Introduction. Identifying the causes of contraindications to continuing work at gas transportation enterprises is an important task for preserving the professional longevity of their employees.

The study aims to assess the risks of determining contraindications to continuing work under the influence of harmful and dangerous production factors typical for a gas transportation enterprise operating in conditions equated to the Far North.

Materials and methods. The authors have analyzed the results of the examination of the professional suitability of employees of the main and auxiliary production facilities at the gas transportation enterprise operating in the territory equated to the Far North over three-year period.

Results. There are contraindications to work in the conditions of the Far North and equivalent areas in all professional groups due to the pathology of the gastrointestinal tract and dental diseases. A typical reason for determining contraindications to work at height are refractive errors. Industrial noise is the main harmful production factor for gas transportation enterprises, however, even in groups specializing in the maintenance of noise-hazardous equipment, scientists have identified contraindications to working under its influence with a frequency of no more than 7.0%. Their main cause is sensorineural hearing loss in the stage from moderate to higher. General medical contraindications in most cases were due to pathology of the circulatory system and endocrine diseases. The most common contraindications to continuing work exist for employees of auxiliary production: car drivers and firefighters. This circumstance is due to the most stringent requirements of regulations for their health. The risk of loss of professional fitness among workers of the main production is significantly reduced when conducting planned wellness programs and redistributing production tasks.

Limitations. At an enterprise operating in southern climatic zones and using less noisy hazardous equipment, other results can be obtained.

Conclusion. Differences in the working conditions of the company's employees determine the significantly different risks of their loss of professional health due to chronic diseases. For employees of the main production of the gas transportation enterprise engaged in work with harmful and dangerous working conditions, there are the greatest risks of determining contraindications for performing work in conditions of industrial noise and working at height, due to the development of diseases of the circulatory system and sensorineural hearing loss.

Contribution:
Ikonnikova N.V. — collecting and processing material, writing text;
Grebenkov S.V. — concept and design of research, analysis, editing;
Boyko I.V. — concept and design of research, analysis, editing;
Nikanov A.N. — writing the text, editing.

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 11.11.2022 / Accepted: 07.03.2023 / Published: 10.04.2023

Introduction. Organic solvents have a hematotoxic effect, which leads to the development of anemia. Endometrial hyperplasia may also be the cause of a decrease in blood hemoglobin levels. The phenotype of anemia in combination of these diseases is still insufficiently studied. Exposure to organic solvents is associated with a carcinogenic risk, while their role in the development of precancerous conditions is little known.

The study aims to research the features of anemia in patients with endometrial hyperplasia under the influence of organic solvents and depending on the obesity factor.

Materials and methods. The design of the study is a single–center, single-stage observational. The researchers formed 2 groups of women with endometrial hyperplasia confirmed by histological examination, who worked under conditions of exposure to organic solvents (n=140, the main group, 70 of them obese according to WHO criteria) or who had no health risks (n=140, the comparison group, 68 of them obese). The patients of the main group are painters at a machine-building enterprise. Organic solvents concentrations at the workplace air were 1.2–5.0 times above occupational exposure limits, length of service was 21.5 (18; 28) years.

Results. Scientists have registered anemia in 72.9% of obese workers, 54.2% of non-obese workers, 33.8% and 25.0% of patients in the comparison group with obesity and normal body weight, respectively, χ²=8.2, p=0.008. In contact with organic solvents, 60.7% of patients had anemia normal- or macrocytic, normal- or hyperchromic, hyporegenerative. In the subgroup of obesity and atypical endometrial hyperplasia, we have watched the minimum values of hemoglobin — 95 (90; 105) g/l and reticulocytes — 1 (0.5; 2), the maximum values of the average erythrocyte volume — 98 (92; 107) fl and the average hemoglobin content in the erythrocyte — 35(34; 38) pg. The researchers have determined the association of this variant of anemia with atypical endometrial hyperplasia by logistic regression, OR 2.51, 95% CI 1.08–5.85, p=0.033. In comparison group, all patients had iron-deficiency anemia.

Limitations. The limitations of the study are related to the recruitment of patients in one center.

Conclusion. Anemia in women with endometrial hyperplasia in conditions of organic solvents exposure is normo- or hyperchormic, normo- or macrocytic, hyporegenerative, most prominent in patients with obesity, and associated with atypical histological type of the disease.

Ethics. The authors have carried out the study in compliance with the Ethical principles of conducting scientific medical research with human participation, set out in the Helsinki Declaration of the World Medical Association and in accordance with the Ethical norms and rules provided for by the Bulletin of the Higher Attestation Commission of the Ministry of Education of Russia No. 3 of 2002 "On the procedure for conducting biomedical research in humans". The study was approved by the Ethics Committee of the Federal State Budgetary Educational Institution of the Russian Ministry of Health.

Contribution:
Lisova E.S. — research concept and design, data collection, data analysis and interpretation, writing the text
Marinkin I.O. — research concept and design, data analysis and interpretation, writing the text
Shpagina L.A. — research concept and design, data analysis and interpretation, writing the text
Kotova O.S. — data collection, writing the text
Karmanovskaya S.A. — data collection
Loktina K.E. — data collection

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 27.02.23 / Accepted: 17.03.2023 / Published: 10.04.2023

Introduction. Nowadays it has become especially vital to reveal basic regularities in workers’ health formation in order to provide early diagnostics and to reduce overall and occupational morbidity.

The aim of the study was to examine polymorphism in ADD1 Gly460Trp rs4961 gene in workers exposed to chemical occupational factors at their workplaces (exemplified by saturated hydrocarbons).

Materials and methods. We examined workplace air and biological media (urine and buccal epithelium) of exposed workers from the test group (n=162) and workers who didn’t deal with any technological processes at their workplaces (the reference group, n=83); both groups were employed at a potash flotation factory.

To assess exposure to saturated hydrocarbons (hexane and heptane) in workplace air, we performed laboratory-instrumental tests of air inside workshops (11) and in administrative rooms with GANK-4 gas analyzer. Biological media (urine) were examined to determine contents of saturated hydrocarbons (hexane and heptane) in them by analyzing vapor phase in equilibrium on "Kristall-5000" gas chromatographer according to methodical Guidelines MUK 4.1.764-99.

We analyzed polymorphism in ADD1 Gly460Trp rs4961 gene. Genetic typing was accomplished by polymerase chain reaction (PCR) in real time mode through allele discrimination with using TaqMan-probes on CFX96 (Bio-Rad) system as well as oligonucleotide primers and probes synthesized by "Sintol" company (Moscow).

We applied Student’s t-test and Fischer’s Z-test to estimate authenticity of differences in obtained results. Pearson’s chi-square test (χ²) was used to check normalcy of quantitative data. We also assessed whether frequencies of candidate gene genotypes conformed to Hardy–Weinburg equilibrium.

Results. Hexane was detected in workplace air in concentrations within 14–68 mg/m³ range (0.1MPC_workplace) during the observation period; heptane, 20–84 mg/m³ (0.1MPC_workplace). We assessed contamination of workers’ urine with hexane and heptane depending on their working experience that involved occupational contacts with saturated hydrocarbons, from 1 year and up to longer than 10 years. The assessment revealed that hexane contents were by 1.5 times higher and heptane contents by 1.22 times higher in workers with their working experience being longer than 10 years against workers with shorter working experience (less than 10 years).

The results of a comparative analysis of the features of genetic polymorphism in the workers of the observation group in relation to the comparison group allowed us to establish significant differences between the frequencies of genotypes and alleles of the adducine gene ADD1 Gly460Trp rs4961, characterized by an increase in the frequency of the wild GG genotype of the gene. The assessment of the odds ratio (OR) of the presence in the observation group of the variation of the genotype GG of the gene ADD1 Gly460Trp rs4961 according to the multiplicative (for G allele inherited by dominant type OR=2.94; CI: 1.46–5.94; p<0.005) and general (for GG genotype, OR=3.14; CI: 1.44–6.86; p<0.005) inheritance models, as well as an assessment of the relative risk (for the G allele RR=1.38; CI: 1.23–1.53), allowed us to verify the reliable probability of the formation of genetically determined disorders associated with the development of arterial hypertension.

Limitations. A limitation of the study is the study of the polymorphism of the ADD1 Gly460Trp rs4961 adducin gene only when exposed to two saturated hydrocarbons, hexane and heptane.

Conclusion. Our research revealed that workers with basic production occupations and with working experience at the factory that was longer than 10 years had authentically higher hexane and heptane contents in their urine, by 1.5 (р<0.01) and 1.22 (р<0.048) times accordingly, than workers with their working experience at the factory being shorter than 10 years.

We established that detection of hexane in concentrations equal to 0.006±0.002 mg/dm³ in urine of workers with basic production occupations who contacted saturated hydrocarbons vapors corresponded to 81% of the variation of the ADD1 Gly460Trp rs4961 gene in the form of a wild GG genotype (p<0.05) corresponded, which in conditions of contamination with marginal hydrocarbons can form the risk of cardiovascular pathology.

Ethics. The research was performed in full conformity with ethical principles for medical research involving human subjects stipulated by the Declaration of Helsinki issued by the World Medical Association (the latest edition); all the participants gave their informed voluntary consent to take part in the research.

Contribution:
Zaitseva N.V. — research concept, editing;
Dolgikh O.V. — research concept, editing;
Nurislamova T.V. — relevance, conclusion;
Kazakova O.A. — collection and processing of material;
Chinko T.V. — materials and methods, results;
Maltseva O.A. — collection, processing of material, statistical processing of material.

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 06.03.2022 / Accepted: 17.03.2023 / Published: 10.04.2023

Relevance. In the new edition of the Labor Code (as amended on 02.25.2022), risk-oriented approaches to management in the field of labor protection are fixed, which necessitated the revision of regulatory and methodological documents, including in the field of occupational medicine based on the methodology for assessing occupational risk to workers' health.

The study aims to substantiate and develop a numerical scale for assessing the group attributive risk of hearing loss from exposure to industrial noise.

Materials and methods. The authors have carried out an expert-analytical study of materials on qualitative and quantitative a priori and a posteriori assessment of occupational risk.

Results. The scientists have confirmed the advantage of attributive risk over other indicators for assessing the risk of hearing loss from noise. The numerical scale of the assessment of the attributive risk of hearing loss in relation to the risk-oriented hygienic classification of working conditions and the assessment of the relationship of hearing impairment from noise with work, depending on the magnitude of the attributive risk and etiological proportion, is substantiated. We have justified the categorization of the attributive risk of hearing.

Limitations. Features of the model for assessing hearing loss due to noise exposure according to GOST R ISO 1999:2017.

Conclusion. The development of a quantitative scale for assessing the attributive risk of hearing loss not only harmonizes the hygienic assessment of the noise risk factor with international practice, but also contributes to the development of the methodology for assessing and managing occupational risk.

Ethics. In preparing the article, the authors were guided by the Ethical principles of medical research set out in the Helsinki Declaration of the World Medical Association of the last revision.

Contribution:
Prokopenko L.V. — concept and design of the study, editing;
Courierov N.N. — concept and design of the study, analysis of normative and methodological documentation, calculations and analysis of results, writing the text;
Lagutina A.V. — analysis of normative and methodological documentation, editing.

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 20.03.2023 / Accepted: 24.03.2023 / Published: 10.04.2023

Introduction. Of interest are the processes developing in vibration disease (VD) in combination with metabolic syndrome (MS) or diabetes mellitus (DM), combined forms of diseases worsen their course and prognosis.

The study aims to assess the features of the state of central afferent conductive structures and peripheral nerves in patients with vibration disease, burdened with diabetes mellitus or metabolic syndrome.

Materials and methods. The scientists have examined 155 workers with VD — group one with an established diagnosis of VD (86 people); group two — with VD combined with DM (30 people); group three — with VD burdened with MS (39 people). The authors have conducted the electroneuromyographic examination and registration of somatosensory evoked potentials, with stimulation of the median nerve in the wrist. Abduction points — Erb point, cervical spinal cord, from the scalp of the projection area of the precentral gyrus. The researchers have applied multivariate discriminant analysis from the STATISTICA — version 6 application software package of StatSoft Inc (USA).

Results. With VD complicated by MS, changes were in the distal part of the motor axons, with VD burdened with DM, the amplitude of the motor component of the median and tibial nerves decreased, the speed of the pulse in the proximal part of the median nerve. Somatosensory evoked potentials in VD in combination with MS revealed an increase in latency of N13 and N20. The duration of N13–N18, N13–N20, latency N18, N20, N30 increased in the case of WB, burdened with DM.

Limitations. The limitation of the study is the use of unrelated samples for statistical analysis. The study of the state of central and peripheral conductive structures in connected samples should be considered evidence-based: metabolic syndrome and further — diabetes mellitus.

Conclusion. The patterns of peripheral nerve damage in VD associated with exposure to general and local vibration, burdened with DM or MS, were disorders of afferent axons of the upper and lower extremities, as well as changes in the distal parts of the motor component of the tibial and median nerves. The features of the peripheral nerve states in VD, burdened with DM, were the complex involvement of the motor component in the pathological process, characterized by changes in the amplitude, pulse transit time at the level of the terminal unmyelinated fibers of the median and tibial nerves and changes in the proximal part of the median nerve. In VD complicated by MS, pathological changes were characteristic of the distal part of the motor axons. The patterns of afferent conductive structures lesion in VD, burdened with DM or MS, consisted in a violation of the activity of neurons of the cervical spinal cord and the somatosensory cortex. The peculiarity of the state of the central afferent conducting structures in VD, burdened with DM, was the slowing down of the afferent excitation wave in the area of thalamic structures to the somatosensory zone of the cortex, a violation of the conduction from the trunk to the cortical projections of the somatosensory zone. In case of VD, complicated by MS — the time of the afferent excitation wave at the level of the cervical spine and the somatosensory cortex.

Ethics. Conclusion of the MEC of the Federal State Budgetary Scientific Institution "East Siberian Institute of Medical and Environmental Research" No. 32 dated 09.10.2019.

Contribution:
Rusanova D.V. — concept and design of research, collection and processing of material, writing and design of the article, editing;
Lakhman O.L. — concept and design of research, editing.

Funding. The funding was carried out within the framework of the State Task on fundamental and Exploratory scientific research. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 01.03.2023 / Accepted: 07.03.2023 / Published: 00.00.2023

Introduction. Since March 2020, the introduction of a self-isolation regime and significant restrictions on personal contacts at work and school in connection with the COVID-19 pandemic has led to an expansion of the introduction of information technologies and a sharp restriction of direct interpersonal communication. The introduction of these restrictions has had a stressful effect on the body of both workers and students of various age groups, including young people. For a successful analysis of the impact of COVID-19 restrictions on the psychophysiological state of these categories of young workers and students, it seems appropriate to assess the state of maladaptation, self-assessment of nervous and somatic well-being.

The study aims to assess the impact on the adaptive psychophysiological parameters of young trade workers and students of the changed working and study conditions against the background of the COVID–19 epidemic situation (self-isolation).

Materials and methods. The object of the study was two groups of people who have a wide range of communication with colleagues and people around them, but differ in the content of their activities: students and trade workers. Scientists have conducted the study in two stages: before the pandemic (2013) and during the pandemic (December 2020) due to drastic changes in the algorithm of existence and work/study. We have examined 119 students aged 20–24 years (RGSU). There were 61 people at the first stage of the study (2013), there were 58 people at the second stage (2020, December). The second group (trade workers): 66 people aged 20–29 years. At the first stage of the study (2013), 34 people were included, at the second stage — 32 people. Experts have carried out the assessment of the psychophysiological parameters of the examined according to the questionnaire of neuropsychiatric maladjustment (ONPD). The condition for inclusion in the groups in 2020–2021 is the absence of a history of transferred COVID-19.

Results. During the tense epidemic situation (2019-2021), against the background of the spread of COVID-19 and forced self-isolation of all population groups, the lifestyle has radically changed. Face-to-face communication has been minimized, but communication using information technology in all spheres of life (daily life, study, work) has increased dramatically. The researchers found that among the surveyed population groups (students and sales workers), the spread of signs of mental discomfort increased.

Limitations. The study was limited to a sample of age groups: 20–24 years for students, 20–29 years for trade workers (in both periods).

Conclusion. The calculation of the odds ratio (OR) allowed us to establish with a high degree of confidence that signs of mental discomfort, including asthenic and depressive signals, were significantly more often recorded during the period of self-isolation in both study groups: for students who are on distance learning (December 2020 compared to 2013): the coefficient of OR=5.4, (χ²=14.7; p<0.001); for sales workers: coefficient OR=15.0; (χ²=9.5; p<0.001).

Ethics. Questions whose content does not meet ethical standards were not included in the study, as a result of which the conclusion of the biomedical ethics committee or other documents was not required.

Contribution:
Yakovleva T.P. — research concept and design, material collection and data processing, statistical processing, text writing;
Gaponenko A.V. — collecting material, writing text;
Soshenko M.V. — collecting material, editing;
Rubtsov M.Yu. — research concept, editing.

Gratitude. The authors express their gratitude to Olga Igorevna Yushkova, Dr. of Sci. (Med.), for a useful discussion.

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 26.02.2022 / Accepted: 09.03.2023 / Published: 10.04.2023

According to the International Labor Organization, 50–60% of all lost working days are associated with work-related stress. Back in the late 80s, early 90s of the last century, Yu.V. Moikin emphasized that labor physiologists face the need to identify psychophysiological and neurophysiological mechanisms of transition from the norm to the occurrence of nervous overstrain under the influence of chronic emotional stress. Currently, it is possible to recognize the fact that the prolonged influence of hormones of the pituitary-adrenal, sympathoadrenal, thyroid systems involved in the development of stress reactions and causing changes in lipid, carbohydrate, electrolyte metabolism and other metabolic processes in the body leads to the development of diseases. Stress-limiting systems, including GABAergic, opioid, dopaminergic, serotonergic, protect the body from the excessive influence of stress factors. The interface between the stress-implementing and stress-limiting systems is genetically determined. The modern concept of occupational stress suggests the need to analyze both external factors and individual characteristics that play an important role in the development of stress reactions and their fixation in the form of stable negative manifestations. The analysis of the genetic correspondence of an individual to the position and the nature of the work performed will contribute to the optimal realization of professional skills and abilities of a person.

Contribution:
Kuzmina L.P. — concept and design of the study, editing;
Bezrukavnikova L.M. — data collection and processing, text writing;

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 16.03.2022 / Accepted: 20.03.2023 / Published: 10.04.2023

The circadian system plays an important role in regulating the functions of the human body. As a result of violations of the circadian system, functional disorders such as sleep disorders, carbohydrate metabolism, metabolic syndrome turning into obesity, cardiovascular pathology, oncological processes occur. One of the socially significant causes of circadian rhythm disorders is a shift work schedule.

The study aims to explore the genetic status of employees and identify markers of predisposition to the formation of "intolerance" of shift work.

Researchers have examined two groups of employees of the enterprise: observation group — 40 people gave 23–63 years old (30 women, 10 men) with a shift work schedule, the comparison group consisted of 51 people 24–62 years old (41 women, 10 men) of the administrative apparatus with a daily work schedule. Typing of polymorphic loci of the circadian system genes was carried out by sets of the company "Syntol" (Russia) using the Real-Time PCR method on a CFX96 device with allelic discrimination of fluorescence curves.

Genotyping of the loci of the five main circadian genes allowed us to establish that the occurrence of the minor allele T of the MTNR1A melatonin receptor gene (rs34532313) in continuous production workers is 30%, which is five times higher than in workers with a standardized work schedule (p<0.05). At the same time, workers with a shift schedule had a significant hypo-expression of serum serotonin (1.54 times, p<0.05) relative to the comparison group.

Continuous production workers have an increased occurrence of the minor allele of the MTNR1A melatonin receptor T gene (rs34532313) with a simultaneous decrease in the expression of serotonin catecholamine, which in shift work conditions can affect the formation of dysregulatory disorders of the functioning of homeostatic systems and the course of physiological metabolic processes. As a result, the polymorphism of the MTNR1A gene (rs34532313) can use as a marker of "intolerance" to shift work.

Limitations. There are quantitative restrictions on the observation group of persons of different genders.

Ethics. When conducting the study, the authors were guided by the Ethical principles of conducting medical research with the participation of a person as a subject, set out in the Helsinki Declaration of the World Medical Association of the last revision. The patients signed a voluntary informed consent for the examination.

Contribution:
Subbotina A.A. — collection and processing of the material, writing the text, editing, approval of the final version of the article, responsibility for the integrity of all parts of the article;
Dolgikh O.V. — the concept and design of the study, editing, approval of the final version of the article, responsibility for the integrity of all parts of the article.

Gratitude. The authors express their gratitude to: V.B. Alekseev, the Director of the Federal Scientific Center for Medical and Preventive Health Risk Management Technologies, Dr. of Sci. (Med.); N.V. Zaitseva, the scientific supervisor, Dr. of Sci. (Med.), Academician of the RAS; staff of the Department of Immunological diagnostic methods for their assistance in conducting the study.

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 09.02.2022 / Accepted: 17.02.2022 / Published: 10.04.2023