Peritoneal cancer and occupational exposure to asbestos: results from the application of a job-exposure matrix

Our plain-English summary of Peritoneal cancer and occupational exposure to asbestos: results from the application of a job-exposure matrix, by P. Cocco, M. Dosemeci (American Journal of Industrial Medicine, 1999).

The study

• Authors: P. Cocco, M. Dosemeci
• Journal: American Journal of Industrial Medicine
• Published: 1999;35(1):9-14
• Cited by: 32 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Because of the rarity of peritoneal mesothelioma, occupational risks associated with it have seldom been studied, particularly among women. In this respect, death certificates databases may provide numbers large enough for analysis, although the International Classification of Diseases, 9th revision (ICD-9) does not single out mesothelioma from the rest of peritoneal cancers. The aim of this paper is twofold: to explore occupational risks of peritoneal cancer among men and women, and to test the performance of a job-exposure matrix in detecting its association with asbestos exposure using the occupation and industry reported in the death certificate.

Methods: From a large database containing information on the 1984-1992 death certificates of 24 U.S. states, we identified 657 deaths from peritoneal cancer and 6,570 controls who died from non-malignant diseases, 1:10 matched by region, gender, race, and 5-year age group.

Results: Occupations at risk included insulators among men, and machine operators among women. Among men, we found a significant increase in risk associated with employment in manufacturing industries, such as industrial and miscellaneous chemicals; miscellaneous non-metallic mineral and stone products; construction and material handling machines; and electrical machinery, equipment, and supplies; as well as in services to dwellings and other buildings. Industries at increased risk among women included elementary and secondary schools; miscellaneous retail stores; and publishing and printing. Our job-exposure matrix classified 17 male cases and 3 controls in the high probability category of exposure to asbestos (OR = 61.6). Among men, risk of peritoneal cancer increased significantly by probability and intensity of exposure to asbestos. No such pattern was observed among women. The job-exposure matrix did not classify any female subjects in the high probability or intensity of asbestos exposure.

Discussion: This study provides evidence that death certificate data and job-exposure matrices are useful tools to observe well-established associations, such as the one existing between peritoneal cancer and asbestos exposure among men, in spite of crude information, disease misclassification, and occupational misclassification. These factors are more likely to preclude meaningful results among women.

In plain English

This was a case-control study based on U.S. death certificates from 24 states for the years 1984 to 1992. The authors compared 657 people (249 men and 408 women) whose death was coded as cancer of the peritoneum with 6,570 people who died of non-malignant diseases. The death-certificate codes could not separate peritoneal mesothelioma from other peritoneal cancers. Asbestos exposure was estimated with a job-exposure matrix, a rating of each job and industry, applied to the one job and industry listed on each certificate. Among men, 17 cases and 1 control were insulation workers (odds ratio 180, 95% CI 23.5 to 1375). Men rated at high probability of asbestos exposure (17 cases, 3 controls) had an odds ratio of 61.6 (17.5 to 216), an excess the authors said was entirely driven by insulators. Among men, risk rose significantly with probability and intensity of exposure. No woman was rated at high exposure, and trends among women were not statistically significant. The authors concluded that death certificates and job-exposure matrices could detect this association in men, and they cautioned that misclassification limited the findings, especially for women.

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: Case-control study using occupation and industry codes from death certificates, with asbestos exposure assigned by a job-exposure matrix designed by the authors
• Who was studied: 657 cases (249 men and 408 women) aged 20 or more whose underlying cause of death was cancer of the peritoneum (ICD-9 codes 158.8 and 158.9). There were 6,570 controls who died from non-malignant diseases, 10 per case, frequency-matched by geographic region, race, gender and 5-year age group. All came from 1984 to 1992 death certificates in 24 U.S. states. Subjects were White or African-American; Asian and Native American subjects were excluded.
• Exposure: Occupational asbestos exposure, unspecified fiber type, estimated from the single occupation and industry on the death certificate. The job-exposure matrix gave scores for intensity and probability of exposure, grouped as none, low, medium or high. No duration of employment was available. Because only 1.5% of subjects (70/7227) could be rated as having no possible exposure, the reference group also included subjects with low probability and low intensity of exposure.
• Main results:
  • Men who were insulation workers: 17 cases and 1 control, odds ratio 180 (95% CI 23.5 to 1375). Of the 17 insulators, 13 worked in the construction industry.
  • All men rated at high probability of asbestos exposure: 17 cases and 3 controls, odds ratio 61.6 (95% CI 17.5 to 216). All were white men, and the authors stated the excess was entirely driven by insulators.
  • All men rated at high intensity of asbestos exposure: 22 cases and 48 controls, odds ratio 4.8 (95% CI 2.8 to 8.3). Among all men, the test for trend was p = 0.0004 by probability and p less than 0.0001 by intensity of exposure.
  • Industries with a significant excess among men:
• construction: 43 cases and 288 controls, odds ratio 1.7 (95% CI 1.2 to 2.4)
• miscellaneous non-metallic mineral and stone products: 5 cases and 6 controls, odds ratio 7.6 (2.3 to 25.5)
• electrical machinery, equipment and supplies: 6 cases and 12 controls, odds ratio 5.1 (1.8 to 13.9)
• services to dwellings and other buildings: 3 cases and 9 controls, odds ratio 3.9 (1.0 to 14.8)
  • Industries with a significantly elevated risk among women:
• printing and publishing: 5 cases and 14 controls, odds ratio 3.8 (95% CI 1.3 to 10.8)
• miscellaneous retail stores: 4 cases and 9 controls, odds ratio 5.0 (1.5 to 16.6)
• elementary and secondary schools: 33 cases and 179 controls, odds ratio 1.5 (1.0 to 2.4)
  • Among women, no cases or controls were rated at high probability or high intensity of asbestos exposure, and trends were not statistically significant. The highest odds ratio among all women was for medium intensity: 7 cases and 45 controls, odds ratio 1.8 (95% CI 0.8 to 4.1), not significant.
  • When the authors applied the exposure criteria of an earlier study (Spirtas et al.) to men in this study, they obtained an odds ratio of 1.8 (95% CI 1.3 to 2.4).
• The authors' conclusion: The authors concluded that occupational exposure to asbestos was associated with a very high risk of peritoneal cancer, with insulators showing the highest risk. They said the strong association in men indicated that cause-of-death and usual occupation information on death certificates is reliable, and that job-exposure matrices are an appropriate first-step approach. They called for a conservative evaluation of most positive findings among women.
• Limitations the authors state:
  • Only the ICD-9 code was available, so mesothelioma could not be distinguished from other peritoneal cancers.
  • Only one occupation and industry was recorded per person, with no duration of employment.
  • Three-digit Census codes may not separate exposed from unexposed subjects well. The authors said the resulting misclassification would bias risk estimates toward the null.
  • Occupational information on death certificates is less reliable for women than for men, so negative findings should be interpreted with caution.
  • Death certificates tend to list the most recent occupation, so earlier or short-term asbestos work may not be recorded.
  • There was no information on spouses' occupations, which might have explained some findings among women.

Topics

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

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Peritoneal Mesothelioma, Death Certificate, Mesothelioma, Asbestos Exposure, Insulator.

Related studies

• Mesothelioma in occupational cohort studies: methodological considerations — N.C. Wojcik, A.R. Schnatter, et al. (2014)
• Occupational asbestos exposure and mesothelioma risk in Los Angeles County: application of an occupational hazard survey job-exposure matrix — C. Cicioni, S.J. London, et al. (1991)
• Death certificates in epidemiological studies, including occupational hazards: inaccuracies in occupational categories — I.J. Selikoff (1992)
• Influence of age at death on accuracy of death certificate disease diagnosis: findings in 475 consecutive deaths of mesothelioma among asbestos insulation workers and asbestos factory workers — I.J. Selikoff (1992)
• Use of death certificates in epidemiological studies, including occupational hazards: variations in discordance of different asbestos-associated diseases on best evidence ascertainment — I.J. Selikoff, H. Seidman (1992)
• Recovering missing mesothelioma deaths in death certificates using hospital records — V.S. Santana, E. Algranti, et al. (2018)

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