Photo of a airplane spraying pesticides on a field
Organochlorine insecticides have been largely banned in the US, but they are so toxic and persistent that they are still being linked to health problems in women

Banned pesticides increase endometriosis risk

6 November, 2013

Natural Health News — A new study has found that exposure to two organochlorine pesticides are associated with an increased risk of endometriosis, a condition that affects up to 10% of reproductive-age women.

Specifically, researchers observed that women with higher exposures to two such pesticides,  mirex and beta-hexachlorocyclohexane  had a 30-70% increase in endometriosis risk.

Beta-hexachlorocyclohexane isa relative of lindane, the insecticide banned in agriculture but still used in some shampoos and lotions to control headlice.

The findings are published online ahead of the print issue of Environmental Health Perspectives, a journal of the US National Institute of Environmental Health Sciences (NIEHS).

A chronic and debilitating condition

Endometriosis is a noncancerous condition that occurs when the tissue that lines the inside of the uterus, or womb, grows outside of the organ and attaches to other structures or organs. The condition most often affects the ovaries, fallopian tubes and lining of the pelvic cavity. The most common symptoms include chronic pelvic pain, painful menstrual periods and infertility.

“For many women, the symptoms of endometriosis can be chronic and debilitating, negatively affecting health-related quality of life, personal relationships and work productivity,” said lead author Kristen Upson, PhD, a postdoctoral fellow at the Epidemiology Branch of the NIEHS.

“Since endometriosis is an estrogen-driven condition, we were interested in investigating the role of environmental chemicals that have estrogenic properties, such as organochlorine pesticides, on the risk of the disease,” said co-lead researcher Victoria Holt, Ph.D., a joint member of the Epidemiology Research Unit in the Public Health Sciences Division at Fred Hutch and professor of epidemiology at the University of Washington School of Public Health.

“This research is important, as endometriosis is a serious condition that can adversely affect the quality of a woman’s life, yet we still do not have a clear understanding of why endometriosis develops in some women but not in others,” she added. “Our study provides another piece of the puzzle.”

Banned but still causing harm

The researchers focused on organochlorine pesticides, which were widely used for decades but mostly have been banned due to health concerns. They break down slowly in the environment and persist for many years in human tissue.

To look at the potential link they tested blood from 248 women in Seattle with clinically diagnosed endometriosis and 538 healthy women for traces of 11 organochlorine pesticides and by-products.

“We found it interesting that despite organochlorine pesticides being restricted in use or banned in the US for the past several decades, these chemicals were detectable in the blood samples of women in our study and were associated with increased endometriosis risk,” Upson says. “The take-home message from our study is that 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.”

Policymakers should pay attention

The results of this study are consistent with those of a smaller study published last year, which linked HCH exposure and endometriosis. Likewise, previous studies in rodents suggest that organochlorine pesticides and other chlorinated compounds may act as hormone disruptors, altering uterine and ovarian function and raising the risks of reproductive diseases.

“Given these actions, it’s plausible that organochlorine pesticides could increase the risk of an estrogen-driven disease such as endometriosis,” says Upson. “We hope our findings will help inform current global policymaking to reduce or eliminate their use.”