Introduction: Information about the rise and development of the system of sanitary inspection in institutions for children and adolescents is scattered and scarce in scientific publications. This fact has determined the purpose of the study to analyze the history of the Russian sanitary surveillance in pediatric hygiene in the 19^th to 21^st centuries.

Materials and methods: We analyzed scientific papers and historical sources, including government and departmental regulations and guidelines, reviews, works of hygienists published in 1936–2021 and related to the formation of the system of sanitary inspection and providing for safe conditions in institutions for children and teenagers. Of more than 150 papers reviewed, we selected 31 sources found eligible for inclusion.

Results: School doctors were the first to conduct sanitary surveillance at the end of the 19^th century. In the early 20^th century, school health organizations, and later the departments of the municipal health bureaus, solved a wide range of tasks, including those of hygiene, pediatrics, and epidemiology. At the stage of formation, sanitary inspection was carried out in close contact with teachers and specialists from related branches. After the revolution, the absence of the national sanitary legislation was replenished by government acts enforcing hygienic standards important for protecting health of the child population. The improvement and update of the regulatory framework, forms and methods of sanitary control in children’s institutions became feasible in the early 1960s owing to the intensive development of pediatric hygiene as a scientific discipline.

Conclusion: Priority tasks of surveillance in children’s institutions varied depending on socio-economic realities, infectious and general disease rates, changes in education, and the development of related branches of hygiene, epidemiology, pedagogy, construction industry, and jurisprudence. This was accompanied by elaboration and improvement of the legislative framework, forms and methods of sanitary control and inspection of children’s institutions. The emergence of new health risk factors for the child population requires appropriate control and surveillance activities enabling a timely response to contemporary challenges. 

Introduction: A high level of competition for the quality and quantity of acquired knowledge is observed in modern society. It entails an increase in time children spent studying in school and doing their homework, the latter being an integral and critical component of the educational process.

Objective: To summarize and systematize the results of research on physiological, hygienic and pedagogical challenges of doing homework as well as on rationalization and optimization of this type of schoolchildren’s activity in the digital educational environment aimed at preventing fatigue and school-related diseases, including in the historical perspective.

Materials and methods: Appropriate publications in Russian and English languages were search for in the Russian Science Citation Index, PubMed, and Scopus databases, print editions of scientific journals, and other sources. Forty-two full-text papers published in 1989–2021 were eligible for inclusion in the review.

Results and discussion: The data analysis shows that contemporary schoolchildren spend significantly more time doing homework than is recommended, which disrupts their daily routine by reducing the duration of walks and night sleep and deteriorates health. Distance learning during the COVID-19 pandemic only exacerbated the situation. A whole number of publications in pedagogy are devoted to didactic issues of homework while little attention is paid to health-related improvement of conditions and organization of this important type of educational activity.

Conclusion: Global digitalization and the associated transformation of the education system necessitates hygienic optimization of all the components of the learning process, including homework, the content of which has undergone significant changes. 

Introduction: Sleep disturbance is a widespread and very significant sociomedical problem, the solution of which is largely dependent on preventive measures ensuring compliance with the relevant hygienic requirements.

Objective: To assess the sleep schedule and risks of its breaking on school days and weekends in elementary school children.

Materials and methods: In February–March 2022, we conducted a questionnaire-based survey of parents of 302 first to fourth graders (mean age: 8.21 ± 0.75 years) attending a gymnasium in the town of Balashikha, Moscow Region, to assess sleep patterns and reveal sleep disturbances in the children. Using nonparametric methods and statistical analysis programs, the relative risk (RR), odds ratio (OR), etiological fraction (EF), and 95 % confidence interval (CI) were calculated.

Results: We found that on school days, only 30.9 % of children went to bed before 9 p.m. while 15.8 % fell asleep after 10 p.m. The recommended sleep duration of more than 10 hours was observed only in 21.4 % of the schoolchildren. On weekends, the proportion of children going to bed after 10 p.m. increased to 42.6 %. Complaints of various sleep disorders were registered in 65.9 % of the children. The most pronounced risks of complaints of difficulty falling asleep were noted on weekends when going to bed after 11 p.m. (RR = 2.28; CI = 1.24–4.19; EF = 56 %). When going to bed after midnight, the risk of complaints of sleep disturbance increased (RR = 2.42; CI = 1.22–4.80; EF = 59 %).

Conclusion: Our findings indicate a high prevalence of sleep disorders in elementary school children having an adverse effect on their well-being. The established risks of sleep disturbance should be taken into account when assessing and monitoring the compliance of sleep schedule with health requirements. 

Background: Properly organized nutrition of school-age children and adolescents is an important prerequisite for their health maintenance. In the context of digitalization of education, given the pronounced physical inactivity, in-home eating develops and forms new eating habits affecting the consumption of breakfasts and lunches at school and at home. Modern schoolchildren do not follow a daily routine or a regimented diet; they often overeat or undereat and refuse unfamiliar foods not eaten at home but served for school meals, thus reducing their daily nutrient intake critical for normal growth. Under modern educational conditions, both school catering and the analysis and timely correction of the dietary pattern of schoolchildren at home, bearing in mind the continuity of home and school nutrition, are important for proper child development.

Objective: To assess nutrition of modern schoolchildren at home.

Materials and methods: To establish home food preferences, a survey of first to eleventh grade students and their parents was conducted in 2018–2021 based on a self-administered questionnaire specially developed in the light of principles of a healthy diet recommended by the World Health Organization. The form contained questions about the children’s diet, eating schedule, breakfasting, and consumption of fruit, fish, side dishes, soups, and confectionery.

Results: The findings showed that the regular diet of students of all grades lacked a whole number of recommended dishes while high school students rarely ate breakfast at home and had fewer vegetable side dishes, soups and porridges in their diet than the younger children. Only 69.5 % of the respondents reported having regular breakfasts at home on school days. The percentage of such respondents was significantly lower among high school students (p < 0.05), which could be attributed to lower parental control and greater independence of adolescents in this age group. The survey showed that 16 % of elementary school children did not have breakfast at home, but this rate decreased significantly to 8.5 % among fifth to eighth graders (p < 0.05).

Conclusion: Nutrition of schoolchildren at home shall be corrected and improved. A competent choice of healthy foods requires food literacy interventions as a promising strategy for educating both parents and children. Previously formed and newly acquired eating habits shall be taken into account when developing a diet for children.

Introduction: It is impossible to imagine the modern world without digital technologies currently used in all branches of industry, science, and education. Application of electronic learning tools in schools and universities has shown the need for regulating their use in order to prevent such adverse outcomes as visual and general fatigue. The Government of the Russian Federation has developed the Concept of Children’s Information Security aimed at creating the information environment that promotes positive socialization, optimal personal, cognitive, and physical development, maintenance of mental and psychological health and well-being. The rationale for optimal screen time duration, including that during distance learning, is of particular importance.

Objective: To assess risks of visual impairment and ill-being posed by the use of e-learning tools for high school, college, and university students during distance education.

Materials and methods: An anonymous survey of 190 high school students in Moscow and Omsk, college students and firstyear Omsk university students was conducted using an online questionnaire about well-being and health complaints during distance education of different duration. The study was carried out in March–April 2021, when students were learning online. Data processing was carried out by generally accepted statistical methods; the chi-square test was performed and relative risks and etiologic fractions were estimated.

Results: We collected new information on the prevalence of self-assessed visual impairment in modern high school, college, and medical university students. According to our findings, 42.9 % of high school students, 51.8 % of vocational school students, and only 37.2 % of university students had no visual impairment. We estimated screen time duration and established the related prevalence of ill-being, irritability, headaches, neck and back pain in the respondents. The health risk assessment performed showed that distance learning should be limited to five hours in order to avoid its potential adverse health effects in students. The results have limitations associated with a relatively small regional sample.

Conclusions: Our survey results are aimed at preventing visual impairment and psychological stress in students working in the digital environment during distance learning. They have been used to develop guidelines for prevention of vision problems and creation of safe e-learning conditions. 

Background: The transition from high school to university can impair the adaptive potential of adolescents.

Objective: To assess the level of adaptation of freshmen to higher education environment based on their blood parameters.

Materials and methods: Blood samples were collected from healthy 17-year-old adolescents (n = 50) on the first week at university and then two and six weeks after. The general blood test was accompanied by measurements of protein and protein fractions, immunoglobulins A, M and G, cortisol and testosterone levels. Nonspecific adaptive reactions of the body were assessed by the lymphocyte count.

Results: The level of cortisol in the blood was higher or equal to the upper limit of the normal range in 50.0 to 70.0 % of the adolescents at different stages of observation. At the beginning of the study, the lymphocyte count indicated stress in 10.0 % of the students, and 1.5 months after, it demonstrated overactivation of the immune response already in 35.0 % of the freshmen. The levels of albumins and α1-globulins increased while α2 -, β-, and γ-globulins decreased; serum immunoglobulins M increased and immunoglobulins A were below the normal range, indicating impairment of humoral immunity. The compensatory response was manifested by an increased mean corpuscular volume, a decreased amount of hemoglobin in erythrocyte, a low hemoglobin concentration in the cell volume, and a decreased mean platelet volume. High albumin levels in conjunction with changes in red blood demonstrated an electrolyte imbalance, while decreased testosterone levels against the increased cortisol ones showed the prevalence of catabolic processes in the body.

Conclusion: Hematological parameters provide objective information about the health status of first-year university students. They are related to previous competitive selection that included evaluation of medical contraindications and physical fitness, examination stress, and adaptation to novel learning conditions, and require timely correction. 

Introduction: The number of studies on health effects of social networking in young people has increased recently, but their results are inconsistent.

Objective: To analyze the impact of social networking on the development of Internet addiction disorders among medical university students.

Materials and methods: A survey of 403 medical students from the Russian cities of Moscow, Kaliningrad, and Voronezh was conducted in January–March, 2022 using a questionnaire developed by S.A. Kulakov to identify the influence of Internet or an already developed Internet addiction, and later tested and recommended for hygienic research by Academician of the Russian Academy of Sciences A.G. Sukharev. The mean age of students was 20.1 ± 0.08 years. Statistical data analysis was carried out using standard methods in Microsoft Excel and Statistica 13.0; we also did descriptive statistics and estimated relative risks.

Results: According to the Screen Time app, the average time of social networking among the students was 250.3 ± 14.0 minutes a day. Three or more social networks were used daily by 53.5 % of the respondents. Our questionnaire-based survey revealed 2.3 % of the students with Internet addiction disorders and 13.9 % of those strongly influenced by the Net.

Conclusion: The relative risk of developing Internet addiction among the medical university students posed by two or more hours a day of social networking was 4.167 (95.0 % CI, 2.558–31.130). This factor, however, is manageable and should be taken into account in health education of medical students. 

Introduction: Chemical compounds polluting the environment and contained in cigarette smoke affect the immune system and the respiratory tract contributing to the development of diseases. Given the sexual dimorphism of innate and acquired immunity, the objective of the study was to identify characteristics of the local and systemic immunity in adolescent girls and boys exposed to harmful environmental and cigarette smoke chemicals.

Materials and methods: During two years of the study, we examined 546 active and passive teenage smokers of both sexes living in industrial cities with high ambient air pollution. Levels of interleukins-2 and -10, alpha- and gamma-interferons, immunoglobulin A in blood serum, nasal and oral washings of high school students were tested.

Results: We established sex-specific differences in local and systemic immune responses of adolescents to effects of the combined air pollution and cigarette smoke exposure. Significant differences in the content of cytokines and immunoglobulin A were found only for males. The levels of alpha and gamma interferons in the oral lavage fluid of smoking boys were lower while the level of interleukin-2 was higher than those in non-smokers. Blood levels of alpha interferon and immunoglobulin A in male smokers were higher than in non-smokers.

Conclusion: Sex-specific differences in the response to the combined effect of air pollution and cigarette smoke necessitate a differentiated approach to elaborating preventive and therapeutic measures aimed at preventing immunological and upper respiratory disorders in adolescent boys and girls. 

Introduction: The etiological role of human papillomavirus has been proven in the development of cervical cancer and other tumors of the anogenital tract and oropharyngeal region. Vaccination against papillomavirus infection is carried out in most countries of the world, including Russia, to reduce cancer incidence rates.

Objective: To study clinical and epidemiological features of malignant neoplasms associated with the human papillomavirus (HPV) in order to improve vaccine prevention in the North-West of Russia.

Materials and methods: We analyzed morbidity, distribution by stages of the tumor process and mortality from cancer of the cervix, oral cavity, tonsils, oropharynx, larynx, anus and anal canal, vulva, vagina, and penis based on data collected by Form 7 “Data on Malignant Neoplasms” and population cancer registries of St. Petersburg and the Kaliningrad Region for the years 2011–2020. The number of incident cases of those neoplasms in St. Petersburg, the Leningrad and Kaliningrad Regions was 13,117, 3,204, and 2,898 cases, respectively. In 2018–2021, the total number of people vaccinated against papillomavirus infection was 9,603. We applied methods of retrospective epidemiological analysis, while statistical processing of the collected data was carried out using Statistica 12 and WinPepi software.

Results: In 2011–2019, the incidence of cervical cancer increased in the city of St. Petersburg and the Kaliningrad Region. The incidence of laryngeal cancer among the male population of the Northwestern regions of Russia did not change significantly. The proportion of patients with oropharyngeal cancer of stages 3 and 4 was more than 60 %, those with cervical cancer – about 50 % of cases. An increase in mortality from oropharyngeal cancer was detected in the age group of 60–69 years. We also revealed low coverage with vaccination against HPV in the Northwestern Federal District.

Conclusion: To reduce morbidity and mortality from HPV-associated malignant neoplasms in the North-West of Russia, it is necessary to develop a system of epidemiological surveillance and vaccine prevention of human papillomavirus infection. 

Introduction: The assessment of actual nutrition of the population, both at the individual and population level, strongly depends on the accuracy of data on the chemical composition of food products. Milk is an important component of a diet, and a precise estimation of micro- and macronutrients consumed with it is essential for public health assessment.

Objective: To develop an algorithm for obtaining statistically accurate values of average concentrations and variability of basic micro- and macronutrients in milk.

Materials and methods: To elaborate and check the algorithm, we used milk fat test results collected within the Federal Project on Public Health Strengthening by the laboratories of the Federal Service for Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) in the years 2020–2021.

Results: Due to numerous missing and outlying values of milk composition testing, an appropriate adjustment of the algorithm was necessary. The best separating ability was demonstrated by the approach of dividing types of milk into clusters based on their fat and calcium content. The three clusters obtained included milk with a 2.5 % fat content and the average calcium concentration of 1,144 mg/L, milk with a 3.2 % fat content and the average calcium concentration of 1,180 mg/L, and milk with both fat contents and the mean calcium level of 597 mg/L. The algorithm was validated by checking the completeness of data on the fatty acid composition and a low variability of values.

Conclusion: The developed algorithm has enabled us to obtain up-to-date information on the chemical composition of milk sold by food retailers in the Russian Federation. Low-calcium milk on the market is of special concern as its average consumption fails to satisfy human physiological needs. At the same time, the content of saturated fat was below 2.2 g/100 g in the cluster of milk types with the maximum fat content, thus raising no additional health concerns. Further studies should be aimed at determining the acceptable and correct stages of data preprocessing that maintain a balance between the obtained accuracy of values and their actual reproducibility.