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Bras cause breast cancer? No support for that claim, Fred Hutch study finds

Population-based, case-control analysis should put internet rumors to rest, cancer experts say

Sept. 5, 2014
Bra

No, despite rumors, bras do not cause breast cancer, a new study confirmed.

Photo by iStock

Wearing a bra can be a rite of passage or a royal pain, a fashion statement or a political stance. But one thing it’s not is a cause of breast cancer, a new Seattle study finds – despite persistent rumors to the contrary.

Researchers at the Fred Hutchinson Cancer Research Center conducted a population-based, case-control study to consider whether the brassieres worn daily by millions of women might be linked to the disease that kills about 40,000 in the U.S. each year.  

What they found was a resounding no, no matter how many ways they looked at bra-use data from more than 1,000 Seattle-area women diagnosed with invasive breast cancer between 2000 and 2004.

“Our study found no evidence that wearing a bra increases a woman’s risk for breast cancer,” said Lu Chen, a researcher in the Public Health Sciences Division at Fred Hutch. “The risk was similar no matter how many hours per day women wore a bra, whether they wore a bra with underwire, or at what age they began wearing a bra.”

The researchers conducted in-person interviews to determine the bra-wearing habits of 1,044 women aged 55 to 74 diagnosed with the two most common types of breast cancer, invasive ductal carcinoma, or IDC, and invasive lobular carcinoma, or ILC.

They asked about demographics, family history of cancer and reproductive history, along with lifetime patterns of bra use. They compared the findings with those from 469 cancer-free women and published the results Friday in the journal Cancer Epidemiology, Biomarkers & Prevention. The analysis showed no association between the undergarments and disease.

“We weren’t really surprised,” Chen said. “We knew that the biological plausibility of a link between bras and breast cancer was really weak.”

The study was aimed in part at answering a persistent question that has circulated in published accounts and Internet rumors for nearly 20 years. It started in 1995, with the book “Dressed to Kill: The Link Between Breast Cancer and Bras,” by husband-and-wife team Sydney Ross Singer and Soma Grismaijer.

The authors suggested that breast cancer was common in Western cultures, but not in indigenous cultures because women in developed countries wear bras. They concluded that constant bra use blocks eliminations of toxins from the lymphatic system, causing breast cancer, which affects about one in eight American women during their lifetimes and kills about 40,000 women each year, according to the American Cancer Society, or ACS.

Both the theory and the authors’ research methods were debunked by the ACS, along with a 1991 Harvard study that appeared to find a link between bra-wearing and breast cancer. It was criticized for design flaws, including not adjusting for known breast cancer risks such as weight and age.

The National Cancer Institute and the Susan G. Komen foundation say that bras are not among the factors that increase breast cancer risk.

Still, rumors of a link between bras and breast cancer have lingered. More than a decade ago, a 2002 ACS/DiscoveryHealth survey found that 6 percent of people surveyed believed that underwire bras can cause breast cancer and 31 percent expressed uncertainty.

As recently as this summer, writer Louise Kuo Habakus posted a piece on her blog, Fearless Parent, once again urging women to ditch their bras because of a possible link with breast cancer. “Societal convention has most of us trussing up before going out,” she said.

Such information raises concerns in a country where nearly 675 million bras are sold each year, according to the American Apparel & Footwear Association. It's not only misguided, however; it also can be harmful, said Dr. Ted Gansler, director of medical content for the ACS.

“Among women who do not have a personal history of breast cancer, this concern could be a source of anxiety and a distraction from proven strategies for prevention and early detection,” he wrote in an email. “Among women already diagnosed with breast cancer, this claim might be a source of guilt.”

He praised the Fred Hutch study for shedding new light on the science of the issue and using rigorous analysis to reach their conclusions.

“Their use of sophisticated statistical methods relieves potential concerns regarding influence of other factors obscuring or distorting a potential connection between bras and breast cancer,” Gansler added.

The “Dressed to Kill” authors aren’t backing down. In an email, Sydney Ross Singer questioned why the Fred Hutch authors studied post-menopausal women rather than pre-menopausal women and said that their conclusion “suggests a pro-bra bias.”

Not at all, said the Fred Hutch’s Dr. Christopher Li, an epidemiologist and breast cancer expert in the PHS Division. Li, along with fellow PHS epidemiologist Dr. Kathleen Malone and researcher Chen, used data from a larger study of post-menopausal breast cancer patients because most breast cancers are diagnosed in older women – and they also have the longest lifetime exposure to wearing bras.

The aim was to address a question that has caused apparently needless anxiety about the common undergarments, said Li.

“We decided to look at this question because of the nearly complete lack of prior studies evaluating this question which is of interest to women in general given the public health importance of breast cancer.”

Whether the internet catches up with the new conclusions remains to be seen, but in Gansler’s view, the question should be settled. 

“The study … should reassure women that they can safely ignore this matter,” he wrote. 

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JoNel Aleccia is a staff writer at Fred Hutchinson Cancer Research Center. From 2008 to 2014, she was a national health reporter for NBC News and msnbc.com. Prior to that she was a reporter, editor and columnist for more than two decades at newspapers in the Northwest. Reach her at jaleccia@fredhutch.org

Solid tumors, such as those of the breast, are the focus of Solid Tumor Translational Research, a network comprised of Fred Hutchinson Cancer Research Center, UW Medicine and Seattle Cancer Care Alliance. STTR is bridging laboratory sciences and patient care to provide the most precise treatment options for patients with solid tumor cancers.

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Fred Hutchinson Cancer Research Center is a world leader in research to prevent, detect and treat cancer and other life-threatening diseases.