The rate of thyroid cancer has more than tripled in the US in the past 40 years. Much of that increase is due to early screening that’s found early-stage cancers that used to be missed—and many of these cancers are slow-growing tumors that would never cause harm.
But under the surface, more disturbing evidence is also emerging—that the rise in new thyroid cancer cases isn’t entirely caused by increased screening. Over the same period, there has been a small rise in the incidence of the most aggressive, deadly cases of thyroid cancer. Now a new study points to a possible culprit—chemicals in our homes and cars that were meant to keep us safe. One of these chemicals is now statistically linked to an increase in the kind of thyroid cancer that is most likely to be fatal.
Here’s what the investigators found—and how to protect yourself…
Background: Doctors initially thought the rise in thyroid cancer cases was being fueled solely by higher-quality methods of detecting and diagnosing harmless tumors, ones that would never cause symptoms or require treatment. While there is indeed overdiagnosis and overtreatment, a new report in JAMA concluded that there has also been a real rise in new cases—3.6% a year from 1974 to 2013 (the latest data available). Most new cases were papillary thyroid cancer, the most common and least aggressive form. But there has also been a rise in aggressive tumors that spread throughout the body. Indeed, deaths from all types of thyroid cancers have risen about 1% per year from 1994 to 2013, researchers reported.
What’s behind the rise? The JAMA researchers point to several possible causes including rising rates of obesity, which affects hormones and has been linked to increased thyroid cancer risk…less smoking, which, ironically, is associated with reduced risk for thyroid cancer…and environmental hormone disrupters.
At Duke University, researchers looked more closely at connections between specific hormone disrupters—flame retardant chemicals—and thyroid cancer. These chemicals were introduced in the mid-1970s, and their widespread use in upholstery, bedding, electronics, cables and insulation has mirrored the rise of thyroid cancer.
Study: Duke University researchers identified 70 people with papillary thyroid cancer and matched them with 70 other people of the same age and sex who were cancer free. Blood samples from the participants were taken so that the researchers could measure the levels of a biomarker that indicates exposure to hormone-disrupting chemicals. Researchers also analyzed dust from participants’ homes so that they could measure their exposure to the specific flame retardants associated with thyroid cancer, decabromodiphenyl ether (BDE-209) and tris(2-cloroethyl) phosphate (TCEP).
Results: Participants in households with higher dust concentrations of BDE-209 were more than twice as likely to have papillary thyroid cancer than those in households with lower levels of the flame retardant. The other flame retardant, TCEP, was associated with larger, more aggressive tumors—the kind most likely to spread and become deadly. People in homes with the highest concentrations of TCEP in dust were more than four times as likely to have cancerous tumors spread from the thyroid gland to other parts of their bodies.
Bottom line: TCEP, aka Tris, is a notorious chemical. It was once used in children’s pajamas until the industry voluntarily removed it due to suspected pediatric cancer risk. But it’s still legal for manufacturers to use flame retardants in many household products, including in the foam that’s in many sofas and mattresses. While the Duke study is relatively small, so not definitive, we already know that flame retardants act as hormone disrupters, so it makes sense to limit your exposure to all of them, including BDE-209 and TCEP. Here’s how…
- If you’re in the market for new furniture or a bed, pay attention to state laws—many states from Alaska to Maine have passed laws banning flame retardants from furniture. Besides the health risks, it turns out that they don’t work very well to prevent fires—and they expose firefighters to toxic fumes. If your state hasn’t passed such a law, the safest approach is to buy new furniture and mattresses stuffed with wool or cotton or latex filling, not synthetic foam.
- If you’re buying a mattress online, you can search for one that is certified organic. If it meets the “Global Organic Textile Standard” (GOTS), or for products that contain latex, the “Global Organic Latex Standard,” then it will not only be made with 95% organic materials, but it won’t contain any chemical flame retardants.
- Get rid of (toxic) dust bunnies. Use a vacuum with a HEPA filter to clean rugs and furniture cushions and wet-mop floors—it’s more effective at picking up dust than dry mopping.
- According to the Environmental Working Group, a nonprofit educational organization, one good way to get rid of toxic dust includes regularly wiping down electronics—a big source of flame-retardant chemicals—with a damp cloth. These include televisions, cell phones and laptop computers. How long they continue to emit these compounds isn’t known. It’s also a good idea to dust tabletops with damp cloths, too—and use green cleaning products whenever possible to avoid adding to the chemical stew in your house.
