Hormone-disrupting chemicals are everywhere -- in plastics, pesticides and makeup -- and two of them, phthalates and DDE, have been particularly strongly linked with common female reproductive conditions, such as fibroids.
In a new study, researchers estimate that the problems caused by these two chemicals alone could cost the European Union at least 1.41 billion euros a year, the U.S. equivalent of about $1.58 billion.
A panel of experts previously estimated the health cost of a range of endocrine-disrupting chemicals -- of which bisphenol-A, or BPA, is probably the most infamous -- based on a slew of conditions they have been associated with, including obesity, IQ loss and male infertility.
The economic toll attributed to the chemicals in that analysis was 157 billion euros, or $177 billion.
For the current study, the researchers turned their attention toward fibroids and endometriosis, two common conditions that affect an estimated 70 percent of women and are leading causes of female infertility.
The researchers looked at studies of many different endocrine-disrupting chemicals and determined that the strongest evidence, albeit still from only a handful of studies, implicated a role for DDE, or diphenyldichloroethene, and phthalates in fibroids and endometriosis, respectively.
"There are substantial human and toxicological studies (in mice and other lab animals) that suggest that exposure to these endocrine-disrupting chemicals, many of which are increasing in use, are contributing to female reproductive conditions," said Dr. Leonardo Trasande, associate professor of pediatrics at New York University School of Medicine.
Trasande carried out the earlier study on the economic impact of these chemicals and is the lead author of the new study, published on Tuesday in the Journal of Clinical Endocrinology & Metabolism.
DDE is a breakdown product of the insecticide DDT that, although banned in the United States in 1972 and in Europe starting in the 1970s, still lingers in the environment and enters our body through food. The main exposure to phthalates is through eating food and drink stored in plastic containers that have phthalates.
Trasande and his colleagues determined that 56,700 cases of fibroids among women in Europe were probably due to DDE exposure, and 145,000 cases of endometriosis were probably caused by phthalates. The researchers arrived at these estimates through studies that looked at typical DDE exposures in women of reproductive age in Europe and the association between DDE levels in the blood and fibroid diagnoses.
In a similar way, they relied on a study that linked higher phthalate levels in women who had been diagnosed with endometriosis compared to healthy women.
Calculating the economic toll
The researchers estimated the economic burden of these extra cases of fibroids and endometriosis based on the typical cost of treating these conditions, such as by surgery, in European countries. The cost for fibroids was 163 million euros, or $183 million, while endometriosis cases racked up a bill of 1.25 billion euros, or $1.4 billion.
However, as the researchers noted in the study, the costs would be even greater if they had factored in infertility associated with fibroids and endometriosis, and the other health problems those conditions can lead to. For example, endometriosis can increase the risk of cancer and autoimmune disorders.
"In so far as Europe is actively considering criteria for endocrine-disrupting chemicals and they are about to pursue action to limit exposure to chemicals in that category, this work is likely to be extremely important in shaping European policy," Trasande said.
The European Union and the U.S. Food and Drug Administration have already banned the use of certain endocrine disruptors, such as BPA, in baby bottles, though research suggests alternatives to BPA might not be safe.
Although the United States is not as far along in considering restrictions on these chemicals, it could get a jumpstart from European legislation.
"Potentially some of the progress in European activity could actually bring the key stakeholders, such as environmental public health groups and industry, to the table in considering U.S. legislation," Trasande said.
A study by Trasande and his colleagues estimating the health and economic burden of endocrine disruptors on fibroids and other conditions among women in the United States is slated to be published this summer.
Reducing exposure to endocrine disruptors
The health burden -- and healthcare cost -- of endocrine-disrupting chemicals could far exceed what the current study captured looking at only two chemical groups. As Trasande and his colleagues point out in the study, several other chemicals, such as PCBs, or polychlorinated biphenyls, have been linked with female reproductive health problems.
Some of these chemicals, including PCBs and dioxins, have already been restricted through a treaty called the Stockholm Convention on Persistent Organic Pollutants, which went into effect in 2004, said Linda S. Birnbaum, director of the National Institute of Environmental Health Sciences and the National Toxicology Program.
The current study is important because it focused on chemicals that have not been restricted, and in the case of DDE -- which persists in the environment -- are not able to be restricted, Birnbaum said. However, she said she was surprised the researchers did not include an analysis of chemicals such as BPA, which has also been linked to endometriosis risk.
"This study is kind of a wake-up to say endocrine disruptors impact the female reproductive system, and we have some evidence they are associated with an increase in endometriosis and fibroids and it costs a lot of money," Birnbaum said.
However, Birnbaum added that despite the research linking endocrine disruptors with these health problems, "studies are not great and are mostly in animals and experiments on cells (in Petri dishes)."
More studies need to be carried out to look at exposure to endocrine disruptors over a lifetime, from womb through adulthood, because the chemicals could be affecting people differently at different stages of their lives, Birnbaum said.
Although current thinking is that the chemicals are dangerous to girls in the womb because they affect their developing reproductive system, studies have not been done to address this possibility.
Even with all the questions that remain, and few regulations in place, "there are safe and simple steps that families and women can take to reduce exposure to endocrine-disrupting chemicals," Trasande said.
"They can eat organic, reduce canned food consumption, which reduces exposure to BPA, and avoid packaged or highly processed food, which is a major route for phthalates to enter food. They can also open windows to allow chemical dust, which accumulates on the carpet and electronics, to circulate out of homes."