By Adam Welsch
October is National Breast Cancer Awareness Month. It’s a time when lots of information about breast cancer and its causes are promoted via all media channels. The overwhelming share of it is highly credible. Unfortunately, some of it isn’t, and the internet often acts as a catalyst propelling and nurturing related rumors. One such rumor that’s been in existence since the mid-1990s is the idea that wearing bras can cause breast cancer. But is this true? The answer, fortunately, is no. There’s absolutely no scientific evidence suggesting that bras cause breast cancer.
If one stops and thinks about history for a moment, this answer intuitively makes sense. After all, supportive undergarments designed specifically for breasts have been in existence since only the second half of the nineteenth century. Humans, however, have been aware of breast cancer for thousands of years.
The origin of this misinformation is the 1995 book Dressed to Kill written by Sydney Ross Singer and Soma Grismaijer, two self-described medical anthropologists. In it, the authors claim that 70% of breast cancer cases cannot be explained by generally-accepted risk factors, and that women who wear bras 24 hours per day are 125 times more likely to develop breast cancer than women who wear no bras at all. These “findings” are based on the authors’ anthropological observations of various Pacific cultures and comparisons with the habits and views of women in the United States. Singer and Grismaijer theorize that the constriction caused by the tight fit of bras creates blockages in wearers’ lymphatic systems. Such blockages allow toxins to accumulate in breast tissue, and result in breast cancer.
The book’s methodology and conclusions have been soundly refuted by the mainstream medical and academic communities. The authors didn’t subject their study to the scientific peer-review process. Such a review would have highlighted the fact that the authors failed to exclude important variables when reaching their conclusions. For example, the women who wore bras, and developed breast cancer, may have also had other, generally-accepted risk factors. Without controlling for these variables, the book’s conclusions are without merit. Thus, its main argument is a theory supported only by casual observation. It’s a classic example of the logical fallacy that correlation – or the simultaneous existence of two events – proves causation. It doesn’t.
A related piece of pseudoscience is the notion that underwires cause breast cancer. According to Dr. Marisa Weiss, the founder of breastcancer.org , the theory that underwires cause breast cancer makes absolutely no sense, since the lymphatic system carries fluid up and out of the breasts via the armpits, not down through the breast tissue supported by a bra’s underwires.
Credible, scientifically-sound studies of bra usage and breast cancer would help to squelch rumors of a causal connection. So why haven’t any been performed? In a New York Times article earlier this year, Dr. Ted Gansler, director of medical content for the American Cancer Society, said that “because the idea of bras causing breast cancer is so scientifically implausible, it seems unlikely that researchers will ever spend their time and resources to test it in a real epidemiological study.”
So, if bras don’t cause breast cancer, what does? Mutations of DNA cause normal breast cells to become cancerous. But what causes these mutations? Scientists have identified two tumor-suppressing genes, BRCA 1 and 2, whose malfunction leads to breast cancer, and mutations of these genes can be inherited. But inherited mutations of the BRCA genes are responsible for only a small percentage of all breast cancers. What causes the rest? It’s still unclear. However, there are well-documented risk factors that increase the chances that someone will develop the disease. According to the American Cancer Society, these include gender, age, a family and personal history of breast cancer, obesity, the use of combined hormone replacement therapy, alcohol use, smoking, a lack of exercise, race and ethnicity, the density of one’s breast tissue (denser tissue carries a higher risk), whether or not a woman has children and the age at which she has her first child, whether or not a woman breast-feeds, the use of oral contraceptives, and exposure to radiation.
Given breast cancer’s widely-understood risk factors, why does the myth that bras cause breast cancer persist? According to Dr. Susan Love, author of Dr. Susan Love’s Breast Book, it’s the frustration, shared by all women, of not knowing exactly what causes the disease, combined with the human need to blame such afflictions on external causes that are controllable.
How much or how little one chooses to wear a bra is a personal decision. It may be based upon considerations of comfort, appearance, and even cultural mores. But the concern that doing so increases one’s chances of developing breast cancer should not be among those considerations.