Arterial Hypertension and Other Components of Metabolic Syndrome among the Inhabitants of Gornaya Shoria

The dissertation is devoted to an epidemiological study of the prevalence of arterial hypertension, its associated risk factors, and the main components of metabolic syndrome among the population of Gornaya Shoria — a region of the Kemerovo Oblast with specific climatic and geographical conditions and a mixed ethnic composition of inhabitants. The work compares data obtained from the indigenous population (the Shors) and from non-indigenous inhabitants, which makes it possible to identify ethnic and population differences in the frequency of excess body weight, dyslipoproteinemia, smoking, and characteristics of metabolic status. On the basis of the conducted epidemiological, clinical, and laboratory examination, a differentiated approach to the formation of high-risk groups has been developed and a scientifically grounded programme of primary prevention of arterial hypertension has been proposed, taking into account the ethnic affiliation of the population.

Relevance of the problem: Epidemiological studies carried out in many countries of the world have convincingly demonstrated that arterial hypertension (AH) is one of the most widespread chronic non-communicable diseases among the adult population and, alongside ischaemic heart disease (IHD), occupies a leading place in the structure of overall morbidity and mortality among the populations of developed countries [48, 75, 212]. In the structure of causes of overall mortality, cardiovascular diseases (CVD) account for more than half (55%) of all deaths and 48.8% of cases of disability [22, 23, 86, 243].

At present, more than 30% of the population of Russia, i.e. approximately 40 million people, suffer from AH. In the morbidity structure under conditions of a large city, AH accounts for 41.3%, and in the mortality structure for 15.5%, with a tendency toward growth [73].

In the Kemerovo Oblast over the period 1995-1999, the increase in overall morbidity within the group of circulatory system diseases amounted to 30.3%.

In prospective epidemiological studies, the scientific concept of CVD risk factors was formulated [85]. More than 200 factors — environmental, hereditary, and metabolic — have been identified that, to varying degrees, contribute to the development of CVD. A special place among them is occupied by a complex of interrelated metabolic disturbances — metabolic syndrome (MS), the basis of which is insulin resistance (IR). According to data of G. Reaven et al. [226, 227], approximately 25% of the population may have IR. The prevalence of complete MS ranges from 1 to 3% and depends on the geographical and ethnic characteristics of the population, sex, age, and the diabetic status of the examined cohort; among patients with NIDDM it amounts to 9-28% [197]. The development of MS is accompanied by an increase in mortality from IHD by 40%, from AH by a factor of 2.5-3, and from NIDDM by a factor of 4 [88].

There objectively exist climatic, geographical, regional, social, racial, ethnic, and sex-related characteristics of the prevalence of CVD and their risk factors [4, 7, 18, 35, 39, 49, 79, 173, 179, 188]. The study of these characteristics has gradually come to play an important role in the formation of regional and national programmes for the prevention of CVD and mortality from them among the population living in various regions of Russia [27, 33, 43, 86, 109, 132, 171].

Population-genetic studies of small peoples of Siberia have shown that they have retained, up to the present time, features of their traditional centuries-old way of life, a unique gene pool, and a distinctive pattern of morbidity. The growth in the number of newcomers, the expansion of interethnic ties of the indigenous peoples, and changes in their living conditions lead to definite changes in the morbidity structure of these peoples, owing to an increase in the prevalence of AH, atherosclerosis, and others [22, 32, 39, 70, 80, 81, 83]. Data of this kind on the ethnic groups of the indigenous inhabitants of the Kemerovo Oblast (the Shors) are not available in the literature; therefore, the analysis of the prevalence of AH, the risk factors of its development, and the components of MS among the indigenous and non-indigenous population of Gornaya Shoria became one of the tasks of the present study.

Gornaya Shoria, situated in the south of the Kemerovo Oblast, is of great interest because of its climatic and geographical situation (contrasting climate, low winter temperatures, large annual precipitation, and a mountainous type of terrain), its ethnic composition with representatives of various races, and the inaccessibility of the majority of its districts (an underdeveloped road network). Moreover, the population of Kuzbass is steadily declining because of a decrease in the birth rate, and this affects small peoples especially adversely, including the indigenous inhabitants of Gornaya Shoria — the Shors. In this connection, the problem of providing quality medical care to the population of this region is particularly relevant.

Thus, the study of the prevalence of AH and its risk factors, the development of differentiated approaches to the formation of groups with a high level of risk of its development, the analysis of the state of the MS problem, and the creation of an adequate system for the prevention of CVD among the unorganized population of Gornaya Shoria appear relevant for the public health of Kuzbass.

Aim of the study:

To investigate the prevalence of arterial hypertension, the risk factors of its development, and the main components of metabolic syndrome among the indigenous and non-indigenous inhabitants of Gornaya Shoria.

The following tasks were set to achieve this aim:

1. To identify the prevalence of the main risk factors of arterial hypertension (smoking, dyslipoproteinemia, and excess body weight) and their interrelation with socio-demographic characteristics (sex, age, and ethnicity) in the examined population.

2. To assess the prevalence of arterial hypertension and to study its interrelation with risk factors among the inhabitants of Gornaya Shoria of different ethnic origins.

3. To investigate the characteristics of metabolic status and to assess the prevalence of metabolic syndrome components among the indigenous and non-indigenous population of Gornaya Shoria.

4. To develop a scientifically grounded programme of primary prevention of arterial hypertension and its main risk factors in the studied population.

Scientific novelty:

For the first time in Gornaya Shoria, an epidemiological survey has been carried out among the population of different ethnic origins with the aim of obtaining data on the prevalence of AH and its risk factors.

Ethnic characteristics of risk factors and their influence on the prevalence of AH among the population of Gornaya Shoria of different ethnic origins have been revealed. It has been established that the inhabitants of Gornaya Shoria are characterised by a high prevalence of AH and low awareness of the presence of this syndrome, and consequently by a low coverage and effectiveness of treatment-and-prevention measures.

It has been proved that, despite the absence of differences in the frequency of detection of AH among the indigenous and non-indigenous population of Gornaya Shoria, the mechanisms of AH formation differ between the Shors and the non-Shors. Whereas the development of AH in the non-Shor population is associated with insulin resistance syndrome, the significance of this mechanism in the formation of AH in the Shor population is negligible.

Practical significance of the work:

The identified characteristics of the prevalence of AH, its risk factors, and the main components of MS may serve as baseline information for subsequent monitoring of the state of health and the development of regional measures for the prevention of this pathology among the population of Gornaya Shoria of different ethnic origins.

Population differences between the inhabitants of Gornaya Shoria of different nationalities substantiate the need for a differentiated approach to the primary prevention of AH.

The results of the study may be used for improving the model of social development of the indigenous small-in-number population of Gornaya Shoria.