Beryllium and lung cancer: a reanalysis of a NIOSH cohort mortality study
This analysis is motivated by recent reviews on the carcinogenicity of beryllium by the International Agency for Research on Cancer, the U.S. Environmental Protection Agency, and the American Conference of Governmental Industrial Hygienists, and reconsideration by the National Toxicology Program on its classification of the carcinogenicity of beryllium. It reanalyzes data from a 1992 publication of a cohort mortality study conducted by the National Institute of Occupational Safety and Health (NIOSH) of workers employed in seven plants producing beryllium in the United States (Ward et al., 1992). That publication reported an increased risk of lung cancer in these workers and concluded that it is most likely due to occupational exposure to beryllium compounds. This present report uses: (1) an adjustment for smoking based on more germane estimates of the association between smoking and mortality from lung cancer; (2) computations of expected lung cancer rates based on alternative comparison populations; and (3) an overall combined estimate of the findings from the individual plants based on meta-analysis. Our findings indicate lower and generally not statistically significant standard mortality ratios that are not compatible with the interpretation of a likely causal association.