Lung cancer and mesothelioma in the pleura and peritoneum among Swedish insulation workers

Our plain-English summary of Lung cancer and mesothelioma in the pleura and peritoneum among Swedish insulation workers, by B. Järvholm, A. Sandén (Occupational and Environmental Medicine, 1998).

The study

• Authors: B. Järvholm, A. Sandén
• Journal: Occupational and Environmental Medicine
• Published: 1998;55(11):766-70
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: To estimate the risk of cancer and death in Swedish insulation workers some years after their exposure to asbestos had stopped. One hypothesis was that the risk of lung cancer would tend to decrease some years after the exposure had ended.

Methods: In a cohort study the cancer morbidity and cause of death was investigated in 248 insulation workers and compared with the corresponding morbidity and mortality in the general population. Due to stringent regulations, exposure to asbestos of all types had almost ended in Sweden in the mid-1970s. Through a questionnaire, surviving insulation workers were asked about their exposure to asbestos and their smoking habits.

Results: Between 1970 and 1994 there were 86 deaths compared with the 46.0 expected (standardised incidence ratio (SIR) 1.9; 95% confidence interval (95% CI) 1.5 to 2.3), the increase was mainly due to an increased cancer mortality. The morbidity was increased for lung cancer (11 cases v 2.5 expected (SIR 4.4; 95% CI 2.2 to 7.9)), peritoneal mesothelioma (seven cases; no expected incidence could be calculated as the occurrence is too rare in the general population), cancer in pancreas (five cases v 0.7 expected (SIR 7.1; 95% CI 2.3 to 16.7)). No cases of pleural mesothelioma were found. The risk of lung cancer did not tend to approach that of the general population after the exposure to asbestos decreased.

Conclusions: In the 1980s and the early 1990s, Swedish insulation workers still have a highly increased risk of diseases related to asbestos. The attributable risk for death and cancer was about 50%. The study also confirms the previous finding that mesothelioma in insulation workers seems to be situated in the peritoneum more often than in the pleura.

In plain English

This historical cohort study followed 248 male insulation workers affiliated with the Construction Workers Association in Göteborg, Sweden, in the late 1960s. The authors linked them to national death and cancer registers from 1970 and compared them with the general population. Sweden strictly regulated asbestos use in the mid-1970s. Of the 98 men who answered a questionnaire, 87% reported working with chrysotile, 51% with amosite and 43% with crocidolite. There were 86 deaths against 46.0 expected (risk ratio 1.9; 95% CI 1.5 to 2.3), an excess the authors attributed mainly to increased cancer risk. Lung cancer was increased (11 cases versus 2.5 expected; risk ratio 4.4, 95% CI 2.2 to 7.9). The authors saw no sign that this risk had fallen in 1980 to 1992. There were seven peritoneal mesotheliomas, no pleural mesotheliomas, and five pancreatic cancers versus 0.7 expected. The authors concluded that these workers still had a highly increased risk of asbestos-related disease. Attributable risks for 1980 to 1992 were 53% for all-cause deaths and 52% for all cancer sites. They noted that the study was small.

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: Historical cohort study comparing cancer incidence and mortality with the general Swedish population, using national registers and a questionnaire to surviving workers
• Who was studied: 248 men listed as insulation workers affiliated with the Construction Workers Association in Göteborg, Sweden, in the late 1960s. They were followed from 1970, with causes of death available up to 1994 and cancer cases up to 1992. Sixteen men not found in registers and five who refused were excluded. Of 173 living workers sent a questionnaire, 98 (57%) replied.
• Exposure: Asbestos exposure as insulation workers, before strict Swedish regulation in the mid-1970s. Among questionnaire respondents, 12% said they had never worked with asbestos. 87% reported working with chrysotile (white asbestos), 51% with amosite (brown) and 43% with crocidolite (blue) sometimes or often, and about 30% did not know whether they had worked with brown or blue asbestos. Mean exposure time was 14.4 years (range 0 to 46).
• Main results:
  • Whole cohort, 1970 to 1994: 86 deaths compared with 46.0 expected (RR 1.9; 95% CI 1.5 to 2.3). The authors attributed the increase mainly to increased cancer mortality.
  • Whole cohort: lung (bronchial) cancer, 11 cases versus 2.5 expected (RR 4.4; 95% CI 2.2 to 7.9)
  • Lung cancer standardised rate ratios were 4.0 (95% CI 0.8 to 11.7) for 1970 to 1979 and 5.0 (95% CI 2.1 to 9.8) for 1980 to 1992. The authors saw no indication that the risk had approached that of the general population.
  • Seven cases of peritoneal mesothelioma. No expected number could be calculated because the disease is too rare in the general population.
  • No cases of pleural mesothelioma were found
  • Pancreatic cancer: five cases versus 0.7 expected (SIR 7.1; 95% CI 2.3 to 16.7)
  • Deaths from non-malignant lung disease: seven cases versus 2.4 expected. One was asbestosis, five were pneumonia and one was asthma.
  • For 1980 to 1992, the attributable risk was 53% for all causes of death and 52% for all sites of cancer
• The authors' conclusion: The authors concluded that in the 1980s and early 1990s Swedish insulation workers still had a highly increased risk of asbestos-related diseases. They put the attributable risk at about 50% for death from all causes and cancer of all sites in that period. They also concluded that mesothelioma in insulation workers seems to occur in the peritoneum more often than in the pleura.
• Limitations the authors state:
  • The study was small, so its risk estimates are imprecise, and a moderately increased lung cancer risk (below 2) could not be detected
  • Smoking information came only from the 98 respondents, whose habits may differ from those of the dead workers and non-responders
  • Mesotheliomas are accepted in the cancer register only if confirmed by histology, so their number may be underestimated
  • Some pancreatic cancer cases may be misclassified peritoneal mesotheliomas
  • The low incidence of pleural mesothelioma compared with other studies may be due to chance, given the small size of the study

Topics

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

Medical terms in this study, explained in our Lexicon: Lung Cancer, Mesothelioma, Pleura, Peritoneum, Insulator, Cohort Study, Habit, Standardized Incidence Ratio (SIR).

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