Arterial hypertension is the most important modifiable risk factor for cardiovascular diseases ; impact on it can reduce cardiovascular and overall mortality [2, 3]. Kearney P.M. et al. in their systematic review demonstrated that the prevalence of hypertension in population 20 + in the world ranges from 28.5% in the countries with a high level of economic development to 31.5% in countries with a low level of development . The authors mentioned significantly increased incidence of hypertension in the world over the period from 2000 to 2010 (from 25.9–31.1%). In addition, increased awareness of this disease (from 41.4–46.5%), treatment coverage (from 31.8–36.9%) and its effectiveness (from 33.9–37.1%) were also observed during this period.
In general, global studies demonstrate significant differences in the prevalence of hypertension in the countries of the world [5, 6, 7]. For example, an analysis of global trends in blood pressure from 1975 to 2015 that included 1,479 studies with a total population of 19.1 million revealed that over the past four decades high blood pressure levels have shifted from high-income countries to low-income countries in South Asia and sub-Saharan Africa; moreover, blood pressure was consistently high in the regions of central and eastern Europe . The prevalence of hypertension within these global regions varies significantly across different countries. For example, the prevalence of hypertension in sub-Saharan Africa in 2008 was estimated at 16.2% ranging from 10.6% in Ethiopia to 26.9% in Ghana . In the countries of Eastern Europe the value of this parameter was higher – in Serbia 46.8% and 46.2% for men and women, respectively ; in Romania – 50.2% and 41.1%, respectively ; in Poland – 42.1% and 32.9%, respectively , in Lithuania – 44.4% and 49.0%, respectively ; the population parameter in the Czech Republic was 43.6% , and in Belarus – 36.4% .
In addition to interstate differences, many sources describe territorial differences in the prevalence of hypertension within specific countries [16, 17, 18, 19]. At the same time, we surely should mention that individual characteristics have a significant impact on the prevalence, awareness, management and control of hypertension [7, 20], and differences in the structure of population based on the individual characteristics of living areas can, to a certain extent, also cause geographical differences. However, results of studies revealed that there are territorial differences in the prevalence of this disease – additionally to the considered individual features. Even the results of the MONItoring of trends and determinants in CArdiovascular disease (MONICA) project of the World Health Organization revealed that population factors in territorial units explain up to 7–8% of all differences in systolic blood pressure . A particularly strong (up to 20%of the contribution) population effect was found among individuals who took antihypertensive treatment and among women with overweight.
The PURE global study has demonstrated differences in the prevalence, awareness, management and control of hypertension depending on the level of gross national income (according to the World Bank) in several countries of the world . In addition the groups of countries stratified by income (high-, middle-, and low-income countries), within these groups, there are also differences between countries in the prevalence, awareness, management and control of hypertension. This indicates that the level of gross national income is only one of the state factors that have an effect on the prevalence of hypertension. In terms of ecoepidemiology, fundamental factors of different nature, mainly of social one, have an effect on intermediate factors, and these, in turn, influence either behavioral factors, or indirectly – direct factors of cardiovascular risk [23, 24, 25]. Intermediate factors include specific relationships at the local level, public investment and municipal support, legislative and political competence of authorities, physical environment, including artificial one.
Several world-leading epidemiologists Chow C.K., Teo K., Subramanian S.V., McKee M., Yusuf S. mentioned that : «…Historical research demonstrates the impact on health of change in social and physical environments… These observations have highlighted the influential role of population level determinants of health… They are sometimes expressed as ‘upstream’ determinants, such as social norms, culture and geography, which shape behaviour, as well as the political, economic and legal factors that encourage or constrain the choices that individuals make. There is a now a growing body of research addressing these issues, from a range of disciplinary perspectives… The evidence reviewed above shows that the environments that individuals inhabit influence their risk of CVD, and there are a growing number of methods by which these environments can be assessed. Yet, while population level interventions offer considerable promise for prevention of CVD, they have received much less attention than individual determinants of disease…».
Place of living and its characteristics at different levels have an effect on cardiovascular diseases (CVD): the possibility of developing coronary heart disease [27, 28, 29, 30], myocardial infarction , ischemic stroke [29, 32], mortality from CVD [30, 33, 34], hospitalization for CVD . Several publications have demonstrated that territorial features of the place of living have an effect on the prevalence, awareness, management and control of hypertension [36, 37, 38]. Moreover, there are many articles that address the issue of the influence of individual living environment [39, 40]. However, it should be mentioned that almost all found sources on hypertension describe small areas; there are just sporadic studies of associations at the level of states or large regions. Such papers include a population study of large regions in Columbia , as well as a study performed in the United States where the impact of socioeconomic characteristics of states at an early age on the possibility of hypertension development was analyzed using the example of Alcoa employees .
It should be emphasized that in the large majority of studies, territorial features were considered as 1–2 independent socio-economic parameters: Gini index, crime, average annual income, etc [41, 43, 44, 45], or economic parameters: indices of poverty, deprivation, etc [46, 47, 48]. Only one study was found with an empirical approach and 4 latent factors out of 20 territorial parameters including racial/ ethnic composition, socioeconomic status, age composition, family structure, owner-occupied housing, and housing stability . It is just such empirical studies that allow assessing the whole variety of factors (in addition to socio-economic ones) that have an impact on the state of health.
Epidemiology of hypertension in Russia was studied nationwide in recent years in Epidemiology of Cardiovascular Diseases and Risk Factors in the Regions of the Russian Federation study in 2012–2013 (ESSE-RF-1) and in 2017 (ESSE-RF-2), and similar results were obtained [18, 49]. According to the results of ESSE-RF-2, the prevalence of hypertension was 44.2%; the awareness of this disease was higher among women – 76.8% compared to 69.4% among men; treatment coverage was 53%; half of patients taking antihypertensive drugs (49.7%) control their blood pressure, but if we speak about all subjects with hypertension – only less than a third (24.9%) did the same . ESSE-RF-1 study, with 13 regions of the country involved, revealed regional differences in the prevalence, awareness, management and control of hypertension . However, we don’t know whether it is also influenced by the territorial characteristics of the living conditions of population, in addition to the individual characteristics of the structure of regional samples. No such multilevel analysis has been carried out. The objective of this study was to study the influence of regional characteristics on the possibility of the presence, awareness, management and control of hypertension at the individual level in a cross-sectional study of the Russian population.