Wearing a bra does not increase the risk of breast cancer, according to new research.
A study of around 1,500 post-menopausal women found those who used the garment were no more likely to develop the disease than their braless counterparts.
For more than 20 years the debate has raged, after scientists pointed out breast cancer was unknown for thousands of years until women began wearing bras.
The theory suggests a constricting bra, especially one with underwire, can block the drainage of waste products through the lymphatic glands inhibit the disposal of toxins, leading to more exposure to carcinogenic chemicals.
A previous study of 3,000 women found among bra users, larger cup size was associated with an increased risk of breast cancer among post-menopausal women, but was partly accounted for by obesity.
A 2005 book entitled 'Dressed To Kill: The Link Between Breast Cancer And Bras' also struck fear into the hearts of bra wearers and lingerie manufacturers.
It supported the idea they cause poisons to accumulate in breast tissue.
That prompted a team from the University of Washington to study 1,513 women in the area, aged between 55 to 74.
More than 1,000 had been diagnosed with either invasive ductal carcinoma (IDC) or invasive lobular carcinoma (ICL), while the rest were healthy and acted as a control.
A face-to-face interview gathered answers to questions addressing bra cup and band sizes, the age at which participants started regularly wearing a bra, whether they wore underwire bras and the number of hours per day, and the days per week they wore a bra at different times of their lives.
No evidence of a link between breast cancer risk and bra size, type, or frequency of wearing, was found, researchers said.
Doctoral student Lu Chen, who led the research, said:
'There have been some concerns one of the reasons why breast cancer may be more common in developed countries compared with developing countries is differences in bra wearing patterns.
'Given how common bra wearing is, we thought this was an important question to address.
'Our study found no evidence 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.'
'There has been some suggestion in the lay media bra wearing may be a risk factor for breast cancer.
'Some have hypothesized 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.'
The researchers wrote:
'The findings provide reassurance to women that wearing a bra does not appear to increase the risk for the most common histological types of post-menopausal breast cancer.'
The research was published in the journal of Cancer, Epidemiology, Biomarkers and Prevention.
Considering that most women grew up with the notion that wearing bra for long could increase breast cancer chances, this is very refreshing to know.
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