Study shows no PCB-cancer correlation

By Renate D. Kimbrough Copyright 1999 The Times Union (Albany, NY) March 23, 1999

Our study was the largest ever of workers occupationally exposed to PCBs. It includes all of the 7,075 men and women who worked for at least 90 days between 1946 and June 15, 1977, at the General Electric plants in Hudson Falls and Fort Edward.

There was no increase in deaths due to cancer or any other disease. The death rate due to all types of cancer was at or significantly below the expected level, based on national and regional averages.

Our study had an average follow-up time of 31 years; some employees were followed for as long as 50 years. If PCB exposure were to result in chronic health problems for these employees, I believe the problems would have been apparent during this long latency period. They were not.

The employees had more prolonged exposure to much higher PCB levels than would be expected in the general population. The Agency for Toxic substances and Disease Registry reports that the average blood level of PCBs in people who have been tested ranges from 4 to 8 parts per billion. Some of the GE workers in our study had levels 300 to 600 times higher.

Still, there was no association between PCB exposure and deaths from cancer or any other disease, including heart attacks and strokes.

The findings in our study should come as no surprise to much of the medical and scientific community because they are consistent with the finds of four other earlier studies conducted by other researchers of workers in the same plants.

These earlier studies were performed by the Mount Sinai Medical Center, the National Institute of Occupational Safety and Health, and the Harvard School of Public Health, in conjunction with the New York State Department of Health.

Your columnist, Fred LeBrun, compares our study to a different study of another group of GE workers in another state, but fails to point out that the other researcher, Dr. David Wegman, and we reached the same conclusion -- that there was no association between PCB exposure and death from cancer.

Mr. LeBrun is correct in noting that Dr. Wegman's study was limited by incomplete information on some exposed employees.

But there was no such limitation in our study; we developed thorough identification information on the entire study group through GE's worker history records and earlier records by the National Institute of Occupational Safety and Health, as well as records from the Social Security Administration.

We found 783 workers overlooked in prior studies and lost only 1 percent of the workers to follow-up.

Dr. Arthur C. Upton, former director of the National Cancer Institute, chaired an advisory panel that reviewed our study. He described our work as ''meticulous.''

Finally, Mr. LeBrun refers to me as a ''GE-paid'' researcher. I do not work for GE and never have. I spent nearly 30 years in government service at the Centers for Disease Control, the Food and Drug Administration and the Environmental Protection Agency. Dr. Martha Doemland, who earned her doctorate at the State University at Buffalo and assisted with the study, also does not work for GE.

We work at the nonprofit Institute for Evaluating Health Risks, as the senior medial associate and an epidemiologist, respectively. The institute conducted the study at the request of and with funding from GE. It receives funding in approximately equal parts from government agencies and private-sector organizations.

I am paid a salary; my compensation is not dependent upon GE nor upon the results of any study I perform.

GE had no role of any kind in the conduct of the study, the evaluation of the data or the conclusions drawn. Our work was overseen by a panel of distinguished scientists from government and academic, none of whom are associated with GE or with our organization.

I believe the conclusions of our study are quite significant; they should allay fears that routine environmental exposure or even heavy occupational exposure to PCBs is associated with cancer or other serious illnesses. Renate D. Kimbrough is a medical doctor associated with the Institute for Evaluating Health Risks.

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