Association between increased small airway obstruction and asbestos exposure in patients with asbestosis

Exposure to insulating materials and risk of coronary artery diseases: a cross-sectional study

Background

Although previous reports link exposure to insulating materials with an increased risk of mesothelioma and chronic respiratory diseases, studies evaluating their associations with the risk of coronary artery diseases (CAD) are lacking.

Aims

We aimed at evaluating the associations between exposure to insulating materials and the 10-year risk of CAD among insulators.

Methods

In this cross-sectional study, we recruited 643 adults (≥18 years), full-time insulators from the Local 110 Heat and Frost Insulators and Allied Workers Union in Edmonton, Alberta. We obtained demographic information, personal and family history, and job-exposure history, including experience (years) and types of exposure to insulating materials. Clinical profiling including Framingham risk scores (FRS) was assessed.

Results

Of all insulators, 89% were men (mean ± SD age: 47 ± 12 years), 27% had a parental history of cardiac diseases, and 22% had a comorbid chronic respiratory disease. In total, 53% reported exposure to asbestos, while 61, 82, and 94% reported exposure to ceramic fibers, fiberglass, and mineral fibers, respectively. In single-exposure multivariable regression models adjusted for experience, marital status, and body mass index (BMI), asbestos was found to be associated with higher FRS (β: 1.004; 95%CI: 0.003-2.00). The association remained consistent in multi-exposure models and a higher association was found between asbestos exposure and FRS among insulators with comorbid chronic respiratory disease.

Conclusion

Our study demonstrates that apart from cancer and chronic respiratory diseases, asbestos exposure may also have a cardiac effect, thus warranting the need for systematic surveillance to protect workers from the adverse effects of these materials.

The incidence of malignancies in asbestosis with chrysotile exposure: a large Chinese prospective cohort study

Background

Asbestos exposure is closely related to the occurrence and development of various malignancies. This prospective cohort study aimed to evaluate the incidence rate and potential risk factors in a cohort of asbestosis patients in China.

Methods

The incidence of malignancies was determined in patients who had been exposed to chrysotile asbestos and diagnosed with asbestosis sequentially at Beijing Chaoyang Hospital from 1 January 2007 to 31 December 2019. Cox regression analyses were used to analyze the correlations between clinical variables and asbestosis combined with malignancies.

Results

A total of 618 patients with asbestosis were identified, of whom 544 were eligible for analysis. Among them, 89 (16.36%) were diagnosed with various malignancies. The standardized incidence ratios (SIRs) of patients with asbestosis combined with malignancies were 16.61, 175, 5.23, and 8.77 for lung cancer, mesothelioma, breast cancer, and endometrial carcinoma, respectively. The risks of all malignancies and lung cancer increased with initial exposure before 17 years old, longer asbestos exposure, and smoking.

Conclusions

The SIRs of patients with asbestosis-related malignancies were significantly increased in lung cancer, mesothelioma, breast cancer, and endometrial carcinoma in a hospital-based Chinese cohort. Smoking and the duration of asbestos exposure increased the risk of lung cancer.

High-resolution computed tomography features of asbestosis versus fibrotic hypersensitivity pneumonitis: an observational study

Background

Asbestosis and fibrotic hypersensitivity pneumonitis (FHP) share the pathogenetic mechanisms induced bronchiolocentric fibrotic process secondary to inhalation exposure. Under the occupational and environmental mixed exposures, asbestosis and FHP are needed to make the differential diagnoses on high-resolution computed tomography (HRCT), especially in the countries still using asbestos. The study aimed to analyze the HRCT features of asbestosis versus FHP.

Methods

The patients with asbestosis or with HP were sequentially recruited in this comparative study at Beijing Chaoyang Hospital between January 2006 and December 2016. Patients’ clinical data were obtained from a predesigned charts. The international classification of HRCT for occupational and environmental respiratory diseases was used to categorize chest imaging findings in patients. The calculation of test statistics was used to compare the imaging features of asbestosis and FHP.

Results

341 patients with asbestosis and 158 patients with HP were sequentially recruited, among which 204 patients with asbestosis and 74 patients with FHP were eligible for data analysis. Patients with asbestosis were older and had a longer latent period until disease manifestation than those with FHP. Asbestosis was characterized by irregular and/or linear opacities, with lower lung preponderance, accompanied by ground-glass opacities and mosaic attenuation. Notably, 98.5% of patients with asbestosis showed benign pleural abnormalities, and 39.7% of these patients had diffuse pleural thickening with parenchymal bands and/or rounded atelectasis. Abnormalities of the mediastinal and diaphragmatic pleura were observed only in cases of asbestosis, and this finding showed high specificity for the diagnosis for asbestosis compared with that for FHP. Subpleural dots or diaphragmatic pleural abnormalities showed moderate sensitivity and high specificity for diagnosis of asbestosis compared with that for FHP. Interobserver reliability was good for evaluation of imaging findings including honeycombing, pleural calcification, lymphadenectasis, and lymph node calcification.

Conclusions

HRCT-based imaging findings can distinguish between asbestosis and FHP to a certain extent, particularly with regard to subpleural dots and diaphragmatic pleural abnormalities that characterize the former.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01967-3.

Small airway dysfunction in pneumoconiosis: a cross-sectional study

Background

Although several histological studies have documented airway inflammation and remodelling in the small airways of dust-exposed workers, little is known regarding the prevalence and risk factors of small airway dysfunction (SAD) in pneumoconiosis. The present study investigated the prevalence and characteristics of spirometry-defined SAD in pneumoconiosis and assessed the risk factors for associated with SAD.

Methods

A total of 1255 patients with pneumoconiosis were invited to participate, of whom 1115 patients were eligible for final analysis. Spirometry was performed to assess SAD using the following three indicators: maximal mid-expiratory flow and forced expiratory flow 50% and 75%. SAD was defined as at least two of these three indicators being less than 65% of predicted value. Logistic regression analyses were used to analyse the relationships between clinical variables and SAD.

Results

Overall, 66.3% of patients with pneumoconiosis had SAD, among never-smokers the prevalence of SAD was 66.7%. The proportion of SAD did not differ among the subtypes of pneumoconiosis. In addition, SAD was present across the patients with all stages of pneumoconiosis. Even among those with forced expiratory volume in 1 s (FEV₁) ≥ 80% and FEV₁/forced vital capacity ratio ≥ 70%, 40.8% of patients had SAD. Patients with SAD were older than patients without SAD, more likely to be women and heavy smokers. Importantly, patients with SAD had more severe airflow obstruction, air trapping, and diffusion dysfunction. All patients with both pneumoconiosis and chronic obstructive pulmonary disease had SAD. Based on multivariate analysis, overall, aged 40 years and older, female sex, heavy smoking, body mass index ≥ 25.0 kg/m² and pneumoconiosis stage III were significantly associated with increased risk of SAD. Among the never smokers, risk factors for SAD included female sex, BMI ≥ 25.0 kg/m², pneumoconiosis stage II and stage III

Conclusion

Spirometry-defined SAD is one of the common functional abnormalities caused by occupational dust exposure and should be taken into account when monitoring respiratory health of workers to guide the early precautions and management in pneumoconiosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01929-9.

Plasma Metabolic Profiling in Patients With Silicosis and Asbestosis

OBJECTIVES

To explore the circulating metabolites and related pathways in silicosis and asbestosis exposure to different mineral dust.

METHODS

Plasma of 30 silicosis, 30 asbestosis, and 20 healthy controls was analyzed using liquid chromatography-mass spectrometry. Metabolic networks and the relevance of the identified metabolic derangements were explored.

RESULTS

Compared with healthy controls, 37 and 39 dysregulated plasma metabolites were found in silicosis and asbestosis, respectively, of which the levels of 22 metabolites differed. Three major pathways were identified, among which arginine and proline metabolism was identified as the most closely related metabolic pathway.

CONCLUSIONS

The types and quantities of up-regulated metabolites including lipids, amino acids, and carnitines differed between silicosis and asbestosis. Pathways inducing lung fibrosis were common to mineral dust exposure, while pathways related to oxidative stress and tumorigenesis differed between silicosis and asbestosis.

Survival of patients with asbestosis can be assessed by risk-predicting models

OBJECTIVES

Our aim was to investigate the pulmonary function test (PFT) results of patients with asbestosis and determine whether baseline PFTs and the risk-predicting models such as gender, age and physiologic (GAP) variables model and composite physiologic index (CPI) would be useful in predicting survival in these patients.

METHODS

Demographics and PFTs of 100 patients with asbestosis were evaluated. The survival difference between the GAP stages was determined with Kaplan-Meier survival curves with statistical significance analysed with log-rank test. The suitability of the risk-predicting models and baseline PFTs to predict the survival of patients was analysed with Cox regression.

RESULTS

At baseline, the mean value of diffusion capacity for carbon monoxide (DLCO) was 65%; for forced vital capacity it was 81%, with restrictive lung function being the most common impairment. The median estimated survival of the patients was 124 months, that is, 171 months in GAP stage I, 50 months in stage II and 21 months in stage III (p<0.001). CPI, DLCO% predicted, age at baseline and GAP stage were significant predictors of mortality (all p values under 0.001).

CONCLUSIONS

GAP and CPI as well as baseline DLCO% predicted were significant parameters in the evaluation of the prognosis of the patients with asbestosis; they may be useful in clinical practice when considering treatment strategies of individual patients.

Telomerase gene variants and telomere shortening in patients with silicosis or asbestosis

OBJECTIVES

Telomerase gene variants that lead to accelerated telomere shortening are linked to progressive-fibrosing interstitial lung diseases. However, little is known about their relationships with pneumoconiosis. This study aimed to identify TERT/TERC variants and leucocyte telomere lengths (LTL) in patients with silicosis or asbestosis.

METHODS

In the present study, Sanger sequencing of TERT/TERC variants was performed in 193 Chinese Han patients with pneumoconiosis, including 109 with silicosis and 84 with asbestosis. Quantitative PCR was used to measure LTL in peripheral blood of the patients and 200 age and sex-matched healthy controls.

RESULTS

In total, 7.3% patients with pneumoconiosis had 17 TERT/TERC variants. Among which 8.3% of patients with silicosis and 3.6% of patients with asbestosis had TERT variants, respectively. No TERC variants were detected in silicosis, whereas 3.6% of patients with asbestosis had TERC variants. Telomeres were significantly shorter in the patients with pneumoconiosis compared with healthy controls (p<0.001). No significant differences in LTL were found between TERT/TERC variant carriers and non-carriers. Exposure to silica dust was associated with the severity of pneumoconiosis after adjusting for covariates (OR 4.92, p=0.002). However, TERT/TERC variants and short telomeres were not associated with the severity of pneumoconiosis.

CONCLUSION

Telomerase gene variants and short telomeres may be identified in the patients with silicosis and asbestosis in response to the exposure to silica or asbestos dust but are not related to disease severity.

Association of occupational dust exposure with combined chronic obstructive pulmonary disease and pneumoconiosis: a cross-sectional study in China

OBJECTIVES

Occupational dust exposure may induce various lung diseases, including pneumoconiosis and chronic obstructive pulmonary disease (COPD). The features of combined COPD and pneumoconiosis have not been well described, and this may hamper the management. This study aimed to describe the prevalence and characteristics as well as the risk factors of the combined diseases.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

758 patients with pneumoconiosis were recruited at a single-medical centre. Of these, 675 patients with pneumoconiosis, including asbestosis, silicosis, coal workers' pneumoconiosis and other pneumoconiosis, was eligible for analysis.

PRIMARY OUTCOME MEASURES

COPD was diagnosed based on clinical features and/or history of exposure to risk factors and post bronchodilator forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) ratio <0.7. Clinical data were collected from predesigned medical reports. The patients underwent both chest radiograph and high-resolution CT scans. Risk factors for combined COPD and pneumoconiosis were analysed using regression analysis.

RESULTS

COPD prevalence overall was 32.7% (221/675) and was the highest in silicosis (84/221) and coal workers' pneumoconiosis (100/221). COPD prevalence increased with smoking pack-years, dust exposure duration and pneumoconiosis stage. Patients with combined diseases had lower body mass index, higher smoking index and worse pulmonary function. Risk factors for combined diseases included heavy smoking, silica or coal exposure and advanced pneumoconiosis. The interaction between dust exposure and smoking in COPD was also identified. The risk of combined COPD significantly increased with heavy smoking and silica or coal exposure (OR 5.49, 95% CI 3.04 to 9.93, p<0.001).

CONCLUSIONS

COPD is highly prevalent in patients with pneumoconiosis, especially patients with silicosis and coal workers' pneumoconiosis. Occupational dust exposure as well as heavy smoking is associated with an increased risk of combined COPD and pneumoconiosis, which demands an effective preventive intervention.

Fractional Exhaled Nitric Oxide (FeNO) Combined with Pulmonary Function Parameters Shows Increased Sensitivity and Specificity for the Diagnosis of Cough Variant Asthma in Children

Background

Cough variant asthma in children presents with a dry nonproductive cough. This study aimed to investigate the diagnostic value of fractional exhaled nitric oxide (FeNO) combined with small airway functional parameters in cough variant asthma.

Material/Methods

Children with asthma (n=136) were divided into a cough variant asthma (CVA) group (n=57; mean age, 8.03±2.1 years) and a non-cough variant asthma (nCVA) group (n=79; mean age, 8.61±1.7 years). In both groups, FeNO and other pulmonary function parameters were measured including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), maximum mid-expiratory flow (MMEF), forced expiratory flow (FEF), and maximum expiratory flow at 25%, 50%, and 75% expired volume (MEF25, MEF50, and MEF75). Receiver-operating characteristic (ROC) curve analysis compared the sensitivity and specificity between the diagnostic parameters.

Results

The FeNO values were significantly increased in the CVA group compared with the nCVA group (Z=6.890, p<0.001). The MMEF, MEF25, MEF50, and MEF75 values were significantly lower in the CVA group compared with the nCVA group (p=0.000, p=0.014, p=0.000, and p=0.000, respectively). The FeNO values were negatively correlated with MEF25, MEF50, and MMEF (r=−0.334, r=−0.257 and r=−0.276, respectively). FeNO was significantly more efficient diagnosing cough variant asthma comparing with pulmonary parameters (p<0.05), and was most sensitive and specific when combined with MMEF/MEF50 compared with single diagnostic parameters (p<0.05).

Conclusions

FeNO combined with pulmonary function parameters of MMEF/MEF50 showed increased sensitivity and specificity for the diagnosis of cough variant asthma.

3-Dimensional Quantification of Composite Pleural Plaque Volume in Patients Exposed to Asbestos Using High-resolution Computed Tomography: A Validation Study

RATIONALE

As pleural plaque has been reported as a risk factor in the occurrence of lung cancer and mesothelioma, a reproducible and precise method of measurement of pleural plaque volume (PPV) is needed to further describe these relationships. The aim of the study was to assess the reproducibility of a 3-dimensional computed tomography (3D-CT) volumetric analysis of PPV in patients with occupational exposure to asbestos.

MATERIAL AND METHODS

A total of 28 patients were retrospectively randomly selected from the multicenter APEXS (Asbestos Post Exposure Survey) study, which was held between 2003 and 2005. All patients underwent a 3D-CT scan. Two readers specialized in chest radiology completed the 3D semiautomated quantification of lung volume using dedicated software. They also had to categorize the visual extent of pleural plaque in terms of thickness and circumference. Reproducibility of the continuous PPV variable was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. Reproducibility of categorical variables was assessed using the κ test.

RESULTS

Intraobserver reproducibility of PPV was almost perfect (ICC=0.98 [95% interval: 0.97-0.99]), and interobserver reproducibility was very good (ICC=0.93 [0.88-0.97]). At Bland-Altman analysis, the mean differences were 0.1 (limit of agreement: -11.0 to 11.2) and 3.7 cc (-17.8 to 25.2), respectively. Visual analysis of both plaque in terms of thickness and circumference were fair to moderate, with κ values ranging from 0.30 to 0.60.

CONCLUSIONS

3D semiautomatic quantification of PPV is feasible and reproducible using CT in patients with occupational exposure to asbestos. PPV measurement may be useful to correlate with other asbestos-related disease outcomes and prognosis.