By Dr. Mercola
It’s estimated that nearly 57,000 new cases of thyroid cancer will be diagnosed in the U.S. in 2017, a far lower number than many other adult cancers, like colorectal, lung, breast and prostate.1 However, the number is noteworthy because it has risen significantly in recent years.
Rates of thyroid cancer have tripled in the last decade, making it — papillary thyroid cancer in particular — the most rapidly increasing cancer in the U.S.2
While part of this rise is blamed on the increased use of thyroid ultrasound detecting small thyroid nodules that may otherwise have gone undiagnosed, environmental factors may also be playing a role.
In fact, a study published in JAMA in March 2017 revealed that the overall incidence of thyroid cancer increased 3 percent annually in the U.S. from 1974 to 2013, representing a true increase.3
Dr. Julie Ann Sosa, chief of endocrine surgery at Duke University Medical Center in North Carolina, led a recent study on the topic, which suggests flame retardant chemicals may be involved. She said at a press briefing:4
“There is a pandemic of thyroid cancer around the world … For too long, we've ascribed this to [sic] entirely to overdiagnosis, so we are restricting screening … [Studies like this] suggest we should be redirected to understanding what additional causative factors are at play."
Exposure to Flame Retardants Linked to Thyroid Cancer
Research presented at the Endocrine Society's 2017 99th annual meeting in Orlando, Florida, revealed that exposure to flame retardants in the home is associated with the most common type of thyroid cancer, papillary thyroid cancer (PTC).
The researchers analyzed house dust to determine levels of exposure to the chemicals, as personal exposure correlates with levels of flame retardants in house dust.
Two types of flame retardants — decabromodiphenyl ether (BDE-209), belonging to the polybrominated diphenyl ethers (PBDEs) class, and tris(2-chloroethyl) phosphate (TCEP), an organophosphate flame retardant — were linked to papillary thyroid cancer diagnosis and severity.5
For BDE-209, those living in homes with elevated levels in their household dust were more than twice as likely to have been diagnosed with PTC. Further, a press release by the Endocrine Society explained:6
“Participants with high levels of TCEP in their house dust were more than four times as likely to have larger, more aggressive tumors that extended beyond the thyroid …
In contrast, participants with the highest dust levels of BDE-209 were 14 times as likely to be a PTC patient that did not have a common gene mutation (BRAF V600E). This mutation has been linked to PTC that tends to behave more aggressively.”
How Do Flame Retardants Harm Your Thyroid?
Estrogen levels regulate thyroid hormones, and PBDEs are known to disrupt estrogenic activity as well as thyroid levels. Past research has suggested, for instance, that PBDEs can lead to decreases in TSH (thyroid-stimulating hormone).7
In another study, researchers found women with the highest concentrations of PBDEs in their blood had an increased risk of thyroid disease compared to those with lower concentrations.8 That link was particularly strong among post-menopausal women.
Duke University environmental chemist Heather Stapleton, Ph.D., who was also involved in the featured flame-retardant/thyroid cancer study, explained that the chemical structure of one class of flame retardants is very similar to human thyroid hormones.
“There are a number of different pathways by which these chemicals can interfere with thyroid hormone regulation,” she said. “And we know that their use, and our exposure to these chemicals, has increased tremendously over the past several decades.”9
Yale epidemiologist Dr. Yawei Zhang, associate professor in the Department of Environmental Health Sciences, who has also researched the potential link between flame retardants and thyroid cancer explained, “PBDEs seem to mimic the thyroid hormone and disrupt thyroid homeostasis. That can cause tumors.”10
Flame Retardants Linked to Other Types of Cancer as Well
PBDEs resemble the molecular structure of PCBs, which have been linked to cancer, reproductive problems and impaired fetal brain development. Ironically, the chemicals may make entering a burning home even more dangerous for firefighters than it would be otherwise.
Unbeknownst to many, furniture and other objects doused in flame-retardant chemicals can still catch on fire.
Worse, they may release higher levels of toxic chemicals upon burning than untreated objects. California female firefighters aged 40 to 50 are six times more likely to develop breast cancer than the national average. Why California? Likely because in 1975 California Technical Bulletin 117 (TB117) was passed.
It required furniture sold in California to withstand a 12-second exposure to a small flame without igniting — a requirement manufacturers met by loading up furniture with flame retardants.
Firefighters of both genders also have higher rates of cancer, in part because of the high levels of dioxins and furans they're exposed to when flame-retardant chemicals burn.
A study from the American Chemical Society (ACS) even found certain flame retardant chemicals increased the amount of toxic carbon monoxide and hydrogen cyanide gas in a fire.11
Inhaling these gasses is the leading cause of death in fires, not burns. It’s no wonder, then, why firefighters are among those seeking bans on these toxic chemicals.
Children Are at Serious Risk From Flame Retardants
Thyroid cancer is only one potential risk from exposure to flame retardants, and it’s not only adults who are affected. In fact, children are among those most at risk. These chemicals, which are used in your furniture, electronics and baby toys, have been found to have both prenatal and childhood neurodevelopmental consequences.
Researchers have demonstrated that exposure in childhood is strongly associated with poor attention span, reduced fine motor coordination and a decrease in cognitive ability.12 In addition, flame retardants are linked to neurodevelopmental delays and hyperactivity in children.
These toxic chemicals also accumulate in breast milk. Research has demonstrated that children born to mothers with higher levels of flame retardant chemicals in their body had a 4.5-point average decrease in IQ.13 Flame retardant chemicals also affect your unborn baby.
At a public hearing in California, Gretchen Lee Salter, senior program and policy manager for the Breast Cancer Fund, testified, "Toxic flame retardants cross the placental barrier and can alter normal breast development setting that child on a path for increased breast cancer risk."14
Remember, pound for pound, children have a greater exposure to toxic chemicals, in the air, food, household dust and from other sources. Children and pets, who are closer to the ground, are also more likely to ingest them.
Do You Want to Know What Types of Flame Retardants Are Lurking in Your Furniture?
Duke University scientists will test a sample of your polyurethane foam, which is commonly used in upholstered furniture, padded chairs, car seats and more. All you need to remove is a sample the size of a marble and it will be tested for the presence of seven common flame retardants. Here's how it works:
1. Complete an electronic sample request to generate your Sample ID Number
2. Prepare your sample
• Cut a piece of foam, 1 cubic centimeter in size (a little bigger than the size of a marble).
• Wrap the foam in aluminum foil.
• Place each foam sample in its own re-sealable sandwich bag; be sure to completely seal the bag.
• Attach or write the Sample ID Number on the re-sealable sandwich bag.
3. Mail it in
Enclose the following in a box or envelope:
• Foam sample with Sample ID Number written on bag (Step 2)
• Copy of confirmation email (Step 1)
Duke Superfund Foam Project
Box 90328 - LSRC
Durham, NC 27708
The research lab only has the capacity to analyze 50 samples per month, and they close submissions once the quota is reached. Before sending in your sample, check with the Duke University Superfund Submit a Sample website to see if they're still accepting submissions (for best results, check in on the first of the month).
How to Reduce Your Exposure to Flame Retardants
Flame retardants are so widely used that it's difficult to avoid them completely. However, there are steps you can take to reduce your exposure, including these tips from the Green Science Policy Institute:
- Avoid upholstered furniture with the TB117 label. If the label states, "This article meets the flammability requirements of California Bureau of Home Furnishings Technical Bulletin 117 … " it most likely contains flame retardants. However, even upholstered furniture that's unlabeled may contain flame retardants.
- Furniture products filled with cotton, wool or polyester tend to be safer than chemical-treated foam; some products also state that they are "flame-retardant free." Organic wool (100 percent) is naturally flame-resistant.
- Avoid baby products with foam. Nursing pillows, high chairs, strollers and other products containing polyurethane foam most likely contain flame retardants.
- Avoid foam carpet padding. If possible, minimize the use of foam carpet padding, which often contains flame retardants. If removing carpeting, take precautions to avoid exposures. You'll want to isolate your work area from the rest of your house to avoid spreading it around, and use a HEPA filter vacuum to clean up.
- PBDEs are often found in household dust, so clean up with a HEPA-filter vacuum and/or a wet mop often.
Be especially careful with polyurethane foam products manufactured prior to 2005, such as upholstered furniture, mattresses and pillows, as these are most likely to contain PBDEs. If you have any of these in your home, inspect them carefully and replace ripped covers and/or any foam that appears to be breaking down. Also avoid reupholstering furniture by yourself as the reupholstering process increases your risk of exposure.