Asbestos pleural effusion: a clinical entity

Our plain-English summary of Asbestos pleural effusion: a clinical entity, by G. Mårtensson, S. Hagberg, K. Pettersson, et al (Thorax, 1987).

The study

• Authors: G. Mårtensson, S. Hagberg, K. Pettersson, G. Thiringer
• Journal: Thorax
• Published: 1987;42(9):646-51
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000334).

Abstract

In a case-control study asbestos exposure in 64 consecutive men with idiopathic pleural effusion and 129 randomly sampled age matched male controls was compared. Furthermore, seven women and 64 men with idiopathic pleural effusion were studied, including a three year re-examination, in an attempt to identify characteristics that might distinguish asbestos exposed from non-exposed patients. Asbestos exposure was significantly (p less than 0.01) more frequent in men with idiopathic effusions than in controls. The idiopathic effusions seen in asbestos exposed patients were compatible with the diagnosis "asbestos pleural effusion." Two features were characteristic of patients with asbestos pleural effusion: a chest radiograph at the initial examination showing converging pleural linear structures or rounded atelectasis or a history of recurrent pleural effusion, or both.

In plain English

This study from the University of Göteborg, Sweden, examined pleural effusion (fluid around the lung) that had no identifiable cause. Between April 1976 and August 1979, 99 women and 235 men with effusions lasting at least three weeks were referred. After extensive testing, 7 women and 64 men were classed as having 'idiopathic' effusions with no probable cause; of the 66 still alive after three years, 61 attended a re-examination. In a case-control comparison, the authors compared asbestos exposure in the 64 men with 129 randomly chosen, age matched men, of whom 103 gave work histories. Work histories were rated without knowing who was a patient. Asbestos exposure was found in 42 of 64 male patients (66%) and 45 of 103 controls (44%), p less than 0.01. Among patients, those exposed more often had major radiographic pleural lesions at the first examination. Recurrent effusions were significantly more frequent in those exposed for at least 10 years. No immunological differences were seen. The authors concluded that the effusions in exposed patients were compatible with 'asbestos pleural effusion'.

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: Case-control study comparing asbestos exposure in men with idiopathic pleural effusion and age matched male controls, combined with a clinical study of patients with idiopathic effusion that included a three year re-examination
• Who was studied: Patients with pleural effusions lasting at least three weeks, referred to a department of pulmonary medicine in Göteborg, Sweden, from April 1976 to August 1979 (99 women and 235 men). A definite cause was found in 92 women and 171 men, leaving 7 women and 64 men with idiopathic effusions. Only two of the seven women had occupational asbestos exposure, and the women were not evaluated further. The controls were 129 age matched men randomly selected from the Göteborg County population register; 103 (80%) provided occupational histories. Of the 66 patients still alive at three years, 61 took part in the re-examination.
• Exposure: Occupational asbestos exposure over the whole working life, taken from standardised interviews and rated blind by an occupational hygienist. Exposure was assessed by duration in years and by latency from first exposure. Exposure of less than two days was counted as no exposure. No fiber types were specified. Mean duration of exposure was 17 years for patients and 16 years for controls.
• Main results:
  • Of the 71 patients with idiopathic effusions, 66 were alive after three years; 61 took part in the re-examination.
  • Asbestos exposure was found in 42 of 64 (66%) male patients with idiopathic effusion and in 45 of 103 (44%) age matched male controls (p less than 0.01).
  • At the initial examination, major pleural lesions on the chest radiograph were significantly (p less than 0.05) more common in asbestos exposed patients.
  • At the initial examination, converging pleural linear structures and rounded atelectasis were seen in nine asbestos exposed patients and two non-exposed patients.
  • At the initial examination, a history of recurrent idiopathic effusion was significantly more frequent (p less than 0.05) when patients exposed for at least 10 years were compared with those with shorter or no exposure.
  • Pleural plaques were associated with asbestos exposure at a level of p less than 0.1.
  • At the three year re-examination, recurrent effusion (before the initial examination or during follow-up) differed significantly (p less than 0.01) between patients exposed for at least 10 years and those with shorter or no exposure.
  • Three patients had recurrent effusion during the three year follow-up, and all three had been exposed for more than 10 years.
  • During follow-up, converging pleural linear structures and rounded atelectasis developed in five exposed patients and also in six non-exposed patients.
  • No immunological differences were seen between asbestos exposed and non-exposed patients.
• The authors' conclusion: The authors concluded that the idiopathic effusions in asbestos exposed patients were compatible with the clinical entity 'asbestos pleural effusion'. They identified two distinguishing features: certain radiographic lesions at the initial examination (converging pleural linear structures or rounded atelectasis), or a history of recurrent effusion, or both. They also wrote that the results indicate asbestos exposure is a common, but not the only, cause of idiopathic pleural effusion.
• Limitations the authors state:
  • The authors considered that asbestos associated malignant effusions might have been included by mistake. They argued against this, citing the extensive diagnostic work and three years of follow-up without signs of malignancy.
  • The lesions that developed in 'non-exposed' patients during follow-up somewhat contradicted the initial findings. The authors suggested this might reflect remote, forgotten asbestos exposure, meaning some patients may have been misclassified as unexposed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Pleural Effusion, Case-Control Study, Asbestos Exposure, Idiopathic, Chest X-Ray, Rounded Atelectasis.

Related studies

• Benign mesothelial proliferation with effusion. Clinicopathologic entity that may mimic malignancy — R.M. Hansen, J.G. Caya, et al. (1984)
• Clinical Investigation of Benign Asbestos Pleural Effusion — N. Fujimoto, K. Gemba, et al. (2015)
• Clinical significance of pleural effusion mesothelin in malignant pleural mesothelioma — S. Yamada, C. Tabata, et al. (2011)
• Evolution of idiopathic pleural effusion: a prospective, long-term follow-up study — J.S. Ferrer, X.G. Muñoz, et al. (1996)
• Pleuroperitoneal shunt for recurrent malignant pleural effusions — V. Tsang, H.C. Fernando, et al. (1990)
• Unilateral Ga-67 uptake in the hemithorax after recurrence of pleural effusion — G. Panoutsopoulos, K. Syrigos, et al. (2001)

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