The effect of synthetic chemicals on human health and the risk of cancer is a complex and growing area of research. The Canadian Breast Cancer Foundation provides an introduction to some of the key topics in this area and how we can use this information in our everyday lives.
The International Agency for Research on Cancer has identified over 100 known carcinogens (cancer-causing substances) in our environment, with many more suspected as probable or possible causes of cancer.
You may be surprised to know that most of the chemicals made and used in North America have not been assessed for their risk to human health or their impact on the environment. Since 1994, Canada has included health and environmental effects in its assessment of the risk of chemicals. However, the risk-assessment approach looks at chemicals in isolation, whereas in real life we are exposed to a mix of chemicals at low levels every day.
Cancer research and studies of workers’ health have proved that some chemical exposures cause cancer. The most recent research that contributes to this growing body of knowledge is a landmark Canadian study published in November 2012 in the journal Environmental Health, which examined the health effects of exposure to chemicals in the workplace. Dr. James Brophy and Dr. Margaret Keith were part of an international team that analyzed workplace risks in southern Ontario, with funding from the Canadian Breast Cancer Foundation. This research links some workplaces with a significant increase in female workers’ risk of developing breast cancer.
Key areas of breast cancer research on chemical exposures
Research is probing the effects of synthetic chemicals on human health, including factors that may increase the risk of breast cancer. The following are some of the key research areas that will help to deepen our understanding of the links between chemical exposures and breast cancer risk:
The health effects of hormone-disrupting chemicals. Evidence suggests that some synthetic chemicals alter how our natural hormones work and may influence the development of breast cancer. A number of these chemicals are found in consumer products, including personal care products. Research is exploring the links between these hormone-disruptors including the influence of xenoestrogens, and the increased risk of breast cancer.
The health effects, including breast cancer risk, of low-level exposure to chemicals over a lifetime and the daily exposure to a mixture of chemicals in our environment. Research has found traces of synthetic chemicals in human blood, urine, breast milk and breast tumours. Women tend to have higher levels of these chemicals than men.
The physical and health effects of chemical exposures during critical periods of human development, including for the fetus during pregnancy, in infancy, and during puberty.
Safe alternatives to the known carcinogens that are found in Canadian workplaces and consumer products.
Improved, faster and cheaper methods to test new and existing chemicals for health and environmental effects. Over 200 chemicals have been linked to the development of breast cancer in at least one animal research study.
More research is needed to better understand the effects of chemical exposure, how they may influence the development of breast cancer, and how to protect against these risks. The Canadian Breast Cancer Foundation supports the use of the precautionary principle as a way to apply evolving breast cancer prevention evidence in our daily lives. By following the precautionary principle in your life, when scientific evidence is inconclusive you put your health first and err on the side of caution.
We encourage you to take precautions that put your health and the health of others first. Start by limiting your daily exposure to chemicals at home and in the workplace.
Brody, J. G. & Rudel, R. A. (2008). Environmental Pollutants and Breast Cancer: The Evidence from Animal and Human Studies. In Breast Diseases: A Year Book Quarterly, Vol. 19, No. 1. Accessed July 31, 2011.
Brophy, J., Keith, M., Watterson, A., Park, R., Gilbertson, M., Maticka-Tyndale, E., Beck, M., Abu-Zahra, H., Schneider, K., Reinhartz, A., DeMatteo, R., & Luginaah, I. (2012). Breast cancer risk in relation to occupations with exposure to carcinogens and endocrine disruptors: A Canadian case control study. In Environmental Health. Accessed November 22, 2012.
Gray, J. (Sixth Ed, 2010). State of the Evidence: The Connection Between Breast Cancer and the Environtment. Breast Cancer Fund. Accessed July 31, 2011.
Griffin, S. (2009) Environmental Exposure: The CancerSmart Guide to Breast Cancer Prevention. Toxic Free Canada.
Gilbertson, M. & Brophy, J. (2001). Community Health Profile of Windsor, Ontario, Canada: Anatomy of a Great Lakes Area of Concern. In Environmental Health Perspectives Supplements Vol 109, Number S6, Dec. 2011. Accessed July 31, 2011.
Reuben, S. H. for the President’s Cancer Panel. (April 2010). Reducing Environmental Risk. What We Can Do Now. U.S. Department of Health and Human Service, National Institutes of Health and National Cancer Institute. Accessed July 31, 2011.
Government of Canada. (Nov 2009). Overview of the Chemicals Management Plan. Accessed July 31, 2011.
International Agency for Research on Cancer, Agents Classified by the IARC Monographs, Vols 1-100. Accessed July 31, 2011.
Occupational Health Clinics for Ontario Workers Inc. (2001). Preventing Occupational and Environmental Cancer. Accessed July 31, 2011.
Schwarzman, M. & Janssen, S. (2010). Pathways to Breast Cancer: A Case Study for Innovation in Chemical Safety Evaluation. A report of the Breast Cancer and Chemicals Policy Project, produced by the University of California, Berkeley and the Natural Resources Defense Council. Accessed July 31, 2011.