Alice Hamilton Awards: Research Updates for 2011 - Human Studies

It has been estimated that 28,000-100,000 U.S. workers are exposed daily to average beryllium levels greater than 0.1 µg/m3 (as an 8-hour time-weighted average). A research program has been established at NIOSH to evaluate risks of beryllium sensitization and chronic beryllium disease (CBD) among exposed workers. Additionally, there has been long-standing interest in the association between beryllium exposure and other diseases, including cancer, among beryllium workers. A seminal cohort of beryllium processing plant workers was established within the NIOSH Division of Surveillance, Hazard Evaluations, and Field Studies decades ago. Early analyses of this cohort led to beryllium's addition to the NIOSH carcinogen list in 1975, and to its designation by the International Agency for Research on Cancer as a carcinogen in 1993 (reaffirmed in 2009). These early studies identified an increase in lung cancer compared to the general population but did not assess beryllium exposure levels within the cohort to permit quantitative evaluation of the exposure-response association. Such evaluation is necessary for risk assessment, which has received increasing interest among several governmental organizations, including the Department of Defense, U.S. Environmental Protection Agency (EPA), and the Occupational Safety and Health Administration (OSHA).

A set of three manuscripts, which received the 2011 Alice Hamilton award in the category of human studies, describe the latest findings in the NIOSH cohort study of health effects from beryllium exposure at seven beryllium processing plants. These manuscripts describe the creation of a job-exposure matrix (JEM) at one of the beryllium processing plants. This JEM was used, along with JEMs at two additional plants, to evaluate whether an association exists between quantitative beryllium exposure metrics and several diseases of interest, including cancers of the lung, nervous system, and urinary tract, as well as chronic obstructive pulmonary disease (COPD), chronic beryllium disease (CBD), cor pulmonale, and chronic renal disease. The studies also evaluated whether existing exposure limits are protective against excess risk of lung cancer. The main findings we reported were that several diseases studied (i.e., lung, nervous system and urinary tract cancers and COPD) were significantly associated with cumulative and maximum beryllium exposure, particularly among workers employed longer than one year. The risk assessment for lung cancer found that expected increases in lung cancer risk may be unacceptably high at current NIOSH and OSHA exposure limits (of 0.5 µg/m3 and 2.0 µg/m3, respectively).

Several activities have taken place since publishing these manuscripts. We have met with scientific staff from EPA and OSHA to discuss the applicability of our findings to their respective risk assessment activities for beryllium. We have also supplied de-identified data sets from all three manuscripts to various requestors from government, academia, and industry to permit their re-analyses of our datasets (a typical outcome for NIOSH's epidemiologic analyses). In the case of the JEM, researchers from NIOSH and elsewhere have requested and received it to use in epidemiologic analyses of the same or similar cohorts. In accordance with NIOSH notification policy, we have also informed members of our cohort about the findings of our study.

For the study notification, which was coordinated by Amy Mobley, informational materials were mailed to more than 2500 living cohort members and posted to the internet on September 22, 2011. The materials that were mailed consisted of a cover letter and a fact sheet (http://www.cdc.gov/niosh/pgms/worknotify/pdfs/Beryllium_Notification.pdf) that summarized the study and its main findings. Because most cohort members retired years ago, we also developed a worksite poster for the one plant still operating, in order to inform current workers regarding the findings of our study (http://www.cdc.gov/niosh/pgms/worknotify/pdfs/Beryllium_Poster.pdf). Following the notification, we received telephone, email, or postal mail contact from more than 50 workers who had received the notification materials. Of those contacts, most sought information on medical screening for CBD, or asked a question related to compensation for beryllium-induced disease. Many also wanted additional details about the study or the illnesses we evaluated, or to discuss their experiences working with beryllium and their health. Interest in the health effects of exposure to beryllium has not abated since the first studies were published in the 1970s, and that research and analysis in this area will continue.

The study authors would like to thank all the current and former staff at NIOSH who helped with the project, including Steven Ahrenholz, Steven Allee (Emergint Technology, Inc.), Faith Armstrong, Pi-Hsueh Chen, William Ehling, Christine Gersic, Denise Giglio, Scott Henn, Kim Jenkins, Patricia Laber, Amy Mobley, Adriane Mohlenkamp , Lynn Seel, Lisa Thomas, Chih-Yu Tseng, and Kathleen Waters. Without their efforts, this study could not have been completed and communicated to the workers.