Cancers in Relation to Type of Fibre, Dose, Occupation and Duration of Exposure

Our plain-English summary of Cancers in Relation to Type of Fibre, Dose, Occupation and Duration of Exposure, by H. Bohlig, E. Hain (1972).

The study

• Authors: H. Bohlig, E. Hain
• Published: Biological Effects of Asbestos Lyon, October 2-5, 1972. Paper 34.
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This conference paper mostly reviewed knowledge of cancers, chiefly mesothelioma, in people exposed to asbestos outside work. This could come from living near mines, factories or shipyards, from family members, or from spare-time work. The authors proposed five criteria, only as a basis for discussion, for judging whether such a tumour was asbestos-induced. These were tissue proof of the tumour; a history of non-occupational asbestos contact and no occupational contact; exposure starting at least 15 years earlier; more such cancers locally than in the rest of the population; and evidence of asbestos, seldom shown in tumour tissue but to be measured in lung tissue. They then described 38 non-occupational mesotheliomas, 1958 to 1968, among residents near one Hamburg asbestos factory that blew its dust into the air before the Second World War. They gave a mesothelioma incidence rate of 0.96% for that residential area, against 0.056% for Hamburg's general population. The cases seemed to follow the prevailing wind direction. Latency times ranged from 20 to 48 years. The authors spoke of causality only with reservations and called for retrospective studies in other cities.

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: Conference paper: a review of the literature on non-occupational (environmental) asbestos-related cancers, proposed diagnostic criteria, and a brief survey of mesothelioma cases near one factory
• Who was studied: 38 people with non-occupational mesothelioma living near one asbestos processing factory in Hamburg, Germany, 1958 to 1968, after cases in former asbestos workers were removed
• Exposure: Neighbourhood (non-occupational) exposure to asbestos dust blown into the air from a Hamburg asbestos factory before World War II. The fibre type used by this plant is not stated for this survey.
• Main results:
  • The authors proposed five criteria for an asbestos-induced environmental cancer: tumour proved by histology; a history of non-occupational asbestos contacts with no occupational contacts; exposure onset at least 15 years before the tumour; analogous cancers more frequent in the region than in the rest of the population; and evidence of asbestos, seldom shown in tumour tissue, whose presence in lung tissue ought to be recorded quantitatively
  • The mesothelioma incidence rate in the residential area around the factory was given as 0.96%, compared with 0.056% for the general population of Hamburg over the past decade (figure found in 1969). No denominators were given.
  • General population of Hamburg: mesothelioma incidence rate of 0.056%
  • The clustering of the 38 non-occupational cases around the factory appeared to depend on the prevailing wind direction
  • Patients living near the plant reported severe, visible, snowfall-like dust pollution from the factory
  • Among the 38 cases, latency times ranged from 20 to 48 years, with average latency periods of 30 to 40 years
  • Most of the mapped cases met the first four of the authors' five proposed criteria for an asbestos-induced environmental cancer
  • A further 251 proved mesotheliomas were collected from Hamburg hospital pathology departments, with histories obtained in 150. These were to be published later and were not reported here.
• The authors' conclusion: The authors said evidence on mesothelioma after every kind of asbestos exposure was so meagre that causality could be spoken of only with reservations. They expected that retrospective studies in other cities would find similar results, and they called for such studies.
• Limitations the authors state:
  • The authors said their proposed criteria for environmental asbestos cancers were only a basis for discussion
  • Asbestos can seldom be shown in tumour tissue
  • Knowledge about mesothelioma after every sort of asbestos exposure was described as meagre, so causality could be stated only with reservations

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Incidence, Latency.

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