Case series: rheumatological manifestations attributed to exposure to Libby Asbestiform Amphiboles

Our plain-English summary of Case series: rheumatological manifestations attributed to exposure to Libby Asbestiform Amphiboles, by R. Diegel, B. Black, J.C. Pfau, et al (Journal of Toxicology and Environmental Health. Part a, 2018).

The study

• Authors: R. Diegel, B. Black, J.C. Pfau, T. McNew, C. Noonan, R. Flores
• Journal: Journal of Toxicology and Environmental Health. Part a
• Published: 2018;81(15):734-747
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Unlabelled: An increased risk for Systemic Autoimmune Diseases (SAID) has been reported in Libby, Montana, where extensive exposures to fibrous amphiboles occurred due to mining and use of asbestos-laden vermiculite. In addition, positive antinuclear autoantibody tests are associated with exposure to Libby Asbestiform Amphiboles (LAA) in both humans and mice. Among 6603 subjects who underwent health screening at the Center for Asbestos Related Diseases (CARD, Libby MT), 13.8% were diagnosed with an autoimmune disease, with prevalence values for the most common SAID being significantly higher than expected in the United States. Among the CARD screening population, serological and clinical profiles are diverse, representing symptoms and autoantibodies reflective of systemic lupus erythematosus (SLE), scleroderma, rheumatoid arthritis, and other rheumatic syndromes, including undifferentiated connective tissue disease (UCTD). Based upon screening of medical records by physicians with rheumatology expertise, the evolving nature of rheumatological disease in these patients is often atypical, with mixed diagnostic criteria and with a 1:1 male-to-female ratio. Through the Libby Epidemiology Research Program, cases were identified that illustrate clinical autoimmune outcomes with LAA exposure. Our goal was to better characterize SAID in Libby, MT in order to improve recognition of autoimmune outcomes associated with this exposure. In view of recent discoveries of widespread exposure to fibrous minerals in several areas of the U.S. and globally, it is critical to evaluate rheumatologic manifestations in other cohorts so that screening, surveillance, and diagnostic procedures are able to detect and recognize potential autoimmune outcomes of asbestos exposure.

Abbreviations: ANA, antinuclear autoantibody; ARD, Asbestos-Related Diseases; ATSDR, Agency for Toxic Substances & Disease Registry; CARD, Center for Asbestos Related Diseases; CCP, Cyclic citrullinated peptide antibody; CREST, limited cutaneous form of scleroderma; CT, computed tomography; DIP, Distal Interphalangeal Joint; DLCO, Diffusing Capacity of the Lung for CO2; DMARD, Disease Modifying Anti-Rheumatic Drugs; ENA, Extractable Nuclear Antigen antibodies; FVC, Forced Vital Capacity; LAA, Libby Asbestiform Amphiboles; LERP, Libby Epidemiology Research Program; MCP, Metacarpal Phalangeal Joint; PIP, Proximal Interphalangeal Joint; PIP, rheumatoid arthritis; RV, Residual Volume; SAID, Systemic autoimmune diseases; SLE, systemic lupus erythematosus; SSc, Systemic Sclerosis; TLC, Total Lung Capacity.

In plain English

This article was a case series describing autoimmune (rheumatological) illness in ten people exposed to Libby Asbestiform Amphiboles (LAA), fibers linked to vermiculite mined near Libby, Montana. Nine of the ten were men. Research team physicians chose the cases to show unusual presentations of severe autoimmune disease. All had relatively high, mostly environmental exposure, and all had some form of asbestos-related lung or pleural disease. Their diagnoses varied and included rheumatoid arthritis, lupus, a CREST variant of systemic sclerosis, psoriatic arthritis, Behçet's disease and urticarial vasculitis. These were often atypical, combined, or changing over time. Two of the cases were a married couple. The authors also reported that 13.8% of 6603 people screened at Libby's Center for Asbestos Related Diseases had an autoimmune diagnosis other than diabetes. Lupus, rheumatoid arthritis, scleroderma and sarcoidosis were significantly more common there than published U.S. expected values. Multiple sclerosis and psoriatic arthritis were somewhat higher than expected but not significantly so, and ankylosing spondylitis matched the expected value. The authors concluded that the cases suggested many different clinical presentations rather than one underlying autoimmune disease associated with LAA exposure.

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: Case series of 10 patients, with a prevalence table from a clinic screening database compared against published expected U.S. prevalence values
• Who was studied: Ten patients (nine men, one woman, per Table 2) selected by research team physicians from the Libby Epidemiology Research Program cohort of adult current or former residents of Libby and Troy, Montana. The prevalence data came from 6603 patient records in the Center for Asbestos Related Diseases (CARD) screening program in Libby.
• Exposure: Libby Asbestiform Amphiboles (LAA) from asbestos-laden vermiculite. Exposure was relatively high and mostly environmental, and lifelong for most cases. Sources included home insulation, ore piles, contaminated ball fields, recreation in the Rainy Creek area, and dust brought home by family members.
• Main results:
  • Of 6603 patient records in the CARD screening program, 13.8% had a diagnosis of an autoimmune disease other than diabetes
  • Counts in the CARD screening population (out of 6603) were: rheumatoid arthritis 387 (6%) against 1% expected (ratio 6); SLE 67 (1%) against 0.08% expected (ratio 12.5); scleroderma 10 (0.2%) against 0.028% expected (ratio 7.1); sarcoidosis 47 (0.7%) against 0.05% expected (ratio 14.0). These ratios were marked statistically significant, p less than 0.01 (Chi Square Test with Yates Correction).
  • In the CARD screening population, multiple sclerosis was 15 (0.23%) against 0.15% expected (ratio 1.5), and psoriatic arthritis was 13 (0.2%) against 0.1% expected (ratio 2). Neither ratio was marked statistically significant.
  • In the CARD screening population, ankylosing spondylitis was 14 (0.2%) against 0.2% expected (ratio 1). The authors described the prevalence of multiple sclerosis, ankylosing spondylitis and psoriatic arthritis as not different from expected.
  • All ten cases had some form of pulmonary asbestos-related disease
  • Among the ten cases, autoimmune symptom onset ranged from age 20 to 69
  • Among the ten cases, some showed atypical presentations of systemic autoimmune disease, sometimes in combinations, with symptoms and diagnoses changing over time
  • Case 2 (rheumatoid arthritis) and Case 3 (rheumatoid arthritis with pleurisy) were wife and husband
  • Case 7 had been diagnosed with seronegative rheumatoid arthritis with a negative ANA, but later testing showed a positive ANA at 1:2560 titer
  • Case 6 (psoriatic arthritis, later chronic lymphocytic leukemia) had a negative ANA in July 2013, and later testing showed a positive ANA at a titer of 1:1280
• The authors' conclusion: The authors concluded that the cases suggest there is not one underlying autoimmune disease associated with LAA exposure, but rather a large number of clinical presentations in this exposed cohort

Topics

Medical terms in this study, explained in our Lexicon: Asbestiform, Amphibole Group, vermiculite, Epidemiology, Asbestos Exposure, ATSDR, Diffusing Capacity (DLCO), Total Lung Capacity (TLC).

Related studies

• Pulmonary abnormalities as a result of exposure to Libby amphibole during childhood and adolescence-The Pre-Adult Latency Study (PALS) — J. Szeinuk, C.W. Noonan, et al. (2017)
• Libby Amphibole Disease: Pulmonary Function and CT Abnormalities in Vermiculite Miners — A. Miller, J. Szeinuk, et al. (2018)
• Prevalence of anti-nuclear autoantibodies in subjects exposed to natural asbestiform fibers: a cross-sectional study — C. Ledda, R. Caltabiano, et al. (2018)
• Lung cancer screening in patients with Libby amphibole disease: High yield despite predominantly environmental and household exposure — G. Loewen, B. Black, et al. (2019)
• Libby amphibole-induced mesothelial cell autoantibodies bind to surface plasminogen and alter collagen matrix remodeling — R. Hanson, C. Evilia, et al. (2016)
• Internalization of Libby amphibole asbestos and induction of oxidative stress in murine macrophages — D.J. Blake, C.M. Bolin, et al. (2007)

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