THE DOUBT THAT DOES NOT OFFEND: ASBESTOS AND IDIOPATHIC PULMONARY FIBROSIS
Author: Francisco Báez Baquet
Dedication: we dedicate this work to Dr. Joan Benach, in gratitude for allowing us to disseminate information about the content of our book “Asbestos: a Genocide with impunity”, at the headquarters of the University «Pompeu Fabra» (Barcelona).
A possible causal link between exposure to asbestos and idiopathic pulmonary fibrosis (with which, that last adjective would already be inappropriate) -see: Sobradillo (2010) -, was already pointed out in Gaensler et al. (1991). See also: Taskar & Coultas (2006).
Consider the following process schema:
- a) – Certain cases of idiopathic pulmonary fibrosis are established.
- b) – A closer examination, with more powerful means (electron microscopy), determines that several of these cases classified as idiopathic fibrosis, evidence the presence of asbestos fibers in the lung parenchyma, at levels of the same order of magnitude as that found in cases clearly diagnosed as asbestosis.
- c) – As a consequence of the above, these cases are re-diagnosed as asbestosis -see: Monsó et al. (1991) -. This requalification has medico-legal effects, given that asbestosis determines the right to compensation, and, on the other hand, idiopathic fibrosis does not.
- d) – Acting in this way, if there really is a causal link between the so-called idiopathic fibrosis and exposure to asbestos, the casuistic evidence that these cases would provide would be eliminated. Therefore, “we would have thrown the child, along with the bath water”.
The idiopathic fibrosis has also been associated with a malignant pathology nonspecifically associated also with exposure to asbestos, as is the case of lung cancer: Nagai et al. (1992), Mizuzhma & Kobayashi (1995).
Since before of 1991, exposure to asbestos has been linked to other fibrosis, outside the pulmonary parenchyma. This is the case of retroperitoneal fibrosis -see, for example: Boulard et al. (1995), van Bommel et al. (2009), Goldoni et al. (2014) -, or that of mediastinal structures: O’Brien & Franks (1987).
These associations, by extension, confer plausibility to the possibility, to the hypothesis, of a causal nexus between asbestos and “idiopathic” fibrosis of the pulmonary parenchyma, in those cases in which there are no other signs and symptoms characteristic of asbestosis, in the strict sense.
This, in general terms, would come to be “the state of the art”, in which the research of the team whose main member is Dr. Carl Reynolds, of the Imperial College of London is framed.
The research, which was presented at the International Congress of the European Respiratory Society (Munich, Germany, September 9, 2014), provided new mortality data for idiopathic pulmonary fibrosis, asbestosis and mesothelioma.
This investigation is based on the assumption that asbestosis is the name given to lung disease developed by people with a known history of exposure to asbestos.
The symptoms, and the presentation of this disease, may be identical to those of idiopathic pulmonary fibrosis.
The only difference between the two diseases is whether a patient knows anything about their exposure to asbestos.
People with asbestosis are not currently eligible for new treatments for idiopathic pulmonary fibrosis, despite the fact that these treatments work in the cure of that disease, identical in its symptoms and signs.
The aforementioned researchers have suggested that a certain proportion of cases of idiopathic pulmonary fibrosis may be due to unknown exposure to asbestos.
Mortality rates of idiopathic pulmonary fibrosis, asbestosis, and mesothelioma were analyzed throughout England and Wales.
The data were obtained from the National Statistical Office on the annual number of deaths due to idiopathic pulmonary fibrosis, mesothelioma and asbestosis, for the period 1974-2012, disaggregated by age, sex and region.
When analyzing deaths from mesothelioma and asbestosis, they found a similar upward trend in mesothelioma, but with a relatively small increase in deaths from asbestosis.
The analysis revealed national and regional correlations between the three diseases, which supports the theory that a proportion of cases of idiopathic pulmonary fibrosis are due to unknown exposure to asbestos.
If exposure to asbestos were known, it would be likely that these patients were diagnosed with asbestosis, instead of idiopathic pulmonary fibrosis.
There were also high rates of deaths due to idiopathic pulmonary fibrosis, in certain regions in the northwest and south-east of England, which have a history of work in shipyards and, therefore, of potential exposure to asbestos dust.
The Dr. Reynolds stated that “the results are consistent with the hypothesis that a proportion of cases of idiopathic pulmonary fibrosis are probably caused by unknown exposure to asbestos. More research is needed in this area, particularly in patients who are exposed to asbestos and who are not currently considered as candidates for new treatments for idiopathic pulmonary fibrosis, and this may be inappropriate.”
In Barber et al. (2015), in a paper entitled “Imports of asbestos from the United Kingdom and mortality due to idiopathic pulmonary fibrosis”, the authors show the following summary:
“Previous studies have shown that the increased mortality due to mesothelioma and asbestosis, can be predicted from the historical use of asbestos. Mortality due to idiopathic pulmonary fibrosis (IPF) is also increasing, with no apparent explanation.
To compare the mortality from these conditions and to examine the relationship between the mortality and the national imports of asbestos, the mortality data from FPI and asbestosis in England and Wales were available from the Office of National Statistics.
The data on deaths from mesothelioma in England and Wales, and historical data on imported asbestos from the United Kingdom, were available from the Health and Safety Executive.
The number of annual deaths, due to each condition, was represented separately by sex, in comparison with the asbestos imports of the United Kingdom, in the previous 48 years. Linear regression models were constructed.
For mesothelioma and IPF, there was a significant linear relationship between the number of deaths of men and women each year, and the historical data on imports of asbestos from the United Kingdom.
For the asbestosis mortality, a similar relationship was found for male deaths, but not for women.
The annual figures of deaths due to asbestosis in both sexes were lower than those of FPI and mesothelioma.
The strength of the association between IPF mortality and historical data on asbestos imports was similar to that observed in a disease already established as related to asbestos, that is, with the mesothelioma.
This finding could be explained in part, by the diagnostic difficulties, in the separation between asbestosis and IPF and highlights the need for a more accurate method to assess exposure to asbestos, in work for life.”
In our personal opinion, the results that highlight the geographical coincidence between areas of intensive use of asbestos and the grouping in the number of cases of idiopathic pulmonary fibrosis are particularly convincing, and in that sense, we consider it would be very convenient that such type of study extended to other different regions, in which also the industrial use of asbestos was especially lavished.
Eventually, one of the possible results of all this research, could be that the pathology concept for idiopathic pulmonary fibrosis, end up disappearing, like a sugar in a cup of tea, because of “idiopathic” already would have nothing.
Apart from considerations of a purely medical nature, here is another question, which is nothing else, that if the causal link of idiopathic pulmonary fibrosis is corroborated with respect to asbestos, it automatically opens the door to the eventuality that this ailment may be grounds for compensation claims.
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