A new study has put to rest a persistent myth that bras with underwire can cause breast cancer among postmenopausal women.

There have been some concerns that "the reason breast cancer is more common in developed countries than in developing countries is because more women in richer countries war bras," CTV News reported.

"Given how common bra wearing is, we thought this was an important question to address," researcher Lu Chen said in a statement.

However, researchers found no association between bra wearing and an increased risk of developing breast cancer, The Examiner reported.

"There has been some suggestion in the lay media that bra wearing may be a risk factor for breast cancer. Some have hypothesized 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 said.

For the study, researchers collected data from more than 1,500 women.

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.

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. Questions included age at which the study participant started wearing a bra, whether she wore a bra with an underwire, the number of hours per day and number of days per week she wore a bra, and if her bra-wearing patterns ever changed at different times in her life.

They found that no aspect of wearing a bra was associated with an increased risk of either IDC or ILC.

The findings were recently published in Cancer Epidemiology, Biomarkers & Prevention.