Epidemiologic results of US semiconductor and computer manufacturing worker studies

In 2003, as part of a lawsuit on behalf of IBM workers, a proportional mortality analysis of the corporate mortality file revealed excess deaths due to cancer and other causes compared to national or statewide patterns during the period 1969-2001. Despite company efforts to prevent publication, and after a subsequent Court ruling, the main results were published in peer-reviewed scientific articles (Clapp, 2006; Clapp and Hoffman, 2008). At approximately the same time, a company-sponsored study of mortality and cancer incidence in three IBM manufacturing plants was completed and published in a series of articles (Beall, et al., 2005; Bender, et al., 2007). The methods and results of the various studies of IBM workers will be compared and interpreted, with emphasis on the similarities with respect to specific cancers among manufacturing workers. In particular, findings with respect to brain and central nervous system cancer will be discussed. In addition, an industry-sponsored study of cancer mortality in US semiconductor workers (Boice, et al., 2010) will be reviewed. Implications of study population and study design will be discussed in the context of changing manufacturing practices and how these factors may affect interpretation of results. Lastly, a critical overview of the US semiconductor and computer manufacturing industry worker studies to date will be presented.