The study evaluated the role of 45 pesticides and found that methyl bromide was linked to the risk of prostate cancer in the group. NIOSH lists methyl bromide as a potential occupational carcinogen. Exposure to six other pesticides was associated with an increased risk of prostate cancer only among men with a family history of the disease. The six pesticides are chlorpyrifos, coumaphos, fonofos, phorate, pemethrin and butylate.
The study, published in the May 1 issue of the American Journal of Epidiemiology, is part of an ongoing study of 90,000 participants by the National Cancer Institute, the National Institute of Environmental Health Sciences and the Environmental Protectiona Agency called the Agricultural Health Study.
"Associations between pesiticide use and prostate cancer risk among the farm population have been seen in previous studies; farming is the most consistent occupational risk factor for prostate cancer," said NCI's Michael Alavanja, Dr.P.H., principal investigator of the AHS.
The current study included 55,332 men classified as either "private pesticide applicators" (farmers or nursery workers) or "commercial pesiticide applicators" (employees of pest control companies or warehouses or grain mills that use pesticides regularly). Between 1993 and 1999, 566 new prostate cancers developed among applicators, compared to 495 predicted for the group. This means the risk of developing prostate cancer was 14 percent greater for the pesticide applicators compared to the general population.