Women are exposed to nearly a thousand chemicals linked to breast cancer almost every day, a study has found.
Researchers analyzed official databases of tens of thousands of common chemicals used in the food, consumer products and other industries to reveal the chemicals linked to the most common cancer in America.
In total, they identified 900 chemicals that have been linked to breast cancer, through animal or laboratory studies showing a link to breast tumors.
Women are most often exposed to the breast cancer-causing chemicals through pesticides – used on fruits and vegetables – and in Cosmetic products such as anti-wrinkle cream, make-up, shampoo and soap.
The chart above shows daily items that scientists said contained chemicals that have been linked to breast cancer
Dr. Jenny Kay, a toxicologist and lead researcher, called on regulators to take action to phase out dangerous chemicals for alternatives.
To limit exposure to the toxic chemicals, Dr. Kay recommended washing fruits and vegetables (especially non-organic ones) and reducing the amount of makeup applied each day.
Breast cancer is the most common form of cancer in the US, with approximately 240,000 cases diagnosed annually.
But in recent years there has been an increase in cases among younger women — under 50 — that doctors say cannot be explained by genetics.
It is also the second leading cause of cancer death in women; only 30 percent of women whose cancer is discovered in the late stages survive more than five years after diagnosis.
For the study, published today in the journal Environmental health perspectivesresearchers searched databases of tens of thousands of chemicals.
This included the studies from the International Agency for Cancer Research (IACR), the National Toxicology Program and the US Environmental Protection Agency.
They looked for chemicals that had been linked to the development of mammary tumors, or breast cancer, in animals.
They also looked for chemicals found to trigger the production of estrogen, with high levels of this hormone a known risk of breast cancer.
In total, the researchers compiled a list of 922 chemicals that they said could increase the risk of breast cancer in women.
On the list, about 278 of these chemicals had been linked to mammary tumors in animals.
And another 420 were found to both damage DNA and change hormones, which could make them riskier.
The list included the pesticides atrazine and malathion, which are among the most commonly used in the United States.
And others, such as cycloate, which is used as a herbicide on spinach, spirozamine, which is used on grains, and simazine, which is used on many fruits and vegetables.
Pesticides can increase the risk of cancer by causing gene mutations that increase the risk of a cell dividing uncontrollably.
A number of chemicals used in hair dyes – such as 1,4-benzenediamine – and in cosmetic products including retinol cream – the chemical retinol – and in soaps, shampoos and shaving cream – octyl gallate – were also on the list.
Last year, women took legal action against L’Oreal and other beauty brands, claiming their chemical hair straighteners had caused breast and uterine cancer.
The women say the diagnoses have cost them time with their grandchildren and that they would never have used the hair straighteners if they had known the risks.
The Massachusetts-based researchers’ list also included common medications such as aspirin, an over-the-counter drug used to reduce fever and pain.
They also suggested that prednisone could increase the risk of breast cancer, a drug prescribed to more than 25 million people annually to treat arthritis.
Doctors have previously suggested that aspirin could reduce the risk of breast cancer and the disease returning – although this was not supported by clinical trials.
Previous studies have suggested that corticosteroids – such as prednisone – may increase the risk of breast cancer. Doctors say this may be because it causes more mutations in cells.
Mifepristone – used in abortions – was also on the list alongside levonorsterl – which can prevent pregnancy by preventing the release of an egg.
This has been examined repeatedly, with studies showing mixed results. The American Cancer Society says studies currently “do not support the idea that abortion of any kind increases the risk of breast cancer.”
The list also included several chemicals used in paints and plastics, such as packaging and laptop covers.
Dr. Kay told DailyMail.com that the research was intended to raise awareness of the widespread chemicals that could increase the risk of breast cancer and to encourage action from regulators.
However, she added that exposure to a small amount of the chemicals for short periods would likely not significantly increase the risk of breast cancer.
Dr. Ruthann Rudel, the institute’s research director, urged regulators to take action, saying it was “not ethical” to wait for studies to reveal the risks.
“And it’s another reason why we need better tools to predict which chemicals are likely to lead to breast cancer, so we can avoid that exposure,” she added.
Factors believed to be behind the increase include women having fewer children and higher obesity rates.
Dr. Kay said, ‘The biggest surprise to me in doing this research was how few chemicals currently in use in the US the EPA has screened for breast cancer risk.
“They viewed less than 2,300 out of tens of thousands; there is a worryingly large group that has not been checked.’