We examined the relationship between exposure to beryllium and the presence of beryllium sensitization (BeS) and chronic beryllium disease (CBD) in a cohort of workers in a beryllium precision machining facility. Twenty workers with BeS or CBD (cases) were compared with 206 worker-controls in a case-control study. Exposure for each job title was measured using cascade impactors placed in the workers’ breathing zone to measure total beryllium exposure and exposure to particles <6 μm and <1 μm in aerodynamic diameter. Cumulative exposure was calculated as Σ (job title exposure estimate × years in job title). Individual lifetime-weighted (LTW) exposure was calculated as Σ [(job title exposure × years in job title) ÷ total years employment)]. Workers in the case group were more likely to have worked as machinists (odds ratio, 4.4; 95% confidence interval, 1.1 to 17.5) than those in the control group. The median cumulative exposure was consistently greater in the cases compared with the controls for all exposure estimates and particle size fractions, although this was not statistically significant. The median cumulative exposure was 2.9 μg/m3-years in the cases versus 1.2 μg/m3-years in the controls for total exposure, and 1.7 μg/m3-years in the cases versus 0.5 μg/m3-years in the controls for exposure to particles <6 μm in diameter. With cumulative exposure categorized into low-, intermediate-, and high-exposure groups, the odds ratios were 2.4 (95% confidence interval, 0.7 to 8.2) for the intermediate-exposure group and 1.2 (95% confidence interval, 0.4 to 4.2) for the high-exposure group compared with the low-exposure group. The median LTW exposure was 0.25 μg/m3 in both groups. The median LTW exposure to particles <6 μm was 0.20 μg/m3 in the cases compared with 0.14 μg/m3 in the controls. The differences in cumulative and LTW exposure were not statistically significant. None of the 22 workers with LTW exposure <0.02 μg/m3 had BeS or CBD. Twelve workers (60%) in the case group had LTW exposures >0.20. In conclusion, increased cumulative and LTW exposure to total and respirable beryllium was observed in workers with CBD or BeS compared with the controls. These results support efforts to control beryllium exposure in the workplace.
From the Division of Environmental and Occupational Health Sciences, National Jewish Medical and Research Center, Denver (Dr Kelleher, Dr Martyny, Ms Mroz, Dr Maier, Dr Newman); and the Department of Medicine and Department of Preventive Medicine and Biometrics
University of Colorado Health Sciences Center (Dr Kelleher, Dr Maier, Dr Ruttenber, Dr Young, Dr Newman).
Dr. Kelleher is a Commander in the United States Navy Medical Corps. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or US government.
The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the National Institute for Occupational Safety and Health.
Address correspondence to: Dr Lee S. Newman, Division of Environmental and Occupational Health Sciences, National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206; e-mail NewmanL@njc.org.