This email rumor states that wearing a bra for the
whole day compresses the lymphatic system of the breast, resulting in
accumulation of toxins that cause breast cancer. It says "Bra-burning
is no longer a feminist issue...it is now a battle between life and
death."

Fact:

There are no scientifically valid studies that show wearing bras of
any type causes breast cancer. The email appears to be based on the
writings of a husband and wife team of medical anthropologists who link
breast cancer to wearing a bra. The two anthropologists suggested this
association in a book called Dressed to Kill. Their study was
not conducted according to standard principles of epidemiological
research and did not take into consideration other variables, including
known risk factors for breast cancer.

We know of only one scientifically-conducted epidemiologic
study that investigated a possible link between bra use and breast
cancer. This study suggested that breast cancer might be less common
among women who do not wear bras than among bra wearers. However,
breast cancer risk in the two groups was not significantly different,
according to standard statistical criteria, and the researchers
themselves expressed uncertainty regarding this correlation. They also
noted that if there is any connection, it would most likely have
occurred indirectly, because women who are obese or have larger breasts
are less likely to go braless. Obesity has been identified by numerous
studies as a breast cancer risk factor, and having large breasts has
been suggested in some studies as increasing breast cancer risk for
young women who are not overweight.

We do not know of any epidemiologic studies published in
scientific journals that suggest bras directly contribute to breast
cancer risk or that lymphatic compression by bras might cause breast
cancer.

Regardless of the size of a woman's breast and whether she is
slim or heavy, there is no convincing epidemiologic evidence that her
choices regarding bra use will influence her breast cancer risk.
Furthermore, the alleged mechanism suggested in the book and in chain
e-mails (blocked lymphatic vessels causing toxins to accumulate) is
inconsistent with scientific concepts of breast physiology and
pathology.

요약 : "유방암과 브라를 착용하는 것에 대해 상관관계를 과학적으로 증명한 것은 전혀 없습니다. 두 의류학자가 Dress to kill 이란 책에서 이 관계를 언급했으나 여러가지 지역, 인종 및 다양한 변수에 대해 조정을 하지 않았고 특히 기존에 유방암의 위험 인자에 대한 변수 통제역시 하지 않아 과학적인 증명은 될 수 없었습니다"