April 6, 2011 / 6:17 PM / in 9 years

PFCs linked to earlier menopause

NEW YORK (Reuters Health) - Women exposed to high levels of certain household-product chemicals may go through menopause at a younger age than other women, a new study finds.

The chemicals in question are called perfluorocarbons, or PFCs, and they have historically been widely used in products ranging from furniture and carpeting to non-stick pans, plastic food containers and clothing. Their use in the U.S. is set to be phased out by 2015.

But PFCs persist in the environment, and the chemicals are found in water, soil, plants, animals and people. A 2004 U.S. government study detected PFCs in 98 percent of blood samples taken from a large pool of Americans.

Animal research suggests that PFCs act as endocrine disruptors — meaning they interfere with normal hormone function.

“But up until now, basically nothing has been known about the effects in women,” said Dr. Sarah S. Knox, a professor at the West Virginia University School of Medicine in Morgantown and lead researcher on the new study.

Knox and her colleagues found that among women older than 42, those with relatively higher blood levels of PFCs were more likely to have gone through menopause. They also tended to have lower estrogen levels than other women.

Whether PFCs were the cause is not known, Knox said.

“It’s a correlation, and correlation is not causation,” she told Reuters Health in an interview. “We can’t say that PFCs cause early menopause.”

“But we think that these findings are a red flag, and this warrants further investigation,” Knox said.

The main concern with earlier menopause and waning estrogen levels is that they could raise a woman’s risk of conditions such as heart disease and osteoporosis.

The findings, published in the Journal of Clinical Endocrinology & Metabolism, are based on 26,000 West Virginia women whose drinking-water supplies had been contaminated with PFCs from a nearby DuPont plant in 2005 and 2006. The blood testing was performed as part of a lawsuit over the water contamination.

On average, area residents’ levels of one type of PFC, called PFOA, were very high — 500 percent higher than the average American’s. However, their average level of another PFC, called PFOS, was similar to the U.S. norm.

The researchers found that among women older than 42, those with relatively higher levels of PFOS were more likely to have already gone through menopause.

Of women between the ages of 42 and 51, those in the top 20 percent for PFOS levels were 40 percent more likely to have gone through menopause, versus women in the bottom 20 percent.

The odds were even greater among women older than 51. Those with the top PFOS levels were twice as likely to have gone through menopause as those with the lowest levels of the chemical.

In addition, the women’s blood levels of estrogen generally dipped as their PFOS levels rose.

Since the study group was similar to the U.S. average when it came to PFOS levels, Knox said the findings could be widely relevant.

There was also a correlation between PFOA levels and menopause among women older than 51, though it was not as strong.

More studies are needed to find out whether PFCs themselves alter women’s hormonal function, according to Knox.

In the meantime, she said there are steps people can take that may curb their PFC exposure. That includes avoiding fabrics with stain- or water-resistant treatments; non-stick cookware; and food in containers designed to be grease-resistant — french fries, pizza and microwave popcorn being common examples.

SOURCE: bit.ly/hZwGpM Journal of Clinical Endocrinology & Metabolism, online March 16, 2011.

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