Higher cancer risk for PC manufacturers: Study

Employees of computer factories are at an increased risk of getting cancer when compared with the general population, reported Richard W. Clapp, M.P.H., D.Sc., of Boston University, in a study published in the open access journal Environmental Health.

The study was initiated by Dr. Clapp when he received consultancy fee by a plaintiffs' law firm to conduct the study.

Dr. Clapp procured data for the general public from the Mortality and Population Data System, whereas the data pertaining to IBM employees was procured from the IBM corporate mortality file.

Clapp’s task was to compare the death rates in computer manufacturing firms with death rates among the general population. More specifically, he was required to search for patterns of excess mortality among the employees of IBM.

The data under study included 31,941 records (27,272 males and 4,669 females) concerning decedents who had worked at IBM’s 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.

Work history was available for a subset of 10,219 of the deceased workers. Duplicate records and records for which the sex, birth date, or death date was unknown were excluded from the sample.

The results revealed that cancer was a more common cause of death in the IBM employees than in the general U.S. population. The proportional cancer mortality ratio (PCRM) for all cancers was 107 (107% of expected, 95% confidence interval 105 to 109) in men and 115 (95% CI 110 to 119) in women.

The study also revealed that cancer appeared to target specific organs, such that among men, the proportional cancer mortality ratios were 166 for cancers affecting the brain and central nervous system, 162 for kidney cancer, 179 for melanoma and 126 for pancreatic cancer.

Correspondingly the PCMRs in women were 212 for kidney cancer and 163 for cancer of all lymphatic and hematopoietic tissue.

The 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.