Activist/Scientist Connections: Newsletter Resources

Activist/Scientist Connections

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In addition to conducting research, Silent Spring Institute strives to be a resource for accessible information on advances in breast cancer and environment science. Each article below provides a short overview of a topic of scientific importance. We hope these papers will provide insight into research priorities, inspire new inquiry, and guide action. In addition, you may use them in outreach efforts, including as handouts, newsletter articles, or by adapting them for talking points.

If you reprint or draw from these materials, please cite Silent Spring Institute as the source and send us a copy of your final product. We welcome your feedback and your input on future topics.

Rachel Carson's Legacy

Chemicals and Cancer

Pollution Hits Home

Ten Suggestions to Reduce Your Exposure to Suspect Chemicals

Environmental Risks and Breast Cancer CD

Review of Environmental Factors and Breast Cancer

Floor Finish May Be Source of Banned PCBs

Breast Cancer and the Environment: Science News from Silent Spring Institute
July 2004

Rachel Carson’s Legacy

This year marks the 40th anniversary of Rachel Carson’s death. A courageous and outspoken woman, an extraordinary scientist and naturalist with a gift for lyricism about the mundane doings of insects, shellfish, and birds, Carson died of breast cancer just two years after the 1962 publication of her book Silent Spring touched off the modern environmental movement. When she testified about the dangers of DDT just before her death, she wore a wig to hide her treatment as she forthrightly told Congress, “I hope this committee will give attention to the right of the citizen to be secure in his own home against the intrusion of poisons applied by other persons. This should be one of the basic human rights.” Since Carson’s death, many have wondered whether there is a connection between the environmental toxins that inspired her work and the disease that killed her.

As a new generation of remarkable women brought breast cancer out of hiding with growing activism since the 1990s, questions about breast cancer and the environment became ever more compelling. Women with breast cancer have stood together at rallies, walks, and swims and in the halls of Congress; and by becoming visible in our communities, they have transformed that gnawing question, “Why did I get breast cancer?” into “Why do we have rising breast cancer rates worldwide? What can we learn to bring risk back down and truly end the epidemic?” When we see that a woman’s lifetime risk of breast cancer went from 1 in 14 in Rachel Carson’s day to 1 in 8 in the 1990s and 1 in 7 today, we know that prevention is a realistic goal.

Faced with statistics like these, many have been frustrated, though, that the breast cancer research establishment is focused so heavily on treatment with little investment in prevention. So in 1993, when leaders in the Massachusetts Breast Cancer Coalition learned that breast cancer incidence was higher on Cape Cod than in the rest of the state, they decided that breast cancer activists across the country needed “a lab of our own” to find out why. They founded Silent Spring Institute the next year as a partnership of scientists and activists with a mission to study the links between the environment and women’s health, beginning with breast cancer.

As we reflect on the ten years since the Institute began, studies of the environment are still a miniscule fraction of the breast cancer dollar. But we see key discoveries that together build our confidence that investments in environmental studies will one day lead to prevention. In one stunning discovery last year, the New York Breast Cancer Study Group reported that among women with the high-risk mutations BRCA1 and BRCA2, the risk of being diagnosed with breast cancer by age 50 was 24% for those born before 1940 but rose to 67% for women born more recently. Physical exercise and healthy weight in adolescence were associated with later onset of disease. But what about the possible role of the 70,000-plus synthetic chemicals that have come onto the market since the 1940s?

To celebrate our tenth anniversary, Silent Spring Institute is launching a column to update breast cancer activists about environmental science. This is our first edition. We hope it will provide insight into research priorities, inspire new inquiry, and guide action.
In the next edition, we will address the question: What does lab science tell us about the biological mechanisms that may link chemicals and breast cancer?

Julia G. Brody, Ph.D., Silent Spring Institute

Activist Voices: What can I do?
“Tell somebody in your family or community that breast cancer rates keep rising and that means we can learn ways to prevent this disease. I believe environmental studies are the best medicine for my daughter’s generation.” -- Cheryl Osimo, Massachusetts Breast Cancer Coalition

Please click here for a printable version of this article.

Breast Cancer and the Environment: Science News from Silent Spring Institute
October 2004

Chemicals and Cancer

The statistics on worldwide increases in breast cancer risk are grim. In the US, a woman’s lifetime risk of breast cancer moved up this year to 1 in 7 from 1 in 8. And the risk is 1 in 6 when in situ diagnoses are taken into account. Rapidly increasing risk in the developing world, where mammography is still rare, tells us we are seeing more disease, not just more diagnosis. The increase cannot be due to inherited genes either, because inherited genes can’t change over just a couple of generations. Studies that show increased risk for women who move from low-incidence regions to high-incidence countries, like the US, point to something about the way we live in industrial societies. Thus far, scientists have been able to explain less than half of breast cancer risk with all the identified risk factors. That means that additional, unknown causes must be at work. If we can find out why incidence is increasing, we can learn to prevent future disease.

Where should we look for clues to prevention? Synthetic chemicals that poured into the marketplace after World War II are one promising direction, because laboratory studies point to three mechanisms that could link various chemicals to breast cancer:

Chemical carcinogens can damage DNA
Tumor promoters can make cells grow
Developmental toxicants can leave the mammary gland more vulnerable to carcinogens.

The US National Toxicology Program has identified 42 chemicals as breast carcinogens in laboratory animals, and about 100 have been identified internationally. Many are common. For example, we are exposed to carcinogenic polycyclic aromatic hydrocarbons (PAHs) in grilled and smoked food, tobacco smoke, and air pollution from auto exhaust, power plants, and other fossil fuel-burning processes. Until recently, ethylene oxide was commonly used in hospitals and medical facilities to sterilize instruments, though the Occupational Safety and Health Administration set limits to reduce exposures. Other mammary carcinogens are found in certain furniture finishes, dyes, and solvents, for example.

Once a cancer begins, other chemicals, called tumor promoters, may stimulate growth. We have known for years that natural estrogens and pharmaceutical estrogens (e.g., in hormone replacement therapy) affect breast cancer risk. We now know that synthetic chemicals can also make human breast cancer cells proliferate in laboratory studies. Drs. Ana Soto and Carlos Sonnenschein at Tufts University pioneered the study of estrogen mimics in breast cancer cells after they found a chemical that was accidentally leaching from plastic tubing in their experiments was causing cell growth. Estrogen mimics are part of a larger group of chemicals known as endocrine disrupting compounds (EDCs) because they affect hormones. EDCs are in some plastics, pesticides, detergents, and cosmetics, among other sources.

Most recently, scientists at the US Environmental Protection Agency discovered a third way that chemicals may increase breast cancer risk. When they dosed laboratory animals with the pesticide atrazine during certain weeks of pregnancy, the offspring never developed fully mature mammary glands, leaving the daughters more vulnerable throughout life to carcinogenesis.

Making the link from strong laboratory evidence to epidemiologic studies in women remains a challenge, because it’s so hard to measure exposure to a complex mixture of pollutants over a lifetime. But the laboratory studies can help us target precautionary public health policies to reduce exposure, and they point us to urgent areas for breast cancer studies.

For more scientific detail and a list of mammary carcinogens and EDCs, please visit this article from Environmental Health Perspectives on the Silent Spring Institute web site:
http://library.silentspring.org/publications/pdfs/brody_rudel_EHP03.pdf

Julia G. Brody, Ph.D., Silent Spring Institute

Activist Voices: What can I do?
“I never thought about buying a car as anything to do with breast cancer. Knowing that the auto exhaust contains mammary carcinogens puts fuel efficiency in a whole new light. ”

Please click here for a printable version of this article.

Breast Cancer and the Environment: Science News from Silent Spring Institute
May 2005

Pollution Hits Home

In 1987, Dr. Ana Soto at Tufts University faced a perplexing problem. She was studying how exposure to estradiol – a natural estrogen – makes estrogen-sensitive human breast cancer cells grow. But, unexpectedly, the unexposed control cells in her lab began to proliferate! It took years to figure out that new plastic test tubes in her laboratory were to blame. The tubes were leaching nonylphenol, a synthetic chemical found in many common products, such as detergents, plastics, and pesticides.

With this discovery, Dr. Soto began a new area of research that has led her laboratory and others to identify more than 150 chemicals that mimic estrogen, block androgen, or otherwise affect hormones. These chemicals are known as endocrine disrupting compounds (EDCs). They are found in building materials, furniture, and everyday products – detergents, pesticides, plastics, cosmetics – and in air and water pollution.

Given that natural estrogen and pharmaceutical estrogens, such as HRT, increase breast cancer risk, it makes sense to target estrogen mimics and other EDCs in breast cancer research. If we find links between these chemicals and breast cancer, we will be a big step closer to breast cancer prevention.

In order to study the links between chemicals and breast cancer, we need to first measure and understand how women are exposed. Because many of the EDCs are in consumer products and because all of us, and especially women, spend a lot of time at home, Silent Spring Institute decided to tackle EDCs in a study of exposures in homes.

We tested for 89 EDCs in air and dust in 120 homes on Cape Cod, where we have been studying possible environmental links to breast cancer for the last ten years. Results were published in the scientific journal Environmental Science and Technology, which called the study “the most comprehensive assessment to date” of pollutants in homes. For 30 of the chemicals we tested, ours are the first measurements ever reported from indoor environments.

We found 67 target compounds in all, with an average of about 20 per home. That’s a reminder that when we think about effects of chemicals on health, we have to take into account multiple exposures rather than the one-at-a-time approach that is currently used for chemicals regulation.

The study showed that chemicals break down very slowly indoors. We found DDT, which was banned more than 30 years ago, in about two thirds of the homes. As toxicologist Ruthann Rudel says, “Think about what your furniture would look like if you left it out on the street for thirty years. Now think about it in your living room. Protected from sun, rain, and wind, materials stay pretty much intact.” The lesson here is that we need to be more careful about testing chemicals before we put them into use, because banning them later won’t get them out of our homes.

The most abundant pollutants were phthalates (from plastics and personal care products, such as nail polish and hair spray) and certain phenols from disinfectants, detergents, and adhesives, for example in furnishings.

We found phthalates in every home. Researchers have found phthalates are associated with androgen-blocking effects in males, including lowered sperm count and certain hormonal birth defects. Their effects on girls and women have not been investigated much yet. Many breast cancer activists have joined the recent effort to remove phthalates from cosmetics, as the Europeans are doing; and 116 cosmetics manufacturers have agreed. (Go to www.safecosmetics.org to learn more.)

We found 27 different pesticides in all.

We found the flame retardant PBDE’s at ten times the levels reported in Europe, where these chemicals are not used as much.

Julia G. Brody, Ph.D., Silent Spring Institute

For more scientific detail, please visit the Silent Spring Institute web site resources on household exposure: http://library.silentspring.org/news/hesresults.asp.

Please click here for a printable version of this article.

Ten Suggestions to Reduce Your Exposure to Suspect Chemicals

Chemicals that mimic estrogen, a known risk factor for breast cancer, and chemicals that cause mammary tumors in laboratory studies are top priorities for our research. Silent Spring Institute is developing new testing methods and making first-ever measurements of indoor levels of many chemicals identified as endocrine disruptors – compounds that affect hormones. While more studies need to be done, we can take precautionary steps now to reduce exposure to suspect chemicals that are found in a multitude of everyday products.

1. Use glass containers in the microwave and encourage your family/friends to do the same.
Some plastic containers contain chemicals that mimic or disrupt hormones. These chemicals can leach into food when they are heated.

2. Ask for dry cleaning services that do not use “PERC” or ask for “wet cleaning.”
The familiar smell of dry cleaning comes from residues of perchloroethylene (PERC). Solvents, such as PERC, are under study for breast cancer and are associated with other cancers. If you must use traditional dry cleaning with PERC, remember to open the plastic bags on your clothing in an open space and air them out before putting them in a closet.

3. Take time to read labels and avoid “phthalates” and “fragrance” in products.
Phthalates are endocrine disrupting compounds that have been associated with cancer, impaired fertility, and male birth defects. They are found in hundreds of products including shampoo, lotion, perfume, cosmetics, vinyl and plastics, including toys. They are now being monitored by the U.S. Centers for Disease Control. The most common phthalates are: dibutyl phthalate (DBP), diethyl phthalate (DEP), and diethylhexyl phthalate (DEHP), and phthalates are often an ingredient in “fragrance.” Look for labels that say “phthalate-free” and don’t hesitate to ask your favorite retailer or manufacturer if products are phthalate-free. Consumer questions help to bring about change.

4. When grilling foods, minimize “char” by reducing the heat level and/or using marinades.
“ Char” contains PAHs – polycyclic aromatic hydrocarbons – that are known to cause mammary tumors in animals. In the Long Island Breast Cancer Study, women who had more DNA damage from PAHs had higher breast cancer risk.

5. Purchase organic foods when possible and encourage stores you patronize to expand their selection of organic foods.
Buying organic reduces your exposure to pesticides and protects your family. It also protects the workers who produce our food, water supplies where they live and work, and wildlife living nearby. Many pesticides are endocrine disruptors. Pesticides are also known to affect brain development and neurological function.

6. Monitor what goes down the drain in your home.
You can help protect your indoor air as well as your community’s water supply by using minimal amounts of the least toxic cleaning products and pesticides. Baking soda is a tried and true cleaning alternative. Never put cleaning solvents, pesticides, paint thinners, automobile oil, or gas down a drain.

7. Remember that all vacuums are not created equal.
Carpets can harbor pesticides, mold and allergens, flame retardants, and other chemicals. Vacuums with strong suction, a brush on/off switch, a multi-layered bag for dust collection, and a HEPA filter are considered the best to avoid recycling dust back into the air.

8. Look for electronic equipment and furniture without PBDEs.
PBDEs (polybrominated diphenyl ethers) are commercially produced flame retardants that are often added to polyurethane foam, various plastics, and electronics equipment. They are endocrine disruptors that affect thyroid hormones. Ask if your favorite manufacturer uses PBDEs in their products. When possible, choose carpet pads, bedding, cushions, and upholstered furniture made from natural fibers including wool, cotton, and hemp.

9. Use organic practices for gardening/lawn care, and encourage neighbors to do the same.
Many pesticides are endocrine disruptors. Pesticides and herbicides used on gardens and lawns are tracked into the house on shoes and by pets. Children and pets that play on the lawn are exposed, and the chemicals can leach into waterways and drinking water wells.

10. Encourage your town to adopt policies of using natural/non-toxic solvents in public buildings, especially schools, and using organic practices in the care of green spaces.
Using safer cleaners and eliminating pesticides on a town-wide basis will reduce exposure to compounds that mimic estrogen or otherwise disrupt hormones.

Please click here for a printable version.

Breast Cancer and the Environment: Science News from Silent Spring Institute
March 2007

College Students Spread the Word about Environmental Links to Breast Cancer

A new, multimedia CD features information about how the environment can affect breast cancer risk. The Vassar College Environmental Risks and Breast Cancer CD is an information resource developed by a team of faculty, students, and technical professionals from Vassar College with guidance and scientific review by Silent Spring Institute researchers.

The CD explores some of the important, and potentially controllable, risks in our environment that have been implicated in the high rate of breast cancer. The creators’ goal is to empower personal and community choices to decrease exposures to substances that may increase breast cancer risk.

“ Known breast cancer risk factors explain about half of the cases of breast cancer. That means that we don’t know what’s causing the other 50 percent of breast cancer diagnoses. Scientific evidence increasingly shows that preventable, environmental exposures may be playing a role,” according to Janet Gray, the project director, a professor in the Department of Psychology, and the director of the Program in Science, Technology & Society at Vassar College. She added, “these exposures may come from products we use routinely, including personal care products, detergents, pesticides and herbicides, products made from flexible plastics, and PVCs and other commonly used plastics.”

She hopes that “the CD will be a tool that provides easily accessible information about the links between the environment and breast cancer and inspires individuals to make changes to decrease exposures for themselves, their children, and future generations.”

Jessica Schifano, one of the first Vassar students to collaborate with Dr. Gray in developing the CD, is now working at Silent Spring while pursuing a dual degree in law and public health from Northeastern and Tufts Universities, respectively. Notes Ms. Schifano, “developing the CD strengthened my interest in environmental risks and breast cancer. I feel very fortunate that I was able to intern at Silent Spring Institute the summer between my junior and senior years. Not only did this experience make me well-equipped to do my part on the CD, but it increased my interest in this field. Following graduation, I was lucky enough to return to Silent Spring to continue with this work while pursuing my graduate studies."

The CD includes a review of the role the environment and a woman’s reproductive history play in breast cancer risk. It also offers practical suggestions on how to minimize exposures to compounds suspected of increasing risk.

The Environmental Risks and Breast Cancer CD was featured in the October 2006 issue of Vogue. Each CD includes both an English and Spanish version. For more information visit erbc.vassar.edu.

Please click here for a printable version.

Breast Cancer and the Environment: Science News from Silent Spring Institute
June 2007

Comprehensive Research Review Advances Search for Preventable Causes

If you’ve ever wondered how much is known about chemical or environmental exposures and the relationship to breast cancer, you’re not alone. Individuals who want to make healthy lifestyle choices, policymakers, scientists, activists, and funding organizations all need this information to target breast cancer prevention alongside screening and treatment.

Recognizing the importance of this question, Susan G. Komen for the Cure invited Silent Spring Institute to lead a multi-disciplinary team to determine where there is consensus within the scientific community on the relationship between environmental factors and breast cancer and where additional research or improved research methods are needed.

The results of this effort were published May 14 in a supplement of Cancer, a journal of the American Cancer Society. The project also created the largest online database of chemicals shown to cause mammary gland tumors in animal studies. The database references 900 studies, covering human studies of physical activity, body size, diet, and environmental pollutants, as well as interactions of these factors with inherited genes.

The database shows that exposure is widespread for many of the 216 compounds that caused breast tumors in animal tests:

•73 have been present in consumer products or as contaminants in food,

•35 are air pollutants,

•25 have been associated with occupational exposures affecting more than 5,000 women a year, and

•29 are produced in the U.S. in large amounts, exceeding 1 million pounds per year.
The database is publicly available at http://www.silentspring.org/sciencereview

Two examples of environmental exposures for which the researchers found evidence of increased risk of breast cancer include:

•polychlorinated byphenols (PCBs --banned chemicals previously used in electrical equipment and other products) in women genetically susceptible to the effects of these chemicals, and

•polycyclic aromatic hydrocarbons (PAHs), ubiquitous air pollutants from vehicle exhaust and combustion.

The analysis also reveals that the overwhelming majority of chemicals people are exposed to have never been tested for cancer risk. Therefore, the research team concludes, expanding and improving chemical testing is essential.

Silent Spring Institute Executive Director Dr. Julia Brody noted, "Because breast cancer is so common and mammary carcinogens are pervasive throughout society, reducing exposures would have a profound effect on public health, sparing thousands of women.”

She added, “In addition to guiding future research, we hope this information will be considered by regulators for decisions about limiting human exposure and by manufacturers in reformulating products and re-engineering processes to avoid suspect chemicals.”

The results of the lifestyle portion of the study underscore the importance of regular, life-long physical activity to lower a woman’s risk of developing breast cancer. Reducing alcohol consumption and avoiding weight gain or being overweight after menopause also lower risk. The study team concluded that further research is needed to determine the relationship between dietary factors and breast cancer.

The second phase of the Institute’s study, also funded by Komen for the Cure, will focus on the toxicology of endocrine disruptors, perinatal and early life exposures, non-hormonal pharmaceuticals, tobacco smoke, occupational exposures, exposure to light at night, and stress and social factors.

Partnering with Silent Spring Institute were researchers from Harvard University, Roswell Park Cancer Institute and the University of Southern California.

Please click here for a printable version.

Breast Cancer and the Environment: Science News from Silent Spring Institute
March 2008

Floor Finish May Be Source of Banned PCBs

You may think once a chemical is banned from use, you no longer need to worry about being exposed. A new study by the Silent Spring Institute may make you think again. Researchers found high levels of now-banned PCBs in the homes and blood of some Cape Cod residents. The likely culprit? A wood floor finish applied half a century ago.

PCBs (polychlorinated biphenyls) are toxic industrial chemicals that were widely used in electrical equipment before being banned in 1977. They have been linked with a host of health problems including effects on brain development, thyroid function, and cancer. Four studies found that women with both high PCB exposure and a genetic variation that affects how their bodies process chemicals have three times higher breast cancer risk than women who don’t have this combination of factors.

When Silent Spring Institute researchers discovered PCBs in nearly one-third of 120 Cape Cod homes, and alarmingly high levels in two of the homes, they knew they needed to look for the source so residents could reduce their exposures. The research team retested air and dust in the homes with very high levels and collected blood samples from the residents. Air and dust levels remained high five years after the first test. In addition, blood levels were higher than 95% of a representative sample of the US population, and one resident had higher blood levels than any reported in the US Centers for Disease Control’s National Health and Nutrition Examination Survey.

The likely source of PCBs was discovered during interviews with study participants when one resident recalled using the hardwood floor and bowling alley finish Fabulon. Searches in an old reference text showed that Fabulon, popular in the 1950s and 1960s, contained PCBs until they were removed in 1969.

Much of the estimated 1.5 billion pounds of PCBs produced lingers in the environment, slowly breaking down. Because PCBs move up the food chain and accumulate in fat, eating fish from contaminated waters and fatty meat and dairy foods is thought to be the most common source of human exposure. Indoor sources such as paints, caulk, and flooring used in schools and other buildings can also be important, new studies show. “Our findings suggest that the exposure potential posed by historic use of PCBs in buildings may be significantly underestimated,” said Ruthann Rudel, lead study researcher.

If you suspect a floor was finished with Fabulon, don’t sand it; that could increase exposure. Using a vacuum with strong suction, a brush on/off switch, a multi-layered bag for dust collection and a HEPA filter should help reduce exposure to PCBs and other harmful chemicals in house dust. Consumer Reports rates vacuums for how well they get rid of dust.

Silent Spring Institute Executive Director Julia Brody noted, “This study is a lesson in the dangers of putting untested chemicals into consumer products. Once they’re out there, we can’t easily get rid of them.”

The study appeared in the January 17 issue of Environmental Health. It was funded by the Commonwealth of Massachusetts and National Institutes of Health. Go here www.silentspring.org/newweb/research/household_pcbs.html to learn more about the study.

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Updated Monday, March 31, 2008 4:43 PM