Respiratory cancer incidence in Swedish construction workers exposed to man-made mineral fibres and asbestos

Our plain-English summary of Respiratory cancer incidence in Swedish construction workers exposed to man-made mineral fibres and asbestos, by G. Engholm, A. Englund, A.C. Fletcher, et al (The Annals of Occupational Hygiene, 1987).

The study

• Authors: G. Engholm, A. Englund, A.C. Fletcher, N. Hallin
• Journal: The Annals of Occupational Hygiene
• Published: 1987;31(4B):663-75
• Cited by: 34 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000311).

Abstract

The incidence of respiratory cancer has been studied in relation to exposure to man-made mineral fibres (MMMF) within a large cohort of Swedish construction workers. The cohort comprised some 135 000 men, who were all examined by Bygghalsan at regular health check-ups in 1971-1974. The cohort has been followed for mortality through 1983 and for cancer incidence through 1982 by linkage to various national registries. A case-control study within the cohort has been carried out on 518 cases diagnosed as having respiratory cancer. For each case, five controls were selected among those who had not developed such a cancer with individual matching for age and year of first check-up. Subjects selected have been classified into categories based on self-reported exposure and on estimates of average intensity of exposure in occupations concerned. In the analysis smoking habits and density of population in parish of residence were included as potential confounders. Results of an analysis of the incidence of pleural mesothelioma in relation to exposure indicates that subjects in the cohort to some extent are unaware of their exposure to asbestos. The strong association between asbestos exposure and MMMF exposure makes it difficult to separate effects of the two exposures. The results, however, appear compatible with the known effect of asbestos exposure on lung cancer incidence. Subjects classified as heavily exposed to MMMF do not have a significantly higher incidence than unexposed subjects.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This study enrolled 135,037 male Swedish construction workers first examined at Bygghalsan check-ups in 1971-1974; 11 could not be linked to national registries, leaving 135,026. Deaths were followed through 1983, cancers through 1982. A questionnaire asked about work with asbestos or glass or mineral wool (man-made mineral fibres, MMMF). Hygienists rated exposure intensity for most jobs. Lung cancer cases were compared with matched cohort controls. Pleural cancers numbered 23 against 11 expected; all were mesotheliomas. Self-reported exposure alone was not linked to lung cancer. Categories 3-5 meant self-reported exposure, 15 or more years' latency, and jobs rated 2 or higher. In these categories, the asbestos lung cancer relative risk, disregarding MMMF, was 2.89 (95% confidence interval 1.02-8.14). Analysed together in these categories, the risks were 2.53 (0.77-8.32) for asbestos and 1.21 (0.60-2.47) for MMMF. Of the 23 mesothelioma cases, 21 had answered no to the asbestos question. The authors concluded there appeared to be an asbestos-related risk but no evidence of an MMMF risk after allowing for asbestos. They judged the data insufficient to evaluate MMMF.

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: Cohort follow-up through national registries, with a case-control study nested within the cohort (five individually matched controls per case)
• Who was studied: 135,037 male Swedish construction workers first examined at Bygghalsan health check-ups in 1971-1974. Eleven could not be linked to the national files and were excluded, leaving 135,026 in the analysis. They were followed for mortality through 1983 and for cancer incidence through 1982.
• Exposure: Asbestos (including spraying asbestos and sawing or drilling asbestos cement sheets such as Eternit and Invarit) and MMMF (glass wool or mineral wool). Exposure was measured two ways: self-reported questionnaire answers, and hygienists' 0-5 exposure intensity ratings for most of the 160 job tasks. Asbestos fiber types are not named.
• Main results:
  • Overall mortality in the cohort was lower than in the general Swedish population: 7356 deaths observed versus 10,896 expected (SMR 68).
  • Cancers of the pleura in the cohort were in excess: 23 cases versus 11 expected (SIR 213). The cancer registry classified all 23 as mesotheliomas.
  • Overall lung cancer incidence in the cohort was below that expected.
  • For self-reported exposure alone, analysed simultaneously, the lung cancer relative risk was 0.83 (95% CI 0.56-1.22) for asbestos and 1.19 (0.91-1.55) for MMMF. Neither was associated with lung cancer.
  • For exposure Categories 3-5 combined, the lung cancer relative risk was 2.89 (1.02-8.14) for asbestos when MMMF was disregarded. For MMMF when asbestos was disregarded, it was 1.45 (0.80-2.62).
  • When asbestos and MMMF in Categories 3-5 were analysed simultaneously, the lung cancer relative risk was 2.53 (0.77-8.32) for asbestos and 1.21 (0.60-2.47) for MMMF.
  • Category 3-5 meant job exposure intensities 2-5 plus self-reported exposure with a latency period of 15 years or more. The authors judged that estimates for this category indicated an effect on lung cancer from asbestos in both separate and simultaneous analyses.
  • Of the 23 pleural mesothelioma cases, 21 had answered no to the asbestos exposure question.
• The authors' conclusion: The authors concluded that there appeared to be a lung cancer risk related to asbestos exposure, but no evidence of a risk related to MMMF exposure after allowing for asbestos.
• Limitations the authors state:
  • The authors judged the data insufficient to evaluate MMMF risk for three reasons. Asbestos and MMMF exposures were highly correlated. No one was in a high exposure category for one fiber while unexposed to the other. Follow-up since MMMF became widely used was relatively short.
  • Because of the strong association between the two exposures, the risk estimates remained unstable.
  • Workers' answers to the asbestos question were a weak indicator of their true asbestos exposure.

Topics

Medical terms in this study, explained in our Lexicon: Case-Control Study, Habit, Pleural Mesothelioma, Asbestos Exposure, Lung Cancer.

Related studies

• Lung dust analysis in the assessment of past exposure of man-made mineral fibre workers — J.C. McDonald, B.W. Case, et al. (1990)
• Determinants of respiratory symptoms in insulation workers exposed to asbestos and synthetic mineral fibres — P. Ernst, S. Shapiro, et al. (1987)
• Man-made vitreous fibers and risk of respiratory system cancer: a review of the epidemiologic evidence — I.M. Lee, C.H. Hennekens, et al. (1995)
• Occupational exposures and risk of esophageal and gastric cardia cancers among male Swedish construction workers — C. Jansson, A.L. Johansson, et al. (2005)
• Health aspects of man-made mineral fibres. A review — J.W. Hill (1977)
• The impact of asbestos exposure in Swedish construction workers — B. Järvholm, A. Englund (2014)

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