Death rates, both overall and cancer-related, are considerably higher among workers engaged in manufacturing computers and component parts, when compared with the general population, according to a report in the journal Environmental Health.
While similar findings have been reported among employees who work in plants that manufacture computers, semiconductors, integrated circuits and other components, this report involves the largest database to date, Dr Richard W. Clapp notes in the report.
A court order required that IBM provide to the plaintiffs in litigation "the IBM Corporate Mortality file," maintained by the company. It includes 31,941 records concerning decedents who had worked at their plants for at least 5 years. The data included the sex, birth date, death date, and underlying cause of death for the period from 1969 and 2001.
The lawyers for the plaintiffs handed the records over to Clapp, an epidemiologist at Boston University School of Public Health, to search for patterns of excess mortality among the employees. For comparison with the general population, Clapp procured data from the Mortality and Population Data System at the University of Pittsburgh.
Results showed that among the company employees, proportional mortality ratios (PRM) averaged 107 among men and 115 among women, as compared with the general population.
Cancer appeared to target specific organs, such that among men, the proportional cancer mortality ratios (PCMR) were 166 for cancers affecting the brain and central nervous system, 162 for kidney cancer, 179 for melanoma and 126 for pancreatic cancer.
In women, PCMRs were 212 for kidney cancer and 163 for cancer of all lymphatic and hematopoietic tissue.
There were also excessive numbers of deaths due to multiple sclerosis, Parkinson's disease, and ALS.
In his report, Clapp notes that employees were routinely exposed to solvents and chemicals such as photoresist; metals, such as arsenic, nickel and chromium; electromagnet fields, especially ultraviolet light, radiofrequency, and x-ray radiation.
"When comparing four plants around the country, the findings were remarkably similar, in revealing excess cancers of the brain, non-Hodgkin's lymphoma, and kidney, primarily among manufacturing workers," Clapp told Reuters Health.
IBM still may be ahead of Clapp's work, the epidemiologist added, "because they had data to which we had no access, such as job titles, work groups, types and duration of exposure to carcinogenic agents.