Wearing a bra does not cause breast cancer: study

Wearing a bra does not increase the risk of breast cancer - even if it is underwired or worn all year long, according to new research.
A population-based case-control study found no association between bra wearing and increased breast cancer risk among postmenopausal women, researchers said.
"There have been some concerns that one of the reasons why breast cancer may be more common in developed countries compared with developing countries is differences in bra-wearing patterns," said Lu Chen, from the Public Health Sciences Division at Fred Hutchinson Cancer Research Centre and doctoral student in the Department of Epidemiology at the University of Washington School of Public Health.

"Given how common bra wearing is, we thought this was an important question to address.
"Our study found no evidence that wearing a bra increases a woman's risk for breast cancer. The risk was similar no matter how many hours per day women wore a bra, whether they wore a bra with an underwire, or at what age they first began wearing a bra," said Chen.
"There has been some suggestion in the lay media that bra wearing may be a risk factor for breast cancer. Some have hypothesised that drainage of waste products in and around the breast may be hampered by bra wearing. Given very limited biological evidence supporting such a link between bra wearing and breast cancer risk, our results were not surprising," Chen added.

According to the researchers, this study characterises various bra-wearing habits in relation to breast cancer risk using a rigorous epidemiological study design.

"The findings provide reassurance to women that wearing a bra does not appear to increase the risk for the most common histological types of postmenopausal breast cancer," researchers noted.
Study participants were 454 women with invasive ductal carcinoma (IDC) and 590 women with invasive lobular carcinoma (ILC), the two most common subtypes of breast cancer, from the Seattle-Puget Sound metropolitan area; 469 women who did not have breast cancer served as controls. All women were postmenopausal, ages 55 to 74.

The researchers conducted in-person interviews and obtained information on demographics, family history, and reproductive history.
They also asked a series of structured questions to assess lifetime patterns of bra wearing.
The research was published in the journal Cancer Epidemiology, Biomarkers & Prevention.