Asbestos exposure increases the incidence of histologically confirmed usual interstitial pneumonia

Our plain-English summary of Asbestos exposure increases the incidence of histologically confirmed usual interstitial pneumonia, by Y. Kawabata, Y. Shimizu, E. Hoshi, et al (Histopathology, 2016).

The study

• Authors: Y. Kawabata, Y. Shimizu, E. Hoshi, K. Murai, T. Kanauchi, K. Kurashima, Y. Sugita
• Journal: Histopathology
• Published: 2016;68(3):339-46
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Aims: We hypothesized that asbestos exposure increases the incidence of macroscopically visible and histologically confirmed usual interstitial pneumonia (histological UIP).

Methods And Results: We retrospectively examined 1718 cases (1202 males; mean age 66.7 years) who underwent lobectomy for resection of pleuropulmonary tumours. Objective markers for asbestos exposure included: the presence of malignant pleural mesothelioma, the presence of pleural plaques (PPs) and asbestos bodies in the histological specimen. Risk factors for histological UIP were examined. Two separate groups were studied: 183 with asbestos exposure, and 239 with histological UIP. The 183 cases with asbestos exposure had higher rates of positive occupational history and histological UIP (31%) than the remaining 1535. Among the asbestos-exposed group, small numbers of asbestos bodies were found in histological specimens of 21 cases of histological UIP. PPs and asbestos bodies were more frequent in the 239 patients with histological UIP than in the remaining 1479 UIP-negative patients. Multivariate analysis showed that asbestos exposure, especially positivity for asbestos bodies, that does not meet the current criteria for asbestosis increases the risk of histological UIP (P < 0.0001).

Conclusions: Asbestos exposure causes asbestosis and increases the incidence of histological UIP.

© 2015 John Wiley & Sons Ltd.

In plain English

This retrospective study reviewed 1718 patients (1202 men, 516 women) who had at least a lobectomy for chest tumours at one referral centre in Saitama, Japan, from 1996 to 2012. Patients counted as asbestos-exposed if they had malignant pleural mesothelioma, pleural plaques, or asbestos bodies in lung tissue, and 183 qualified. The authors looked for usual interstitial pneumonia (UIP), a lung-scarring pattern, confirmed by eye and under the microscope. UIP was found in 57 of the 183 exposed patients (31%). Among unexposed patients, it was found in 12 of 83 (14%) with an occupational history of asbestos exposure and 170 of 1452 (12%) without one. Of the 57, four met pathological criteria for asbestosis and 21 had asbestos bodies below that threshold. In multivariate analysis, asbestos exposure had an adjusted odds ratio for UIP of 2.240 (95% confidence interval 1.535 to 3.267), and asbestos bodies 10.227 (4.001 to 24.141). The authors concluded that asbestos exposure causes not only asbestosis but also UIP. They noted that not all cases were stained for asbestos bodies, fibres were not analysed by electron microscopy, chrysotile-related asbestosis may have been missed, and occupational histories were often incomplete.

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: Retrospective study of surgical lung specimens and clinical records, with comparison of groups and logistic regression analysis
• Who was studied: 1718 patients (1202 males, 516 females; mean age 66.7 years) who underwent at least lobectomy for pleuropulmonary tumours at Saitama Prefectural Cardiovascular and Respiratory Centre, Japan, from the beginning of 1996 to the end of 2012
• Exposure: Asbestos exposure defined by objective markers: malignant pleural mesothelioma, pleural plaques, or asbestos bodies in the histological specimen. Occupational history of asbestos exposure, taken from clinical records, was recorded separately and was not used as a definite marker. Fiber types were not identified.
• Main results:
  • 183 patients were in the asbestos-exposed group, with some overlap between markers: 165 with pleural plaques, 11 with malignant pleural mesothelioma, and 34 positive for tissue asbestos bodies
  • Histological UIP was found in 57 of 183 (31%) in the asbestos-exposed group, 12 of 83 (14%) in the non-exposed subgroup with an occupational history, and 170 of 1452 (12%) in the non-exposed subgroup without an occupational history
  • Of the 57 asbestos-exposed patients with histological UIP, 4 had more than 2 asbestos bodies per square centimetre and met the pathological criteria for asbestosis (two cement factory workers, one asbestos spray worker and one bus driver). Another 21 had asbestos bodies (0.07 to 0.9 per square centimetre) but did not meet the criteria, and 32 had no tissue asbestos bodies.
  • Overall, histological UIP was found in 239 patients (14%). Of these, 84 (35%) had clinical disease (78 idiopathic pulmonary fibrosis, four asbestosis, two rheumatoid arthritis-related UIP) and 155 had subclinical interstitial lung disease.
  • Compared with the 1479 patients without UIP, the 239 patients with UIP more often had asbestos exposure (23.8% versus 8.5%), pleural plaques (20.1% versus 7.8%), tissue asbestos bodies (10.4% versus 0.6%) and an occupational history (14.9% versus 6.8%). Mesothelioma did not differ significantly (0.4% versus 0.6%).
  • In multivariate analysis, the independent risk factors for histological UIP were older age (odds ratio 1.052 per year), smoking history (odds ratio 4.372, 95% CI 2.297 to 8.323), asbestos exposure (adjusted odds ratio 2.240, 95% CI 1.535 to 3.267, P less than 0.001) and tissue asbestos bodies (odds ratio 10.227, 95% CI 4.001 to 24.141, P less than 0.001)
• The authors' conclusion: The authors concluded that the asbestos-exposed group had a significantly higher incidence of histological UIP. They considered asbestos exposure, especially tissue asbestos bodies, a risk factor for histological UIP, and stated that asbestos exposure causes not only asbestosis but also histological UIP, which complicates telling idiopathic pulmonary fibrosis apart from asbestosis.
• Limitations the authors state:
  • Not all lobectomy cases were examined with iron-stained slides. Only 50 control cases without an occupational history or UIP were checked.
  • Asbestos fibres were not identified or counted by scanning electron microscopy with energy-dispersive X-ray analysis
  • Asbestosis caused by chrysotile exposure may not have been detected
  • Occupational history details were often incomplete, and the duration and degree of exposure could not be checked from clinical records

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Lung cancer, Mesothelioma, Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Interstitial, Pleural Mesothelioma, Pleural Plaques, Asbestos Bodies, Occupational History, Multivariate Analysis.

Related studies

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• Dyskeratosis congenita showing usual interstitial pneumonia — S. Imokawa, A. Sato, et al. (1994)
• Asbestosis and environmental causes of usual interstitial pneumonia — M. Gulati, C.A. Redlich (2015)
• Incidence of interstitial lung disease in patients with mesothelioma in the west part of Japan — S. Nojiri, K. Gemba, et al. (2011)
• Electron microscopic studies in desquamative interstitial pneumonia associated with asbestos — B. Corrin, A.B. Price (1972)
• Imatinib mesylate inhibits fibrogenesis in asbestos-induced interstitial pneumonia — K. Vuorinen, F. Gao, et al. (2007)

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