Assessment of the respiratory system condition in tractor drivers of agricultural production

S. V. Raikova; Райкова С. В.; S. I. Mazilov; Мазилов С. И.; N. E. Komleva; Комлева Н. Е.; T. A. Novikova; Новикова Т. А.; N. V. Skvortsova; Скворцова Н. В.; A. A. Chernyshova; Чернышова А. А.

doi:10.17816/pmj42186-96

Assessment of the respiratory system condition in tractor drivers of agricultural production

Authors: Raikova S.V.¹, Mazilov S.I.¹, Komleva N.E.¹, Novikova T.A.¹, Skvortsova N.V.¹, Chernyshova A.A.¹
Affiliations:
1. Federal Scientific Center for Medical and Preventive Technologies of Health Risks Management
Issue: Vol 42, No 1 (2025)
Pages: 86-96
Section: Preventive and social medicine
Submitted: 01.07.2024
Published: 13.03.2025
URL: https://permmedjournal.ru/PMJ/article/view/633982
DOI: https://doi.org/10.17816/pmj42186-96
ID: 633982

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Abstract

Objective. To assess the state of the respiratory system of agricultural tractor drivers for the further substantiation of target programs for bronchopulmonary diseases prevention.

Materials and methods. During the medical examination of 168 agricultural tractor drivers, a spirometric functional assessment of the respiratory system state was carried out, medical and social aspects of life, anthropometric data with calculation of body mass index, allergic anamnesis, and the presence of confirmed respiratory diseases were studied. The median age of agricultural machine operators was 51 [41; 58] years, the median professional experience was 20 [10; 32] years. A hygienic assessment of work-related factors was carried out using Statistica 10 software package for statistical analysis.

Results. It has been determined that harmful production factors that negatively affect the respiratory system are silicate-containing dust, harmful chemicals of hazard classes I–IV, and unfavorable microclimatic conditions. 15.2 % of workers are registered at the dispensary with a confirmed respiratory disease of non-occupational genesis. 11.2 % of workers not diagnosed with any respiratory disease complained on some symptoms of this system. Chronic bronchitis significantly more often occurs in people with abdominal obesity than in people without it (16.1 and 4.0 %, respectively, p = 0.039) and in patients with allergies than in those with negative allergic history (25.0 and 9.6 % respectively, p = 0.033). Impaired respiratory function according to spirometry results was revealed in 36.3 % of workers. Statistically significant differences in spirometric readings and the proportion of persons with deviations in the results of spirometry depending on age, abdominal obesity, and allergies were not revealed (p>0.05). Statistically significant lower values of FEV₁ and FEV₁/VC and the proportion of persons with deviations in spirometric readings in the group of smoking agricultural tractor drivers were determined.

Conclusions. A large incidence of non-occupational bronchopulmonary diseases associated with abdominal obesity and positive allergy history, and a considerable proportion of workers with external respiratory function disorder according to spirometry readings, associated with smoking status, were revealed. The lowest spirometric indicators and the largest proportion of people with abnormal spirometry results were registered in the youngest age group and among workers with little work experience. Taking into account the regional limitation of the study and the small number of workers examined, further study in this field is required.

Keywords

agricultural tractor drivers, bronchopulmonary pathology, risk factors

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Introduction

High labor productivity of the working population is ensured by compliance of the health status of workers with the requirements of the profession, largely determined by the presence or absence of chronic non-communicable diseases [1], which make a huge contribution to morbidity and, as a consequence, to the loss of working capacity and mortality of the population throughout the world [2], among them a significant role belongs to diseases of the respiratory system [3]. Respiratory diseases retain their leading position in the structure of overall morbidity of the population of the Russian Federation in 2023 – 29,91 versus 26,3 % in 20222. There is also an increase in the number of cases and days of temporary disability due to respiratory diseases in the dynamics of recent years3.

Agricultural tractor drivers are exposed to a range of harmful factors in the production environment that negatively affect the state of the respiratory system in the course of their professional activities: unfavorable microclimatic conditions; air pollution in the working area with mixed dust (particles of plant or animal origin, various types of microorganisms and their waste products, crystalline silicon dioxide and silicates), pesticides, agrochemicals, a mixture of hydrocarbons, carbon monoxide, nitrogen oxides [4]. In addition, agricultural workers are affected by a number of behavioral risk factors for the development of bronchopulmonary diseases (smoking, alcohol, poor nutrition, stress) [5], as well as environmental factors (chemical and biological pollution of the atmosphere, adverse weather conditions, etc.) [5; 6]. The combined effects of industrial and non-industrial factors can lead to the development of respiratory diseases: chronic mechanic bronchitis, chronic obstructive pulmonary disease, bronchial asthma, hypersensitivity pneumonitis [7; 8].

Thus, the study of the respiratory system of agricultural tractor drivers is a relevant study for the further development of preventive measures, taking into account the impact of professional and non-professional factors that have a negative impact on the respiratory system.

The aim of the study is to assess the state of the respiratory system of agricultural tractor drivers for further substantiation of targeted programs for the prevention of bronchopulmonary diseases.

Material and Methods

For the period 2023–2024, the state of the respiratory system of 168 agricultural tractor drivers of farms in the Saratov region was analyzed based on the results of an in-depth medical examination at the Clinic of General and Occupational Pathology of the Saratov Medical Scientific Center for Hygiene of the Federal Budgetary Scientific Institution “Federal Scientific Center for Medical and Preventive Technologies for Managing Population Health Risks”. Age was 51 [41; 58] years, professional experience – 20 [10; 32] years. Inclusion criteria: age from 22 to 65 years, work experience in the profession of five years or more. Exclusion criteria: lack of written consent to participate in the study.

Medical and social factors, anthropometric data with calculation of body mass index (BMI), determination of abdominal obesity by waist circumference (WC), allergy history, presence of established respiratory diseases of workers were studied. Clinical examination included spirometry (microprocessor spirograph SMP-21/01-R-D, Russia) with assessment of results according to R.F. Klement et al.4

The hygienic assessment of the factors of the working environment and the work process was carried out in accordance with the current regulatory requirements5 and hygienic criteria6. The Statistica 10 software package was used for statistical analysis of the study results. Nonparametric Mann-Whitney and Fisher tests (two-tailed) were used to assess statistical differences between the groups.

Results and Discussion

According to the medical records (form 025/u) of the study participants, it was revealed that 25 agricultural tractor drivers (14.9 %) were registered with the dispensary, of which 2 had a diagnosis of bronchial asthma (J45.0), 2 had chronic obstructive pulmonary disease (J44.9), and 21 had chronic bronchitis (J41.0). At the time of the examination, all workers were in remission. No occupational respiratory diseases were registered. A link was established between the prevalence of bronchopulmonary pathology (BLP) and age: All cases of established diagnosis were registered in the 2nd and 3rd age groups, with the proportion of workers being 16.7 and 16.1%, respectively (p = 1.0 for the two-tailed Fisher test). 19.1% of workers had a burdened allergy history, while in the group of workers with an aggravated allergic anamnesis, the proportion of people with chronic bronchitis was significantly higher compared to workers with a negative allergy history: 25.0 and 9.6 % respectively (p = 0.033 for the two-tailed Fisher test).

16 people (11.2 %) had complaints out of the 143 study participants who did not have an established diagnosis of a respiratory disorder.

The assessment of the pulmonary function (PF) was carried out based on the results of the assessment of VC, FEV₁, FEV₁/VC– as indicators that most reliably reflect the violation of pulmonary ventilation of the obstructive type and allow one to suspect the presence of restrictive ventilation changes. 36.3 % of workers had PF disorders according to the results of the spirometric study (the presence of obstructive and suspicion of the presence of restrictive PF disorders).

The study participants were divided into three age periods in accordance with the accepted classification to assess PF depending on age [9]. When assessing PF depending on age, no statistically significant differences were found in the values of spirometric indicators and the proportion of individuals with deviations in the results of spirometric testing between age groups. However, a certain trend is observed in the proportion of people with spirometric disorders of PF: 47.1; 37.5 and 25.8 % in the first, second and third age groups, respectively.

There is considerable evidence on the importance of abdominal obesity in the development of pulmonary ventilation disorders [10; 11]. It has been established that patients with a high BMI suffer from chronic cough more often than others [12]. In this regard, the relationship between BMI and the presence of PF disorders was studied. In a comparative analysis of PF in individuals with a BMI value of ≤ 25 (normal value) and ≥ 30 (obesity), no statistically significant differences in spirometric PF indices and incidence of bronchopulmonary diseases were found. However, an elevated BMI does not always indicate the presence of abdominal obesity, in connection with which the functional state of the respiratory system of workers was studied depending on waist circumference (WC). Abdominal obesity was defined as a WC > 94 cm [13]. When comparing PF values in individuals with WC < 94 cm and WC > 94 cm, no statistically significant differences in spirometric data were found. Moreover, chronic bronchitis is significantly more common in individuals with WC> 94 cm than in individuals with WC < 94 cm: 16.1 and 4.0%, respectively (p = 0.039 for the two-tailed Fisher test). The groups were comparable in age, smoking experience (p = 0.447 and p = 1.0 for the Mann-Whitney test, respectively), and smoking status (p = 0.401 for the two-tailed Fisher test).

More than half of the workers under study (54.8 %) used classic smoking tobacco products, the pack-year index was 23.8 [15; 40], which confirms the literature data on the high commitment to smoking among agricultural workers [14]. Numerous studies have confirmed the role of tobacco smoking in the development of obstructive disorders in agricultural workers [15], in connection with which the respiratory function of workers was studied taking into account smoking status (Table 1).

Table 1 Comparative analysis of observation groups formed taking into account smoking status (% of the expected, Me [Q₁; Q₃])

Indicator	Those who use smoking tobacco products, n = 92	Those who don’t use smoking tobacco products, n = 76	Level р
Age, years	51 [41; 57]	54 [44; 59]	0.235*
Experience, years	20 [11; 30]	23 [11; 36]	0.257*
BMI, kg/m²	28.7 [23.9; 31.9]	29.3 [26.1; 32.3]	0.236*
VC, %	84.0 [76.0; 95.0]	85.0 [71.0; 91.0]	0.879*
FEV₁, %	83.0 [69.0; 91.0]	91.0 [80.5; 101.0]	0.006*
FEV₁/ VC, %	97.0 [85.0; 109.0]	109.0 [100.5; 117.5]	< 0.001*
Number of persons with deviations according to spirometry results, abs. (%)	42 (45.7)	19 (25.0)	0.006**

Note: * – level of statistical significance for the Mann–Whitney test; ** – level of statistical significance for the two-tailed Fisher test.

The results presented in Table 1, prove that the groups are comparable in age, work experience, BMI, therefore, the presence of statistically significant lower FEV₁ and FEV₁/VC values and the proportion of individuals with deviations in the results of spirometric testing in the group of smokers is probably due to the smoking factor.

In 2022–2023, the main reason for the development of chronic occupational pathology was determined to be a long period of work with harmful production factors (43.69 % in the structure of the main circumstances and conditions of occurrence).

As a result of the conducted hygienic assessment of working conditions, it was established that agricultural tractor drivers are exposed to a complex of harmful factors, among which those that have a negative effect on the respiratory system are silicate-containing dust, harmful chemical substances of I–IV hazard classes that have a highly directional and irritating effect (carbon oxide, nitrogen oxide), hydrocarbons, mineral oil vapors and unfavorable microclimatic conditions. Dust which is contained in the breathing zone of tractor drivers is a fibrogenic aerosol of mixed composition. In tractor cabins, dust is predominantly of soil origin, in grain harvester cabins – predominantly of plant origin, containing seeds, pollen, and particles of crushed plants. The content of free silicon dioxide in the dust composition, depending on the type of technological process, ranged from 1.9 to 9.5 %. One-time dust concentrations in the breathing zone of workers ranged from 9.0 to 119.0 mg/m³ with a MAC of 4 mg/m³. Average shift concentrations exceeded the MAC by 2.32–11.07 times, which corresponds to harmful working conditions of 1–4 degrees (classes 3.1–3.4).

In order to study the possible negative impact of professional factors on respiratory function, the study participants were divided into four groups depending on their length of service in the profession of agricultural tractor drivers (Table 2). The presented length of service groups was comparable in terms of the proportion of smokers, BMI, WC.

Table 2 Comparative analysis of observation groups formed taking into account professional experience (% of the required), Me [Q₁; Q₃]

Indicator	Professional experience, years				Level of p
Indicator	5–10, n = 44	11–20, n = 41	21–30, n = 38	31 and more, n = 45	Level of p
Average age, years	41 [36; 50]	47 [40; 55]	52 [48; 57]	59 [56; 61]	p_1–2 = 0.015. p_1–3 < 0.001. p_1–4 < 0.001. p_2–3 = 0.036. p_2–4 < 0.001. p_3–4 < 0.001
Number of smokers, abs. (%)	24 (54.5)	25 (61.0)	23 (60.5)	20 (44.4)	p_1–2 = 0.661. p_1–3 = 0.657. p_1–4 = 0.399. p_2–3 = 1.000. p_2–4 = 0.137. p_3–4 = 0.187
The «pack-year» index	15.3 [12.5; 30.0]	20.0 [17.5; 30.0]	30.0 [15.5; 40.0]	40.0 [21.5; 40.0]	p_1–2 = 0.395. p_1–3 = 0.063. p_1–4 = 0.002. p_2–3 = 0.178. p_2–4 = 0.002. p_3–4 = 0.080
BMI, kg/m²	29.4 [25.9; 34.3]	27.8 [23.9; 31.3]	29.3 [25.7; 31.6]	28.3 27.1; 31.4]	p_1–2 = 0.101. p_1–3 = 0.590. p_1–4 = 0.404. p_2–3 = 0.205. p_2–4 = 0.264. p_3–4 = 0.839
Waist circumference, cm	101 [90; 111]	99 [93; 114]	103 [90; 122]	101 [85; 115]	p_1–2 = 0.977. p_1–3 = 0.490. p_1–4 = 0.845. p_2–3 = 0.520. p_2–4 = 0.927. p_3–4 = 0.370
Number of persons with established diagnoses of bronchopulmonary pathology, abs. (%)	2 (4.5)	8 (21.1)	8 (23.5)	7 (16.7)	p_1–2 = 0.044. p_1–3 = 0.039. p_1–4 = 0.157. p_2–3 = 1.000. p_2–4 = 0.778. p_3–4 = 0.575
VC, %	82.5 [68.0; 91.0]	89.5 [82.0; 101.0]	83.4 [78.0; 94.0]	82.5 [73.5; 94.0]	p_1–2 = 0.011. p_1–3 = 0.222. p_1–4 = 0.480. p_2–3 = 0.130. p_2–4 = 0.073. p_3–4 = 0.645
FEV₁, %	82.5 [64.0; 96.0]	87.0 [79.0; 102.0]	91.0 [78.0; 101.0]	84.0 [69.5; 92.5]	p_1–2 = 0.072. p_1–3 = 0.127. p_1–4 = 0.572. p_2–3 = 0.747. p_2–4 = 0.211. p_3–4 = 0.296
FEV₁/ VC, %	99.0 [93.0; 116.0]	101.5 [91.0; 111.0]	109.0 [89.0; 117.0]	105.0 [95.0; 109.5]	p_1–2 = 0.672. p_1–3 = 0.511. p_1–4 = 0.617. p_2–3 = 0.200. p_2–4 = 0.559. p_3–4 = 0.382
Number of persons with deviations according to the results of spirometry, abs. (%)	23 (52.3 %)	12 (29.3 %)	10 (26.3 %)	16 (35.6 %)	p_1–2 = 0.047. p_1–3 = 0.024. p_1–4 = 0.137. p_2–3 = 0.807. p_2–4 = 0.646. p_3–4 = 0.477

Note: * – level of statistical significance for the Mann–Whitney test; ** – level of statistical significance for the two-tailed Fisher test.

The results presented in Table 2 indicate that the lowest values of spirometric indicators and the highest proportion of individuals with deviations in the results of spirometric testing were recorded in the short-service group of workers, despite the lowest value of the pack-year index and the proportion of individuals with bronchopulmonary pathology. The median age of this group was 41 [36; 50] years, which indicates the presenceof significant long-term work experience before starting work in the profession of agricultural tractor driver. It is impossible to clarify the working conditions at the previous place of work of each of those examined, but it can be assumed that the conditions at the previous place of work could have had a negative impact on health, which is why the change in employment occurred. At the same time, with more than 10 years of experience in the profession and with a subsequent increase in experience in the profession, a decrease in the main spirometric indicators of respiratory function and an increase in the proportion of people with deviations according to the results of spirometric testing are not observed. This may indicate the absence of a negative impact of production factors on the respiratory system of the examined workers. On the other hand, the results obtained can be explained from the position of successful adaptation to work in harmful working conditions, as well as from the position of the "healthy worker effect", which is a "natural" and professional selection among workers employed in harmful working conditions, which is accompanied by an improvement in health indicators in the studied population [16].

Respiratory diseases and lung function disorders are recognized occupational health problems among agricultural workers worldwide [17]. The most important factor for assessing the health status of the population is the identified incidence of bronchopulmonary diseases, while for taking medical and preventive measures, diagnostics and early detection of markers of bronchopulmonary pathology, in particular respiratory function disorders, are more important. However, this is associated with a number of difficulties in relation to agricultural workers, due to the low availability of specialized medical services [18], in particular the lack of timely spirometric testing and consultation with a pulmonologist in the presence of complaints from the respiratory system [19], which increases the risk of late diagnosis and adequate treatment of a number of diseases of the respiratory system [20].

Conclusions

The main harmful production factors that can have a negative effect on the respiratory system of agricultural tractor drivers are dust, which is an aerosol of fibrogenic action of mixed composition, and unfavorable microclimatic conditions.
The examined group of agricultural tractor drivers was characterized by a significant incidence of respiratory diseases that do not have an occupational genesis, and a significant proportion of individuals with deviations according to the results of spirometric testing. At the same time, the lowest spirometric indicators and the largest proportion of individuals with deviations according to the results of spirometry were registered in the youngest age group and among workers with little experience.
The indices of external respiration function and the proportion of individuals with deviations in spirometry results in the examined group of agricultural tractor drivers were associated with smoking, and the presence of chronic bronchitis was associated with abdominal obesity and a history of allergies.
Given the regional limitation of the study (Saratov region) and the small number of workers surveyed, this study requires further continuation.

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