Cancer incidence among asbestos-exposed chemical industry workers: an extended observation period

Our plain-English summary of Cancer incidence among asbestos-exposed chemical industry workers: an extended observation period, by B. Hilt, A. Andersen, J. Rosenberg, et al (American Journal of Industrial Medicine, 1991).

The study

• Authors: B. Hilt, A. Andersen, J. Rosenberg, S. Langård
• Journal: American Journal of Industrial Medicine
• Published: 1991;20(2):261-4
• Cited by: 8 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. 004869).

Abstract

A previous study on the incidence of cancer in a cohort of 286 asbestos-exposed electrochemical industry workers observed from 1953 through 1980 has been extended with another 8 years of follow-up. The incidence of cancer was derived from the Cancer Registry of Norway, and the expected figures were calculated by a life table method. During the extended follow-up period from 1981 through 1988, among the cohort members there were 12 new cancer cases versus 14.2 expected (SIR 85, 95% CI 44-158). In a lightly exposed sub-cohort, the extended follow-up revealed 4 cases of lung cancer or pleural mesothelioma (ICD, 7th revision 162-163) versus 1.6 cases expected (SIR 256, 95% CI71-654). In a heavily exposed sub-cohort, the corresponding figures were 3 and 0.5 (SIR 588, 95% CI 118-1,725).

In plain English

This short communication added eight years of follow-up (1981 through 1988) to the authors' earlier study of cancer among asbestos-exposed production and maintenance workers at a Norwegian nitric acid plant, followed from 1953 through 1980. Asbestos had been used as tightening material in the plant's nitric acid towers and as gasket material in large incinerators. The article does not name the fiber type. The 287 workers were 190 lightly and 97 heavily exposed. Cancers were identified through the Cancer Registry of Norway and compared with numbers expected from national rates. During 1981-1988 there were 12 new cancers versus 14.2 expected (SIR 85, 95% CI 44-158). For lung cancer and pleural mesothelioma combined, the lightly exposed group had 4 cases versus 1.6 expected (SIR 256, 95% CI 71-654). The heavily exposed group had 3 versus 0.5 (SIR 588, 95% CI 118-1,725). The authors concluded that the increased risk for lung cancer and malignant tumors of the pleura had persisted. Except in the lightly exposed group, rate ratios were lower than in 1985, which the authors suggested might reflect a survivor population.

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 study (extended follow-up of an earlier cohort), using linkage with the national cancer registry and expected numbers from national incidence rates; published as a short communication
• Who was studied: 287 asbestos-exposed production and maintenance workers from a nitric acid plant in Norway: 190 in a lightly exposed group and 97 in a heavily exposed group. They were followed from 1953 through 1988, with the extension covering 1981 through 1988.
• Exposure: Asbestos used, since the plant opened in 1928, as a tightening material in nitric acid towers built from granite blocks and as gasket material in large incinerators. Fiber type and doses are not given in this article; the exposure was described in the authors' 1985 report.
• Main results:
  • Total cohort, extended follow-up 1981-1988: 12 new cancer cases versus 14.2 expected (SIR 85, 95% CI 44-158).
  • The 12 new cases (1981-1988) were 5 lung cancers, 2 malignant mesotheliomas, 2 stomach cancers, 2 prostate cancers and 1 laryngeal cancer.
  • Lightly exposed group, 1981-1988: 4 cases of lung cancer or pleural mesothelioma (ICD 162-163) versus 1.6 expected (SIR 256, 95% CI 71-654).
  • Heavily exposed group, 1981-1988: 3 cases of lung cancer or pleural mesothelioma versus 0.5 expected (SIR 588, 95% CI 118-1,725).
  • The SIR was significantly reduced for cancer sites other than those listed specifically in the tables.
  • The SIR increased with time since first exposure for total cancers, lung cancer, cancer of the pleura, stomach cancer and cancer of unknown origin.
  • Over the whole period 1953-1988, workers first exposed before 1950 showed the greatest increase: 17 lung cancers versus 4.2 expected, and 5 cancers of the pleura versus 0.09 expected.
  • Colon cancer, malignant melanoma of the skin and cancer of unknown origin had been increased in the 1985 report. There were no new cases of any of these during 1981-1988.
• The authors' conclusion: The authors concluded that the 8-year extension indicates the increased cancer risk had persisted for lung cancer and malignant tumors of the pleura.
• Limitations the authors state:
  • Except for the lightly exposed group, rate ratios in the extended follow-up were lower than in 1985. The authors suggested this might reflect that they were now partly studying a survivor population.
  • The extended follow-up added no new information on how asbestos exposure and smoking together affect lung cancer risk.

Topics

Medical terms in this study, explained in our Lexicon: Cancer Registry, Lung Cancer, Pleural Mesothelioma.

Related studies

• Incidence of cancer and mortality among workers exposed to mercury vapour in the Norwegian chloralkali industry — D.G. Ellingsen, A. Andersen, et al. (1993)
• Dangerous and cancer-causing properties of products and chemicals in the oil refining and petrochemical industry: Part V--Asbestos-caused cancers and exposure of workers in the oil refining industry — M.A. Mehlman (1991)
• A cancer incidence and mortality study of Dow Chemical Canada Inc. manufacturing sites — C. Burns, K. Harrison, et al. (2005)
• Incidence of cancer among workers producing calcium carbide — H. Kjuus, A. Andersen, et al. (1986)
• Asbestos disease in maintenance workers of the chemical industry — R. Lilis, S. Daum, et al. (1979)
• Cancer incidence in a chlorochemical plant in Isère, France: an occupational cohort study, 1979-2002 — V. Bonneterre, G. Mathern, et al. (2012)

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