Environmentally mediated disorders of the respiratory tract

Our plain-English summary of Environmentally mediated disorders of the respiratory tract, by M.J. Utell, J.M. Samet (The Medical Clinics of North America, 1990).

The study

• Authors: M.J. Utell, J.M. Samet
• Journal: The Medical Clinics of North America
• Published: 1990;74(2):291-306
• Type of article: Review
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Although much of the evidence in environmental lung disease remains equivocal, some environmental exposures are known to be clinically relevant. Ambient air pollution remains of concern as a source of morbidity, particularly for susceptible populations such as persons with asthma, chronic obstructive pulmonary disease, or cardiac disease and the elderly. The adverse effects of several components of indoor air pollution have been established. Environmental tobacco smoke contributes to lower-respiratory illness in infants; office workers exposed to thermophilic actinomycetes contaminating ventilation systems have developed hypersensitivity pneumonitis; and in the home, components of house dust and fungus spores may provoke asthma via immediate hypersensitivity. The evidence is less compelling for a link between other exposures and disorders of the respiratory tract. For example, formaldehyde may be responsible for provoking vague respiratory symptoms and even nasal cancers; however, the associations are unproved. Likewise, the relation between low-level exposure to asbestos and the development of lung cancer, although a concern, is not conclusively established. The clinician should be aware of practical measures for patients who inquire about air cleaning. Often, relatively simple solutions are effective. A knowledge of sources and exposures as well as an understanding of the principles of inhalation lung injury should prove useful in directing patient care.

In plain English

This 1990 article was a narrative review for internists and primary care clinicians of how indoor and outdoor air pollutants, including asbestos, affect the respiratory tract. It reported no new study data. The authors described how amphibole asbestos fibers tend to align with airflow, while chrysotile fibers are more likely to deposit where airways branch. They cited Lippmann's conclusion that mesothelioma is most closely associated with fibers longer than 5 micrometers and thinner than 0.1 micrometers, and lung cancer with fibers longer than 10 micrometers and thicker than 0.15 micrometers. They stated that most nonoccupational exposures, such as those in public buildings, carry little or no risk of asbestosis, and that cigarette smoking is synergistic with asbestos in causing lung cancer. They described a published report of mesothelioma in Native Americans in New Mexico who had not been occupationally exposed. That exposure was traced to asbestos used in making jewelry and whitening ceremonial clothing. The authors concluded that the relation between low-level asbestos exposure and lung cancer, although a concern, was not conclusively established.

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 (no original data)
• Who was studied: No study population. The article is a review written for internists and primary care providers, drawing on published studies and reports.
• Exposure: A range of indoor and outdoor air pollutants, including asbestos. The authors list indoor asbestos sources as insulation or structural components, pipes, furnaces and tiles.
• Main results:
  • The authors described fiber deposition: amphibole fibers are straight and tend to align with the flow of air, while chrysotile fibers are more likely to deposit at airway bifurcations.
  • Citing Lippmann (a separate publication), the authors reported that mesothelioma is most closely associated with the number of fibers longer than 5 micrometers and thinner than 0.1 micrometers.
  • Citing Lippmann, the authors reported that lung cancer is most closely associated with fibers longer than 10 micrometers and thicker than 0.15 micrometers.
  • The authors stated that most nonoccupational exposures, such as those in public buildings, carry little or no risk of asbestosis.
  • The authors stated that cigarette smoking is synergistic with asbestos (and with radon) in causing lung cancer.
  • The authors described a published report (Driscoll and colleagues) of mesothelioma in several Native Americans in New Mexico who had not been occupationally exposed. The exposure source was asbestos used in preparing jewelry and whitening ceremonial clothing.
• The authors' conclusion: The authors concluded that the relation between low-level asbestos exposure and lung cancer, although a concern, is not conclusively established.
• Limitations the authors state:
  • The authors state that much of the evidence on environmental lung disease remains equivocal.

Topics

Medical terms in this study, explained in our Lexicon: Environmental Exposure, Pneumonitis, Lung Cancer.

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