Monday, October 23, 2006

Study Showing Elevated Cancers Among IBM Workers Finally Published

A study has been published showing that IBM worker who work with solvents have a higher incidence of cancer than normal, according to an article last week in the Wall St. Journal (paid subscription).

But that wasn't even the big news. This study, done by Boston University professor of environmental health Richard Clapp, had been suppressed by IBM for several years. Because the giant computer company objected to Clapps used of the data (which had been obtained as part of a lawsuit), Elsevier, the publisher of Clinics in Occupational and Environmental Medicine, refused to publish Clapp's study. Elsevier's action then led to a boycott of the publication by other contributors. After IBM won several lawsuits, the company settled with many of the workers and agreed to release allow the data to be published.

And what did the study find?
The study, "Mortality among U.S. employees of a large computer manufacturing company," looked at death records of men and women who had worked for IBM for five years.

Mr. Clapp then compared the rate of cancer deaths among the workers to the national death rate from particular cancers. Among the 27,272 men who died, there are 7,697 cancer deaths -- "significantly greater" than the 7,206 cancer deaths that were expected based on the national average. Several individual cancers showed particularly high rates compared with national averages, including cancers of the digestive organs, kidneys, brain and central nervous system and malignant melanoma of the skin.

Among the 4,669 female deaths, 1,667 were from cancer, which Mr. Clapp said was well above the 1,454 that were expected based on national data. Breast cancer, lung cancer, female genital cancer, brain and nervous-system cancers rates were all elevated compared with national averages.

Mr. Clapp also concluded that deaths from cancer as a proportion of all deaths were also elevated among IBM manufacturing workers. For this part of his analysis, he used records for workers who had been involved for at least 30 days in semiconductor and disk-drive manufacturing plants in California, Minnesota, New York and Vermont.

Mr. Clapp said cancer rates were somewhat higher in the manufacturing subgroup, including for deaths from breast cancer in women and kidney cancer and melanoma in men.
IBM, as you might imagine, wasn't happy with the results of the study:
An IBM spokesman said the study is "based on flawed methodology and woefully incomplete data." He said an IBM-funded study led by a researcher from the University of Alabama at Birmingham, which has been published, found 126,000 current and former IBM workers at three semiconductor and hard-drive plants over three decades "had lower overall mortality and cancer incidence rates than the general population."

Mr. Clapp said that study's results were largely consistent with his except the IBM study wasn't adjusted to eliminate the "healthy worker" effect. Employed people are generally healthier than nonworkers, so comparing them directly to the general population is misleading, he said.