Asbestos-related radiographic findings among household contacts of workers exposed to Libby vermiculite: impact of workers' personal hygiene practices

Our plain-English summary of Asbestos-related radiographic findings among household contacts of workers exposed to Libby vermiculite: impact of workers' personal hygiene practices, by T.J. Hilbert, A. Franzblau, K.K. Dunning, et al (Journal of Occupational and Environmental Medicine, 2013).

The study

• Authors: T.J. Hilbert, A. Franzblau, K.K. Dunning, E.K. Borton, A.M. Rohs, J.E. Lockey
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2013;55(11):1300-4
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To explore the potential impact of worker hygiene by determining the prevalence of radiographic changes consistent with asbestos exposure among household contacts of workers exposed to Libby vermiculite that contained amphibole fibers.

Methods: Workers and household contacts had chest radiographs and completed questionnaires regarding hygiene and potential exposure pathways.

Results: Participants included 191 household contacts of 118 workers. One household contact (0.5%) had localized pleural thickening, and three (1.6%) had irregular opacities at profusion category 1/0 or greater. Worker radiographs demonstrated pleural changes in 45% and irregular opacities at profusion category 1/0 or greater in 8%.

Conclusions: Libby vermiculite-exposed workers demonstrated an elevated prevalence of pleural and interstitial chest radiographic changes. There was, however, no increased prevalence of similar changes among household contacts, likely because of personal hygiene measures taken by the majority of workers.

In plain English

This study looked at chest X-rays of people who had lived with workers at a plant that expanded vermiculite from Libby, Montana, for use as a carrier in lawn care products. The vermiculite contained asbestos-like minerals that the authors call Libby amphibole. In all, 191 household contacts of 118 workers had a chest X-ray and filled out questionnaires about the workers' hygiene and possible exposure routes. Of the 191 household contacts, one had pleural changes and three had interstitial changes (irregular opacities in the lung). Among the 100 workers with X-rays, 45% had pleural changes and 8% had interstitial changes. For 83.6% of the household contacts, the worker reported wearing coveralls at work. Showering at work was reported by 63.9%. X-ray changes were less common among household contacts of workers who showered or wore coveralls, but these differences were not statistically significant. The authors concluded there was no increased prevalence of these changes among household contacts, likely because of the workers' personal hygiene. They noted possible recall bias, nonparticipation bias that could not be assessed, and too few cases for full statistical analysis.

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: Study of chest radiographs and questionnaires among household contacts of exposed workers, with worker radiographs from related follow-up studies (prevalence study)
• Who was studied: 191 household contacts of 118 workers who had worked at least 1 year at a vermiculite-expanding facility as of June 1980. Household contacts lived within 50 miles of the facility and had lived for at least 1 year with a worker during employment between 1957 and June 1980.
• Exposure: Household (take-home) exposure linked to workers who expanded Libby vermiculite containing asbestiform amphibole minerals (Libby amphibole) for use as a carrier for lawn care products
• Main results:
  • Among the 191 household contacts, one had pleural radiographic changes and three had interstitial changes
  • The three household contacts with interstitial changes (1.6%) had irregular opacities at profusion categories 1/1, 1/1 and 3/2
  • Chest radiographs from 2004 and 2010 follow-up studies were available for 100 of the 118 participating workers
  • Among the workers with radiographs, 45% had pleural changes and 8% had interstitial changes
  • For 83.6% of the 191 household contacts, the corresponding worker reported wearing coveralls at work, rising to 96.2% among those in the vermiculite expander department
  • Showering at work was reported by 63.9% of workers
  • Not statistically significant: X-ray changes in household contacts of workers who showered before going home versus those who did not, 1.6% vs 3.1% (prevalence ratio 0.54; 95% CI 0.08 to 3.70)
  • Not statistically significant: X-ray changes in household contacts of workers who wore coveralls at work versus those who did not, 1.0% vs 5.3% (prevalence ratio 0.20; 95% CI 0.01 to 3.00)
• The authors' conclusion: The authors concluded that household contacts showed no increased prevalence of pleural or interstitial changes, likely because of personal hygiene measures taken by most workers
• Limitations the authors state:
  • Employment and hygiene information was self-reported by workers and household contacts, creating potential for recall bias
  • Potential bias from household contacts who did not participate could not be assessed
  • The low number of cases limits the significance of the prevalence ratios
  • Logistic regression on hygiene practices could not be done because of few cases and high worker participation in hygiene practices

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Libby vermiculite mine, Montana

All asbestos mines

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Libby Vermiculite, Asbestos Exposure, Amphibole Group, Chest X-Ray, Pleural Thickening, Interstitial.

Related studies

• The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part III. Radiographic findings — H.E. Amandus, R. Althouse, et al. (1987)
• Low-level fiber-induced radiographic changes caused by Libby vermiculite: a 25-year follow-up study — A.M. Rohs, J.E. Lockey, et al. (2008)
• Radiographic evidence of nonoccupational asbestos exposure from processing Libby vermiculite in Minneapolis, Minnesota — B.H. Alexander, K.K. Raleigh, et al. (2012)
• Association between cumulative fiber exposure and respiratory outcomes among Libby vermiculite workers — T.C. Larson, V.C. Antao, et al. (2012)
• Exposure to asbestos-containing vermiculite ore and respiratory symptoms among individuals who were children while the mine was active in Libby, Montana — L.C. Vinikoor, T.C. Larson, et al. (2010)
• A clinical assessment and lung tissue burden from an individual who worked as a Libby vermiculite miner — B. Black, R.F. Dodson, et al. (2017)

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