Man-made mineral fibers and interstitial lung diseases

Our plain-English summary of Man-made mineral fibers and interstitial lung diseases, by E. Fireman (Current Opinion in Pulmonary Medicine, 2014).

The study

• Author: E. Fireman
• Journal: Current Opinion in Pulmonary Medicine
• Published: 2014;20(2):194-8
• Type of article: Review
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Purpose Of Review: Manufactured (artificial) fibers represent an important and continuously growing volume among substitutes to natural fibers. A major proportion of the population in an industrialized society has been, is, or will be in contact with these fibers. The fibrous configuration of asbestos is well recognized as being an important parameter in toxicity, and now that of synthetic fibers is also suspected of inducing serious health effects on the respiratory system. There is an ongoing debate about the actual fibrogenic effect of these man-made mineral fibers (MMMFs) in humans.

Recent Findings: Several case reports have demonstrated the biopersistance of MMMFs in the lung of workers who were exposed to rock wool or fiberglass for long periods of time and were diagnosed with interstitial pulmonary fibrosis. A 20-year follow up also identified refractory ceramic fibers in workers' lung tissue, with significant association between cumulative fiber exposure and radiographic pleural changes. Newly emerging man-made fiber industries appear to induce new types of occupational diseases.

Summary: Exposure of workers in MMMFs production plants is correlated to high risk for developing pneumoconiosis. Large epidemiological studies are needed in order to determine dose metrics for risk assessment and management.

In plain English

This was a single-author narrative review of research on man-made mineral fibers (MMMFs), including glass, rock and slag wool and refractory ceramic fibers. The term excludes asbestos. The author summarized animal, laboratory and human studies on how long these fibers stay in the lung and whether they cause disease. A 1995 review the author cited had found no evidence of a pneumoconiosis risk among workers in glass, rock or slag wool production plants. A later study of refractory ceramic fiber workers with no reported asbestos exposure linked cumulative exposures of more than 63 to 110, and more than 110, fiber-months per cubic centimetre with X-ray pleural changes in 8.5% and 11.6% of workers, respectively. It also described single case reports of pulmonary fibrosis in workers exposed to glass or rock wool, and six workers with obliterative bronchiolitis who prepared fiberglass with styrene resins. The author stated that human data on fiber persistence in the lung were too limited for general conclusions about all MMMFs. The author concluded that epidemiological and toxicological studies were urgently needed.

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: narrative review of published animal, in-vitro and human studies and case reports
• Who was studied: No study population of its own; the review drew on published studies and case reports, including workers exposed to rock wool, fiberglass and refractory ceramic fibers
• Exposure: Man-made mineral fibers: continuous filament glass, mineral wools (rock, slag and glass wool) and refractory ceramic fibers; some animal studies cited compared them with crocidolite asbestos
• Main results:
  • Citing the International Agency for Research on Cancer, the review reported that an estimated 9 million tons of MMMFs were produced worldwide in 2001
  • In a sheep study the author cited, ferruginous bodies were not found in any of the three MMMF groups after 2 years but were substantial in the crocidolite group
  • In a cited autopsy study of glass fiber and mineral wool production workers, man-made vitreous silicate fibers were absent from most workers' lungs
  • A cited 20-year follow-up identified refractory ceramic fibers in workers' lung tissue up to 20 years after exposure
  • In the same cited study, among refractory ceramic fiber workers with no reported asbestos exposure, cumulative exposures of more than 63 to 110 and more than 110 fiber-months per cubic centimetre were associated with radiographic pleural changes of 8.5% and 11.6%, respectively
  • A 1995 review the author cited stated there was no evidence of a pneumoconiosis risk among workers in glass, rock or slag wool production plants
  • Case report cited: pulmonary fibrosis in a carpenter with 41 years of glass fiber inhalation
  • Case report cited: interstitial pulmonary fibrosis in a rock wool spray insulator employed for 12 years
  • Case report cited: a bus driver with fibers compatible with glass wool in lung tissue; the bus roof was insulated with glass wool
  • In a cited report on 50 sarcoid-like patients, 14 had an occupational history of exposure to rock wool or glass fibers, and fiber deposits were found in six of 12 available biopsies
  • A cited report identified six workers with obliterative bronchiolitis, all of whom prepared fiberglass with styrene resins; the review said work with glass fiber-reinforced plastics may be a newly identified cause
  • The review stated that existing evidence did not support an increase in obstructive lung disease from glass fiber and rock wool exposure in the production industry
• The authors' conclusion: The author concluded that epidemiological and toxicological studies on the biopersistence of MMMFs were urgently needed, because their potential impact on human health was essentially unknown
• Limitations the authors state:
  • The author stated that human data on biopersistence were too limited for general conclusions about the biopersistence of all MMMFs in the human lung
  • The author noted that many MMMF workers were likely also exposed to asbestos, because plant equipment was insulated with asbestos
  • The author noted that studies of obstructive lung disease were generally inconclusive and hard to compare

Topics

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

Medical terms in this study, explained in our Lexicon: Mineral Fiber, Interstitial Lung Disease, Fibrogenic, Interstitial, Pulmonary Fibrosis, Occupational Disease, Pneumoconiosis, Dose Metric.

Related studies

• Silica, asbestos, man-made mineral fibers, and cancer — K. Steenland, L. Stayner (1997)
• Mineral fiber problems and their management: UK 1890-1935 — M. Greenberg (2004)
• Environmental measurements of total dust and fiber concentration in manufacturer and user of man-made mineral fibers — J.H. Kim, H.S. Chang, et al. (1999)
• Respiratory health effects of man-made vitreous (mineral) fibres — P. De Vuyst, P. Dumortier, et al. (1995)
• Comparative epidemiology of men exposed to asbestos and man-made mineral fibers — J.R. Goldsmith (1986)
• A trial on the quantitative risk assessment of man-made mineral fibers by the rat intraperitoneal administration assay using the JFM standard fibrous samples — S. Adachi, K. Kawamura, et al. (2001)

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