained from the examination of girls in Groups I and II of health can be used as regional norms.

Implementation in practice. The main provisions of the dissertation are used in the practice of a specialized hospital in the city of Yakutsk. The materials of the dissertation work are used in lectures and practical exercises on pediatrics and pediatric gynecology for students of the Yakutsk Medical Institute and in advanced training courses for physicians.

Verification of research results. The main provisions of the dissertation have been presented and published at an International Symposium (Khabarovsk, 1997), at scientific-practical conferences of the Yakutsk State University named after M. K. Ammosova (Yakutsk, 1999, 2000, 2001, 2002), at republican scientific-practical conferences of physicians (2000, 2001, 2002), and at scientific-practical conferences of the Yakutsk Medical Institute (1999, 2000, 2002).

Publications. Ten printed works have been published on the topic of the dissertation.

Structure and volume of the dissertation. The dissertation consists of the following sections: introduction, literature review, materials and methods, results of original research and discussion of obtained results, conclusion, findings, practical recommendations, and reference list. The dissertation is presented in 165 pages of typescript, illustrated with 28 tables and 12 figures. The reference list consists of 358 sources, including 245 domestic and 113 foreign authors.

Main provisions for defense:

1. In the Republic of Sakha (Yakutia), against the background of the unfavorable impact of a complex of socio-economic factors (harmful parental habits, alcohol abuse in the family, parental education, low material standard, housing conditions, dietary patterns), medico-biological factors (complication of pregnancy and childbirth), and ecological factors, a deterioration in the health status of children and adolescents is observed.

2. Health indicators of girls aged 9–17 in Yakutia show negative trends: 4.6% of those examined can be considered healthy, 52.5% have functional health impairments, and 42.6% of children have chronic diseases. The overall morbidity of children in the Northern and Vilyuysk regions exceeds the indicators of the relatively favorable Central region. The prevalence of endocrine, respiratory, circulatory, congenital malformation, and allergic diseases in the ecologically unfavorable Northern and Vilyuysk regions exceeds corresponding indicators in the ecologically cleaner Central region.

3. Gynecological morbidity depends to a greater extent on the age of the girl: in the early and late pre-pubertal periods of development, inflammatory diseases of the external genitalia (vulvovaginitis — 2.2% in Yakut girls and 1.9% in non-indigenous peers) predominate. In the pubertal period of development, the first place in the structure of gynecological morbidity is occupied by menstrual cycle disorders — in 14.8% of cases among indigenous girls and 22% among non-indigenous girls.

4. Physical development corresponding to age norms is observed in 79.2% of the examined children, with the greatest deviations recorded among girls of the Northern and Vilyuysk regions, indicating that physical development depends to a greater extent on health status. A deceleration in growth rates in children of non-indigenous populations has been identified at the current stage.

5. The age dynamics of the development of secondary sexual characteristics in children of the indigenous population have their own characteristics. The main differences are related to the degree of pubic and axillary hair development. Girls of non-indigenous populations outperform their indigenous peers at all stages of secondary sexual characteristic formation.

6. The study of the level of functional state of the endocrine system in children during puberty showed that hormonal regulation of physical and sexual development of girls in Yakutia occurs within reduced timeframes and depends on the region of residence.