Fibre-years, pulmonary asbestos burden and asbestosis

Our plain-English summary of Fibre-years, pulmonary asbestos burden and asbestosis, by M. Fischer, S. Günther, K.M. Müller (International Journal of Hygiene and Environmental Health, 2002).

The study

• Authors: M. Fischer, S. Günther, K.M. Müller
• Journal: International Journal of Hygiene and Environmental Health
• Published: 2002;205(3):245-8
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The relations between cumulative asbestos fibre doses at the work-places and asbestos burden of the lung evaluated by lung dust analyses have been tested on 3 different groups of patients of the German Mesothelioma Register: 1. total collective (n = 366), 2. collective without elevated asbestos burden of the lungs (n = 193), 3. collective with asbestoses/minimal asbestoses (n = 64). The relations between the above mentioned parameters are in general only weak. The limit value of > 25 fibre-years is found in 19.6% of persons without increased pulmonary asbestos burden. In spite of reaching or exceeding the cumulative doses of 25 fibre-years, 24% of the whole collective also show no elevated asbestos-concentrations in their lung tissues. By contrast, 42% of patients with asbestos-associated lung fibroses do not attain 25 fibre-years at their work-places. Considering our data it is doubtful that the postulated limit value of 25 fibre-years can be an adequate parameter for the evaluation of asbestos-associated lung fibroses.

In plain English

This study, from the German Mesothelioma Register in Bochum, compared two measures of asbestos exposure in 366 patients aged 33 to 82. One was the calculated cumulative workplace dose in "fibre-years". The other was the amount of asbestos found in lung tissue by lung dust analysis. The authors focused on 25 fibre-years, a value discussed in Germany as a limit for diagnosing asbestos-associated lung fibrosis. They found the relation between the two measures was only weak: identical fibre doses could go with very low or very high lung burdens. Of 193 patients without elevated lung asbestos burden, 19.6% had 25 fibre-years or more. Of 64 patients with minimal asbestosis or asbestosis, all had elevated lung burden, but only 58% reached 25 fibre-years. That criterion would therefore have excluded 42% of them. Among patients with more than 25 fibre-years, 24% showed no elevated lung burden. The authors concluded that the 25 fibre-year criterion alone is an insufficient parameter for deciding industrial disease claims for asbestos-associated lung fibroses.

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: Analysis of register patient data comparing calculated cumulative workplace asbestos doses (fibre-years) with lung dust analysis results
• Who was studied: 366 patients of the German Mesothelioma Register (Bochum, Germany), aged 33 to 82, for whom both fibre-year calculations and lung dust analyses existed, selected without considering their diseases. Two subgroups were analysed in detail: 193 patients without elevated lung asbestos burden, and 64 patients with higher lung asbestos burden and asbestos-associated lung fibroses (83% minimal asbestoses, 17% asbestoses diagnosed pathologic-anatomically). A comparison group of 46 patients had mesotheliomas. Dates of study are not given.
• Exposure: Occupational asbestos exposure expressed as calculated cumulative fibre-years (range 0.094 to 314), compared with lung asbestos burden measured by lung dust analysis (2 to 1,510,400 asbestos bodies per cm3 of lung tissue). Light microscopy was used for the 193-patient group and electron microscopy for the mesothelioma group. The 25 fibre-year value was examined because it was being discussed as a limit for diagnosing asbestos-associated lung fibroses.
• Main results:
  • Across the 366 patients, the relation between fibre-years and lung asbestos burden was weak; identical fibre doses could correspond to very low or extraordinarily high lung burdens.
  • Of the 193 patients without elevated lung asbestos burden (by light microscopy), 19.6% had a cumulative workplace exposure of 25 fibre-years or more.
  • In 46 patients with malignant mesotheliomas, asbestos fibre concentrations measured by electron microscopy also showed high variation against fibre-years.
  • All 64 patients with asbestos-associated lung fibroses had elevated lung asbestos burden, but only 58% reached or exceeded 25 fibre-years. Requiring 25 fibre-years would have excluded 42% of them.
  • 24% of the patients with more than 25 fibre-years showed no elevated lung asbestos burden. The authors described this as a false-positive rate, and the 42% figure as a false-negative rate.
• The authors' conclusion: The authors concluded that the 25 fibre-year criterion alone is an insufficient parameter for the industrial disease adjudication procedure for asbestos-associated lung fibroses. In their view, fibre-years alone do not allow any prognosis, and individual factors must be considered.
• Limitations the authors state:
  • The authors attributed the weak relation partly to the inaccuracy of fibre-year calculations. They noted that these calculations usually assume worst-case conditions that need not be realistic.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Lung cancer.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Cumulative Dose.

Related studies

• Commentary regarding the article by Fischer et al.: Fibre years, pulmonary asbestos burden and asbestosis. Int. J. Hyg. Environ. Health 205, 245-248 (2002) — D.W. Henderson (2003)
• Commentary regarding the article by Fischer et al.: Fibre years, pulmonary asbestos burden and asbestosis. Int. J. Hyg. Environ. Health 205, 245-248 (2002) — K. Rödelsperger, H.J. Woitowitz (2003)
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• Incidence of cancer among Finnish patients with asbestos-related pulmonary or pleural fibrosis — A. Karjalainen, E. Pukkala, et al. (1999)

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