B cell neoplasms and occupational asbestos exposure

Our plain-English summary of B cell neoplasms and occupational asbestos exposure, by D.A. Schwartz, T.L. Vaughan, N.J. Heyer, et al (American Journal of Industrial Medicine, 1988).

The study

• Authors: D.A. Schwartz, T.L. Vaughan, N.J. Heyer, T.D. Koepsell, J.L. Lyon, G.M. Swanson, N.S. Weiss
• Journal: American Journal of Industrial Medicine
• Published: 1988;14(6):661-71
• Cited by: 20 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. 000273).

Abstract

To evaluate the etiologic role of asbestos exposure in B cell neoplasms, we compared the estimated level of occupational exposure to asbestos of cases with chronic lymphocytic leukemia (CLL; N = 429) and multiple myeloma (MM; N = 698) with that of controls (N = 1,683). Cases were identified through four population-based cancer registries in the U.S. and controls were randomly selected from the same geographic areas. Exposure to asbestos was assessed by classifying each job held by a subject into one of four categories, based on the estimated intensity of exposure to asbestos. Evidence was found for a modest increasing risk of CLL with increasing asbestos exposure. Relative to persons with no known occupational exposure to asbestos, the risk for CLL was 1.1 (95% confidence interval (CI) = 0.8-1.6) for low, 1.2 (CI = 0.8-1.8) for medium, and 1.4 (CI = 0.8-2.3) for high peak asbestos exposure (p value for trend = 0.13). The association was strongest in white study subjects and in those individuals exposed 10 to 19 years prior to the interview. No association was observed between MM and occupational exposure to asbestos in the entire study population or within specific subgroups. Given the pattern of immunologic abnormalities that occur with increased frequency in asbestos-exposed persons, our observation of an association between occupational asbestos exposure and CLL deserves attention in subsequent studies.

In plain English

This case-control study examined two B cell cancers: chronic lymphocytic leukemia (CLL) and multiple myeloma (MM). The authors compared 429 people with CLL and 698 with MM, found through four U.S. cancer registries, with 1,683 controls from those areas. Exposure was estimated by rating each job in a person's work history as no, low, medium or high asbestos exposure. Compared with people with no known occupational asbestos exposure, CLL risk rose modestly with peak exposure: 1.1 for low (95% confidence interval 0.8 to 1.6), 1.2 for medium (0.8 to 1.8) and 1.4 for high (0.8 to 2.3). This trend was not statistically significant (p for trend 0.13). The trend was somewhat stronger in white subjects, and the highest estimates were in people 10 to 19 years from first exposure. The authors had not hypothesized this timing beforehand, saw no clear biological reason for it, and said it needed validation. No association was seen for MM. The authors concluded asbestos may raise CLL risk but chance is a plausible explanation. They noted reliance on job histories alone and the study's modest size.

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: Population-based, multicenter case-control study; a secondary analysis of a study originally designed to examine antigenic stimulation in CLL and MM
• Who was studied: 429 people with chronic lymphocytic leukemia (82% of 521 eligible) and 698 with multiple myeloma (87% of 804 eligible), under 80 years of age, reported by cancer registries as diagnosed between July 1, 1977 and June 30, 1981. They lived in King and Pierce counties (Washington); Davis, Salt Lake and Weber counties (Utah); metropolitan Detroit (Michigan); and metropolitan Atlanta (Georgia). They were compared with 1,683 controls (83% of 2,025 eligible) from the same areas. 68% of MM patients and 83% of CLL patients answered the interview directly. The remaining case interviews were completed with a spouse or relative as proxy. Only 1% of control interviews used a proxy.
• Exposure: Occupational asbestos exposure, with no fiber type specified. It was inferred from lifetime work histories: each occupation-industry pairing was rated none, low, medium or high, based on the estimated probability and intensity of exposure (system of Pannett et al.). From these ratings the authors built two measures: peak exposure, and a time- and intensity-weighted exposure score.
• Main results:
  • CLL, all subjects, compared with no known occupational asbestos exposure, by peak exposure: relative risk 1.1 (95% CI 0.8-1.6) for low, 1.2 (CI 0.8-1.8) for medium, and 1.4 (CI 0.8-2.3) for high; p value for trend 0.13.
  • The authors described the increase in CLL risk with peak exposure as modest and not statistically significant.
  • CLL risk showed a similar trend with weighted asbestos exposure, although the estimate for high exposure was slightly lower than for medium exposure.
  • For CLL, the trend of increasing risk with increasing exposure was somewhat stronger in white subjects. Results among direct respondents and among males were similar to those for all subjects.
  • For CLL, in all subjects and in white subjects, the highest relative risk for either exposure measure was in people 10 to 19 years from first exposure.
  • Multiple myeloma, all subjects, by peak exposure: relative risk 0.9 (CI 0.7-1.3) for low, 0.9 (CI 0.6-1.3) for medium, and 1.1 (CI 0.7-1.8) for high. The authors found no evidence relating MM to asbestos exposure.
  • No subgroup, defined by demographic characteristics or time since first exposure, appeared to be at increased risk of MM from occupational asbestos exposure.
• The authors' conclusion: The authors concluded that their data suggest occupational asbestos exposure may place a person at excess risk of CLL. They added that it is distinctly possible there is no true association and the finding is due to chance, and that additional studies in different populations seem warranted. They concluded that their results suggest occupational asbestos exposure does not increase the risk of MM.
• Limitations the authors state:
  • Exposure was based only on the subjects' occupational history, which the authors say undoubtedly misclassified some individuals.
  • The study was of modest size, with low power to detect small elevations in risk, so chance remains a plausible explanation for all of the associations seen.
  • The small excess CLL risk may be due to other occupational exposures occurring at the same time, undetected confounding factors, or chance.
  • The higher CLL risk in the second decade after first exposure was not hypothesized before the analysis. The authors saw no clear biological reason for it and said further investigation is needed to validate it.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Neoplasm, Asbestos Exposure, Occupational Exposure, Myeloma, confidence interval.

Related studies

• Asbestos-associated neoplasms of B cell lineage — E. Kagan, R.J. Jacobson, et al. (1979)
• Multiple myeloma and diesel and other occupational exposures in swedish construction workers — W.J. Lee, D. Baris, et al. (2003)
• Lymphoid and plasma cell malignancies: asbestos-related disorders of long latency — E. Kagan, R.J. Jacobson (1983)
• Plasma cell myeloma presenting with diffuse pleural involvement: a hitherto unreported pattern of a new mesothelioma mimicker — A. Colonna, G. Gualco, et al. (2010)
• A case-control study of multiple myeloma nested in the American Cancer Society prospective study — P. Boffetta, S.D. Stellman, et al. (1989)
• Risk Alleles for Multiple Myeloma Susceptibility in ADME Genes — F. Scionti, G. Agapito, et al. (2022)

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