Asbestos Exposure and Severity of COVID-19

Our plain-English summary of Asbestos Exposure and Severity of COVID-19, by G. Granados, M. Sáez-López, C. Aljama, et al (International Journal of Environmental Research and Public Health, 2022).

The study

• Authors: G. Granados, M. Sáez-López, C. Aljama, J. Sampol, M.J. Cruz, J. Ferrer, Se-Covid-Team
• Journal: International Journal of Environmental Research and Public Health
• Published: 2022;19(23)
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The aim of this study was to analyse the relationship between occupational exposure to asbestos and the severity of SARS-CoV-2 infection.

Methods: We evaluated patients who survived admission in our centre for COVID-19 pneumonia. Demographic, analytical, and clinical variables were collected during admission. After discharge, a previously validated occupational exposure to asbestos questionnaire was administered. Spirometry, CO diffusion test, the 6-min walk test, and high-resolution chest CT were performed. Patients who required respiratory support (oxygen, CPAP, or NIV) were considered severe.

Results: In total, 293 patients (mean age 54 + 13 years) were included. Occupational exposure to asbestos was detected in 67 (24%). Patients with occupational exposure to asbestos had a higher frequency of COVID-19 pneumonia requiring respiratory support (n = 52, 77.6%) than their unexposed peers (n = 139, 61.5%) (p = 0.015). Asbestos exposure was associated with COVID-19 severity in the univariate but not in the multivariate analysis. No differences were found regarding follow-up variables including spirometry and the DLCO diffusion, the 6-min walk test, and CT alterations.

Conclusions: In hospitalised patients with COVID-19 pneumonia, those with occupational exposure to asbestos more frequently needed respiratory support. However, an independent association between asbestos exposure and COVID-19 severity could not be confirmed.

In plain English

This prospective observational study at a university hospital in Barcelona, Spain, asked whether past work exposure to asbestos was linked to more severe COVID-19. It included 293 patients who had survived hospital admission for COVID-19 pneumonia between March and August 2020. After discharge, patients completed an asbestos exposure questionnaire adapted from QEAS-7, and 67 were classed as exposed. Severe illness meant needing any respiratory support, such as oxygen. Support was needed by 52 of 67 exposed patients (77.6%) and 139 of 226 unexposed patients (61.5%). Exposed patients were also older and more often male and smokers. Once age and sex were taken into account, the link with severity was no longer statistically significant. At follow-up, lung function and chest CT findings were similar between the groups, apart from a lower FEV1/FVC ratio (a breathing-test measure) in exposed patients. The authors concluded that asbestos exposure could not be established as an independent risk factor for severe COVID-19. They noted that only survivors from a single centre were studied.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Prospective observational study (single centre)
• Who was studied: 304 patients screened and 293 included, all of whom had survived admission to a university hospital in Barcelona, Spain, for COVID-19 pneumonia between 1 March and 8 August 2020. They were evaluated at post-COVID-19 pulmonology outpatient offices between June and October 2020.
• Exposure: Occupational asbestos exposure (fiber type not specified), assessed after discharge with a questionnaire adapted from the validated QEAS-7 checklist. Exposure was classed as certain/probable or non-existent. 67 patients were classed as exposed, with a mean exposure duration of 17.5 years (SD 11.3). Construction workers made up 33 of the 67 exposed patients (49.3%).
• Main results:
  • Respiratory support during admission (the study's definition of severe COVID-19) was needed by 52 of 67 exposed patients (77.6%) versus 139 of 226 unexposed patients (61.5%), p = 0.015.
  • Compared with unexposed patients, exposed patients were older (mean age 63.1 vs 57 years), more often male (86.6% vs 44.2%) and more often smokers (44.8% vs 23.4%). They also more often had diabetes and cardiological and respiratory conditions.
  • Unadjusted logistic regression (model 1): odds ratio for severe COVID-19 with asbestos exposure 3.467 (1.952–6.157), p less than 0.001.
  • Adjusted for age and sex (model 2): odds ratio for asbestos exposure 1.288 (0.645–2.57), p = 0.473, not statistically significant.
  • Adjusted for age, sex and number of comorbidities (model 3): odds ratio for asbestos exposure 1.159 (0.573–2.348), p = 0.681, not statistically significant.
  • At follow-up, exposed patients had a lower FEV1/FVC ratio (78.3% vs 80.9%, p = 0.0133). No other spirometry differences were detected.
  • At follow-up, exposed patients reported more intense breathlessness on the mMRC scale (p = 0.050). The authors described this difference as almost reaching statistical significance.
  • There were no differences in other lung function measures, in the 6-minute walk test, or in lung sequelae on chest CT (41 exposed, 61.2%, vs 120 unexposed, 53.3%, p = 0.256).
• The authors' conclusion: The authors concluded that severe COVID-19 was more frequent in patients with occupational asbestos exposure, but their data could not establish asbestos exposure as an independent risk factor for COVID-19 severity. They added that exposed patients without asbestos-derived diseases would seem not to be at higher risk of severe COVID-19 than the general population, and that further investigation could be useful.
• Limitations the authors state:
  • Only patients who survived hospital admission were included, so the effect of asbestos exposure on mortality could not be assessed.
  • The observational, single-centre design means the results cannot be generalised to other settings.
  • Confounding by age, sex, smoking and comorbidities may have prevented detection of an independent association in this relatively small sample.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Occupational Exposure, Spirometry, Multivariate Analysis, Diffusing Capacity (DLCO).

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