Retinal nerve fiber layer thickness and retinal vascular caliber alterations in coal miners in northern China: a community-based observational study

AIM: To evaluate retinal nerve fiber layer thickness and retinal vascular caliber alterations in coal mine workers. METHODS: The community-based observational cross-sectional study included 4004 participants of a sub-population of the Kailuan Study. All the study participants underwent structured interviews with a standardized questionnaire, fundus photography and spectral-domain optical coherence tomography (OCT) examinations performed by trained doctors. RESULTS: The retinal nerve fiber layer thickness was significantly higher (P=0.006) and the central macular thickness was lower in coal miners (n=659, 51.0±7.8y) as compared to the control (working above the ground; n=477, 51.8±7.5y; P=0.032). Additionally, the downhole workers showed a significantly thicker retinal artery (P=0.012) and vein diameters (P<0.001). In multivariable regression, a thicker retinal nerve fiber layer was associated with a higher cumulative silica dust exposure (P=0.005) after adjusting for younger age and larger spherical equivalent. In a reverse pattern, a higher cumulative silica dust exposure (P=0.004) was significantly associated with a thicker retinal nerve fiber layer after adjusting for age, high-density lipoproteins and uric acid. Wider retinal vein diameters were associated with higher cumulative silica dust exposure (P=0.036) after adjusting for younger age and larger spherical equivalent. CONCLUSION: The retinal vessels diameters and retinal nerve fiber layer thickness are significantly thicker in long term of coal mining. The results of our study indicate that underground working environment may lead to retinal vessel dilation and inflammation. Thus, ocular examination might be needed within coal miners in order to monitor the occupational eye health as well as the incidence and progression of eye diseases.

Analysis of Histopathological Findings of Lung Carcinoma in Czech Black Coal Miners in Association with Coal Workers’ Pneumoconiosis

Coal miners with coal workers’ pneumoconiosis (CWP, J60 according to ICD-10) were previously found to have a significantly higher risk of lung carcinoma compared to the general male population. The presented study aimed to analyze the (i) incidence of lung carcinoma in miners, (ii) histopathological findings in cohorts with and without CWP, and (iii) effect of smoking cessation on the histopathological profile. Analyzed cohorts consisted of miners with (n = 3476) and without (n = 6687) CWP. Data on personal and working history obtained from the medical records were combined with information on lung cancer from the Czech Oncological Register and histopathological findings. Statistical analysis was performed using non-parametric tests and the incidence risk ratio at the significance level of 5%. In 1992–2015, 180 miners (2.7%) without CWP and 169 (4.9%) with CWP, respectively, were diagnosed with lung carcinoma. The risk of lung cancer in miners with CWP was 1.82 (95% CI: 1.48–2.25) times higher than in those without CWP. Squamous cell carcinoma (37%) was the most common histopathological type, followed by adenocarcinoma (22%) and small cell carcinoma (21%). A statistically significant difference between the cohorts (p = 0.003) was found in the histopathological subtypes, with the incidence of small cell carcinoma being 2 times higher in miners without CWP than in those with CWP. Only a few individuals with lung carcinoma were non-smokers. The incidence of small cell carcinoma, which is strongly associated with smoking, is significantly higher in miners without CWP. Smoking constitutes the most important risk factor for developing lung carcinoma even in that cohort. However, CWP remains a very important risk factor.

Cancer and mortality in coal mine workers: a systematic review and meta-analysis

Coal mine workers are exposed to a number of workplace hazards which may increase the risk of cancer and mortality. We conducted a systematic review and meta-analysis to investigate cancer and mortality in coal mine workers We searched in Ovid Medline, PubMed, Embase and Web of Science databases using keywords and text words related to coal mines, cancer and mortality and identified 36 full-text articles using predefined inclusion criteria. Each study’s quality was assessed using the Newcastle-Ottawa Scale. We performed random-effect meta-analyses including 21 of the identified articles evaluating cancer and/or mortality of coal mine workers. The meta-analysis showed an increased risk of all-cause mortality (SMR 1.14, 95% CI 1.00 to 1.30) and mortality from non-malignant respiratory disease (NMRD) (3.59, 95% CI 3.00 to 4.30) in cohorts with coal workers’ pneumoconiosis (CWP). We found a somewhat increased risk of stomach cancer (1.11, 95% CI 0.97 to 1.35) and of mortality from NMRD (1.26, 95% CI 0.99 to 1.61) in the cohorts of coal miners with unknown CWP status. The meta-analysis also showed a decreased risk of prostate cancer and cardiovascular and cerebrovascular mortality among coal miners. This may be a result of the healthy worker effect and possible lower smoking rates, and perhaps also reflect the physically active nature of many jobs in coal mines. The meta-analysis for lung cancer did not show increased risk in coal miners with CWP (1.49, 95% CI 0.70 to 3.18) or for coal miners of unknown CWP status (1.03, 95% CI 0.91 to 1.18). Lower smoking rates in coal mine workers could explain why case–control studies where smoking was controlled for showed higher risks for lung cancer than were seen in cohort studies. Coal mine workers are at increased risk of mortality from NMRD but decreased risk of prostate cancer and cardiovascular and cerebrovascular mortality. Studies of coal mine workers need long-term follow-up to identify increased mortality and cancer incidence.

The influence of smoking on the formation of occupational lung diseases in workers who come into contact with industrial aerosols

The formation of a healthy lifestyle is one of the most important tasks of disease prevention. Among the factors that negatively affect the health of the population, smoking is of great importance. The influence of smoking on the formation of occupational diseases in workers in harmful and (or) dangerous working conditions has not been sufficiently studied. Based on the knowledge of the pathogenesis of common diseases, it can be assumed with a high degree of probability that smoking can provoke the development of occupational pathology of the respiratory organs, malignant neoplasms, vascular pathology.The aim of the work was to study the clinical manifestations of chronic bronchitis, characterizing the state of the bronchopulmonary system, in smokers and non-smokers who had long-term contact with industrial dust, as well as to analyze the literature data on the impact of smoking on the development of occupational lung diseases in workers exposed to asbestos dust.Materials and methods of research. In the clinic “Research Institute of Occupational Medicine named after Academician N.F. Izmerov”, 55 workers were examined under the influence of industrial aerosols of fibrogenic action. The group of smokers consisted of 45 people: 25 people were coal miners, 20 people were foundry workers. The group of non-smokers consisted of 10 people: 6 coal miners and 4 foundry workers. The severity of the course of professional and non-professional chronic bronchitis in patients was assessed taking into account the clinical manifestations and frequency of exacerbations of the disease, as well as taking into account the severity of respiratory disorders and gas exchange disorders.Results and discussion. In the group of smoking patients, 93,3% had occupational chronic bronchitis, 6.7% had no such pathology. In the group of non-smoking patients with and without occupational chronic bronchitis, there were equally – 50,0%. In the group of smoking patients, 55,5 of the examined patients had respiratory insufficiency of the II degree; 15,5% were diagnosed with respiratory insufficiency of the III degree; cases without respiratory function impairment (DN0 art.) were only 8,8%. In the group of non-smoking patients, grade II DN was more than three times less frequent, amounting to 20,0%, while 40,0% had grade 0 DN and 40,0% had grade I DN; grade III DN was never diagnosed in this group of patients.Conclusion. Smoking, as an independent factor, can play a significant, and in some cases, obviously, a determining role in the development and progression of chronic bronchitis in people exposed to industrial aerosols.The health risks associated with tobacco should be taken into account as an integral part of the assessment of the risks of developing occupational diseases.

Study on the Relationship Between Musculoskeletal Disorders, BDNF Gene, TPH-2 Gene, and Mental Health in Coal Mine Workers in China

Background: Coal is the core energy source of the global energy system. To ensure the sustainable development of the coal industry, the mental health of coal miners is crucial. Methods: This cross-sectional study was conducted between August 2018 and June 2019. A total of 1,675 coal miners were surveyed using the Musculoskeletal Disorders (MSDs) Questionnaire and the Symptom Checklist-90 (SCL-90). At the same time, polymorphisms in the BDNF gene (rs6265, rs10835210) and TPH2 gene (rs4570625, rs4131347) in whole blood DNA were detected to analyze the influence of a gene-environment interaction on mental health. Results: The results showed that the mental health status of coal miners was poorer than the Chinese norm (P < 0.05). The mental health status of workers with MSDs was lower; MSDs interact with the BDNF gene rs6265 and TPH2 gene rs4570625, which affects mental health. Conclusions: It is suggested that employers should improve the working environment of workers, shorten the working time, pay attention to the mental health of workers, and provide timely psychological counseling to workers who suffer from mental health problems, so as to improve workers’ mental health and working ability, as well as their quality of life.

The Role of Work Engagement in the Association between Psychological Capital and Safety Citizenship Behavior in Coal Miners: A Mediation Analysis

With the development of science and technology and the increasing importance attached by to these domains by the state and government departments in recent years, China’s coal production and safety supervision level continue to increase. However, the prevalence of frequent coal mine safety accidents has not been effectively curbed. The main purpose of this study was to explore the mediating role of work engagement in the relationship between psychological capital and safety citizenship behavior among Chinese coal miners. Data for 317 coal miners were collected from five coal and energy enterprises. The Psychological Capital Questionnaire (PCQ), the Job Engagement Scale (JES), and the Safety Citizenship Behavior Scale (SCBS) were used to evaluate the coal miners’ psychological capital, work engagement, and safety citizenship behavior. The causal steps approach and bootstrap Method were used in this study to assess the proposed mediation models. A correlation analysis indicated that psychological capital, work engagement, and safety citizenship behavior were significantly correlated with each other. Furthermore, the mediation analysis showed that work engagement mediated the relationship between psychological capital and safety citizenship behavior. Psychological capital does not only have a direct impact on coal miners’ safety citizenship behavior, but it also has an indirect impact on coal miners’ safety citizenship behavior via work engagement. Therefore, effectively enhancing an individual’s psychological capital and work engagement may be a basic factor determining coal miners’ safety citizenship behavior, which further promotes safety production within the enterprise.