Domestic asbestos exposure: a review of epidemiologic and exposure data

Our plain-English summary of Domestic asbestos exposure: a review of epidemiologic and exposure data, by E. Goswami, V. Craven, D.L. Dahlstrom, et al (International Journal of Environmental Research and Public Health, 2013).

The study

• Authors: E. Goswami, V. Craven, D.L. Dahlstrom, D. Alexander, F. Mowat
• Journal: International Journal of Environmental Research and Public Health
• Published: 2013;10(11):5629-70
• Type of article: Meta-analysis, Review
• Cited by: 56 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Inhalation of asbestos resulting from living with and handling the clothing of workers directly exposed to asbestos has been established as a possible contributor to disease. This review evaluates epidemiologic studies of asbestos-related disease or conditions (mesothelioma, lung cancer, and pleural and interstitial abnormalities) among domestically exposed individuals and exposure studies that provide either direct exposure measurements or surrogate measures of asbestos exposure. A meta-analysis of studies providing relative risk estimates (n = 12) of mesothelioma was performed, resulting in a summary relative risk estimate (SRRE) of 5.02 (95% confidence interval [CI]: 2.48-10.13). This SRRE pertains to persons domestically exposed via workers involved in occupations with a traditionally high risk of disease from exposure to asbestos (i.e., asbestos product manufacturing workers, insulators, shipyard workers, and asbestos miners). The epidemiologic studies also show an elevated risk of interstitial, but more likely pleural, abnormalities (n = 6), though only half accounted for confounding exposures. The studies are limited with regard to lung cancer (n = 2). Several exposure-related studies describe results from airborne samples collected within the home (n = 3), during laundering of contaminated clothing (n = 1) or in controlled exposure simulations (n = 5) of domestic exposures, the latter of which were generally associated with low-level chrysotile-exposed workers. Lung burden studies (n = 6) were also evaluated as a surrogate of exposure. In general, available results for domestic exposures are lower than the workers' exposures. Recent simulations of low-level chrysotile-exposed workers indicate asbestos levels commensurate with background concentrations in those exposed domestically.

In plain English

This article was a review of published research, not a new study of patients. The authors searched literature from the 1960s to 2012 on domestic (take-home) asbestos exposure: fibers brought home on workers' clothing or bodies, and handling or laundering that clothing. A meta-analysis of 12 cohort and case-control studies gave a summary relative risk of mesothelioma of 5.02 (95% confidence interval 2.48 to 10.13) for people domestically exposed through workers in occupations with a traditionally high risk from asbestos. Removing one cohort study (Ferrante et al.) lowered it to 3.34 (2.15 to 5.19). The authors called the two lung cancer studies extremely limited and not supportive of an association. They said studies of pleural and interstitial abnormalities supported an association, largely due to pleural abnormalities. From short simulation studies of handling the clothing of friction-product workers exposed to chrysotile, the authors calculated 8-hour average exposures that they described as indistinguishable from background. The authors concluded that risk was increased where the worker held a traditionally high-risk job involving amphibole asbestos. They noted that the airborne data did not match the populations in the disease studies.

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: Review of published epidemiologic and exposure studies (literature from the 1960s to 2012), including a meta-analysis of mesothelioma studies
• Who was studied: Published articles: 143 identified for inclusion, 108 evaluated. These included 32 case reports and case series, 14 case-control and 3 cohort studies of mesothelioma, 6 studies of pleural and interstitial abnormalities, and 19 exposure studies.
• Exposure: Domestic (take-home, para-occupational) exposure: asbestos fibers brought into the home on workers' clothing or bodies, and handling or laundering workers' contaminated clothing. Fiber types varied by study; the authors report that workers in the disease studies were mostly in high-risk trades with amphibole or mixed-fiber exposure.
• Main results:
  • Meta-analysis of 12 cohort and case-control studies of mesothelioma in domestically exposed people: summary relative risk estimate 5.02 (95% CI 2.48 to 10.13), with heterogeneity evident (p-H less than 0.0001)
  • The authors stated that this finding of increased risk applies to domestically exposed people whose associated workers were in traditionally high-risk occupations involving asbestos exposure
  • With the Ferrante et al. cohort study removed in a sensitivity analysis, the summary relative risk estimate was 3.34 (95% CI 2.15 to 5.19), still statistically significant
  • The two cohort studies combined: summary relative risk estimate 8.51 (95% CI 0.93 to 78.35), elevated but not statistically significant
  • The 10 case-control studies combined: summary relative risk estimate 3.57 (95% CI 2.17 to 5.88), statistically significant
  • Lung cancer: only two studies were found; the authors described them as extremely limited and not supportive of an association
  • Pleural and interstitial abnormalities: according to the authors, the six studies supported an association with domestic exposure, largely due to pleural abnormalities
  • The authors calculated 8-hour time-weighted averages from short simulation studies of handling the clothing of friction-product workers. These were about two orders of magnitude lower than the 8-hour average for automobile mechanics (0.0001 f/cc vs. 0.04 f/cc). The authors described the resulting daily exposures as indistinguishable from background, which they gave as 0.00001 to 0.0001 f/cc.
• The authors' conclusion: The authors concluded that the epidemiologic and lung-burden studies support an increased risk of mesothelioma, and of interstitial but more likely pleural abnormalities, in domestically exposed people whose associated worker was in a traditionally high-risk occupation involving amphibole asbestos. They also concluded that simulation data for low-level chrysotile workers show domestic exposures lower than the workers' and commensurate with background.
• Limitations the authors state:
  • None of the epidemiologic studies reported the exposure levels experienced by the domestically exposed cases
  • The available airborne data, mostly for low-level chrysotile exposure, do not correspond to the populations in the epidemiologic studies, which were exposed through high-risk, amphibole-exposed workers
  • Only two cohort studies were available, and they were heterogeneous
  • The two lung cancer studies had potential confounding by other occupational exposures and did not consider smoking history
  • The comparison based on simulation studies was limited by small sample sizes, short exposure durations and differing fiber analysis methods
  • For studies in foreign languages, only the English abstract was used

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Mesothelioma, Lung Cancer, Interstitial, Meta-Analysis, Relative Risk, confidence interval, Insulator.

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