Endometriosis is a common condition that affects around 10% of women in their reproductive years. New research has found that two organochlorine pesticides - once widely used in the US for pest control and agriculture but now banned - are linked to an increased risk of the chronic condition.
Researchers from Fred Hutchinson Cancer Research Center in Seattle, WA, published the results of their study in Environmental Health Perspectives, a journal of the National Institute of Environmental Health Sciences (NIEHS).
They note that though endometriosis is noncancerous, it is characterized by tissue - which normally lines the inside of the uterus or womb - growing outside and attaching to other areas or organs, affecting the ovaries, fallopian tubes and lining of the pelvic cavity.
Common symptoms typically include painful menstrual periods, pelvic pain and infertility.
Kristen Upson, PhD, a study author who is now a postdoctoral fellow at the Epidemiology Branch of the NIEHS, says:
"For many women, the symptoms of endometriosis can be chronic and debilitating, negatively affecting health-related quality of life, personal relationships and work productivity."
Because endometriosis is a condition led by estrogen, Upson notes that they "were interested in investigating the role of environmental chemicals that have estrogenic properties, such as organochlorine pesticides, on the risk of the disease."
Pesticides raise endometriosis risk to 30-70%
In the US, certain pesticides that are no longer in use are still in blood samples of women today, and this recent study links the chemicals to an increased risk of endometriosis.
According to the US Geological Survey (USGS), organochlorine pesticides are man-made chemicals that were used in the recent past for agricultural and household pest problems.
Dichlorodiphenyltrichloroethane (DDT) is one of the most well-known organochlorines, and it was "heavily applied in agricultural regions," says the USGS. Although these types of pesticides are no longer used in the US, the organization notes that they are still present in the environment.
To conduct their study, the researchers used data from the Women's Risk of Endometriosis study, which is a population-based case-control study of endometriosis in women aged 18- to 49-years-old.
There were 248 women who had recently been diagnosed with endometriosis and 538 women without the condition who served as controls.
Results of the research showed that women who had higher exposures to two organochlorine pesticides - beta-hexachlorocyclohexane and mirex - had a 30-70% increased risk of endometriosis.
The study authors say they found it interesting that these types of chemicals were found in the blood samples of women from the study, despite the fact that organochlorine pesticides have been banned in the US for several decades.
"The take-home message from our study," says Upson, "is that the persistent environmental chemicals, even those used in the past, may affect the health of the current generation of reproductive-age women with regard to a hormonally driven disease."
'Another piece of the puzzle'
This research is important, say the authors, because the medical community still does not entirely understand why some women develop endometriosis while others do not.
Study co-author Prof. Victoria Holt adds that their study "provides another piece of the puzzle."
They point to other lab studies of human tissue that have shown organochlorine pesticides display "estrogenic properties" and "adverse reproductive effects," which can alter the uterus, ovaries and hormone production.
"Given these actions," says Upson, "it's plausible that organochlorine pesticides could increase the risk of an estrogen-driven disease such as endometriosis."
Medical News Today recently reported that pesticides have been linked to type 2 diabetes.