Ekologiya cheloveka (Human Ecology)

Most physiological processes in the human body are governed by genetically determined biorhythms, which are key factors of natural selection and adaptation. Circadian rhythms regulate not only daily biological processes but also their underlying molecular basis. This knowledge may be useful for developing therapeutic strategies for a range of diseases. Particular importance is attributed to research in biological rhythms for professions involving shift work and night work, as it allows identifying periods of increased vulnerability of the human body. Changes in living, working, and rest conditions may lead to disturbances and disruptions of biological rhythms: the internal biological clock may accelerate or decelerate, resulting in desynchronization, deterioration of well-being, and the development of chronopathological conditions, including an increased risk of cardiovascular and endocrine disorders, psychoemotional disturbances, and reduced work capacity. Therefore, chronomedicine addresses the application of knowledge about biorhythm patterns for the prevention, diagnosis, and treatment of human diseases. Monitoring of human biorhythms can be performed using various biological fluids (blood, urine, saliva), depending on the research objectives and laboratory capabilities.

BACKGROUND: Age-related changes in autonomic regulation and microcirculation may be substantially modified by urban environmental factors; however, comparative analyses of these processes in settlements with different levels of urbanization remain insufficiently studied.

AIM: The work aimed to assess the effect of age on spectral parameters of heart rate variability and microcirculation among residents of cities with different levels of urbanization.

METHODS: Volunteers from three age groups (group 1, 18–44 years; group 2, 45–59 years; group 3, 60–74 years) permanently residing in a large city (Nizhny Novgorod), an industrial city with a developed chemical industry (Dzerzhinsk), and a small tourist city (Semenov) were examined. Heart rate variability was analyzed using the Poly-Spectrum hardware–software system (Neurosoft, Russia). Microcirculation was assessed by laser Doppler flowmetry (LAZMA analyzer, Russia). Statistical comparisons were performed using Student’s t test with Bonferroni correction.

RESULTS: With increasing age, a decrease in total spectral power of heart rate variability (p < 0.05) and individual spectral components was observed. Age-related changes in the heart rate variability spectrum were universal: the greatest increase in the contribution of the very low-frequency component was recorded at the age of 45–59 years among residents of the large city (by 66%), the industrial city (by 38%), and the small city (by 29%) compared with group 1, followed by an increase in high-frequency power at the age of 60–74 years: by 3-fold in large city residents, by 1.4-fold in industrial city residents, and by 1.6-fold in small city residents compared with group 2. However, a very low-frequency component was persistently elevated only among residents of the industrial city aged 60–74 years, exceeding that in group 1 by 21% (p < 0.05). In microcirculation, aging was associated with a decrease in cardiac rhythm amplitude and an increase in endothelial rhythm amplitude across all groups. In individuals aged 60–74 years living in the large city and the industrial center, a reduction in myogenic rhythm amplitude was observed, whereas in the tourist city, this parameter demonstrated an opposite trend.

CONCLUSION: The type of settlement influences universal age-related changes associated with a reduction in the activity of autonomic regulatory mechanisms as a whole. The greatest strain on regulatory systems was observed in middle-aged individuals (45–59 years), with subsequent persistence in older individuals (60–74 years) residing in an industrial center with a developed chemical industry, compared not only with residents of a small tourist city but also with those of a large city. These findings are relevant for the assessment of prenosological conditions and are important for the development of preventive public health measures.

BACKGROUND: Despite the continued relevance of socially substantial infections, including tuberculosis, their public health aspects remain insufficiently studied, particularly with regard to the strength of influence and hierarchical distribution of associated risk factors within the health preservation system.

AIM: The work aimed to assess the influence of key risk factors on the spread of tuberculosis and to establish their hierarchical distribution within the health preservation system of a single region.

METHODS: An ecological study covering the period from 2010 to 2024 examined the influence of 70 risk factors on tuberculosis incidence in the Republic of North Ossetia–Alania. Twelve factors with zero coefficients or lacking logical interpretability were excluded from the analysis. The assessed risk factor groups included macroeconomic, sociodemographic, medical and organizational, medical and biological, epidemiological, and environmental factors. The hierarchical distribution of tuberculosis risk factors was determined at the population, group, and individual levels of the health preservation system. Data were obtained from the Federal State Statistics Service of the Russian Federation (Rosstat). Cross-correlation analysis was performed using Pearson’s method with min–max normalization and transformation of data into stationary series. Normality of variable distributions was assessed using the Shapiro–Wilk W test, and homogeneity of variances using Bartlett’s test in the R statistical environment. Correlation significance was evaluated using p values and 95.0% confidence intervals for the correlation coefficient (r): values ≤0.39 were considered weak; 0.40–0.59, moderate; 0.60–0.79, strong; and 0.80–1.00, very strong.

RESULTS: In the Republic of North Ossetia–Alania, the hierarchical distribution of public health demonstrated that tuberculosis incidence was predominantly influenced by group-level risk factors, particularly economic factors related to treatment expenditures (r = −0.89), social factors associated with migrant population size (r= 0.75) and disability among women (r= 0.72), medical and organizational factors related to healthcare provision in rural areas, and demographic factors. At the population level, key determinants of tuberculosis spread included social factors such as marriage rates (r = −0.89) and divorce rates (r = 0.56), as well as an environmental factor reflecting hydrocarbon concentrations in ambient air (r = 0.78). Economic factors (gross regional product per capita; r = −0.68) and epidemiological factors (BCG vaccination coverage among children; r = −0.65) also exerted a strong influence on tuberculosis incidence at the population level. Individual-level factors did not demonstrate a significant impact on tuberculosis spread (tuberculosis contacts; r = 0.39; p > 0.193; medical and biological factors).

CONCLUSION: The predominance of group-level risk factors in influencing tuberculosis spread within the hierarchical health preservation system of the Republic of North Ossetia–Alania underscores the need to concentrate tuberculosis control resources on specific population groups, alongside improving socioeconomic living conditions at the population level.

BACKGROUND: The relevance of this study is driven by a substantial increase in the contribution of urbanization to the processes of growth and development in children and adolescents.

AIM: The work aimed to analyze the anthropogenic footprint in the morphological status of children and adolescents based on survey data from schoolchildren in Stavropol.

METHODS: Three datasets were used in the study, comprising data from the examination of Stavropol schoolchildren aged 7–15/17 years: 1958, 1290 individuals; 1987, 1136 individuals; and 2001, 1054 individuals. Each sex- and age-specific group in each dataset included approximately 60 individuals. Body height and chest circumference were assessed (trends of absolute values and annual increments), as well as age at menarche in girls.

RESULTS: Children and adolescents examined in 1958 lagged their peers from later survey years primarily in body height; these differences increased in older age groups, reaching 1.3 and 1.4 standard deviations in boys and girls, respectively, by the age of 16 years. The lowest chest circumference values were observed in boys from the 1958 cohort (lag of 1.0 standard deviation) and in girls from the 2001 cohort. In girls examined in 1958, the peak height velocity occurred at the age of 10 years, amounting to 5 cm, and preceded menarche (14 years) by four years. This represents a set of features indicative of delayed development. In contrast, girls examined in 2001 demonstrated a pattern of accelerated development, with a peak height velocity at the age of 12 years, an intensity of 6 cm, and an interval of only seven months before menarche (12 years 7 months). In boys, the relationship between chronological age and peak growth intensity showed a similar pattern across cohorts.

CONCLUSION: Among groups of Stavropol schoolchildren, a trend toward a temporal increase in body height throughout the second half of the 20th century was observed. The most pronounced lag relative to peers from the 1980s–2000s was noted in adolescents aged 13–16 years examined in 1958, who were born during the years of the Great Patriotic War, reflecting the severe negative impact of military conflicts on physical development. The concurrent temporal reduction in chest circumference, particularly pronounced in girls, supports the presence of a trend toward gracilization and leptosomatization of body build, as described in the global scientific data. Peak height velocity serves as an informative indicator of population growth trends.