© 2008 American Thoracic Society doi: 10.1164/rccm.200802-252ED
Chronic Beryllium DiseaseRisk from Low-Level Exposure
Yale University School of Medicine
CPWR: The Center for Construction Research and Training Beryllium, a valuable metal used in a number of different industries such as aerospace, manufacturing, and electronics, can cause chronic beryllium disease (CBD), a systemic CD4+ T-cell–mediated granulomatous disease that predominantly affects the lungs. In this issue of the Journal (pp. 1012–1017), Maier and colleagues describe a series of cases of CBD diagnosed between 1972 and 2002 among residents of a community surrounding a beryllium manufacturing facility (1). The authors identified eight cases (five definite and three probable) of CBD, that, after careful evaluation, they attribute to environmental exposure from the beryllium facility, and not to occupational exposures. Cases of CBD have previously been reported among residents surrounding this beryllium facility, but the last reported cases were over 40 years ago. Although the beryllium exposures of concern for these cases were many years ago, this report is relevant to several current issues regarding CBD. The clinical presentation and evaluation of these eight cases demonstrate how easily the diagnosis of CBD can be overlooked. CBD can be difficult to distinguish from sarcoidosis and other interstitial lung diseases, especially as CBD can present many years after exposure, and a history of beryllium exposure may not be appreciated. Several of the cases were initially misdiagnosed (two as sarcoidosis and one as silicosis), and/or the diagnosis delayed. A history of beryllium exposure can be difficult to obtain, especially as beryllium typically may be one of many metals present in an alloy, and workers may not be aware of exposure even with inquiry by their physicians. The long latency between the time from first potential exposure to beryllium until diagnosis (19–52 yr in these cases) can also hinder recognition of prior beryllium exposure and diagnosis. Even when CBD is suspected, fulfilling current diagnostic criteria, which include a history of exposure, evidence of beryllium sensitization, and consistent pathologic findings, can be challenging, as occurred in the three probable CBD cases in this report. Patients may not be able to undergo a lung biopsy, adequate lung tissue may not be obtained, and the beryllium proliferation assay (BeLPT) is not routinely available. This report also provides insight into the important question of risk associated with lower levels of occupational beryllium exposure as well as risk from residential exposure. The authors feel confident that workplace exposure was unlikely in these cases. The absence of incidental occupational exposure can be difficult to prove, but appears reasonable in these cases. The estimated potential exposures for the cases, based on historic ambient beryllium air sampling from 1958, are 0.015–0.028 µg/m3, with possible peak exposures of more than 0.35 µg/m3 (until ambient levels were reduced in the 1960s and 1970s). Such levels are well below the current Occupational Safety and Health Administration (OSHA) standard (2 µg/m3) and the more stringent level set by the Department of Energy (DOE) and recommended by American Conference of Industrial Hygienists (0.2 µg/m3). These community CBD cases are consistent with a number of epidemiologic studies of beryllium-exposed workers and case reports that have demonstrated risk of CBD at exposure levels well below the current OSHA standard (2–5). The authors estimate that 63 to 210 additional residents could have or will develop beryllium sensitization or CBD and suggest use of the BeLPT to identify additional cases in this community and to better define risk of CBD. Although there could be additional cases, given the many years that have passed since ambient beryllium levels were reduced around this facility, an investigation of this population using the BeLPT may not be productive. The Agency for Toxic Substances and Disease Registry (ATSDR) has recently investigated exposure to beryllium in two other communities surrounding facilities using beryllium with variable community participation, and has not identified any cases of CBD due to residential exposure (6, 7). The ATSDR developed education and outreach materials for the exposed communities, including physicians. Better physician education is needed to increase awareness, especially among pulmonary specialists, of the risks of beryllium exposure and of the need to obtain a thorough occupational and environmental history. This report may have greater relevance to issues regarding occupational CBD than it has public health implications for communities surrounding historic beryllium facilities. With the expanding use of beryllium in a wide range of industries, including aerospace, automotive, manufacturing, telecommunications, and scrap recovery and recycling, the number of workers with current beryllium exposure is substantial, estimated at up to 134,000 in the United States (8), and potentially many more workers when considering the numerous secondary and tertiary end-user settings, as well as workers with past exposure (9). The BeLPT has been used for surveillance of actively exposed workers to prioritize primary preventive strategies and also as a diagnostic tool to confirm beryllium sensitization in patients with lung disease suspected to be CBD (2). When surveillance has been instituted, previously unrecognized cases of beryllium sensitization and CBD have been identified in settings where CBD was not suspected (10), and ongoing surveillance of selected beryllium workers has confirmed that CBD continues to occur despite reductions in workplace exposures (2, 3). However, surveillance of beryllium-exposed workers is not routine, and thus the number of workers at risk for developing CBD and the exposure settings with greatest risk are not well defined. This case series of CBD in residents surrounding a beryllium facility further supports concerns regarding risk of low-level beryllium exposures, and supports surveillance of beryllium-exposed workers to better define risks and preventive approaches. It also highlights the need for clinicians evaluating patients with interstitial lung disease to have a high index of suspicion for CBD, and to take a careful occupational and environmental history, including distant exposures. FOOTNOTES Conflict of Interest Statement: Neither author has a financial relationship with a commercial entity that has an interest in the subject of this manuscript. REFERENCES
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