A new analysis led by Washington University has shown a possible link between exposure to certain common, long-lasting chemicals and the earlier onset of menopause.
The researchers analyzed information from 1,442 menopausal women who had been tested for what are known as endocrine disrupting chemicals -- chemicals that can affect how hormones work in the body. The data were collected between 1999 and 2008 by the U.S. Centers for Disease Control and Prevention, as part of a national health and nutrition study.
The new analysis focused on 111 potential endocrine disruptors from the following classes of chemicals:
- dioxins and furans (industrial byproducts)
- phytoestrogens (plant-derived estrogens)
- phthalates (found in plastics, pharmaceuticals, and personal care products like lotions, shampoos and cosmetics)
- polychlorinated biphenyls or PCBs (coolants)
- phenolic derivatives (industrial pollutants)
- organophosphate pesticides
- polycyclic aromatic hydrocarbons or PAHs (industrial combustion products)
Washington University reproductive endocrinologist and study lead Dr. Amber Cooper said 15 of the chemicals were correlated with early menopause. In other words, women with high levels of those chemicals in their blood or urine entered menopause two to four years earlier than other women.
Even though some of the chemicals have already been banned in the U.S., they are still present in the environment. "Some of these chemicals, like PCBs, can potentially persist for decades and decades and decades in the soil and in the water," Cooper said.
Because some of the chemicals are industrial byproducts, it's unclear whether they are still being produced or not, she added.
The 15 chemicals include nine PCBs, three pesticides, two phthalates and a furan.
But Cooper cautions that correlation does not equal causation.
"You can’t prove causation in a study like this," Cooper said. "I think it’s important to really say, 'Hey, we are not saying this specific chemical causes earlier menopause.' But in a large study to find such associations really warrants further investigation."
The current study is published online in the journal PLOS ONE.
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