Women exposed to hazardous chemicals at work are 42 percent more likely to develop breast cancer, study finds

A study released today (Nov. 19) in the journal Environmental Health found a statistically significant association between the increased risk of breast cancer among women who work in jobs where they are exposed to a "toxic soup" of chemicals. High risk jobs include farming, auto-plastics manufacturing, and working at bars, casinos and race courses, as well as metalworking and certain jobs in the food industry.

Research on the study was conducted in Canada, the United States and the United Kingdom, and the report was compiled by scholars at the Occupational and Environmental Health and Safety Research Group at the University of Stirling in Scotland, including Drs. James Brophy and Margaret Keith. In addition to their positions at the University of Stirling, both Brophy and Keith are faculty members at the University of Windsor in Ontario.

The study is being released by HealthyStuff.org, a program of the Ann Arbor-based Ecology Center, Canada’s National Network on the Environment and Women's Health, and other groups that have an interest in study and regulation of toxic chemicals in the environment.

HealthyStuff.org has sampled nearly 1,000 cars since 1996 and has identified a range of health hazards due to toxic chemical exposure in vehicles. Many of these hazards, including plasticizers, UV-protectors, pigments, dyes, flame retardants, un-reacted resin components and decomposition products, may be released through the plastic product’s life cycle. Phthalates and PBDEs are examples.

"Consumers are exposed daily to the same toxic soup of chemicals that workers are, and we are greatly concerned that government standards are not enough to protect us from carcinogens and endocrine disrupting chemicals in plastics and vehicles," according to Jeff Gearhart, research director at at HealthyStuff.org.

The case control study, involving 1,005 women with breast cancer and 1,147 without the disease, revealed that women who worked in jobs classified as highly exposed for 10 years increased their breast cancer risk by 42 percent

"Breast cancer incidence rose throughout the developed world in the second half of the twentieth century as women entered industrial workplaces and many new and untested chemicals were being introduced,” Keith said. “Diverse and concentrated exposures to carcinogens and hormone disrupting chemicals in some workplaces can put workers at an increased risk for developing cancer."

The risk of developing breast cancer was found to double for women working in the Canadian car industry's plastics manufacturing sector, the study found. And among those who were premenopausal, the risk was almost five times as great. Many plastics have been found to release estrogenic and carcinogenic chemicals and cumulative exposures to mixtures of these chemicals are a significant concern.

The risk was also doubles for women working in bars, casinos and race-tracks. “The elevated risk of developing breast cancer may be linked to second-hand smoke exposure and night work which has been found to disrupt the endocrine system,” according to the study.

Other occupational sectors with an elevated breast-cancer risk include:

• Farming, which showed a 36 percent increase in breast-cancer risk. “Several pesticides act as mammary carcinogens and many are endocrine disrupting chemicals,” the study found.
• Food canning: the risk of developing breast cancer doubles for women working in the canned food sector, and among those who were premenopausal, the risk was five times as great. Exposures to chemicals in the food canning industry may include pesticide residues and emissions from the polymer linings of tins.
• Metalworking: A statistically significant 73 percent increased breast cancer risk was found in the metalworking sector. Women working in tooling, foundries and metal parts manufacturing are exposed to a variety of potentially hazardous metals and chemicals.

"The study points to the need to re-evaluate occupational and environmental exposure standards, keeping in mind that there may be no determinable safe levels to cancer-causing or hormone-disrupting chemicals," Dr. Keith said.