Occupational lung diseases due to exposure to industrial aerosols for 2016–2020

According to the Moscow City Center and Aktobe City Center for Occupational Pathology data for 2016–2020, diseases caused by exposure to industrial aerosols were first identified in 344 workers. Thus, COB was detected in 202 (58.7%) patients, PC (quartzose dust-induced > 10%) in 59 (17.2%), silicosis (quartzose dust-induced < 10%) in 27 (7.8%), silicotuberculosis in 3 (0.9%), and COPD in 53 (15.4%) patients (Fig. 1).

Fig. 1

Structure of newly detected occupational diseases resulting from exposure to industrial aerosols for 2016–2020

Trends in the structure of occupational dust pathology first detected in 2016–2020 are relatively stable across years (Table 2).

Table 2 Occupational pathology due to exposure to industrial aerosols according to the Centre for Occupational Pathology in 2016–2020

The majority of patients (64%) with newly detected conditions ranged from 50 to 59 years of age. Patients in the 60–69 age group accounted for 16%, the 40–49 age group for 12%, the under-40 age group for 5%, and the 70+ age group for 3% (Fig. 2A).

Fig. 2

Distribution of patients with newly diagnosed occupantional diseases caused by exposure to industrial aerosols in 2016–2020 by age group (A) and work experience with dust hazards (B)

Depending on the experience of working in harmful conditions under exposure to occupational dust, patients were distributed as follows. Those with experience of 21–25 years accounted for 41%, with experience of 31–35 years for 24%, followed by 19% with experience of 16–20 years and 10% with experience of 10–15 years. Less than 10 years had 6% patients (Fig. 2B).

By occupation, metallurgical workers prevailed (casters, molders, cappers), accounting for 43%. Miners comprised 17%, cement production workers—16%, electric and gas welders—14%, other occupations occupied 10% (Fig. 3).

Fig. 3

Distribution of patients with newly diagnosed occupational diseases caused by exposure to industrial aerosols by occupation in 2016–2020

Clinical symptomatology of occupational dust-induced lung diseases

Clinical symptomatology of occupational dust lung diseases of the examined patients is presented in Table 3.

Table 3 Detectability of clinical signs

Patients diagnosed with pneumoconiosis and silicosis presented with no dyspnea at rest, dyspnea occurring during physical activity was observed in 64.5%. Dry cough complaints were registered in 40.4%, cough with sputtering in 36.5%, chest pain was registered in 17.3%, and increased fatigue was observed in 94.2% of patients.

In the group of patients diagnosed with dust-induced COB, dyspnea at physical exercise was reported by 72.2%. Dry cough was observed in 58.3%, cough with sputum in 16.7%, and chest pain in only 5.6%. Increased fatigue was noted in 91.7% of patients.

In the group of patients diagnosed with COPD, dyspnea at rest was observed in 34.6%, and dyspnea only during physical activity was noted in 65.4% of patients. Dry cough was bothering for 61.5%, and cough with sputum for 23.1%. Chest pain was reported by 23.1% and increased fatigue by 69.2% of patients.

Thus, in all three groups of patients, the main complaints were dyspnea during physical exercise, increased fatigue and cough, more often dry.

According to the physical examination data, percussion and a box tone were observed in 41.2% of patients: 34.6% in Group 1, 55.6% in Group 2, and 34.6% in Group 3. On auscultation, attenuated breath sounds were heard in 9.6% of patients (7.7% in Group 1, 13.9% in Group 2, and 7.7% in Group 3); harsh breathing was observed in 63.2% of patients (46.2% in Group 1, 88.9% in Group 2, and 61.5% in Group 3). Dry rales during forced exhalation were noted in 66.7% of patients (51.9% in Group 1, 77.8% in Group 3, and 80.8% in Group 3).

Symptoms of rhinopharyngolaryngitis were noted in 23.5% of patients with PC (20.8%). There are also upper respiratory tract symptoms in 61.1% of dust-induced COB patients and 26.9% of COPD patients.

Thus, in all three groups of dust-induced diseases, the most frequent signs were increased fatigue, shortness of breath on exertion, harsh breathing, and dry rales. According to patients’ complaints, anamnesis, and physical examination, the characteristics of PC, COB, and COPD clinics are similar.

Results of spirographic, echocardiographic, and fibroscopic examination of patients with dust-induced occupational lung diseases

Further clinical examination involved 114 patients with a primary diagnosis of the occupational respiratory disease, who met the selection criteria. Depending on the diagnosis, these patients were divided into three groups: patients diagnosed with PC (group 1), patients diagnosed with COB (group 2), and patients diagnosed with COPD (group 3).

Spirography results in the group of patients with PC detected reduced FVC of lungs at the level of 87.4 ± 7.6% when assessing external respiratory function. Decreased FVC up to 77.5 ± 8.3% was noted in patients with COB. FVC in patients with bronchitis was lower than in those diagnosed with PC (p < 0.05). In patients with occupational COPD, there was a significant decrease of FVC index to 62.8 ± 6.4% (statistical difference with PC and CB patients at p < 0.05).

In patients with PC, the forced expiratory volume in the first second (FEV1) comprised 86.7 ± 8.8%, and the FEV1/FVC ratio, also called the Tiffeneau-Pinelli index, was 94.7 ± 9.6%, indicating restrictive changes. A downward trend was observed in FEV1 values in patients with COB (77.8 ± 8.7%, p < 0.05 compared to PC patients). A more significant decrease in FEV1 was found in COPD patients, amounting to 61.3 ± 6.1% (p < 0.05). FEV1/FVC was 82.6 ± 8.2% (p < 0.05) in COB patients and 58.3 ± 10.6% (p < 0.05) in COPD patients.

In the group of patients with PC, the maximum volume rate at the level of 25% of forced vital capacity of lungs (MEF25%) was 78.4 ± 7,1%. Significant decrease of MEF25% was noted in COB with 62.7 ± 7.7% (p < 0.05) and COPD patients with 51.4% ± 8.3% (p < 0.05). Peak expiratory flow rate (PEFR) in patients with PC was registered at 73.8% ± 9.4%. For patients with COB and COPD, this value was 66.3 ± 6.8% (p < 0.05) and 48.4 ± 7.3% (p < 0.05), respectively (Table 4).

Table 4 Indicators of external respiration function (average values) and changes in the volume flow rate in patients (% of the norm)

According to spirographs in 52 patients diagnosed with PC and silicosis, respiratory failure was not revealed (RF 0) in 5 patients (9.6%), I-degree respiratory failure (RF I) was revealed in 31 patients (59.6%), and II-degree respiratory failure (RF II) was recorded in 16 patients (30.8%). In 36 COB patients, RF 0 was registered in 8 persons (22.2%), RF I in 23 (63.9%), and RF II in 5 (13.9%). In 26 COPD patients, RF 0 was observed in 3 patients (11.5%), RF I in 15 (57.7%), and RF II in 8 (30.8%) (Table 5).

Table 5 Degree of respiratory failure in examined patients

Complex analysis of clinical data and echocardiographic findings allowed diagnosing chronic pulmonary heart disease in 83 patients (72.8%). Of them, 42 (80.8%) were from PC group, 18 (50.0%) represented COB patients, and 14 (53.8%) had COPD. At the same time, decompensated pulmonary heart disease (with different decompensation degrees) was observed in 53.6% across all groups (Fig. 4).

Fig. 4

Echocardiographic signs of cor pulmonale in the examined patients (%). PC, pneumoconiosis; COB, chronic occupational bronchitis; COPD, chronic obstructive pulmonary disease

In the group of 42 patients with PC and pulmonary heart disease, circulatory insufficiency I FC according to the New York Heart Association Functional Classification (NYHA) was revealed in 13 patients (31.0%), II FC in 24 (57.1%) patients, and III FC in 5 patients (11.9%). In 18 patients with pulmonary heart disease in the group of COB patients, circulatory insufficiency I FC was revealed in 3 patients (16.7%), II FC in 11 patients (61.1%), III FC in 4 patients (22.2%). Among 14 COPD patients with this pathology, the findings were as follows: circulatory insufficiency I FC was observed in 3 persons (21.4%), II FC in 8 persons (57.2%), and III FC in 3 persons (21.4%) (Fig. 5).

Fig. 5

Distribution of patients with chronic cor pulmonale by circulatory failure stage (%). PC, pneumoconiosis; COB, chronic occupational bronchitis; COPD, chronic obstructive pulmonary disease

There was a significant increase of right ventricular anterior wall thickness in patients with dust-induced COB (p < 0.05), COPD (p < 0.01), PC (p < 0.01), which suggests right ventricular hypertrophy in response to increased stress. Authentic increase of the diastolic size of the right ventricle (p < 0.01), a decrease of left ventricular stroke volume (p < 0.05), a decrease of respiratory minute volume (p < 0.05), a decrease of ejection fraction (p < 0.01), shortening fraction (p < 0.05) were observed in all groups. Furthermore, a significant increase of systolic pressure in the pulmonary artery was detected (p < 0.001). The resulting data indicate hypokinetic type formation of central hemodynamics.

Fibroscopic examination of patients with pneumoconiosis showed atrophic processes of the bronchial mucosa in 46 (88.5%), and 6 (11.5%) patients had subatrophic processes. Among patients with COB, mucous membrane atrophy was revealed in 22 (61.1%) patients, subatrophic process in 11 (30.6%), and catarrhal symptoms were observed in 8.3% of cases (3 patients). Atrophy of pulmonary mucosa was stated in 8 COPD patients (30.8%), subatrophic changes of bronchial mucosa were observed in 15 patients (57.7%), and catarrhal changes in 11.5% cases (3 patients).

Results of radiological and CT examinations

In the group of patients with PC, interstitial changes in the form of linear bands up to 1.5 mm in diameter (gradation “s”) were detected in 30 patients (57.7%). Among them, 2 s-grade was recorded in 22 patients (42.3%), and 1 s-grade in 8 patients (15.4%). Interstitial changes in the form of bands with a diameter ranging from 1.5 to 3.0 mm (gradation “t”) were revealed in 12 patients (23.1%). Of them, 10 patients (19.2%) had 2t-grade and 2 patients (3.8%) had 1t-grade. Nodular changes of 1r-grade were found in 3 patients (5.8%), and nodules with diameters between 1.5 and 3.0 mm of q-grade were revealed in 2 patients. Also, there were two patients with 3q and 2q grade profusion. Radiography revealed no changes in 5 patients (9.6%).

According to CN scans, interstitial changes in the form of linear bands up to 1.5 mm in diameter (gradation “s”) were found in 22 patients (42.3%) with PC. Of them, 2 s-grade was recorded in 17 patients, and 1 s-grade in 5 patients. Interstitial changes in the form of bands with a diameter ranging from 1.5 to 3.0 mm (gradation “t”) were detected in 19 patients (36.5%). Among them, in 2t was stated in 16, and 3t—in 3. Two patients (3.8%) demonstrated changes looking as bands more than 3.0 mm in diameter and grading 3u. Nodules up to 1.5 mm in diameter were found in 4 patients (7.7%) with 1p-grade. Nodular shadows ranging between 1.5 and 3.0 mm in diameter (gradation “q”) were detected in 5 patients (9.6%), with density classified as 1q (3 patients) and 2q (2 patients). Shadows in the form of nodules greater than 3.0 mm in diameter were detected in 2 patients, one each of 2r and 3r grades.

CT method allowed detecting pathological changes in all 52 patients, while X-ray examination in six people showed no signs of lung lesions. CT scanning showed that the number of patients with nodular PC forms (including silicosis) in the studied groups was also increased.

The analysis of X-ray and CT scan data of COB patients showed an insignificant intensification of bronchial vascular pattern that in 92% of patients (according to X-ray data). No pathology was observed in 8% revealed. The diagnosis in this group of patients was made based on the complaints, medical history, physical examination findings, changes in external respiration function indices, fibrobronchoscopy data, sanitary and hygienic features. According to CT findings, bronchial vascular pattern enhancement was detected in all patients. Furthermore, in 19.4% of cases (7 examined patients), its deformity was detected in addition to enhancement.

In the group of patients with established COPD diagnosis, an increased bronchial vascular pattern was noted in 63.7% of cases. At CT investigation, all patients were found to have increased bronchial vascular patterns, with no deformity detected in 5 of them (19.2%).

According to the results of the radiological examination, only 8 cases (15.4%) showed the signs of pulmonary emphysema in the form of widened intercostal spaces, diffuse increase in transparency, or local areas of lung tissue transparency in the group of patients with the diagnosis of PC. The CT diagnostics revealed the signs of emphysema in 38 patients (73.1%). When evaluating CT data of the lungs, small paraseptal air cavities in the apices were revealed in 17 patients, small paraseptal and centrilobular air cavities in 18 patients, multiple small paraseptal air cavities in mediabasal parts of the lungs in 3 patients.

No emphysema was detected in the group of patients with COB during radiological examination. According to CT scans, emphysema was detected in 17 COB patients (47.2%). Of them, small paraseptal and centrilobular air cavities were observed in 14 patients, multiple small paraseptal air cavities in 2, and panlobular areas of decreased lung tissue pneumotization was observed in one patient had.

According to radiological examination, there were no signs of emphysema in the group of patients diagnosed with COPD. They were detected only during lung CT investigation in 10 patients (38.5%) and appeared as small (6 patients) and multiple (4 patients) paraseptal air cavities in the lung apices.

X-ray examination revealed no pathological changes of the pleura in any of the PC patients examined. According to CT scans, pleural thickenings were observed in 28 patients (53.8%). Pleural thickenings up to 5 mm wide (gradation “a”) were registered in 18 patients (45.8%), and pleural thickenings with width from 5 to 10 mm (gradation “b”) in 11 patients.